JP7581982B2 - MOTOR CONTROL DEVICE AND METHOD FOR ADJUSTING COMMUNICATION ENVIRONMENT IN MOTOR CONTROL DEVICE - Google Patents

Description

The present invention relates to a motor control device and a method for adjusting the communication environment in the motor control device.

In industrial systems such as servo systems, various ideas have been proposed for setting operating conditions between devices. For example, Patent Literature 1 discloses a technique for changing the communication method of a communication processing device in response to a command from a host device. In this technique, the host device transmits a Field Programmable Gate Array (FPGA) for communication protocol processing to be updated to the communication processing device.
The communication processing device transmits FPGA circuit data to the FPGA circuitry, and upon receiving the data, reconfigures the FPGA circuitry, enabling flexible configuration of the communication environment.

For example, Patent Document 2 discloses a technology for easily changing the communication method for communicating with an encoder in a motor control device. In this technology, a feedback signal acquisition unit in a servo driver includes a reconfigurable device, and when communication method information is received from the outside, the reconfigurable device is reconfigured according to the communication method information, thereby making it possible to change the communication method for communicating with the encoder.

JP 2017-69777 A JP 2019-161855 A

In a servo system in which a motor control device performs servo control of a motor according to commands from a higher-level device, it is preferable for the servo system to have a safety function that controls the system to the safe side in the event of a failure in the system, in order to more appropriately ensure safety for workers. For this reason, a safety encoder may be used that enhances the safety function of the encoder that detects the displacement of the motor's output shaft. A safety encoder has multiple detection units that detect the displacement of the motor's output shaft, and in order for the safety encoder and the motor control device to communicate with each other and realize servo control and safety control of the motor, the motor control device needs to have communication protocol information corresponding to the detection signal of the safety encoder and to appropriately understand the detection signal from the safety encoder according to the communication protocol information.

When using a safety encoder like the one described above, there is a risk that the safety control of the motor may be hindered if the communication environment with the safety encoder is changed without permission, so the combination of a motor with a safety encoder and a motor control device is generally fixed. Therefore, it was not possible to reconnect a motor with a safety encoder with a different communication protocol to the motor control device while leaving the motor control device as it was. In such a case, it was necessary to prepare a separate motor control device that was compatible with the communication protocol of the new safety encoder, resulting in increased costs.

The present invention was made in consideration of these problems, and aims to provide technology that enables changing to a safety encoder with a different communication protocol without the need to replace the motor control device.

A motor control device according to one aspect of the present invention is a motor control device that servo-controls a motor, and includes a receiving unit that receives a detection signal from a safety encoder having a plurality of detectors that detect the displacement of the output shaft of the motor, the receiving unit being configured to be changeable according to communication protocol information for realizing communication between the safety encoder and the motor control device, an acquiring unit that acquires first communication protocol information corresponding to the changed first safety encoder when the safety encoder connected to the motor control device is changed, and a processing unit that adapts the receiving unit to a configuration corresponding to the first safety encoder according to the first communication protocol information after a predetermined confirmation process that confirms the suitability of the combination of the acquired first communication protocol information and the first safety encoder.

In the motor control device, the receiving unit that receives the detection signal from the safety encoder is configured to be changeable in accordance with the communication protocol information. For example, the receiving unit is a programmable logic device (PLD) whose circuit configuration for receiving the detection signal is changeable (the circuit configuration is rewritable).
Examples of PLDs include field programmable gate arrays (FPGAs), and dynamically reconfigurable processors (DRPs) may also be used.

Here, if the safety encoder connected to the motor control device is changed to the first safety encoder and its communication protocol is also changed, even if the first safety encoder is connected to the motor control device as it is, communication cannot be established between the first safety encoder and the motor control device due to the different types of communication protocols, and servo control and safety control of the motor cannot be realized. Therefore, first, the acquisition unit acquires first communication protocol information, which is information on the communication protocol corresponding to the changed first safety encoder. Then, the processing unit executes a predetermined confirmation process to confirm whether the combination of the first communication protocol information and the first safety encoder is appropriate. The reason why the predetermined confirmation process is executed in this manner is that when safety control of the motor is to be performed using the safety encoder, an inadvertent change in the communication protocol causes a problem in communication between the safety encoder and the motor control device, hindering the execution of safety control, and this must be avoided as much as possible.

