JP7315980B2 - BASE STATION, COMMUNICATION SYSTEM AND METHOD OF CONTROLLING BASE STATION - Google Patents

Description

The present invention relates to a base station, a communication system, and a method of controlling a base station.

A control communication network for industrial equipment deployed in a factory or the like is constructed by connecting not only fixed equipment but also mobile equipment such as a robot or a carrier. A wired network using cables is used to connect devices that are fixedly arranged. On the other hand, wireless networks using wireless links are useful for connecting mobile devices.

Industrial equipment networks use a ring communication standard such as EtherCAT (registered trademark) from the viewpoint of redundancy and immediacy.

Patent Literature 1 discloses a communication device capable of making some links in a wired network of industrial equipment cableless, that is, wireless.

JP 2019-29790 A

A communication device that performs wireless communication checks in advance whether wireless communication is being performed using the frequency (channel) that the device uses for wireless communication before transmitting data or the like by wireless communication. After confirming that no communication is being performed, execute wireless communication. Specifically, a communication device that performs wireless communication searches for a radio signal using a channel that the device uses for wireless communication before the device transmits data by wireless communication (so-called carrier sense). is required. Carrier sense can avoid radio wave interference in wireless communication due to the use of the same channel.

On the other hand, when the communication device detects a radio signal other than the own device on the channel to be used for wireless communication by carrier sense, the communication device performs wireless communication after waiting for a predetermined time. Therefore, the wireless communication performed by the communication device is delayed for the predetermined time.

In the above-described ring-type network, when a delay occurs or periodically If communication is not executed, there is a possibility that a malfunction will occur in the operation of the child device. Thus, in a ring system network, periodic and low-delay communication is required.

The present invention provides a base station and the like that can suppress the occurrence of delay in wireless communication.

A base station according to an aspect of the present invention is one base station in a communication system in which a plurality of base stations communicate via a ring wired network, and includes a wired interface connected to the wired network, and a controlled a wireless interface for wirelessly communicating with a device; and a timing signal received via the wired interface, the timing signal indicating the timing at which each of the plurality of base stations starts wireless communication. a calculation unit for calculating a period of wireless communication with a control device; and, when receiving a command for the controlled device via the wired interface, receiving the command for the controlled device within the period calculated by the calculation unit. a device control unit that wirelessly communicates with the controlled device via the wireless interface based on the wireless interface.

According to this, for example, even when each base station wirelessly communicates with the controlled device using the same channel, each base station can wirelessly communicate with the controlled device at different timings. Therefore, according to such a configuration, the occurrence of waiting time (waiting period) due to carrier sensing is suppressed. Thus, according to the base station according to one aspect of the present invention, it is possible to suppress the occurrence of delay in wireless communication.

Further, for example, when the device control unit receives a command for the controlled device via the wired interface, the device control unit determines whether or not the current time is within the period calculated by the calculation unit. , if it is determined that the current time is within the period calculated by the calculation unit, wireless communication with the controlled device is started, and the current time is not within the period calculated by the calculation unit If it is determined that the current time is within the period, wireless communication with the controlled device is started.

According to this, the base station can appropriately perform wireless communication with the controlled device within the period calculated by the calculator.

Further, for example, the device control unit is connected to the plurality of controlled devices via the wireless interface so as to be capable of wireless communication, and controls two of the plurality of controlled devices via the wired interface. When the above commands for the controlled devices are received at the same time, the two or more controlled devices are controlled within the period and at different timings based on the commands for the two or more controlled devices. Communicate wirelessly with each of the devices.

According to this, even when the base station wirelessly communicates with two or more controlled devices using the same channel, the period of wireless communication with the two or more controlled devices should not overlap each other. can. Therefore, radio wave interference can be avoided during wireless communication with the two or more controlled devices.

Also, for example, the timing signal is a synchronization signal for synchronizing the plurality of base stations.

For example, in a network conforming to EtherCAT, each base station synchronizes with other base stations in order to synchronize the time of its own RTC (Real Time Clock) or the like. Therefore, the base station according to one aspect of the present invention determines a period during which the own device performs wireless communication based on the synchronization signal. According to this, without using a new signal or the like for each base station to calculate the relevant period, each base station calculates the period during which its own device wirelessly communicates based on the synchronization signal. can.

Further, for example, in wireless communication with the controlled device, the device control unit transmits a command for the controlled device to the controlled device, and transmits response data corresponding to the command for the controlled device to the controlled device. It performs transmission processing of a request signal requested from the controlled device and reception processing of the response data.

According to this, the base station can receive the response data from the child device by wireless communication, and transmit the response data to the master via the ring-type wired network.

Further, for example, the calculation unit performs (a) a process of transmitting a command to the controlled device to the controlled device, (b) a process of transmitting the request signal, and a process of receiving the response data. Calculation of the period for executing each individually, and a waiting period during which wireless communication with the controlled device is not performed between the process of transmitting a command to the controlled device to the controlled device and the process of transmitting the request signal to the controlled device do.

According to this, by appropriately calculating the waiting period, the base station can allow another base station to occupy the period even when it takes a long time for the controlled device to generate the response data. It can be used as a period to do.

Further, a communication system according to an aspect of the present invention includes a plurality of base stations described above, and each of the plurality of base stations wirelessly communicates using the same channel as each of one or more of the controlled devices. and the base stations that wirelessly communicate using the same channel are classified in advance into one of a plurality of groups so that they belong to different groups, and based on the timing signal and the number of the plurality of groups , when a period of wireless communication with one or more of the controlled devices is calculated, and commands for two or more of the plurality of controlled devices are simultaneously received via the wired interface; , wirelessly communicates with each of the two or more controlled devices within the period and at different timings from each other, based on commands for the two or more controlled devices.

For example, even when a plurality of base stations wirelessly communicate with a controlled device using the same channel, the plurality of base stations can wirelessly communicate with a plurality of controlled devices at different timings. That is, according to the base stations according to one aspect of the present invention, even when wirelessly communicating with a controlled device using the same channel, the periods of wireless communication between the base stations can be prevented from overlapping each other. One aspect of the present invention is suitable for a system having a plurality of base stations, each of which wirelessly communicates with a controlled device.

Further, a communication system according to another aspect of the present invention includes a plurality of the base stations described above, and the plurality of base stations each wirelessly communicate with the controlled device using the same channel. are classified in advance into one of a plurality of groups so that each belongs to a group different from each other, and the device control units provided in the plurality of base stations each control the controlled device and the controlled device during the same period for each group. In the wireless communication of No., a process of transmitting a command for the controlled device to the controlled device, a process of transmitting a request signal requesting response data from the controlled device in response to the command to the controlled device, and the response data reception processing, wherein the calculation units provided in the plurality of base stations perform (a) transmission processing of a command for the controlled device to the controlled device; and (b) transmission processing of the request signal. , and the response data reception processing, respectively, and the period between the transmission processing of the command for the controlled device to the controlled device and the transmission processing of the request signal A waiting period during which wireless communication with the controlled device is not performed is calculated based on the timing signal and the number of the plurality of groups.

According to this, each of the plurality of base stations provided in the communication system appropriately calculates the standby period, so that even if the slave device with which the plurality of base stations wirelessly communicates takes a long time to generate response data, , that time is available for sending and receiving for another group.

Further, a base station control method according to an aspect of the present invention is a control method for one base station in a communication system in which a plurality of base stations communicate via a ring wired network, wherein the base station comprises: A wired interface connected to the wired network and a wireless interface for wirelessly communicating with a device to be controlled, wherein the control method of the base station is a timing signal received via the wired interface, a calculating step of calculating a period of wireless communication with the controlled device based on a timing signal indicating the timing at which each of the plurality of base stations starts wireless communication; a wireless communication step of wirelessly communicating with the controlled device via the wireless interface based on the command to the controlled device within the time period calculated in the calculating step, if received via the wireless interface.

According to this, the same effect as the base station according to one aspect of the present invention described above can be obtained.

In addition, these comprehensive or specific aspects may be realized by a system, method, integrated circuit, computer program, or a recording medium such as a computer-readable CD-ROM. and any combination of recording media.

ADVANTAGE OF THE INVENTION According to this invention, the base station etc. which can suppress generation|occurrence|production of the delay in wireless communication can be provided.

FIG. 1 is a schematic diagram showing the configuration of a communication system including a base station according to Embodiment 1. FIG. 2 is a block diagram showing functional configurations of a base station and a slave device according to Embodiment 1. FIG. FIG. 3 is a first explanatory diagram of a radio frame including commands according to the first embodiment. FIG. 4 is a second explanatory diagram of a radio frame including commands according to the first embodiment. FIG. 5 is an explanatory diagram of a process of writing to a radio frame according to the first embodiment. 6 is a flowchart showing a processing procedure of the base station according to Embodiment 1. FIG. FIG. 7 is a diagram for explaining the timing at which each of a plurality of base stations included in the communication system according to Embodiment 1 wirelessly communicates. FIG. 8 is a schematic diagram showing the configuration of a communication system including a base station according to Embodiment 2. FIG. 9 is a block diagram showing functional configurations of a base station and a slave device according to Embodiment 2. FIG. FIG. 10 is a diagram for explaining timings at which each of a plurality of base stations included in the communication system according to Embodiment 2 performs wireless communication. FIG. 11 is a diagram for explaining timings at which each of a plurality of base stations included in the communication system according to the comparative example performs wireless communication. 12 is a flowchart of a processing procedure of a base station according to Embodiment 2. FIG.

Hereinafter, embodiments will be specifically described with reference to the drawings.

All of the embodiments described below represent specific examples of the present invention. Numerical values, shapes, materials, components, arrangement positions and connection forms of components, steps, order of steps, and the like shown in the following embodiments are examples and are not intended to limit the present invention. Further, among the constituent elements in the following embodiments, constituent elements not described in independent claims will be described as optional constituent elements.

In addition, the same code|symbol may be attached|subjected to the same component and description may be abbreviate|omitted.

(Embodiment 1)
[composition]
<Communication system>
First, configurations of a base station and a communication system according to Embodiment 1 will be described.

FIG. 1 is a schematic diagram showing the configuration of a communication system 1 including a base station 10 according to Embodiment 1. As shown in FIG. In FIG. 1, the devices capable of wired communication are connected by solid lines, and the devices capable of wireless communication are connected by dashed lines (more specifically, dashed arrows).

The communication system 1 includes a master M, base stations 10, 11, 12, 13, 14, 15, 16, and 17, slaves 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34 and 35. The master M and the base stations 10 to 17 are communicably connected (more specifically, wired communicable) through a ring-type wired network (wired network N).

