JP4019946B2 - Network system monitoring method, monitoring system, repeater and monitoring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a monitoring method and monitoring system for a network system, and a repeater and a monitoring device.
[0002]
[Prior art]
PLC (programmable controller) used in FA (factory automation) inputs ON / OFF information of input devices such as switches and sensors, and performs logical operations according to a sequence program (user program) written in a ladder language. Execute. Then, the PLC performs control by outputting a signal of ON / OFF information to an output device such as a relay, a valve, or an actuator according to the obtained calculation result.
[0003]
As one form of such a PLC, there is one in which a plurality of units generated for each function are prepared and electrically and mechanically connected. As a unit for constituting such a type, there are various types such as a power supply unit, a CPU unit, an I / O unit, and a master unit.
[0004]
The master unit described above is connected to a control system network, and can communicate with various slaves connected to the control system network via the control system network. An example of this type of slave is a remote IO. In other words, the input device and output device described above may be connected to the I / O unit constituting the PLC, but if all the input / output devices are directly connected to the I / O unit, these input / output devices are connected. There are as many wirings connecting the I / O units to the I / O units, and a large number of such wirings are routed in the factory starting from the PLC (I / O unit), which is not preferable. .
[0005]
Therefore, a remote IO serving as a terminal block for connecting an input / output device near the control target is installed, and various input / output devices are connected to the remote IO. Then, each remote IO is connected to the network cable connected to the PLC (master unit). Then, I / O data is transmitted / received between each remote IO and PLC through master-slave communication, and information is transmitted to the actual input / output devices via the remote IO. Yes.
[0006]
By the way, as a device for monitoring the configuration of a network system including slaves such as remote IOs connected via a network as described above, for example, in DeviceNet (registered trademark) which is one form of a control network, the network is connected to the network. A function is provided that monitors the node number and model of the master and slave using software on the personal computer. An example of a monitor screen displayed by this monitoring function is as shown in FIG. As shown in this figure, the slaves are arranged in the order of node addresses, for example, # 00, # 01, # 02,.
[0007]
As a display device for displaying the configuration of a network system to which a plurality of PLCs are connected, for example, there is a “communication data display device and method, storage medium” disclosed in Patent Document 1. Also in this patent document 1, as shown in FIG. 6 of the publication, the PLCs constituting the network are displayed in a state of being arranged in the order of the node addresses.
[0008]
Further, although not an FA network, a device that creates a network configuration diagram in consideration of the connection relationship of network devices such as computers and printers connected to the network and displays the network configuration diagram on a monitor is disclosed in “Patent Document 2”. Network configuration diagram display method and system ". In this patent document 2, a network relay device having a plurality of connection ports is arranged at a predetermined position on a network, and each network device is connected to the network via the network relay device. The network relay device has information about a device connected to itself such as a so-called “hub”. Therefore, the management computer uses the network relay device to collect the connection status of the network devices, and when displaying the objects of the network relay device and the network device on the display screen, the management computer displays predetermined objects according to the collected connection status. By connecting, a network configuration diagram is created.
[0009]
[Patent Document 1]
JP 11-154004 A
[Patent Document 2]
JP 2001-308873 A
[0010]
[Problems to be solved by the invention]
In the FA system, a device called a repeater is mounted on a network, and a master unit and a slave may send and receive data via the repeater. In other words, when the communication line constituting the network becomes longer, the signal level becomes lower and noise is more likely to ride, so that the waveform is disturbed. Therefore, there is a problem that accurate information cannot be transmitted. In order to solve the problem, a repeater called a repeater that performs waveform shaping is provided at an appropriate position so that the disturbed waveform is corrected to a clean pulse waveform of 1/0 and the transmission distance is increased. ing. In addition to increasing the transmission distance in this way, for example, connecting multiple slaves under the repeater when managing multiple slaves that control the same device as one group There is also. This repeater has a function of shaping a signal input from one side and outputting the waveform to the other, but does not have a function of a relay device such as the hub described in Patent Document 2.