For example, the processing unit may request the user to input information on a communication protocol corresponding to the changed safety encoder, and execute the process of comparing the information input by the user with the first communication protocol information acquired by the acquisition unit as the predetermined confirmation process. That is, in addition to the acquisition of the first communication protocol information by the acquisition unit, the processing unit requests the user to input information on a communication protocol corresponding to the changed safety encoder (e.g., the first safety encoder), and compares the input result with the first communication protocol information acquired by the acquisition unit. If no problems arise in the comparison result, this means that a communication protocol appropriate to the user's intention is about to be set, and it is considered that there is little risk of interference with the safety control of the motor.

If there is no problem with the comparison result by the processing unit, the receiving unit is adapted to a configuration corresponding to the first safety encoder in accordance with the first communication protocol information. This results in the configuration of the receiving unit being reconstructed so that communication with the changed first safety encoder is possible. Note that if there is a problem with the comparison result by the processing unit, for example, if there is a difference (deviation) between the user's input result and the first communication protocol information acquired by the acquisition unit, adaptation of the receiving unit configuration in accordance with the first communication protocol information acquired by the acquisition unit is not performed.

In this way, the motor control device described above ensures an optimal safety control environment for the motor using a safety encoder, while making it possible to change to a safety encoder with a different communication protocol without having to replace the motor control device.

Here, a specific form for acquiring the first communication protocol information will be mentioned. In a first form, the device may further include a storage unit that stores one or more pieces of communication protocol information corresponding to one or more safety encoders of a type that the receiving unit can handle. In this case, the acquiring unit may acquire the first communication protocol information from the one or more pieces of communication protocol information stored in the storage unit. In a second form, the device may further include a communication unit that communicatively connects an external device that stores one or more pieces of communication protocol information corresponding to one or more safety encoders of a type that the receiving unit can handle. In this case, the acquiring unit may acquire the first communication protocol information from the one or more pieces of communication protocol information stored in the external device. Note that the acquiring unit may acquire the first communication protocol information in forms other than these.

In the second embodiment, the communication unit may be configured to permit communication between the external device and the motor control device when a predetermined security signal is input from the external device. By adopting such a configuration, it is possible to prevent inadvertent access to the motor control device by an external device, and to ensure an environment for optimal safety control of the motor using a safety encoder.

Here, the motor control device described above may further include a servo control unit that is communicatively connected to the safety encoder via a first communication path and executes servo control of the motor based on the detection signal of the safety encoder obtained via the first communication path, and a safety control unit that is communicatively connected to the safety encoder via a second communication path different from the first communication path and executes safety control regarding the operation of the motor based on the detection signal of the safety encoder obtained via the second communication path. Then, after the processing unit adapts the receiving unit to a configuration corresponding to the first safety encoder according to the first communication protocol information, the safety control unit executes the safety control based on the detection signal of the first safety encoder obtained via the second communication path, and the servo control unit is prohibited from acquiring the detection signal from the first safety encoder via the first communication path, and the safety control unit receives the detection signal obtained via the second communication path from the safety control unit and executes the servo control based on the received detection signal.

Before the safety encoder is changed to the first safety encoder, the servo control of the motor by the servo control unit and the safety control by the safety control unit are executed using the communication protocol of the safety encoder known in advance as a common standard. Therefore, even if the detection signal of the safety encoder is transmitted to the servo control unit and the safety control unit via the first communication path and the second communication path, which are different from each other, the servo control and the safety control are executed in a favorable cooperative state. On the other hand, when the safety encoder is changed to the first safety encoder, the communication environment between the first safety encoder and the motor control device, which is the premise of the servo control by the servo control unit and the safety control by the safety control unit, is changed, and depending on the content of each control, there is a risk of a problem such as a deviation in control timing. Therefore, as described above, after the receiving unit is adapted to a configuration corresponding to the first safety encoder according to the first communication protocol information, the servo control unit receives the detection signal of the first safety encoder via the safety control unit, rather than receiving the detection signal of the first safety encoder via the first communication path. By adopting this configuration, a common detection signal is used between the servo control unit and the safety control unit, and problems such as a deviation in control timing caused by the change of the safety encoder can be suppressed.