The master M is connected to the wired network N and is a control device (so-called host controller) that controls the base stations 10 to 17 that are also connected to the wired network N. FIG. In addition, the master M has one or more child devices (hereinafter also referred to as controlled devices) 20 to 35 that are not connected to the wired network N and are capable of wireless communication with any of the base stations 10 to 17. , through the base stations 10-17.

The wired network N is, for example, a network according to EtherCAT.

In the following description, the case where the wired network N is a network conforming to EtherCAT will be described as an example. The wired network N may be a network conforming to a ring communication standard such as SERCOS III.

The master M transmits an EtherCAT frame (simply referred to as a frame) to the wired network N of the ring system. A frame sent by the master M circles around the wired network N and returns to the master M again. For example, if master M transmits a frame in direction D shown in FIG. .

Each of the base stations 10 to 17 is a slave to the master M and receives command data (hereinafter also simply referred to as command) transmitted from the master M. FIG. Base stations 10 to 17 are connected to a wired network N, respectively. Also, each of the base stations 10 to 17 receives the frame transmitted by the master M via the wired network N, reads the command included in the received frame, or writes data to the received frame. and transmit the frame to the wired network N.

For example, when each of the base stations 10-17 receives a frame containing a command, it operates according to the command contained in the received frame.

The commands include, for example, a write command requesting that a controlled device controlled by the master M write predetermined data in a frame, a read command requesting response data from the controlled device, and the like.

For example, when each of the base stations 10 to 17 receives a frame containing a write command, each of the base stations 10 to 17 writes predetermined data according to the write command. Alternatively, when each of the base stations 10 to 17 receives a frame containing a read command, for example, it writes response data in a predetermined field in the received frame and transmits the frame to the wired network N.

Also, the base stations 10-17 are connected to the child devices 20-35 so as to be able to communicate wirelessly with each other. The base stations 10 to 17 control the child devices 20 to 35 by wirelessly communicating with the child devices 20 to 35, respectively.

For example, when the base station 10 receives a frame including a command for the child device 20 transmitted by the master M via the wired network N, the base station 10 transmits (transfers) the received command to the child device 20 by wireless communication. Further, for example, when receiving the response data transmitted by the slave device 20 by wireless communication, the base station 10 transmits (transfers) the received response data to the master M via the wired network N.

Similarly, when each of the base stations 11 to 17 receives a frame transmitted by the master M and including a command for a child device with which it can communicate wirelessly, each of the base stations 11 to 17 transmits the received command to a child device with which it can communicate wirelessly. Send (transfer) data to the child device via wireless communication. Similarly, when the base stations 11 to 17 receive response data transmitted by a child device capable of wireless communication with the base station 11 to 17 by wireless communication, the received response data is sent to the master M via the wired network N. Send (transfer).

Thus, in this embodiment, the base stations 10-17 function as repeaters between the master M and the child devices 20-35. Specifically, in a system conforming to EtherCAT, such as the communication system 1, a command is transmitted from the master M to each slave (base stations 10 to 17). The base stations 10 to 17 transmit response data (0 byte data) to the master M, for example. Further, when the received command is data addressed to a slave device with which the base station 10 to 17 can communicate wirelessly, each of the base stations 10 to 17 stores the data in, for example, a storage unit 107 (see FIG. 2) described later. do. Further, each of the base stations 10 to 17 writes the response data received from the child device to the location where the response data of the EtherCAT data addressed to itself is written, and transmits the response data to the master M. FIG.

The child devices 20 to 35 are controlled devices that operate under the control of the master M, respectively. Each of the child devices 20-35 is connected to one of the base stations 10-17 so as to be able to communicate wirelessly.

In the present embodiment, slave units 20 and 21 are each connected to base station 10 for wireless communication using 36 channels of the 5 GHz band (hereinafter also referred to as Ch.36 or channel 36). Moreover, each of the child devices 22 and 23 is connected to the base station 11 so as to be able to communicate wirelessly using 40 channels of the 5 GHz band (hereinafter also referred to as Ch.40 or channel 40). Moreover, each of the child devices 24 and 25 is connected to the base station 12 so as to be able to communicate wirelessly using 44 channels of the 5 GHz band (hereinafter also referred to as Ch.44 or channel 44). Moreover, each of the child devices 26 and 27 is connected to the base station 13 so as to be able to communicate wirelessly using 48 channels of the 5 GHz band (hereinafter also referred to as Ch.48 or channel 48). Moreover, each of the child devices 28 and 29 is connected to the base station 14 for wireless communication using 36 channels (Ch. 36) of the 5 GHz band. Moreover, each of the child devices 30 and 31 is connected to the base station 15 so as to be able to communicate wirelessly using 40 channels (Ch.40) of the 5 GHz band. Moreover, each of the child devices 32 and 33 is connected to the base station 16 so as to be able to communicate wirelessly using 44 channels (Ch.44) of the 5 GHz band. Moreover, each of the slave units 34 and 35 is connected to the base station 17 so as to be able to communicate wirelessly using 48 channels (Ch.48) of the 5 GHz band.

In this way, at least two or more of the plurality of base stations 10 to 17 included in the communication system 1 wirelessly communicate with the controlled device (slave device) using the same channel.

In this embodiment, each of the base stations 10 to 17 wirelessly communicates using the same channel as two slave units. The number of slave units with which each of the base stations 10 to 17 wirelessly communicates is not particularly limited. Further, when each of the base stations 10 to 17 wirelessly communicates with a plurality of child devices, the channel used for wireless communication with each child device may be the same or different.

For example, slave device 20 receives a command from master M via base station 10 and operates according to the received command. Further, the slave device 20 transmits the response data to the master M via the base station 10 by transmitting the response data to the base station 10 .

The child devices 20 to 35 are, for example, movable mobile devices such as conveyors, sensor devices, motors, and robot arms.

The child devices 20 to 35 may be devices having functions equivalent to each other, or may be devices having functions different from each other.

As described above, according to the communication system 1, the master M not only connects the base stations 10 to 17 directly connected to the wired network N, but also the handsets 20 to 35 not directly connected to the wired network N. can be controlled. Specifically, the master M allows the base stations 10 to 17 directly connected to the wired network N to wirelessly communicate with the slaves 20 to 35 that are not directly connected to the wired network N. to control. According to the communication system 1, for example, even when it is impossible or difficult to lay wiring because the base stations 10 to 17 are physically separated from the child devices 20 to 35, the child device 20 There is an advantage that ~35 can be controlled. Thus, according to the communication system 1, it is possible to improve the flexibility of the network topology of control communication.

Here, according to the conventional method, the communication devices (in the present embodiment, the base stations 10 to 17 and the child devices 20 to 35) that perform wireless communication, before the device itself transmits data etc. by wireless communication , is required to perform carrier sense. Carrier sense can avoid radio wave interference in wireless communication due to the use of the same channel.

For example, in the example shown in FIG. 1, the base station 10 and the base station 14 wirelessly communicate using the same channel (36 channels). Therefore, for example, the base station 10 performs carrier sense, and if wireless communication using 36 channels is not being performed, that is, if the base station 14 is not performing wireless communication, wireless communication is performed. Further, if wireless communication using 36 channels is being performed, that is, if the base station 14 is performing wireless communication, the base station 10 waits for a predetermined time and then performs wireless communication.

Therefore, when the base station 10 detects a radio signal using 36 channels, a delay occurs for the predetermined time.

In this way, in a system having a plurality of communication devices that each communicate wirelessly, if the channels used by each communication device are set differently in order to suppress such delays, the number of communication devices provided in the system increases. The more channels are required, the more channels are required. Since there is a limit to the number of channels that can be used, the problem arises that the number of communication devices provided in the system cannot be increased simply by setting the channels to be used by each communication device differently. Therefore, in a system including a plurality of communication devices each of which wirelessly communicates, it is required to be able to suppress the occurrence of communication delay while suppressing the number of channels used for wireless communication.

As a result of intensive studies, the inventors of the present application have found that it is possible to suppress the occurrence of communication delays by appropriately shifting the timing (radio communication period) at which a plurality of wireless communication devices communicate wirelessly. Specifically, each of the base stations 10 to 17 grasps the timing at which each other starts wireless communication, calculates a period during which other base stations do not perform wireless communication, and allows wireless communication within the calculated period. Communicate wirelessly with other child devices. Specifically, each of the base stations 10 to 17 can mutually grasp the timing at which another base station using the same channel as its own device starts wireless communication, and calculates a period during which the other base station does not perform wireless communication. Then, the self-device wirelessly communicates with a child device capable of wireless communication during the calculated period.

In the following, functional configurations and operations of the base station 10 and the slave device 20 will be described in detail. Note that the slave units 20 to 35 will be described with the slave unit 20 as a representative, and the base stations 10 to 17 will be described with the base station 10 as a representative, but the same description holds for other slave units and other base stations. .

<Base station and handset>
FIG. 2 is a block diagram showing functional configurations of base station 10 and slave device 20 according to the present embodiment.

A base station 10 is one base station in a communication system 1 in which a plurality of base stations 10 to 17 communicate via a ring wired network N. FIG. In the present embodiment, base station 10 is a base station apparatus that transmits commands transmitted from master M to slave units 20 and 21 by wireless communication.

Base station 10 includes wired interface 101 , processing unit 104 , storage unit 107 , and wireless interface 109 .

A wired interface 101 is a communication interface connected to a wired network N. FIG. Wired interface 101 includes input port 102 and output port 103 .

The input port 102 is a port that is connected to the wired network N and receives frames from the wired network N. FIG. The input port 102 is assigned to one physical port.

The output port 103 is a port that is connected to the wired network N and transmits frames to the wired network N. FIG. The output port 103 is assigned to one physical port.

The processing unit 104 is a processing unit that executes various processes of the base station 10 . The processing unit 104 includes a calculation unit 105 and a device control unit 106 .

The calculation unit 105 calculates the controlled device (this embodiment is a processing unit that calculates a period of wireless communication with the child device 20 and the child device 21). The timing signal is, for example, a synchronization signal for synchronizing a plurality of base stations 10-17. More specifically, the timing signal is a so-called interrupt signal (SYNC0).

In this embodiment, the master M and the base stations 10 to 17 share the same clock so that the master M and the base stations 10 to 17 are synchronized. (not shown) is used to synchronize the time ticked by a distributed clock (DC/Distributed Clock) mode.

In the DC mode, among the base stations 10 to 17, the base station that first receives the EtherCAT data from the master M (the base station 10 in this embodiment) serves as a so-called master clock. 17 delay time is measured and corrected.

As a result, in a system in which a plurality of slaves are connected to the wired network N, the master M and each slave operate synchronously in the DC mode.