[0011]
Therefore, for example, slaves # 0, # 3, # 7, and # 21 are connected to the repeater A, and slaves with different numbers are connected to the repeater B, such as slaves # 2, # 8, # 9, and # 31. When the network configuration is monitored for the network system using the invention disclosed in Patent Document 1, the slaves are arranged in the order of the node addresses, and the association between the slave and the repeater cannot be monitored. For this reason, when the number of nodes is large, there is a problem that it is not possible to grasp which device the slave is used by looking at the configuration displayed on the personal computer.
[0012]
On the other hand, aside from whether the invention disclosed in Patent Document 2 can be applied to an FA system as it is, a relay device such as a hub is provided instead of a conventional repeater, and information on slaves connected to the downstream side of the relay device is provided. A specific network configuration can be known by storing and holding and collecting information of slaves held by the relay device. However, adopting such a configuration causes information related to the relay device to be held only for monitoring, and thus the relay device is expensive and impractical.
[0013]
According to the present invention, in a network system including a repeater, it is easy to determine which repeater the slave connected to the downstream side of the repeater is located downstream without holding the slave information connected to the downstream side in the repeater itself. It is an object of the present invention to provide a network system monitoring method, monitoring system, repeater, and monitoring device that can be recognized.
[0014]
[Means for Solving the Problems]
A monitoring method of a network system according to the present invention is a monitoring method in a network system including a configuration in which at least one repeater is interposed between a master and a slave, and the master issues a status read command to the slave The slave that has received the status read command returns a response to the master, and the repeater adds specific information identifying itself to the response when relaying the response, and the response The device that has obtained the information recognizes the connection relationship between the slave and the repeater from the presence / absence of the specific information stored in the response and the content thereof, and monitors the network configuration information.
[0015]
The monitoring system according to the present invention is a monitoring system in a network system including a configuration in which at least one repeater is interposed between a master and a slave, and the master issues a status read command to the slave. The slave has a function of returning a response to the master when receiving the status read command addressed to itself, and the repeater self-replies to the response when relaying the response. The device having the function of adding specific information for identifying the response recognizes the connection relationship between the slave and the repeater from the presence and content of the specific information stored in the response, and Configured with a function to output configuration information to output means It was. And the said master comprises a programmable controller, for example, The said apparatus can be used as the monitor apparatus connected to the said programmable controller. Of course, the device may be a programmable controller such as a master.
[0016]
Furthermore, the repeater of the present invention is a repeater that is mounted between a master and a slave constituting a network system, relays data transmitted between the master and the slave, and receives a status read command issued from the master. When the received slave relays a response sent back to the master, the slave has a function of adding specific information identifying itself to the response.
[0017]
Furthermore, the monitoring apparatus of the present invention includes a configuration in which at least one repeater is interposed between the master and the slave, and the slave that has received the status read command issued from the master is configured such that the slave receives the status read command. This is a monitor device that monitors configuration information of a network system provided with a function of adding identification information that identifies itself to a response when relaying a response sent back toward. Then, it obtains the response returned by the slave, analyzes the contents, and the presence / absence of the specific information stored in the response indicates whether the slave is connected under a predetermined repeater. A function of recognizing the connection relationship between the slave and the repeater by determining under which repeater the slave is connected from the content of the specific information, and obtaining based on the recognized connection relationship A function to output the configuration information of the network to the output means is provided.
[0018]
The output means is a display device in the embodiment, and such a configuration is preferable. However, the present invention is not necessarily limited to the display device, and may be a printing device, a storage device, a communication device, or the like. It can be realized by various things.
[0019]
In the embodiment, the specific information is the node address of the repeater. However, the present invention is not limited to this, and various information such as a manufacturing number or other ID number provided in the repeater or a logical name may be used. it can.
[0020]
The slave connected under the repeater always passes through the repeater before the response returned by the slave reaches the master. Therefore, specific information for identifying the repeater is added to the response. Conversely, if there is a slave that communicates directly with the master without going through the repeater, the specific information is not added to the response.