Furthermore, in the motor control device described above, when the safety encoder connected to the motor control device is changed to a plurality of safety encoders including the first safety encoder, the acquisition unit may acquire predetermined communication protocol information corresponding to the plurality of safety encoders after the change, and the processing unit may go through the predetermined confirmation process for confirming whether or not a combination of the acquired predetermined communication protocol information and the plurality of safety encoders is appropriate, and may adapt the receiving unit to a configuration corresponding to the plurality of safety encoders in accordance with the predetermined communication protocol information. The present invention can also be applied to the case where a plurality of safety encoders are changed in this way.

Here, the present invention can also be seen as a method for adjusting the communication environment with the safety encoder in a motor control device that servo-controls a motor. In this case, the motor control device includes a receiving unit that receives a detection signal from a safety encoder having a plurality of detectors that detect the displacement of the output shaft of the motor, and is configured to be changeable according to communication protocol information for realizing communication between the safety encoder and the motor control device. The method includes, when the safety encoder connected to the motor control device is changed, a step of acquiring first communication protocol information corresponding to the changed first safety encoder, and a step of adapting the receiving unit to a configuration corresponding to the first safety encoder according to the first communication protocol information after a predetermined confirmation process for confirming the suitability of the combination of the acquired first communication protocol information and the first safety encoder. According to the method, while ensuring an environment for suitable safety control of a motor using a safety encoder, it is possible to change to a safety encoder with a different communication protocol without having to replace the motor control device. Note that the technical ideas disclosed in relation to the above motor control device can also be applied to the method as long as no discrepancy occurs.

In addition, with respect to the above method, the motor control device may further include a servo control unit that is communicatively connected to the safety encoder via a first communication path and that executes servo control of the motor based on the detection signal of the safety encoder obtained via the first communication path, and a safety control unit that is communicatively connected to the safety encoder via a second communication path different from the first communication path and that executes safety control regarding the operation of the motor based on the detection signal of the safety encoder obtained via the second communication path. And, after adapting the receiving unit to a configuration corresponding to the first safety encoder according to the first communication protocol information, the method may further include a step of permitting the safety control unit to execute the safety control based on the detection signal of the first safety encoder obtained via the second communication path, prohibiting the servo control unit from acquiring the detection signal from the first safety encoder via the first communication path, and permitting the safety control unit to receive the detection signal obtained via the second communication path from the safety control unit and execute the servo control based on the received detection signal.

Allows changing to a safety encoder with a different communication protocol without the need to replace the motor control device.

1 is a diagram showing a schematic configuration of a servo system incorporating a servo driver which is a motor control device of the present invention; FIG. 2 is a diagram illustrating the function of the servo system shown in FIG. 1 . 10 is a flowchart showing a flow of a method for adjusting a communication environment by changing a communication protocol in a servo driver when changing a safety encoder in the servo system shown in FIG. 1 . FIG. 11 is a first diagram showing a schematic configuration of a servo system after a communication protocol is changed. FIG. 2 is a second diagram showing a schematic configuration of the servo system after the communication protocol is changed.

First Embodiment
FIG. 1 is a schematic diagram of a servo system 100 before a servo driver 4, which is a motor control device disclosed in the present application, is installed. Here, the servo system 100 includes a network (field bus) 1, a motor 2, a servo driver 4, and a PLC (Programmable Logic Controller) 5. The motor 2 includes a motor body 21 and a safety encoder 22. The motor body 21 receives a drive current from the servo driver 4 to drive and rotate an output shaft. The safety encoder 22 is configured to detect the displacement of its output shaft, and further includes a duplicated circuit that enables independent detection signals to be output by simultaneously scanning the safety encoder 22, thereby improving the safety function. The safety function by the safety encoder 22 is realized in cooperation with a safety control unit 52 of the servo driver 4, which will be described later.