As described above, according to the DC mode, the master M and each of the base stations 10 to 17 can share a clock (clock information) that ticks the same time. be able to. Specifically, each of the base stations 10 to 17 generates (generates) an interrupt signal (SYNC0) at a predetermined timing and transmits the generated SYNC0 to the wired network N. FIG. As a result, each of the base stations 10 to 17 corrects the clock time of its own device based on the timing of SYNC0 transmitted by the own device and the timing of receiving SYNC0 transmitted by each of the other base stations. As a result, the base stations 10-17 are synchronized.

Further, among the base stations 10 to 17, the base station that receives the EtherCAT data from the master M first (the base station 10 in this embodiment) generates a reset signal ( SYNC1) is generated (generated) and transmitted to the wired network N.

Each base station 10-17 counts the number of times SYNC0 occurs. SYNC0 generated simultaneously from each of the base stations 10 to 17 is counted as one occurrence of SYNC0.

Here, each of the base stations 10 to 17 resets (initializes) the count of SYNC0 when receiving SYNC1. In this embodiment, for example, the base station 10 generates SYNC1 every time it generates SYNC0 six times (that is, every six cycles). Specifically, in the present embodiment, base station 10 sets SYNC0 to 250 μsec. 250 μsec. SYNC1 is generated later (see FIG. 7). Further, in the present embodiment, base station 10 generates SYNC1 at 250 μsec. SYNC0 (SYNC0 at the first count) is generated later.

As a result, for example, among the base stations 10 to 17, the base station that first receives the EtherCAT data from the master M (the base station 10 in this embodiment) is predetermined to generate SYNC0. As a result, each of the base stations 10 to 17 synchronizes the timing of generating SYNC0, and the count number of the number of times SYNC0 is generated becomes the same.

Also, each of the base stations 10 to 17 periodically and repeatedly generates synchronization signals (SYNC0 and SYNC1).

In the present embodiment, each base station 10 to 17 is assigned in advance a timing for starting wireless communication with a child device for each count number of SYNC0 generated. For example, after the first to third SYNC0 is generated, the base stations 10 to 13 wirelessly communicate, and after the fourth to sixth SYNC0 is generated, the base stations 14 to 17 wirelessly communicate. Thereby, the base stations 10 to 17 determine the period of wireless communication with the child device based on the synchronization signal for synchronizing the base stations 10 to 17. FIG.

Therefore, the calculation unit 105 calculates information (timing information) indicating the timing at which each of the base stations 10 to 17 starts wireless communication with the child device according to the number of counts generated by the SYNC0 assigned to the own device, and the wired network Device control unit 106 wirelessly communicates with child devices 20 and 21 via wireless interface 109 based on the reception timing (timing at which the synchronization signal is generated) of the synchronization signals (SYNC0 and SYNC1) received via N. Calculate duration. For example, the calculation unit 105 of the base station 10 determines whether or not the device control unit 106 can generate a slave signal via the wireless interface 109 based on the period from the timing when the first SYNC0 is generated to the timing when the fourth SYNC0 is generated. A period of wireless communication with the machines 20 and 21 is calculated. The period calculated by the calculation unit 105 also depends on how many child devices under its control contain commands addressed to the frame received from the master M. FIG.

In the present embodiment, it is predetermined that one of the base stations 10 to 17 starts wireless communication with the child device at each timing when each SYNC0 is generated. For example, the base station 10 starts wireless communication with the child devices 20 and 21 at timings when SYNC0 is generated for the first to third times.

Also, the synchronization signal is generated as a signal different from the EtherCAT data and transmitted to the wired network N. FIG.

When the device control unit 106 receives a command (more specifically, a frame containing the command) for the child devices 20 and 21 via the wired interface 101, the device control unit 106 receives the command within the period calculated by the calculation unit 105 (the device control unit is a processing unit that wirelessly communicates with the child devices 20 and 21 via the wireless interface 109 based on the received command during the period of wireless communication with the child devices 20 and 21 via the wireless interface 109 .

For example, when the device control unit 106 receives a command for the child device 20 via the wired interface 101, the device control unit 106 temporarily stores the received command in the storage unit 107, and uses the time slot determined by the calculation unit 105. , the command stored in the storage unit 107 is transmitted to the slave device 20 via the wireless interface 109, a request signal requesting response data is further transmitted via the wireless interface 109, and the response data is sent from the slave device 20. Receive via wireless interface 109 . Thus, the device control section 106 wirelessly communicates with the child device 20 via the wireless interface 109 based on the received command. Specifically, device control section 106 transmits a command to child devices 20 and 21 (first transmission processing), transmission processing (second transmission processing) of a request signal for requesting response data corresponding to a command from slave devices 20 and 21, and response data reception processing. In the present embodiment, the calculation unit 105 calculates, for example, a period for continuously executing command transmission processing, request signal transmission processing, and response data reception processing.

For example, the storage unit 107 stores device list information 108 that is a list of controllable child devices such as the child devices 20 and 21 . When the device control unit 106 receives a command for controlling the child device 20 or the like through the input port 102, it acquires the identifier of the device that is the target of the received command (also referred to as the target device). The device control unit 106 then encapsulates the command in a predetermined format and transmits it to the target child device via the wireless interface 109 . Here, the predetermined format is, for example, a format based on frames conforming to each communication standard of IEEE802.11.

Further, for example, when the device control unit 106 receives a command from the master M for the child device 20 via the wired interface 101, the current time (that is, the time when the command is received) is calculated by the calculation unit 105 as It is determined whether or not it is within the calculated period. For example, when the device control unit 106 determines that the current time is within the period calculated by the calculation unit 105 , wireless communication with the child device 20 is started. On the other hand, for example, if the device control unit 106 determines that the current time is not within the period calculated by the calculation unit 105, the device control unit 106 waits until the current time is within the period, and then communicates with the child device 20 wirelessly. Start communication.

Note that, when there are a plurality of target child devices, the device control unit 106 may sequentially unicast the command to each of the plurality of child devices. Since unicast transmission is provided with a mechanism for acknowledging arrival and controlling retransmission, there is an advantage that commands can be transmitted by wireless communication with higher reliability. Alternatively, when there are a plurality of target slave devices, the device control section 106 may broadcast the command to the plurality of target devices. If broadcast transmission is used, it is possible to obtain the advantage of reducing the wireless communication band by allowing a plurality of slave devices 20 or the like to receive the command in one transmission.

In addition, the device control unit 106 controls writing of response data transmitted by the child device 20 or the like into the frame. Device control section 106 outputs response data indicating a response from child device 20 or the like received via wireless interface 109 through output port 103 . More specifically, when the device control unit 106 receives a read command for reading a response from the child device 20 through the input port 102, the device control unit 106 adds a response indicating the response from the child device 20 or the like to the frame containing the read command. Data is written and output from the output port 103 .

Here, the response data is data indicating a response from the child device 20 or the like based on the control related to the command transmitted by the device control section 106 .

Device control section 106 also receives, via wireless interface 109 , a wireless frame in which response data is encapsulated in a predetermined format from child device 20 or the like. For example, when the device control unit 106 receives response data from the child device 20 or the like, the device control unit 106 temporarily stores the received response data in the storage unit 107, and then includes the read command received via the input port 102. write to the frame.

In addition, when receiving a command via the input port 102, the device control unit 106 may write data indicating that there is no response data to the control in the frame containing the received command, depending on the circumstances. 103 may output. When a command is received, it may not be possible to obtain a response as a result of controlling the child device 20 or the like based on the command. In that case, by writing and outputting data indicating that there is no response data to the control as described above, there is an advantage that the frame transmission delay can be reduced.

Further, the device control unit 106 controls allocation of the functions of the input port 102 and the output port 103 to the physical ports, and transmission/reception of frames by the input port 102 and the output port 103 .

The processing unit 104 is implemented by, for example, a processor such as a CPU (Central Processing Unit) and a control program executed by the processor and stored in the storage unit 107 or the like.

Note that the calculation unit 105 and the device control unit 106 may be realized by one processor, or may be separately realized by two or more processors.

In addition, the processing unit 104 may include a counter that counts the number of times SYNC0 is generated and a timer such as an RTC that measures time.

The storage unit 107 is a storage device (memory or storage) that stores the device list information 108 . A control program executed by the processing unit 104 may be stored in the storage unit 107 .

The device list information 108 is data including information on the slave devices 20 and 21 with which the base station 10 wirelessly communicates. The device list information 108 includes, for example, identification information for identifying the child devices 20 and 21, and information indicating addresses such as IP (Internet Protocol) addresses or MAC (Media Access Control) addresses of the child devices 20 and 21. is associated information.

In addition, the storage unit 107 stores, for example, information indicating the cycle of generating SYNC0 and SYNC1, and the count number of SYNC0 generated indicating the timing at which each base station 10 to 17 starts wireless communication with each child device. Predetermined information indicating information indicating is stored.

A wireless interface 109 is a communication interface for wirelessly communicating with the child devices 20 and 21 . In other words, the wireless interface 109 is a communication interface that wirelessly communicates with the child devices 20 and 21 via wireless links. The wireless interface 109 is connected to the child devices 20 and 21 by wireless communication complying with communication standards such as IEEE802.11a, b, g, and n.

Note that the number of child devices that are wirelessly communicably connected to the wireless interface 109 is not particularly limited. In this embodiment, the wireless interface is connected to a plurality of child devices (child devices 20 and 21) for wireless communication. In this case, when commands for each of the plurality of child devices are simultaneously received via the wired interface 101, the calculation unit 105 calculates a period of wireless communication with each of the plurality of child devices. In this case, for example, the device control unit 106 wirelessly communicates with each of the plurality of child devices via the wireless interface 109 based on commands for each of the plurality of child devices within the period calculated by the calculation unit 105. do.

In this way, for example, when the device control unit 106 is connected to a plurality of child devices via the wireless interface 109 so as to be able to communicate wirelessly, the device control unit 106 connects via the wired interface 101 to a plurality of devices with which the base station 10 can communicate wirelessly. When commands for two or more of the child devices are received at the same time, within a period calculated by the calculation unit 105 based on the commands for the two or more child devices and at different timings Wireless communication is performed with each of the two or more child devices. Here, the two or more child devices may be all of the plurality of child devices with which the device control unit 106 can wirelessly communicate via the wireless interface 109, or arbitrary two or more child devices. It's okay. Also, receiving at the same time means, for example, that one packet transmitted from the master M includes a command for each of two or more child devices. Also, the command for two or more child devices may be a command indicating different instructions from each other, or a command indicating the same instruction that needs to be transferred to two or more child devices (in other words, one command). , two or more sub-units and the base station 10 may be any command that requires wireless communication.