[0021]
Therefore, it can be determined whether or not the slave passes through the repeater based on the presence or absence of the specific information. Further, when specific information is included, it is possible to know which repeater the slave is connected to by recognizing the content of the specific information. Therefore, it is possible to know the connection relationship between the slave and the repeater. Furthermore, even when the number of nodes is large, the target slave can be easily found by grouping by inserting repeaters at appropriate positions.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 2 shows an example of a network system including a repeater to which the present invention is applied. As shown in FIG. 2, the PLC 10, various slaves 20, and the repeater 30 are connected via a field bus 40 to construct a network system. The slave 20 includes a remote IO and other devices. The slave 20 may be directly connected to the field bus 40 connected to the PLC 10, or may be connected to the field bus 40 a connected to the repeater 30 and communicate with the PLC 10 via the repeater 30. . A termination resistor 41 is connected to the ends of the field bus 40 and the field bus 40a.
[0023]
The repeater 30 is also given a node address and is a kind of slave in a broad sense. However, the slave 20 in the present embodiment means a device having a function for controlling the FA system. It is separated from the repeater 30 that relays data transmitted through the bus 40 and the like. Further, in the example shown in FIG. 2, only the slave 20 is connected to the downstream side of the repeater 30. However, another repeater is arranged on the downstream side of the repeater 30. Of course, there may be a form in which a plurality of repeaters 30 exist between the PLC 10.
[0024]
Furthermore, a personal computer 42 as a monitor / setting tool is connected to the PLC 10 to collect and monitor information on each device connected to the network via the PLC 10 and to download a program to the PLC 10 or the slave 20. And data settings can be performed.
[0025]
The PLC 10 is configured by connecting units generated for each function, and includes, for example, a CPU unit 11 and a master unit 12. The master unit 12 is connected to the field bus 40 and communicates with each slave 20 and repeater 30. Further, the IO memory of the CPU unit 11 is accessed via the internal bus of the PLC 10 to read / write IO data and the like.
[0026]
A personal computer 42 as a monitor device connected to the PLC 10 is connected to the CPU unit 11 in the illustrated example. However, the present invention is not limited to this, and it can be connected via a network. Further, it can be connected to the master unit 12 or connected to a special function unit provided on the field bus 40. it can.
[0027]
As shown in FIG. 3, the master unit 12 is connected to a field bus, and performs communication between the master and slave via the communication interface 12a that actually transmits and receives data, and the slave 20 and the repeater 30. ASIC 12b for master to send and receive I / O data to and receive predetermined commands and receive responses based on them, MPU 12d to perform various controls, and used as work area when performing various controls RAM 12c, an EEPROM 12e storing a program for performing the above control, various setting data, and the like, an interface 12h for communicating with other units (for example, a CPU unit), an operation state (communication state), LED display 12f indicating abnormality / normality and address And a setting switch 12g for performing such as a constant.
[0028]
As the control performed by the MPU 12d, the CPU unit 11 communicates with other units or operates the master ASIC 12b. Particularly in relation to the present invention, a status read request is received from the personal computer 42 received via the CPU unit 11, a status read command is sent to the slave 20 connected to the network, and a response from the slave 20 is received. When received, it has a function of analyzing it and returning it to the personal computer 42 via the CPU unit 11. At this time, since the commands handled by the CPU unit 11 and the personal computer 42 are different from the commands handled by the repeater 30 and the slave 20, conversion processing is appropriately performed by the master unit 12. The basic hardware configuration and the like are the same as those of the conventional master unit, and thus detailed description thereof is omitted.
[0029]
As shown in FIG. 4, the slave 20 is connected to the field bus, and actually transmits / receives I / O data and various messages to / from the master unit 12 via the communication interface 20a. The slave ASIC 20b that performs communication between the acquired master and slave and transmits / receives I / O data, receives a predetermined command and transmits a response based thereon, MPU 20d that performs various controls, and performs the above control EEPROM 20e that stores programs, various setting data, IO data, etc., I / O unit 20j that connects to I / O devices and transmits / receives I / O data, and operating status (communication status) and abnormal / normal And a setting switch 20g for setting a node address and the like. That. Furthermore, a power supply unit 20 i that steps down the input voltage (24 V) to 5 V and supplies power to each element in the slave 20 is provided.