The output shaft of the motor 2 is connected to a ball screw 15, and the table 16 attached thereto is displaced by driving the ball screw 15. In addition to this form, the motor 2 may be incorporated into an apparatus, for example, as an actuator for an arm of an industrial robot or a conveying device. For example, the motor 2 is an AC motor. The safety encoder 22 generates a feedback signal (corresponding to a "detection signal") indicating the detected operation of the motor 2 (displacement of the output shaft of the motor body 21) and transmits the feedback signal to the servo driver 4. The safety encoder 22 outputs the feedback signal to the servo driver 4 via a duplicated communication path. The feedback signal includes, for example, position information regarding the rotation position (angle) of the rotating shaft of the motor 2, information on the rotation speed of the rotating shaft, etc. A general incremental type encoder or absolute type encoder can be applied to the safety encoder 22.

The servo driver 4 receives an operation command signal related to the operation (motion) of the motor 2 from the PLC 5 via the network 1. Based on the operation command signal from the PLC 5 and the feedback signal from the safety encoder 22, the servo driver 4 executes servo control related to the drive of the motor 2 by a servo control unit 42 described later, and supplies a drive current to the motor 2. Furthermore, based on the feedback signal from the safety encoder 22, the servo driver 4 executes safety control related to the operation of the motor by a safety control unit 52 described later. The current supplied to the servo driver 4 is AC power sent from the AC power source 11 to the servo driver 4. In this embodiment, the servo driver 4 is a type that receives three-phase AC, but it may also be a type that receives single-phase AC.

Here, the safety function of the servo system will be explained. In general, the system can be roughly divided into an input configuration, an arithmetic configuration, and an output configuration. The input configuration is, for example, a subsystem related to the input to the servo driver 4, and generally, its safety function is largely dependent on the safety function of the safety encoder 22. The arithmetic configuration is a subsystem related to the calculation for calculating the output from the input in the servo driver 4, and for example, depends on the safety function of the calculation circuit using a microprocessor (MPU). The output configuration is a subsystem related to the output from the servo driver 4, and depends on the safety function of the cutoff unit 43 that cuts off the transmission of the drive signal from the servo control unit to the drive unit 44, as described later. The safety function of the entire servo system is determined based on the respective safety functions of the input configuration, arithmetic configuration, and output configuration, and the adoption of the safety encoder 22 for the input configuration contributes to improving the safety function of the servo system 100.

In the servo system 100, the servo driver 4 is configured so that the servo driver 4 can be continuously used even when the motor 2 connected to the servo driver 4 is changed to another motor and the communication protocol corresponding to the safety encoder mounted on the changed motor is different from the communication protocol corresponding to the safety encoder 22. This configuration of the servo driver 4 allows the user to flexibly configure the servo system 100. Therefore, the schematic configuration of the servo system 100 will be described below with a focus on the servo driver 4, based on the functional blocks shown in FIG.

The servo driver 4 has a first receiving unit 41, a servo control unit 42, a cutoff unit 43, and a driving unit 44 as functional units related to the servo control of the motor 2, a second receiving unit 51 and a safety control unit 52 as functional units related to the safety control of the motor, and a communication unit 61, an acquisition unit 62, and a processing unit 63 as functional units related to adjusting the communication environment between the servo driver 4 and the safety encoder 22. Note that the network 1 is omitted in FIG. 2.

The first receiving unit 41 is a functional unit that receives a feedback signal from the safety encoder 22, and the feedback signal from the safety encoder 22 is input to the first receiving unit 41 via a communication path L1. The communication path L1 is a duplicated path corresponding to the output of the safety encoder 22. The first receiving unit 41 includes a reconfigurable device as a configuration related to communication between the safety encoder 22 and the servo driver 4 for reception by the first receiving unit 41. The reconfigurable device can be reconfigured according to communication protocol information for realizing communication between the safety encoder 22 and the servo driver 4 to change the communication method between them. That is, even when the safety encoder 22 is changed to a safety encoder having a different communication protocol, the first receiving unit 41 is configured to be able to continue driving the motor without replacing the servo driver 4 itself even after the change by adapting the communication method in the first receiving unit 41 to the changed safety encoder. As an example, the first receiving unit 41 includes a PLD (Programmable Logic Device) whose circuit configuration can be changed as a reconfigurable device. The communication method of the first receiving unit 41 can be changed by changing the circuit configuration of the PLD according to information related to the communication protocol (communication protocol information). An example of a PLD is an FPGA (Field Programmable Gate Arrays). As an alternative configuration of the first receiving unit 41, it can be configured using a DRP (Dynamically Reconfigurable Processor). The feedback signal received by the first receiving unit 41 from the safety encoder 22 is delivered to the servo control unit 42.