In this embodiment, each of the base stations 10 to 17 wirelessly communicates with a plurality of slave units under its control using the same channel. For example, the base station 10 wirelessly communicates with each of the handsets 20 and 21 using the channel 36 . In addition, the base stations 10 to 17 included in the communication system 1 are classified in advance into one of a plurality of groups such that the base stations that wirelessly communicate with the child device using the same channel belong to different groups. . For example, the base station 10 and the base station 14 that wirelessly communicate with the child device using the channel 36 belong to different groups. For example, the storage unit 107 provided in the base station 10 stores in advance the groups to which the base station 10 belongs and information indicating the number of groups. Based on the timing signal and the number of groups, the base station 10 calculates the period of wireless communication with each of the child devices 20 and 21 . Further, when base station 10 simultaneously receives commands for child devices 20 and 21 via wired interface 101, based on the commands for child devices 20 and 21, respectively, within the period calculated by calculation unit 105, , and wirelessly communicate with each of the child devices 20 and 21 at mutually different timings.

For example, in the base station 10, the storage unit 107 stores in advance information indicating the time required for a series of transmission/reception processes from sending a command, sending a request signal requesting response data, and receiving the response data. . Therefore, for example, when commands for each of a plurality of child devices are received simultaneously via the wired interface 101, the calculation unit 105 calculates the time required for wireless communication from the number of the plurality of child devices. The calculation unit 105, for example, determines the wireless communication timing of each of the plurality of child devices based on the calculated time. For example, if the calculating unit 105 determines that the time for wirelessly communicating with each of the plurality of slaves falls within a period of a certain cycle, it wirelessly communicates with each of the plurality of slaves within that period. On the other hand, for example, when the calculation unit 105 determines that the time to wirelessly communicate with each of the plurality of child devices does not fit within a period in a certain period, the calculation unit 105 wirelessly communicates with at least one of the plurality of child devices within the period, The period is determined so that the rest of the radio communication is performed during the period of the next cycle.

For example, the calculation unit 105 communicates wirelessly with the child device 20 via the wireless interface 109 during the period calculated in the first period by the device control unit 106, and calculates the calculated A period is determined so as to perform wireless communication with the child device 21 during the period.

Calculation unit 105 transmits a command to child device 20 via wireless interface 109 during the period calculated in the first period by device control unit 106, and transmits the command to child device 20 during the period in the second period, which is the next period after the first period. A period may be set so as to perform wireless communication with one slave device over periods in different cycles, such as transmitting a request signal to the slave device 20 and receiving response data at each time.

In the present embodiment, the period calculated by the calculation unit 105 indicates the period during which the base station 10 wirelessly communicates with one of the plurality of child devices (one of the child devices 20 and 21 in FIG. 1), In the above example, both the period in the first period and the period in the second period) are shown.

The child device 20 includes a wireless interface 201 and a child device control section 202 .

A wireless interface 201 is a communication interface for wirelessly communicating with the base station 10 . The wireless interface 201 is connected to the base station 10 so as to be able to wirelessly communicate with the base station 10 through wireless communication conforming to a wireless standard (for example, a communication standard such as IEEE 802.11a, b, g, n). The wireless interface 201 receives commands transmitted by the device control unit 106 of the base station 10 via the wireless interface 109 . The wireless interface 201 is also referred to as a slave-side wireless interface.

The child device control unit 202 is a processing unit that exchanges commands and response data between the base station 10 and the child device 20 . The slave device control unit 202 executes operations based on commands received by the wireless interface 201 . In addition, slave device control section 202 generates response data and transmits it to base station 10 via wireless interface 201 .

The slave device control unit 202 is realized by, for example, a processor such as a CPU and a control program stored in a memory (not shown) provided in the slave device 20, which is executed by the processor.

When encapsulating an EtherCAT frame into a UDP (User Datagram Protocol) datagram or IP packet, IP addresses must be set for the wireless interfaces 109 and 201 .

An IP address is set individually for the wireless interface 109 that is the source of the frame, but an individual IP address may or may not be set for the wireless interface 201 . When an IP address is not individually set for the wireless interface 201, wireless communication is performed by broadcasting from the wireless interface 109. FIG. In this case, the child device 20 determines that the data is addressed to itself by analyzing the destination MAC address in the Ethernet (registered trademark) header in the PSDU or the destination IP address in the IP header.

Also, the wireless communication of the wireless interfaces 109 and 201 is not limited to wireless communication complying with communication standards such as IEEE802.11a, b, g, and n.

<Frame structure>
3 and 4 are explanatory diagrams of a radio frame 40 including commands according to this embodiment.

FIG. 3(a) is an explanatory diagram showing the entire radio frame 40 including command or response data.

The radio frame 40 is a radio frame conforming to the existing IEEE802.11 standard. The radio frame 40 includes a PLCP (Physical Layer Convergence Protocol) preamble 41 , a PLCP header 42 , an IEEE802.11 header 43 , data 44 , and an FCS (Frame Check Sequence) 45 .

A PLCP preamble 41 is a field containing a synchronization signal added to the beginning of an IEEE802.11 frame. The synchronization signal here is, for example, a synchronization signal for synchronizing the base station 10 and the handset 20, and is a signal different from SYNC0.

The PLCP header 42 is a field containing information such as the modulation method, transmission rate, and data length of the IEEE802.11 frame.

The IEEE802.11 header 43 is a field containing information such as the frame type, destination MAC address and source MAC address of the IEEE802.11 frame. For example, when the radio frame 40 includes a command, the destination MAC address is that of the child device 20 and the source MAC address is that of the base station 10 . Alternatively, for example, when the radio frame 40 includes response data, the destination MAC address is that of the base station 10 and the transmission source MAC address is that of the child device 20 .

Data 44 is the field containing the data carried by the IEEE 802.11 frame. Data 44 includes EtherCAT frames containing command or response data.

FCS 45 is a field containing a checksum calculated from the IEEE 802.11 header 43 and data 44 fields.

The fields contained in data 44 are described in further detail.

Data 44 includes an EtherCAT frame. In other words, data 44 encapsulates an EtherCAT frame. Various methods can be employed for the encapsulation method. As the encapsulation method, for example, a UDP datagram encapsulation method, an IP packet encapsulation method, an IEEE802.11 frame encapsulation method, or the like can be adopted. Note that the EtherCAT frame may be encapsulated directly. In this case, the overhead for encapsulation can be reduced.

FIG. 3(b) shows data 44 when an EtherCAT frame is encapsulated in a UDP datagram.

Data 44 includes Ethernet header 50 , IP header 51 , UDP header 52 , EtherCAT header 53 and EtherCAT datagram 54 .

The Ethernet header 50 is a field containing source MAC address, destination MAC address and type. For example, when the wireless frame 40 includes a command, the MAC address of the slave device 20 is the destination and the MAC address of the base station 10 is the source. Alternatively, for example, when the radio frame 40 includes response data, the MAC address of the base station 10 is set as the destination and the MAC address of the child device 20 is set as the source. The type is "0x0800" which means IP.

The IP header 51 is a field containing a source IP address and a destination IP address. For example, when the radio frame 40 includes a command, the IP address of the slave device 20 is the destination and the IP address of the base station 10 is the source. Alternatively, for example, when the radio frame 40 includes response data, the IP address of the base station 10 is set as the destination and the IP address of the child device 20 is set as the source.

The UDP header 52 is a field containing a source port number, a destination port number, and the like. A predetermined value can be adopted for the UDP port number.

The EtherCAT header 53 is the header of the EtherCAT frame and includes the data length and the like of the EtherCAT frame.

EtherCAT datagrams 54 are fields that contain data carried by EtherCAT frames. An EtherCAT datagram 54 may contain data destined for multiple devices. When data addressed to a plurality of devices is included, it has a structure in which a plurality of datagrams including identifiers of the destination devices and data to be transmitted to the devices are concatenated. For example, the EtherCAT datagram 54 has a configuration in which a datagram addressed to the child device 20 (datagram 56 in FIG. 4) and a datagram addressed to the child device 21 (datagram 57 in FIG. 4) are concatenated.

FIG. 4 is an explanatory diagram showing the entire EtherCAT datagram 54. As shown in FIG.

The datagram 56 includes command 56A, device ID 56B, and data length 56C fields. Also, in this example, datagram 56 further includes data 56D.

A command 56A is a field indicating the type of command included in the datagram 56. FIG. A command 56A indicates a command type such as a write command or a read command.

The device ID 56B is a field indicating the destination of the datagram 56. FIG. Device ID 56B includes, for example, a device ID indicating child device 20 .

Data length 56C indicates the data length of data 56D included in datagram 56. FIG. The data length 56C is, for example, in bytes.

Data 56D is the data contained in datagram 56;

Note that the data 56D is not essential. If there is no data 56D, the data length 56C can be zero and the data 56D can be omitted.

The datagram 57 includes command 57A, device ID 57B, and data length 57C fields, as described above. Also, in this example, datagram 57 further includes data 57D. The device ID 57B includes, for example, a device ID indicating the slave device 21. FIG.

Note that the data 44 can also take the form of encapsulating an Ethercat frame into an Ethernet frame. In this case, data 44 includes Ethernet header 50 , EtherCAT header 53 and EtherCAT datagram 54 .

Data 44 may also take the form of encapsulating EtherCAT frames into IEEE 802.11 frames. In this case, data 44 includes EtherCAT headers 53 and EtherCAT datagrams 54 .

FIG. 5 is an explanatory diagram of the process of writing to a wireless frame according to this embodiment. Specifically, FIG. 5 shows a state in which the device control unit 106 writes data to the datagram 56 including write commands and read commands.

5A shows a state in which the device control unit 106 writes data to the datagram 56 including the write command received from the wired network N. FIG.

The device control unit 106 writes data indicating that there is no response from the device to the frame containing the write command. Specifically, the device control unit 106 writes zero to the data length 56C.

5B shows an example of a state in which the device control unit 106 writes data to the datagram 56 including the read command received from the wired network N. FIG.

The device control unit 106 writes the response data received from the device into the frame containing the read command. The device control unit 106 writes, for example, 5-byte response data to the data 56D. The device control unit 106 also writes "5", which means 5 bytes, which is the data length of the response data, into the data length 56C.

Note that FIGS. 5A and 5B respectively show states in which the device control unit 106 writes data to the datagram 56 including a write command and a read command as examples of commands. , and these command types are merely examples, and the same applies to other commands.

[Processing procedure]
Next, the processing procedure executed by the base station 10 will be described in detail.

FIG. 6 is a flow chart showing a processing procedure of base station 10 according to the present embodiment.

First, the device control unit 106 acquires the device list information 108 (S101). Specifically, the device control unit 106 acquires the device list information 108 including the information of the child device with which the base station 10 wirelessly communicates (for example, the identification information of the child device and the address of the child device). In this embodiment, the device list information 108 is pre-stored in the storage unit 107 . The device control unit 106 may acquire the device list information 108 by receiving it from the outside via the wired interface 101 or the wireless interface 109 .