[0030]
In relation to the present invention, the slave 20 has a function of analyzing the status read command sent from the master unit 12 and issuing a response and returning it to the master unit 12 when addressed to itself. Therefore, when the master unit 12 and the personal computer 42 issue a status read command addressed to a certain node address, if there is a response, there is a slave at that node address, and if there is no response, there is no slave at that node address. The node address of the slave 20 connected to the network can be known. Note that the configuration and operational effects of the slave 20 are the same as those of the conventional one, and thus detailed description thereof is omitted.
[0031]
As shown in FIG. 5, the repeater 30 is mounted between the communication interfaces 31 and 32 respectively connected to the master side and the slave side, and between the communication interfaces 31 and 32, and a predetermined amount of data (signal) is transmitted. A repeater ASIC 33 for processing is provided. Furthermore, a power supply unit 34 is provided that steps down the input voltage (24 V) to 5 V and supplies power to each element in the repeater 30. Furthermore, an LED display unit 35 indicating an operation state (communication state), abnormality / normality, and a setting switch 36 for setting a node address and the like are provided.
[0032]
Further, the repeater ASIC 33 basically has a function of adjusting the waveform of a transmitted signal (disturbed), restoring it to a clean 1/0 digital signal, and outputting it. Since this function is a basic function of a conventional repeater, description of a specific configuration / processing procedure is omitted.
[0033]
In the present invention, as a function of the repeater ASIC 33, when data is received from the master-side communication interface 31, the above-described waveform shaping is performed and passed to the slave-side communication interface 32. When the data (response) is received from the slave side communication interface 32, the above-described waveform shaping is performed, and the node address is added to the response, and then passed to the master side communication interface 31. . Furthermore, when passing through a plurality of repeaters 30, the node addresses of the repeaters 30 are added (for example, always added to the back) in the order of passing.
[0034]
Thereby, in the case of the slave 20 that directly transmits and receives data with the master unit 12 without the repeater 30, the response issued to the status read command reaches the master unit 12 without passing through the repeater 30. The node address of the repeater 30 is not given to the response. On the other hand, when the response issued from the slave 20 on the downstream side of at least one repeater 30 passes through the repeater 30, the node address of the repeater 30 is added. Therefore, the master unit 12 and the personal computer 42 identify whether the slave 20 is directly connected to the field bus 40 connected to the master unit 12 based on whether or not the acquired response includes the node address of the repeater 30. Furthermore, when connected under the repeater 30, it is possible to recognize the network configuration such as which repeater 30 is connected from the node address.
[0035]
In order to monitor the network configuration, the personal computer 42 as a monitor device acquires the connection status of each device (slave 20 and repeater 30) configuring the network via the PLC 10 and displays the connection status on the display device 42a. That is, the personal computer 42 is connected to the CPU unit 11 and communicates with the CPU unit 11. Therefore, the personal computer 42 can know the network configuration based on the obtained response by making a status read request sequentially from the node having the node address # 0, for example.
[0036]
Specifically, the entire network system performs monitoring by performing communication according to the flowchart shown in FIG. The data flow (timing chart) between the devices at that time is as shown in FIG. That is, first, the personal computer 42 requests a status read from the next node (ST1). In other words, in the case of a network system in which node addresses are assigned from # 0 to #N, a status read request is first made to the node of # 0 and a response is received or when a timeout occurs, Request a status read. Thereafter, the process is repeatedly executed in order up to #N while increasing the node address values one by one. Such processing is performed in step (1) in FIG.