The servo control unit 42 receives an operation command signal from the PLC 5 and a feedback signal from the safety encoder 22 received by the first receiving unit 41. The servo control unit 42 generates command values for executing position feedback control and speed feedback control based on the operation command signal and the feedback signal. For example, the servo control unit 42 generates a position command value and a speed command value by feedback control based on the operation command signal and the feedback value. The feedback method used in the feedback control is a method that forms a servo loop suitable for a specific purpose (e.g., transporting luggage) of the mechanical device (conveyor device, etc.) in which the motor 2 is incorporated, and can be designed as appropriate. These command values generated by the servo control unit 42 are then sent to the cutoff unit 43 as drive signals.

Next, when the cutoff unit 43 receives an emergency stop command from the safety control unit 52, it stops the drive unit 44 by electrically not passing the drive signal from the servo control unit 42 to the drive unit 44 described below. This stops the output of torque by the motor 2 even if the servo control unit 42 sends a drive signal. On the other hand, when an emergency stop command is not input to the cutoff unit 43, the cutoff unit 43 passes the drive signal accompanied by the command value output from the servo control unit 42 to the drive unit 44 as is.

The driving unit 44 receives a driving signal from the servo control unit 42 via the cutoff unit 43. The driving unit 44 has a circuit composed of semiconductor switching elements such as IGBTs (Insulated Gate Bipolar Transistors), and is an inverter device that generates a signal for turning on and off the switching elements according to the PWM method based on the driving signal from the servo control unit 42, and turns on and off the switching elements according to the signal. This causes an AC driving current to be supplied to the motor 2, and the motor 2 is driven. On the other hand, when the cutoff unit 43 operates and the transmission of the driving signal to the driving unit 44 is cut off, the output from the driving unit 44 is fixed to OFF. This stops the power supply to the motor 2, and the output of torque from the motor 2 stops. In this way, the first receiving unit 41, the servo control unit 42, the cutoff unit 43, and the driving unit 44 are functional units directly related to the servo control of the motor 2.

Next, the functional units related to the safety control of the motor 2 will be described. The second receiving unit 51 is a functional unit that receives a feedback signal from the safety encoder 22, similar to the first receiving unit 41, and the feedback signal from the safety encoder 22 is input to the second receiving unit 51 via the communication path L2. The communication path L2 is a duplicated path corresponding to the output of the safety encoder 22. Similarly to the first receiving unit 41, the second receiving unit 51 also includes a reconfigurable device as a configuration related to communication between the safety encoder 22 and the servo driver 4 for reception by the second receiving unit 51. The reconfigurable device has been described above. The feedback signal from the safety encoder 22 received by the second receiving unit 51 is passed to the safety control unit 52.

The safety control unit 52 is a functional unit that executes safety control regarding the operation of the motor 2 based on the feedback signal from the safety encoder 22. Specifically, the operating state of the motor 2, such as the position and speed of the motor 2, is calculated from the feedback signal, and a judgment is made as to whether the operating state deviates from a predetermined range. If it is judged that the operating state deviates from the range, an emergency stop command is issued from the safety control unit 52 to the cutoff unit 43. The user can appropriately select what judgment to make as the safety control of the operation of the motor 2, and construct the safety control unit 52 according to the judgment content. In addition, since the feedback signal from the safety encoder 22 is input to the safety control unit 52, the safety control unit 52 judges the occurrence of a malfunction in the operation of the safety encoder 22, and if it is judged that a malfunction has occurred, an emergency stop command is issued from the safety control unit 52 to the cutoff unit 43. The malfunction judgment related to the operation of the safety encoder 22 can be realized by using a known method such as comparing the duplicated feedback signals received by the second receiving unit 51 with each other. In this way, the second receiving unit 51 and the safety control unit 52 are functional units directly related to the safety control of the motor 2.