Next, the calculation unit 105 wirelessly communicates with the child device based on the timing signal received via the wired interface 101 and indicating the timing at which each of the plurality of base stations starts wireless communication. A period is calculated (S102). For example, the calculation unit 105 calculates the period from what number of counts of SYNC0 to what number of times wireless communication is to be performed based on the timing information described above. For example, the calculation unit 105 determines that the count information is information indicating counters 1 to 3, and that SYNC0 is 250 μsec. If it is generated every 250 μsec. ×3=750 sec. is calculated as a period for wireless communication (a period during which wireless communication is possible).

Next, the device control unit 106 determines whether or not a command to the child device 20 or 21 has been received via the wired interface 101 (S103).

When the device control unit 106 determines that the command to the child device 20 or 21 has not been received (No in S103), the process returns to step S103.

On the other hand, when the device control unit 106 determines that a command to the child device 20 or 21 has been received (Yes in S103), the device control unit 106 temporarily stores the received command in the storage unit 107 (S104 ).

Next, the device control unit 106 determines whether or not the current timing (current time) is within the period, calculated by the calculation unit 105, during which wireless communication with the child device 20 or 21 is possible (S105).

The following flowchart will be described assuming that the device control unit 106 has received a command to the child device 20 via the wired interface 101 .

If the device control unit 106 determines that the current timing is not within the calculated period during which wireless communication with the child device 20 or 21 is possible (No in S105), the process returns to step S105.

On the other hand, when the device control unit 106 determines that the current timing is within the calculated period (Yes in S105), the device control unit 106 transmits a command to the child device 20 via the wireless interface 109 (S106).

In this way, device control section 106 waits without wireless communication with child device 20 except for the period calculated by calculation section 105 .

Note that the device control unit 106 may delete the command transmitted to the child device 20 via the wireless interface 109 from the storage unit 107 at any timing after the command is transmitted to the child device 20. .

Next, the device control unit 106 transmits a request signal requesting response data to the command transmitted in step S106 to the slave device 20 within a period of time via the wireless interface 109 (S107).

Next, device control section 106 determines whether response data has been received from child device 20 via wireless interface 109 (S108).

When the device control unit 106 determines that the response data has not been received from the slave device 20 via the wireless interface 109 (No in S108), the process returns to step S108.

On the other hand, when the device control unit 106 determines that the response data has been received from the child device 20 via the wireless interface 109 (Yes in S108), the device control unit 106 writes the received response data into an EtherCAT frame and transmits the received response data via the wired interface 101. Send to network N (S109).

Note that when the base station 10 receives commands addressed to both the child device 20 and the child device 21, for example, the processing (wireless communication processing) of steps S106 to S108 is performed by the calculation unit 105. If it is determined that the process will not end within the calculated period, the process returns to step S105 after executing processes that can be completed within the calculated period. good too.

FIG. 7 is a diagram for explaining the timing at which each of a plurality of base stations 10 to 17 provided in communication system 1 according to the present embodiment performs wireless communication. 7, group A channel 36 indicates the base station 10, group A channel 40 indicates the base station 11, group A channel 44 indicates the base station 12, and group A channel 48 indicates the base station. 13. Also in FIG. 7, group B channel 36 represents base station 14, group B channel 40 represents base station 15, group B channel 44 represents base station 16, and group B channel 48 represents base station 16. Station 17 is shown. In FIG. 7, "transmission" indicates that the base station transmits a command to the child device (command transmission processing), and "request" indicates that the base station transmits a request signal to the child device. (request signal transmission processing), and "reception" indicates that the base station receives response data from the child device (response data reception processing).

In the example shown in FIG. 7, SYNC0 is generated at intervals of 250 μs, and SYNC1 is generated at intervals of 1500 μs, which is six cycles of SYNC0.

Each of the base stations 10 to 17 counts up the counter when SYNC0 is received, and resets the counter when SYNC1 is received.

Using such a counter, each of the base stations 10 to 17 sets the slaves belonging to group A (base stations 10 to 13 shown in FIG. 1) to their time slots during which the counter is 1 to 3, and group The slaves belonging to B (the base stations 14 to 17 shown in FIG. 1) calculate so that the period of 4 to 6 in the counter is the time slot of its own device. In the example shown in FIG. 7, for example, the base station 10 (more specifically, the calculation unit 105) has two groups, and the base station 10 belongs to group A. By dividing the period until reception by the number of groups, the period of wireless communication with the child devices 20 and 21 is calculated. The order of wireless communication with the child devices in the plurality of groups may be arbitrarily determined in advance, and is stored in the storage unit 107, for example. In the example shown in FIG. 7, it is predetermined that the base stations wirelessly communicate with the child devices in the order of group A and group B. In the example shown in FIG.

The base stations 10 to 13 belonging to group A transmit commands to the child devices 20 to 27 by radio communication during the period when the counter is 1 (that is, the time from the beginning of the counter 1 to immediately before the counter 2). , a request signal is transmitted to slave units 20 to 27 by wireless communication, and response data is received by slave units 20 to 27 during the period of counter 3 by wireless communication.

The base stations 14 to 17 belonging to group B transmit commands to the child devices 28 to 35 by radio communication while the counter is 4, and transmit request signals to the child devices 28 to 35 by radio communication while the counter is 5. Furthermore, during the period of the counter 6, the slave units 28 to 35 receive the response data by radio communication.

According to this, even if wireless communication (command transmission, request signal transmission, and response data reception) is performed using the same channel (wireless channel) in group A and group B, wireless communication is performed. timing is different. In other words, the base stations 10 to 13 belonging to group A and the base stations 14 to 17 belonging to group B communicate wirelessly using the same channel (frequency slot) and different timing (time slot). Therefore, in the communication system 1, the waiting time due to carrier sense and radio wave interference in wireless communication are avoided.

Also, for example, each of the base stations 10 to 13 belonging to group A wirelessly communicates with two slave units during a period in which the counter is 1 to 3.

Further, for example, when the base station 10 simultaneously receives commands to each of the child device 20 and the child device 21 via the wired network N, by wirelessly communicating with the child device 20, the command from the child device 20 is received. After 1750 μs (250 μs×7) from the reception of the response data, wireless communication with the child device 21 is performed, whereby the response data is received from the child device 21 after 2500 μs (250 μs×10). Thus, for example, the base station 10 wirelessly communicates with each of the slave devices 20 and 21 within the period calculated by the calculator 105 and at different timings. In the example shown in FIG. 7, when the base station 10 simultaneously receives commands for the child devices 20 and 21 via the wired interface 101, the base station 10 receives commands for the child devices 20 and 21 based on the commands for the child devices 20 and 21, respectively. When it is determined that the command is to be transmitted to each of the slave devices 20 and 1, the slave device 20 is within the period of the counters 1 to 3 calculated by the calculation unit 105 and is wirelessly communicated at different timings. 3, waits for the counters 4-6 and 0, and wirelessly communicates with the child device 21 during the next counters 1-3.

In this way, the base station 10 calculates the period of wireless communication with the child devices 20 and 21 based on the timing at which the plurality of base stations 10 to 17 provided in the communication system 1 start wireless communication with the child devices, It communicates wirelessly with the child devices 20 and 21 within the calculated period. Specifically, each of the plurality of base stations 10 to 17 performs wireless communication (in the example shown in FIG. 7, "transmit", "request", and "receive ")do. Also, the plurality of base stations 10 to 17 are classified in advance into one of a plurality of groups such that base stations that communicate wirelessly using the same channel belong to different groups. For example, the base station 10 and the base station 14 that wirelessly communicate with the child device using the channel 36 belong to different groups. For example, the storage unit 107 provided in each of the plurality of base stations 10 to 17 stores in advance the group to which the base station belongs and information indicating the number of groups. Each of the plurality of base stations 10 to 17 sets a period for wireless communication with each of the plurality of child devices (for example, the child devices 20 and 21 in the case of the base station 10) based on the timing signal and the number of the plurality of groups. calculate. For example, the calculation unit 105 of the base station 10, in this example, has two groups. calculates a period during which wireless communication with the child devices 20 and 21 is not performed. Further, when each of the plurality of base stations 10 to 17 simultaneously receives a command for each of the plurality of child devices via the wired interface 101, the calculation unit 105 calculates based on the command for each of the plurality of child devices. wirelessly communicates with each of the plurality of child devices at different timings within the specified period.

Note that the intervals at which SYNC0 and SYNC1 are generated may be set arbitrarily, and are not limited to the above examples.

Also, each of the base stations 10 to 17 may wirelessly communicate with a plurality of child devices using channels different from each other. For example, the base station 10 may wirelessly communicate with the child devices 20 and 21 using the same channel, and further wirelessly communicate with other child devices (not shown) using a different channel.

[Effects, etc.]
As described above, the base station 10 according to Embodiment 1 is one base station in the communication system 1 in which a plurality of base stations 10 to 17 communicate via the wired network N of the ring system. The base station 10 includes a wired interface 101 connected to the wired network N, a wireless interface 109 for wireless communication with a device to be controlled (for example, the child device 20), and a timing signal received via the wired interface 101. A calculation unit 105 for calculating a period of wireless communication with a controlled device based on a timing signal indicating the timing at which each of the plurality of base stations 10 to 17 starts wireless communication, and a command for the controlled device, a device control unit 106 that wirelessly communicates with the controlled device via the wireless interface 109 based on the command for the controlled device within the period calculated by the calculation unit 105 when received via the wired interface 101 .

According to this, for example, even when the base stations 10 to 17 use the same channel to wirelessly communicate with the controlled device, the base stations 10 to 17 can wirelessly communicate with the controlled device at different timings. Therefore, according to such a configuration, the occurrence of waiting time due to carrier sensing is suppressed. Thus, according to the base station 10 according to Embodiment 1, it is possible to suppress the occurrence of delay in wireless communication.

Also, for example, when the device control unit 106 receives a command for the controlled device via the wired interface 101 , it determines whether or not the current time is within the period calculated by the calculation unit 105 . For example, when the device control unit 106 determines that the current time is within the period calculated by the calculation unit 105, the device control unit 106 starts wireless communication with the controlled device. On the other hand, for example, when the device control unit 106 determines that the current time is not within the period calculated by the calculation unit 105, the device control unit 106 waits until the current time is within the period before performing wireless communication with the controlled device. to start.

According to this, the base station 10 can appropriately perform wireless communication with the controlled device within the period calculated by the calculation unit 105 .