[0037]
Next, the status read request issued from the personal computer 42 is output to the field bus 40 via the CPU unit 11 and the master unit 12, and is received by the slave 20 directly or via the predetermined repeater 30 (ST2). Such processing is performed in steps (2) to (5) in FIG. Note that the example shown in FIG. 7 shows a standard one, and when the repeater 30 does not exist up to the slave 20, the step (4) is of course omitted and there are a plurality of repeaters. In this case, the process (4) is executed a plurality of times.
[0038]
Then, when the slave 20 having the desired node address designated in the process (1) receives the status read command and confirms that the command is addressed to itself, it returns its own status information (issues a response) (ST3). . Such processing is performed in step (5) in FIG.
[0039]
This response is transmitted over the network. If the repeater 30 is routed (Yes in ST4), the repeater 30 adds its own address to the response (ST5). Therefore, when the repeater 30 does not exist with the master unit 12 (No in ST4), it is received as it is by the master unit 12, so that the received response is given to the personal computer 42 via the CPU unit 11. (ST6).
[0040]
Accordingly, the personal computer 42 analyzes the acquired response, and recognizes whether or not the node address of the repeater 30 is incorporated in the response, and if it is incorporated, recognizes the specific number, thereby repeating the repeater 30. It is possible to recognize whether the slave 20 that issued the response is connected to which repeater, etc. The node address is also assigned to the repeater 30, and the personal computer 42 knows which node address repeater 30 exists on the network by making a status read request to each repeater 30. Can do.
[0041]
The series of processes described above are performed in steps (6) to (9) in FIG. In addition, the example shown in FIG. 7 shows a standard one, and when the repeater 30 does not exist up to the master unit 12, the step (6) is of course omitted, and there are a plurality of repeaters. If so, the process (6) is executed a plurality of times.
[0042]
6 and 7 show standard ones on the assumption that the target slave exists, but usually there are almost no slaves at all the node addresses, and the numbers become empty numbers. Some node addresses are In that case, since no response is naturally returned, in the example of FIG. 7, the process ends with a time-out until the step (3) or (4). In this case, since there is no response in step 6 in FIG. 6, it is recognized that there is no slave of the node address on the network, and the process returns to step 1 to inspect the next node.
[0043]
As a specific example, as shown in FIG. 8, when the status read command (EVE_frame) is transmitted from the master to the slave # 30, the slave # 30 that has received the command immediately returns a response frame (▲ 1 ▼). Then, while EVE_frame is repeated for the master, repeater # 5 writes its own node address in the response. Accordingly, since the data changes, the CRC (sum check) is recalculated, and the response (of course, waveform shaping) updated to the recalculated CRC is output to the master unit ((2)).
[0044]
Similarly, since this updated response (including: node address of repeater # 5) is taken into repeater # 15, the same processing as repeater # 5 described above is performed here, and the node address of repeater # 5 Is added to the node address of the repeater # 15 (the CRC is also updated), and is output to the master unit 12 ((3)).
[0045]
Therefore, in the master unit 12 (personal computer 42) that has received such a response, the repeaters # 5 and # 15 are written in the data area of EVE_frame. It can be recognized that the connection is made in the order of # 5 → slave.
[0046]
The status data in the response to the above-described status read request can store the addresses of three repeaters in order as shown in FIG. 9, for example. Each repeater adds its own address to a predetermined storage area for status information. Specifically, when the address information of the repeater is not stored in the acquired response, the self address is stored in the storage area of the address information of the first repeater. When the node address of another repeater is already stored in the storage area of the address information of the first repeater and the node address is not stored in the storage area of the node address information of the second repeater, the second repeater concerned Own node address is stored in the node address. Similarly, when the node address of another repeater is already stored in the address information area of the first and second repeaters and the node address is not stored in the storage area of the node address information of the third repeater, 3 The node address of the second repeater is stored in its own node address. Whether or not the node address is stored in the storage area of each node address information can be easily determined by providing, for example, a flag indicating whether or not the node address has been stored or a flag indicating an area to be stored next. Of course, the addition form of the node address is not limited to the illustrated one, and various types can be applied.