Next, the functional units related to adjusting the communication environment between the servo driver 4 and the safety encoder 22 will be described. The communication unit 61 is a functional unit for communicatively connecting to an external device 10 that exists outside the servo driver 4. For example, the external device 10 is a personal computer, and has a calculation unit such as a PCU and a data storage unit such as a memory. The external device 10 shown in FIG. 2 stores in its storage unit one or more pieces of communication protocol information corresponding to one or more types of safety encoders that the first receiving unit 41 and the second receiving unit 51 can handle. In the external device 10, this communication protocol information is stored in the servo driver 4 so that it can be downloaded at the user's choice.

The acquisition unit 62 is a functional unit that acquires communication protocol information corresponding to the changed safety encoder from the external device 10 via the communication unit 61 when the motor 2 connected to the servo driver 4 in the servo system 100 is changed and the communication protocol for the safety encoder mounted thereon becomes different from the communication protocol corresponding to the safety encoder 22 shown in FIG. 2. Note that the acquisition form of the communication protocol information corresponding to the changed safety encoder by the acquisition unit 62 is not limited to the form shown in FIG. 2. For example, if the servo driver 4 has a storage unit (memory) that stores one or more pieces of communication protocol information corresponding to the one or more safety encoders, the acquisition unit 62 may acquire the necessary communication protocol information from the storage unit. In addition, acquisition forms other than these may be adopted.

The processing unit 63 is a functional unit that adapts the first receiving unit 41 and the second receiving unit 51 to a configuration corresponding to the changed safety encoder according to the communication protocol information corresponding to the changed safety encoder acquired by the acquisition unit 62. As described above, the first receiving unit 41 and the second receiving unit 51 have a reconfigurable device as a configuration related to communication between the safety encoder and the servo driver 4. Therefore, the processing unit 63 reconfigures the reconfigurable device to correspond to the changed safety encoder using the communication protocol information corresponding to the changed safety encoder. In addition, in the servo system 100, safety control is performed using a feedback signal from the safety encoder 22, and if the configuration of the first receiving unit 41 and the second receiving unit 51 is reconfigured carelessly, the safety control will be hindered. Therefore, the processing unit 63 performs a predetermined confirmation process to confirm the suitability of the combination of the communication protocol information acquired by the acquisition unit 62 (communication protocol information to be applied to the first receiving unit 41 and the second receiving unit 51) and the changed safety encoder (the safety encoder to be changed from the safety encoder 22). If the specified confirmation process is carried out and it is confirmed that there are no problems, the first receiving unit 41 and the second receiving unit 51 will be reconstructed as described above.

Here, a method of adjusting the communication environment in the servo driver 4 in the servo system 100, including the above-mentioned predetermined confirmation process, when the motor 2 connected to the servo driver 4 is changed to another motor and the communication protocol corresponding to the safety encoder mounted on the changed motor is different from the communication protocol corresponding to the safety encoder 22, will be described with reference to FIG. 3. FIG. 4 shows a schematic configuration of the servo system 100 after the safety encoder connected to the servo driver 4 is changed as described above. As shown in FIG. 4, in this embodiment, the motor 2 is changed to the motor 20, and the changed motor 20 has a motor body 210 and a safety encoder 220. The motor body 210 is substantially the same as the motor body 21 of the motor 2, but the communication protocol corresponding to the safety encoder 220 is different from the communication protocol corresponding to the safety encoder 22.

The method of adjusting the communication environment shown in FIG. 3 is started after the user connects the external device 10 to the servo driver 4 via the communication unit 61. First, in S101, a security check process is performed regarding access from the external device 10 to the servo driver 4. Specifically, key information that enables access to the servo driver 4 is given to the external device 10 in advance, and the external device 10 issues an access request to the servo driver 4 using that key information. When the servo driver 4 acknowledges the request, the external device 10 is permitted to access the servo driver 4. When the process of S101 is completed, the process proceeds to S102.