Further, for example, the device control unit 106 is connected to a plurality of controlled devices via a wireless interface 109 so as to be capable of wireless communication. That is, the base station 10 is connected, for example, to a plurality of controlled devices so as to be capable of wireless communication. In this case, for example, when the device control unit 106 simultaneously receives commands for two or more controlled devices out of a plurality of controlled devices via the wired interface 101, Based on the command, wireless communication is performed with each of the two or more controlled devices within the period calculated by the calculation unit 105 and at different timings.

According to this, even when the base station 10 wirelessly communicates with two or more controlled devices using the same channel, the period of wireless communication with the two or more controlled devices should not overlap each other. can be done. Therefore, radio wave interference can be avoided during wireless communication with the two or more controlled devices.

Also, for example, the timing signal described above is a synchronization signal for synchronizing the plurality of base stations 10-17.

For example, in a network conforming to EtherCAT, each base station synchronizes with other base stations in order to synchronize the time of the clock units such as the RTC that each base station has. Therefore, the base station 10 according to Embodiment 1 determines a period during which the base station 10 wirelessly communicates based on the synchronization signal. According to this, the base station 10 calculates an appropriate period for wireless communication based on the synchronization signal without using a new signal or the like for each of the base stations 10 to 17 to calculate the period. can.

Further, for example, in wireless communication with a controlled device, the device control unit 106 performs a process of transmitting a command to the controlled device to the controlled device, and requests response data from the controlled device in response to the command to the controlled device. A request signal transmission process and a response data reception process are performed.

According to this, the base station 10 can receive the response data from the controlled device by wireless communication, and can transmit the response data to the master M via the wired network N of the ring system.

Further, the communication system 1 according to Embodiment 1 includes a plurality of base stations according to this embodiment (base stations 10 to 17 in this embodiment). Each of the plurality of base stations wirelessly communicates with one or more controlled devices using the same channel, and the base stations wirelessly communicating using the same channel belong to different groups. are classified in advance into one of the following groups. Also, each of the plurality of base stations calculates a period of wireless communication with each of the one or more controlled devices based on the timing signal and the number of the plurality of groups. Further, when each of the plurality of base stations simultaneously receives commands for two or more controlled devices out of the plurality of controlled devices via the wired interface 101, based on the commands for the two controlled devices, , wirelessly communicate with each of the two or more controlled devices at different timings within the period calculated by the calculation unit 105 .

For example, even when a base station wirelessly communicates with a plurality of controlled devices using the same channel, the base station can wirelessly communicate with the plurality of controlled devices at timings different from those of other base stations. In other words, according to the base stations 10 to 17 according to Embodiment 1, even when wirelessly communicating with a controlled device using the same channel, the periods of wireless communication between them can be prevented from overlapping each other. In addition, Embodiment 1 is suitable for a system having a plurality of base stations (communication system 1 having base stations 10 to 17 in this embodiment) each of which wirelessly communicates with a child device.

Also, the method of controlling the base station 10 according to Embodiment 1 is a method of controlling one base station in the communication system 1 in which a plurality of base stations 10 to 17 communicate via the wired network N of the ring system. The control method of the base station 10 is a timing signal received via the wired interface 101, which indicates the timing at which each of the plurality of base stations 10 to 17 starts wireless communication. a calculation step (S102) for calculating a period of wireless communication with the controlled device; and wireless communication steps (S106 to S108) for wirelessly communicating with the controlled device via the wireless interface 109 based on the command for the control device.

According to this, the same effect as the base station 10 according to the first embodiment described above can be obtained.

In addition, these comprehensive or specific aspects may be realized by a system, method, integrated circuit, computer program, or a recording medium such as a computer-readable CD-ROM. and any combination of recording media.

(Embodiment 2)
A base station and a communication system according to Embodiment 2 will be described below. In the description of the second embodiment, the differences from the first embodiment will be mainly described. In the description of the second embodiment, the same reference numerals are assigned to substantially the same configurations as in the first embodiment, and the description may be partially simplified or omitted.

[composition]
FIG. 8 is a schematic diagram showing the configuration of a communication system 1A including a base station 10A according to the second embodiment. In FIG. 8, the devices capable of wired communication are connected by solid lines, and the devices capable of wireless communication are connected by dashed lines (more specifically, dashed arrows).

A communication system 1A includes a master M and a plurality of base stations (eg, base stations 10A, 10B, 10C, and 10D).

Although not shown, Group B to Group F include a plurality of base stations, such as base stations 10A to 10D, respectively, which wirelessly communicate with child devices (controlled devices) on different channels. In the present embodiment, groups B to F each include a base station that wirelessly communicates with slave units using 36 channels (Ch.36) of the 5 GHz band and 40 channels (Ch.40) of the 5 GHz band. A base station that wirelessly communicates with the child device using 44 channels (Ch.44) of the 5 GHz band, and a base station that wirelessly communicates with the child device using 48 channels (Ch.48) of the 5 GHz band. It includes four base stations with base stations in wireless communication with the .

Each of the plurality of base stations included in the communication system 1A is a slave to the master M and receives command data transmitted from the master M, like the base station 10 and the like according to the first embodiment. A plurality of base stations are connected to a wired network N, respectively. Also, each of the plurality of base stations receives the frame transmitted by the master M via the wired network N, and reads the command included in the received frame or writes data to the received frame. to transmit the frame to the wired network N.

Each of the plurality of child devices included in the communication system 1A is a controlled device that operates under the control of the master M, similar to the child device 20 and the like according to the first embodiment. Each of the plurality of child devices is connected to one of the plurality of base stations so as to be able to communicate wirelessly.

In addition, in this embodiment, each of the plurality of base stations is connected so as to be able to communicate wirelessly with one slave device.

For example, the handset 20A is wirelessly communicably connected to the base station 10A using 36 channels (Ch.36) of the 5 GHz band. Further, for example, the handset 20B is wirelessly communicably connected to the base station 10B using 40 channels (Ch.40) of the 5 GHz band. Further, for example, the handset 20C is connected to the base station 10C so as to be able to communicate wirelessly using 44 channels (Ch.44) of the 5 GHz band. Further, for example, the handset 20D is connected to the base station 10D so as to be able to communicate wirelessly using 48 channels (Ch.48) of the 5 GHz band.

Of course, each of the plurality of base stations included in the communication system 1A may be connected to a plurality of slave units so as to be capable of wireless communication.

The plurality of child devices are, for example, movable mobile devices such as carrier devices, sensor devices, motors, and robot arms.

Hereinafter, the functional configuration and operation of the base station 10A will be described in detail. Note that although the base station 10A will be described as a representative of the plurality of base stations included in the communication system 1A, the same description holds true for other base stations. Moreover, since the configurations of the plurality of child devices included in the communication system 1A are substantially the same as those of the child device 20 and the like according to the first embodiment, description thereof is omitted. For example, the child device 20A has substantially the same functional configuration as the child device 20, and includes, for example, a wireless interface 201 and a child device control unit 202 shown in FIG.

FIG. 9 is a block diagram showing functional configurations of the base station 10A and the slave device 20A according to this embodiment.

The base station 10A is one base station in a communication system 1A in which a plurality of base stations communicate via a ring wired network N. FIG. In this embodiment, the base station 10A is a base station device that transmits a command transmitted from the master M to the slave device 20A by wireless communication.

The base station 10A includes a wired interface 101, a processing unit 104A, a storage unit 107, and a wireless interface 109.

The processing unit 104A is a processing unit that executes various processes of the base station 10A. Processing unit 104A includes calculation unit 105A and device control unit 106A.

Calculating section 105A calculates the controlled device (in the present embodiment, , and a processing unit for calculating a period of wireless communication with the child device 20A).

The timing signal is, for example, a synchronization signal (for example, SYNC0 described above) for synchronizing a plurality of base stations. In addition, the base station 10A generates SYNC1 according to the cycle of generating SYNC0 and transmits it to the wired network N. FIG. The calculation unit 105A, for example, calculates information (timing information) indicating the timing at which each base station starts wireless communication with the slave unit according to the count number generated by the SYNC0 assigned to the own device, and through the wired network N device control unit 106A calculates the period of wireless communication with child device 20A via wireless interface 109 based on the reception timing (the timing at which the synchronization signal is generated) of the synchronization signals (SYNC0 and SYNC1) received through the wireless interface 109.

For example, in the storage unit 107, each of the plurality of base stations stores the time required for wireless communication with the child device (command transmission processing, request signal transmission processing for requesting response data, and response data reception processing). Information indicating the time required for a series of transmission/reception processes is stored in advance. The calculation unit 105A calculates a period of wireless communication with the child device 20A, for example, based on the timing signal and the information. The information that each base station uses to calculate the period may be stored in the master M and transmitted to each base station.

When device control unit 106A receives a command (more specifically, a frame including the command) for child device 20A via wired interface 101, device control unit 106A performs a command based on the received command within the period calculated by calculation unit 105A. is a processing unit that wirelessly communicates with the child device 20A via the wireless interface 109. FIG.

For example, when receiving a command for child device 20A via wired interface 101, device control unit 106A temporarily stores the received command in storage unit 107, and uses the time slot determined by calculation unit 105A. That is, during the period calculated by calculation unit 105A, the command stored in storage unit 107 is transmitted to child device 20A via wireless interface 109, and a request signal requesting response data is sent via wireless interface 109. Further, it transmits and receives response data from slave device 20A via wireless interface 109 . In other words, during the period calculated by calculation unit 105A, device control unit 106A performs transmission processing (first transmission processing) of a command for child device 20 to child device 20A in wireless communication (wireless communication processing) with child device 20A. ), request signal transmission processing (second transmission processing) for requesting response data from slave device 20A in response to a command to slave device 20A, and response data reception processing. In the present embodiment, the calculation unit 105A separately performs (a) a process of transmitting a command to the child device 20A to the child device 20A, and (b) a process of transmitting a request signal and a process of receiving response data. and a standby period during which wireless communication with the slave device 20A is not performed between the processing of transmitting a command to the slave device 20A and the processing of transmitting a request signal to the slave device 20A.

The plurality of base stations included in the communication system 1A are classified in advance into one of a plurality of groups such that the base stations that wirelessly communicate with the child device using the same channel belong to different groups. For example, the storage unit 107 provided in the base station 10A stores in advance the groups to which the base station 10A belongs and information indicating the number of groups. The calculation unit 105A calculates a period of wireless communication with the child device 20A and a standby period, for example, based on the timing signal and the number of groups. For example, the calculating units 105A included in a plurality of base stations calculate the period so that each group performs wireless communication with the child device during the same period. In addition, the device control units 106 provided in the plurality of base stations each transmit a command to the child device and a request signal to the child device during the same period for each group in wireless communication with the child device. and reception processing of the response data.