[0047]
Then, by repeatedly executing the above processing for each slave, for example, a network configuration diagram as shown in FIG. 10 can be created and displayed on the monitor screen of the display device 42a. As can be seen from FIG. 10, since it can be seen under which repeater the slave is located on the network, a configuration diagram close to the actual network wiring can be displayed on the personal computer 42.
[0048]
【The invention's effect】
As described above, according to the present invention, in a network system including a repeater, it is possible to easily recognize which repeater the slave connected to the downstream side of the repeater is located downstream. In addition, since the repeater itself can perform the processing without holding the slave information connected to the downstream side, the configuration of the repeater can be made simple and inexpensive.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of a conventional monitor screen.
FIG. 2 is a diagram showing an example of a network system configuration showing an embodiment of the present invention.
FIG. 3 is a diagram illustrating an example of an internal configuration of a master unit.
FIG. 4 is a diagram illustrating an example of an internal configuration of a slave.
FIG. 5 is a diagram showing an example of an internal configuration of a repeater.
FIG. 6 is a flowchart for explaining the operation of the entire network system for carrying out the monitoring method.
FIG. 7 is a time chart for explaining the operation of the entire network system for carrying out the monitoring method.
FIG. 8 is a diagram illustrating the function of a repeater.
FIG. 9 is a diagram illustrating information related to a node address of a repeater in a response data structure.
FIG. 10 is a diagram illustrating an example of a monitor screen displayed by performing the monitoring method of the present invention.
[Explanation of symbols]
10 PLC
11 CPU unit
12 Master unit
12a Communication interface
12b Master ASIC
12c RAM
12d MPU
12e EEPROM
12f LED display
12g setting switch
12h interface
20 slaves
20a Communication interface
20b Slave ASIC
20d MPU
20e EEPROM
20f LED display
20g setting switch
20h interface
20i power supply
20j I / O part
30 repeaters
31, 32 Communication interface
33 ASIC for repeaters
34 Power supply
35 LED display
36 Setting switch
40 Fieldbus
40a Fieldbus
41 Terminal resistance
42 PC
42a display device

Claims (5)

A monitoring method in a network system including a configuration in which at least one repeater is interposed between a master and a slave,
The master issues a status read command to the slave,
The slave that has received the status read command returns a response to the master,
When the repeater relays the response, it adds specific information identifying itself to the response,
The apparatus that has acquired the response recognizes the connection relationship between the slave and the repeater from the presence / absence of the specific information stored in the response and the content thereof, and monitors network configuration information. How to monitor. A monitoring system in a network system including a configuration in which at least one repeater is interposed between a master and a slave,
The master has a function of issuing a status read command toward the slave,
When the slave receives the status read command addressed to itself, it has a function of returning a response toward the master,
The repeater has a function of adding specific information identifying itself to the response when relaying the response,
The device that has acquired the response has a function of recognizing the connection relationship between the slave and the repeater from the presence and content of the specific information stored in the response and outputting the network configuration information to an output unit. Monitoring system. The master constitutes a programmable controller,
The monitoring system according to claim 2, wherein the device is a monitor device connected to the program controller. A repeater that is implemented between a master and a slave constituting a network system and relays data transmitted between the master and the slave,
The slave having received the status read command issued from the master has a function of adding specific information identifying itself to the response when relaying the response returned to the master. A repeater featuring. Including a configuration in which at least one repeater is interposed between the master and the slave, and the repeater relays a response that the slave that has received the status read command issued from the master returns to the master In addition, for the response, a monitoring device that monitors configuration information of the network system having a function of adding specific information for identifying itself,
A function for acquiring the response returned by the slave and analyzing its contents;
From the presence or absence of the specific information stored in the response, it is determined whether or not the slave is connected under a predetermined repeater, and the repeater is connected under which repeater from the content of the specific information A function of recognizing the connection relationship between the slave and the repeater by determining whether or not
A monitor device comprising a function of outputting network configuration information obtained based on the recognized connection relationship to an output means.

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