Device control section 106A also receives, via wireless interface 109, a wireless frame in which response data is encapsulated in a predetermined format from child device 20A. For example, when device control section 106A receives response data from child device 20A, device control section 106A temporarily stores the received response data in storage section 107, and thereafter receives a frame containing a read command via input port 102. write to

In addition, the device control unit 106A controls writing of the response data transmitted by the child device 20A into the frame. Device control unit 106A outputs response data, which is received via wireless interface 109 and indicates a response from child device 20A or the like, through output port 103. FIG.

Alternatively, when a command is received via the input port 102, the device control unit 106A writes data indicating that there is no response data to the control in the frame containing the received command, and outputs the command from the output port 103. may be output. At the time of receiving a command, it may not be possible to obtain a response as a result of controlling child device 20A based on the command. In that case, by writing and outputting data indicating that there is no response data to the control as described above, there is an advantage that the frame transmission delay can be reduced.

Further, the device control unit 106A controls allocation of the functions of the input port 102 and the output port 103 to the physical ports, and transmission/reception of frames by the input port 102 and the output port 103 .

FIG. 10 is a diagram for explaining the timing at which each of the plurality of base stations included in the communication system 1A according to Embodiment 2 performs wireless communication.

Also, in FIG. 10, channels 36 of groups A to F indicate base stations that wirelessly communicate with slave units on channel 36 in each group, and channels 40 of groups A to F represent slave units on channel 40 in each group. Channels 44 of groups A to F indicate base stations that wirelessly communicate with child units on channels 44 in each group, and channels 48 of groups A to F indicate child units on channel 48 in each group. base station that communicates wirelessly with the aircraft. For example, in FIG. 10, for group A, channel 36 indicates base station 10A, channel 40 indicates base station 10B, channel 44 indicates base station 10C, and channel 48 indicates base station 10D. show.

In FIG. 10, "transmission" indicates that the base station transmits a command to the child device (command transmission processing), and "request" indicates that the base station transmits a request signal to the child device. (request signal transmission processing), and "reception" indicates that the base station receives response data from the child device (response data reception processing).

Although SYNC0 and SYNC1 are not shown in FIG. 10, the case where SYNC0 is generated at intervals of 300 μs and SYNC1 is generated at intervals of 5400 μs, which is 18 cycles of SYNC0, is shown. Each base station counts up the counter when it receives SYNC0, and resets the counter when it receives SYNC1. Also, in FIG. 10, illustration of the count 0 is omitted.

PA indicates the period during which each base station of group A communicates wirelessly with the slave, PB indicates the period during which each base station of group B communicates wirelessly with the slave, and PC indicates the period during which each base station of group C communicates with the slave. PD indicates the period during which each base station of group D wirelessly communicates with the slave unit, PE indicates the period during which each base station of group E communicates wirelessly with the slave unit, and PF indicates the period of wireless communication with the slave unit. It shows the period during which each base station in F communicates wirelessly with the child device.

The calculation unit 105A included in each base station belonging to group A calculates the periods when the counter is 1, 7, and 8 as the period during which the own device wirelessly communicates with the child device. Specifically, the calculator 105A included in each base station belonging to group A sets the period during which the counter is 1 as the period during which the command transmission process is performed, and the periods during which the counter is 7 and 8 as the period during which the request signal is transmitted. It is calculated as the period during which the process is performed and the period during which the response data reception process is performed.

Further, the calculation unit 105A provided in each base station belonging to group A calculates the period in which the counter is 2 to 6 as the standby period, which is the period during which the own apparatus does not perform wireless communication with the child apparatus. For example, since the number of groups in the communication system 1A is 6, the calculator 105A calculates the counter period of 6-1=5 as the standby period.

For example, when the device control unit 106A receives a command for the child device 20A via the wired interface 101, the current time (that is, the time at which the command is received) is changed to the period calculated by the calculation unit 105A (for example, It is determined whether it is within PA) shown in FIG. For example, when the device control unit 106A determines that the current time is within the period calculated by the calculation unit 105A, the device control unit 106A starts wireless communication (specifically, command transmission processing) with the child device 20A. On the other hand, for example, when the device control unit 106A determines that the current time is not within the period calculated by the calculation unit 105A, the device control unit 106A waits until the current time is within the period before performing wireless communication with the child device 20A. to start.

Next, the device control unit 106A waits without wireless communication with the child device 20A during the standby period calculated by the calculation unit 105A. Furthermore, the device control unit 106A, for example, determines whether or not the current time (that is, the time after waiting) is within the period (for example, PA shown in FIG. 10) calculated by the calculation unit 105A. For example, when the device control unit 106A determines that the current time is within the period calculated by the calculation unit 105A, the device control unit 106A performs wireless communication with the child device 20A (specifically, request signal transmission processing and response data processing). receive processing). On the other hand, for example, when the device control unit 106A determines that the current time is not within the period calculated by the calculation unit 105A, the device control unit 106A waits until the current time is within the period before performing wireless communication with the child device 20A. to start.

There are two types of response data, such as sensor detection results, which can be generated relatively quickly by the child device, and other types of response data, such as robot movements, which require the child device to perform some calculations and take time to generate. be. If it takes a long time to generate the response data, even if the request signal transmission process is performed immediately after the command transmission process, the slave device may not be able to transmit the response data. If such a situation is recognized, it is difficult to process all transmissions, requests and receptions within the period calculated by the calculator 105A. Therefore, the time after the transmission process is set as a standby time, and the standby time is allocated to wireless communication of other groups. Base station 10A requests and receives during the period for the next group A (the period of counters 7 and 8 in FIG. 10).

FIG. 11 is a diagram for explaining timings at which each of a plurality of base stations included in the communication system according to the comparative example performs wireless communication.

Also, in FIG. 11, channels 36 of groups A to D indicate base stations that wirelessly communicate with slave units on channel 36 in each group, and channels 40 on groups A to F represent slave units on channel 40 in each group. Channels 44 of groups A to F indicate base stations that wirelessly communicate with child units in each group on channel 44, and channels 48 in groups A to F indicate child units on channel 48 in each group. base station that communicates wirelessly with the aircraft.

In FIG. 11, "transmission" indicates that the base station transmits a command to the child device (command transmission processing), and "request" indicates that the base station transmits a request signal to the child device. (request signal transmission processing), and "reception" indicates that the base station receives response data from the child device (response data reception processing).

FIG. 11 omits illustration of SYNC0 and SYNC1, but shows a case where SYNC0 is generated at intervals of 300 μs and SYNC1 is generated at intervals of 5400 μs, which is 18 cycles of SYNC0. Each base station counts up the counter when it receives SYNC0, and resets the counter when it receives SYNC1. Also, in FIG. 11, illustration of the count 0 is omitted.

PA indicates the period during which each base station of group A communicates wirelessly with the slave, PB indicates the period during which each base station of group B communicates wirelessly with the slave, and PC indicates the period during which each base station of group C communicates with the slave. PD indicates the period during which each base station of group D wirelessly communicates with the slave unit, PE indicates the period during which each base station of group E communicates wirelessly with the slave unit, and PF indicates the period of wireless communication with the slave unit. It shows the period during which each base station in F communicates wirelessly with the child device.

Each calculation unit included in each base station belonging to group A calculates a period of 1 to 6 on the counter as a period for wireless communication between the base station and the child device. Specifically, the calculation unit 105A included in each base station belonging to group A sets the period during which the counter is 1 as the period during which the command transmission process is performed, and the period during which the counter is 2 to 5 as the period during which the request signal transmission process is performed. The period during which the counter is 6 is calculated as the period during which the response data reception process is performed.

As shown in FIG. 11, when the period of wireless communication between the base station and the child device is set so that each processing of command transmission processing, request signal transmission processing, and response data reception processing is continuously performed, If it takes a long time to generate the response data, the base station cannot receive the response data even if it sends the request signal to the child device. 4 times) to the child device. Therefore, the period for transmitting the request signal becomes longer.

On the other hand, for example, in the example shown in FIG. 10, a period for the child device to generate response data is calculated as a standby period, and wireless communication between the base station and the child device is not performed during the calculated period. Wireless communication is performed between a base station belonging to a group different from the station and the child device. As a result, even if it takes time to generate the response data, the time from the transmission of the request signal to the reception of the response data can be shortened.

For example, in the example shown in FIG. 10, the time required for each base station provided in the communication system 1A to complete wireless communication with the slave unit (counter is 1 to 18) is 18 slots (the number of counters)×300 μs=5400 μs. Become. Also, during this time, the communication system 1A can perform wireless communication with 24 destinations (the number of base stations with which the base station wirelessly communicates). Therefore, the period for wireless communication per destination is 225 μs.

On the other hand, in the example shown in FIG. 11, the time required for each base station provided in the communication system 1A to complete wireless communication with the child device (the counter counts 1 to 7 for 4 cycles) is 7 slots×4 (counter count number)×300 μs=8400 μs. Also, during this time, the communication system 1A can wirelessly communicate with 16 destinations (the number of base stations with which the base station wirelessly communicates). Therefore, the period for wireless communication per destination is 525 μs.

Thus, in the example shown in FIG. 10, the communication time per destination can be shortened by 43% compared to the example shown in FIG.

The processing unit 104A is realized by, for example, a processor such as a CPU and a control program stored in the storage unit 107 or the like, which is executed by the processor.

Calculation unit 105A and device control unit 106A may be realized by one processor, or may be separately realized by two or more processors.

In addition, the processing unit 104A may include a counter that counts the number of times SYNC0 is generated and a timer such as an RTC that measures time.

[Processing procedure]
FIG. 12 is a flow chart showing the processing procedure of the base station 10A according to the second embodiment.

First, the device control unit 106A acquires the device list information 108 (S101).

Next, the calculation unit 105A wirelessly communicates with the child device based on the timing signal received via the wired interface 101 and indicating the timing at which each of the plurality of base stations starts wireless communication. A period is calculated (S102a). In the present embodiment, calculation section 105A includes a period for performing command transmission processing (first wireless communication period) and a period for performing request signal transmission processing and response data reception processing (second wireless communication period). ) and individually, and a standby period during which wireless communication with the child device 20A is not performed between the command transmission process and the request signal transmission process.

Next, the device control unit 106A determines whether or not a command to the child device 20A has been received via the wired interface 101 (S103).

When the device control unit 106A determines that the command for the child device 20A has not been received (No in S103), the process returns to step S103.

On the other hand, when the device control unit 106A determines that the command for the child device 20A has been received (Yes in S103), the device control unit 106A temporarily stores the received command in the storage unit 107 (S104).

Next, the device control unit 106A determines whether or not the current timing (current time) is within the period calculated by the calculation unit 105A (S105). More specifically, device control section 106A determines whether or not the current time is in the first wireless communication period during which command transmission processing is performed.

If the device control unit 106A determines that the current timing is not within the calculated period (No in S105), the process returns to step S105.

On the other hand, when the device control unit 106A determines that the current timing is within the calculated period (Yes in S105), it transmits a command to the child device 20A via the wireless interface 109 (S106).

Next, device control section 106A determines whether or not an ACK signal has been received from child device 20A via wireless interface 109 (S201).

When the device control unit 106A determines that the ACK signal has not been received from the child device 20A via the wireless interface 109 (No in S201), the process returns to step S201.

On the other hand, when the device control section 106A determines that the ACK signal has been received from the slave device 20A via the wireless interface 109 (Yes in S201), it determines whether or not it is time to transmit the request signal (S202). Specifically, the device control unit 106A determines whether or not the current time is the second wireless communication period during which the request signal transmission process is performed.

When the device control unit 106A determines that it is not time to transmit the request signal (No in S202), the process returns to step S202.

On the other hand, when device control section 106A determines that it is time to transmit a request signal (Yes in S202), device control section 106A transmits a request signal requesting response data to the command transmitted in step S106 to child device 20A via wireless interface 109. within the period (S107).

Next, device control section 106A determines whether response data has been received from child device 20A via wireless interface 109 (S108).

When the device control unit 106A determines that the response data has not been received from the slave device 20A via the wireless interface 109 (No in S108), the process returns to step S108.

On the other hand, when the device control unit 106A determines that the response data has been received from the child device 20A via the wireless interface 109 (Yes in S108), the device control unit 106A writes the received response data into an EtherCAT frame and transmits the received response data via the wired interface 101. Send to network N (S109).

[Effects, etc.]
As described above, the base station 10A according to Embodiment 2 is one base station in the communication system 1A in which a plurality of base stations communicate via the wired network N of the ring system. The base station 10A has a wired interface 101 connected to the wired network N, a wireless interface 109 for wireless communication with a device to be controlled (for example, the child device 20A), and a timing signal received via the wired interface 101. A calculation unit 105A for calculating a period of wireless communication with a controlled device based on a timing signal indicating the timing at which each of a plurality of base stations starts wireless communication; a device control unit 106A that wirelessly communicates with the controlled device via the wireless interface 109 based on the command to the controlled device within the period calculated by the calculation unit 105A when the command is received via the wireless interface 109; The calculation unit 105A sets a period for individually executing (a) a process of transmitting a command to the controlled device to the controlled device, and (b) a process of transmitting a request signal and a process of receiving response data. and a waiting period during which wireless communication with the controlled device is not performed between the processing of transmitting a command to the controlled device and the processing of transmitting a request signal to the controlled device.

According to this, the base station 10A appropriately calculates the waiting period, so that even when the controlled device takes a long time to generate the response data, the other base station occupies the period to perform wireless communication. can be used as a period for

Further, the communication system 1A according to Embodiment 2 includes a plurality of base stations, and the plurality of base stations are groups of different base stations that wirelessly communicate with a device to be controlled (slave device) using the same channel. The device control units 106A provided in the plurality of base stations are classified in advance into one of a plurality of groups so as to belong to the group, and the device control units 106A provided in the plurality of base stations each perform wireless communication with the controlled device during the same period for each group. performing a process of transmitting a command for a device to the controlled device, a process of transmitting a request signal for requesting response data from the controlled device in response to the command to the controlled device, and a process of receiving the response data; The calculation unit 105A provided in the base station separates (a) transmission processing of a command to the controlled device to the controlled device, and (b) transmission processing of the request signal and reception processing of the response data. and a waiting period in which wireless communication with the controlled device is not performed between the transmission of the command to the controlled device and the transmission of the request signal to the controlled device. Calculated based on numbers.

According to this, each of the plurality of base stations provided in the communication system 1A appropriately calculates the standby period, so that the controlled device with which the plurality of base stations wirelessly communicate takes a long time to generate response data. You can also use that time to send or receive another group.

(Other embodiments)
Although the base station, the control system, and the base station control method of the present invention have been described above based on the respective embodiments, the present invention is not limited to the above-described respective embodiments. As long as it does not deviate from the spirit of the present invention, the present embodiment includes various modifications that a person skilled in the art can think of, and the form constructed by combining the components of different embodiments is also included in the scope of the present invention. .

For example, in each of the above embodiments, all or part of the components of the processing units 104 and 104A may be configured with dedicated hardware, or may be configured by executing a software program suitable for each component. may be implemented. The processing units 104 and 104A are realized by a program execution unit such as a CPU (Central Processing Unit) or a processor reading and executing a software program recorded in a recording medium such as a HDD (Hard Disk Drive) or a semiconductor memory. may

Also, the constituent elements of the processing units 104 and 104A may be composed of one or more electronic circuits. Each of the one or more electronic circuits may be a general-purpose circuit or a dedicated circuit.

One or more electronic circuits may include, for example, a semiconductor device, an IC (Integrated Circuit), or an LSI (Large Scale Integration). An IC or LSI may be integrated on one chip or may be integrated on a plurality of chips. Although they are called ICs or LSIs here, they may be called system LSIs, VLSIs (Very Large Scale Integration), or ULSIs (Ultra Large Scale Integration) depending on the degree of integration. An FPGA (Field Programmable Gate Array) that is programmed after the LSI is manufactured can also be used for the same purpose.

Also, general or specific aspects of the invention may be implemented in a system, apparatus, method, integrated circuit or computer program product. Alternatively, it may be realized by a computer-readable non-temporary recording medium such as an optical disk, HDD, or semiconductor memory storing the computer program. Also, any combination of systems, devices, methods, integrated circuits, computer programs and recording media may be implemented.

In addition, it can be realized by applying various modifications to each embodiment that a person skilled in the art can think of, or by arbitrarily combining the constituent elements and functions of each embodiment without departing from the spirit of the present invention. Forms are also included in the present invention.

INDUSTRIAL APPLICABILITY The present invention can be applied to a base station or the like that constitutes a control communication network for industrial equipment and wirelessly communicates with controlled equipment.

1, 1A communication system 10, 10A, 10B, 10C, 10D, 11, 12, 13, 14, 15, 16, 17 base station 20, 20A, 20B, 20C, 20D, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35 cordless handset 40 radio frame 41 PLCP preamble 42 PLCP header 43 IEEE802.11 header 44, 56D, 57D data 45 FCS
50 Ethernet Header 51 IP Header 52 UDP Header 53 EtherCAT Header 54 EtherCAT Datagram 56, 57 Datagram 56A, 57A Command 56B, 57B Equipment ID
M Master N Wired network

Claims (9)

One base station in a communication system in which a plurality of base stations communicate via a ring wired network,
a wired interface connected to the wired network;
a wireless interface for wirelessly communicating with a controlled device;
calculating a period of wireless communication with the controlled device based on the timing signal received via the wired interface, the timing signal indicating the timing at which each of the plurality of base stations starts wireless communication; Department and
When the command for the controlled device is received via the wired interface, the controlled device via the wireless interface based on the command for the controlled device within the period calculated by the calculation unit and a device control unit that communicates wirelessly ,
the plurality of base stations are classified in advance into one of a plurality of groups such that the base stations that wirelessly communicate with the controlled device using the same channel belong to different groups;
The calculation unit calculates the period based on the timing signal and the number of the plurality of groups.
base station. The equipment control unit
determining whether or not the current time is within the period calculated by the calculating unit when a command for the controlled device is received via the wired interface;
when determining that the current time is within the period calculated by the calculation unit, starting wireless communication with the controlled device;
2. When it is determined that the current time is not within the period calculated by the calculation unit, the wireless communication with the controlled device is started after waiting until the current time is within the period. Listed base station. The equipment control unit
connected to the plurality of controlled devices via the wireless interface so as to be capable of wireless communication;
when commands for two or more of the plurality of controlled devices are simultaneously received via the wired interface;
3. The apparatus according to claim 1 or 2, wherein wireless communication is performed with each of the two or more controlled devices at different timings within the period based on commands for the two or more controlled devices. base station. The base station according to any one of claims 1 to 3, wherein the timing signal is a synchronization signal for synchronizing the plurality of base stations. In wireless communication with the controlled device, the device control unit transmits a command to the controlled device to the controlled device, and transmits response data corresponding to the command to the controlled device from the controlled device. The base station according to any one of claims 1 to 4, which performs transmission processing of a request signal to make a request and reception processing of said response data. The calculation unit
(a) a process of transmitting a command for the controlled device to the controlled device;
(b) transmission processing of the request signal and reception processing of the response data;
and a waiting period during which wireless communication with the controlled device is not performed between the process of transmitting a command to the controlled device to the controlled device and the process of transmitting the request signal to the controlled device 6. The base station of claim 5, wherein: A plurality of base stations according to any one of claims 1 to 6,
Each of the plurality of base stations,
wirelessly communicating with each of the one or more controlled devices using the same channel ;
calculating a period of wireless communication with one or more of the controlled devices based on the timing signal and the number of the plurality of groups;
when commands for two or more of the plurality of controlled devices are simultaneously received via the wired interface;
A communication system that wirelessly communicates with each of the two or more controlled devices at different timings within the period based on commands for the two or more controlled devices. A plurality of base stations according to any one of claims 1 to 6 ,
each of the device control units provided in the plurality of base stations transmits a command for the controlled device to the controlled device in wireless communication with the controlled device during the same period for each group; , performing a process of transmitting a request signal for requesting response data from the controlled device in response to a command to the controlled device, and a process of receiving the response data;
The calculation units provided in the plurality of base stations,
(a) a process of transmitting a command for the controlled device to the controlled device;
(b) transmission processing of the request signal and reception processing of the response data;
and a waiting period during which wireless communication with the controlled device is not performed between the process of transmitting a command to the controlled device to the controlled device and the process of transmitting the request signal to the controlled device , based on the timing signal and the number of the plurality of groups. A control method for one base station in a communication system in which a plurality of base stations communicate via a ring wired network, comprising:
The base station
a wired interface connected to the wired network;
a wireless interface for wirelessly communicating with the controlled device,
The method for controlling the base station includes:
calculating a period of wireless communication with the controlled device based on the timing signal received via the wired interface, the timing signal indicating the timing at which each of the plurality of base stations starts wireless communication; a step;
when a command for the controlled device is received via the wired interface, the controlled device via the wireless interface based on the command for the controlled device within the period calculated in the calculating step; a wireless communication step of communicating wirelessly ;
the plurality of base stations are classified in advance into one of a plurality of groups such that the base stations that wirelessly communicate with the controlled device using the same channel belong to different groups;
In the calculating step, the period is calculated based on the timing signal and the number of the plurality of groups.
Base station control method.

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