In S102, the processing unit 63 requests the user to input information on the communication protocol corresponding to the changed safety encoder. Specifically, the processing unit 63 transmits an input request command to the external device 10 via the communication unit 61. The external device 10, which has received the command, displays on its display a request to input information on the communication protocol corresponding to the changed safety encoder, and accepts the user's input. When the user's input is accepted, the input information is sent from the external device 10 to the processing unit 63 via the communication unit 61. Note that the input communication protocol information is only sent from the external device 10 to the processing unit 63, and the acquisition unit 62 does not acquire new communication protocol information based on the information. When the processing of S102 ends, the process proceeds to S103.

In S103, a user operation other than the information input in S102 is used as a trigger to cause the acquisition unit 63 to acquire communication protocol information corresponding to the safety encoder 220. The user operation may be performed by an operation on the external device 10 or by an operation on the servo driver 4. The communication protocol information corresponding to the safety encoder 220 transmitted from the external device 10 to the servo driver 4 is primarily stored in a holding unit (memory) of the servo driver 4. Then, in S104, a predetermined confirmation process is performed. As the predetermined confirmation process, first, based on the binary data of the communication protocol information acquired in S103, confirmation is performed as to whether the data format conforms to the communication protocol information, etc.

Next, in the second process, the information on the communication protocol information input by the user in S102 is compared with the communication protocol information corresponding to the safety encoder 220 acquired in S103 to confirm whether the communication protocol information corresponding to the newly connected safety encoder 220 has been acquired correctly, that is, whether the combination of the acquired communication protocol information and the safety encoder 220 is appropriate. As described above, the process of S102 and the process of S103 are independent with respect to the new communication protocol information. Therefore, by comparing the two in the second process, it is possible to confirm that the communication protocol information that is in line with the intention of the user who is trying to change the safety encoder is being applied to the servo driver 4. If there is no problem in the process of S104, the process of S105 is performed. If there is a problem in the process of S104, the process of adjusting the communication environment of the servo driver 4 is interrupted.

In S105, the processing unit 63 applies the communication protocol information corresponding to the safety encoder 220 acquired by the acquisition unit 62, and adapts the first receiving unit 41 and the second receiving unit 51 to a configuration corresponding to the safety encoder 220 according to the communication protocol information. As a result, the servo driver 4 transitions from a state in which it communicates with the safety encoder 22 and is capable of driving the motor 2 to a state in which it communicates with the safety encoder 220 and is capable of driving the motor 20. When the processing of S105 ends, proceed to S106.

In S106, a process of changing the communication path between the safety encoder 220 and the servo driver 4 is performed, taking into account that communication with the safety encoder 220 has been enabled in S105. Here, in the servo system 100, when the servo driver 4 is connected to the safety encoder 20, the servo driver 4 is designed so that the servo control of the motor 2 by the servo control unit 42 and the safety control by the safety control unit 52 are performed using the communication protocol of the safety encoder 20, which is known in advance, as a common standard. Therefore, even if the feedback signal from the safety encoder 22 is transmitted to the servo control unit 42 and the safety control unit 52 via different communication paths L1 and L2, respectively, the servo control and the safety control can be performed in a favorable cooperative state. However, as described above, if the safety encoder connected to the servo driver 4 is changed to the safety encoder 220, the communication environment between the safety encoder and the servo driver 4, which is the premise of the initial design of the servo driver 4, is changed, and depending on the contents of the servo control and the safety control, problems such as a shift in control timing may occur.

Therefore, in S106, as a process of changing the communication path, the safety control unit 52 is permitted to execute safety control based on the feedback signal of the safety encoder 220 obtained via the same communication path L2 as before the change. That is, the feedback signal received by the safety control unit 52 before and after the change of the safety encoder is the feedback signal received by the second receiving unit 51. On the other hand, the servo control unit 42 is prohibited from acquiring the feedback signal from the safety encoder 220 via the communication path L1 before the change. Instead, the feedback signal from the safety encoder 220 received by the safety control unit 52 via the communication path L2 is handed over from the safety control unit 52 to the servo control unit 42. In FIG. 4, the communication path for handing over from the safety control unit 52 to the servo control unit 42 is represented by L3. The communication path L3 is an internal communication path of the servo driver 4, and can be exemplified by an SPI (serial peripheral interface) communication path. Then, the servo control unit 42 is permitted to execute servo control based on the feedback signal of the safety encoder 220 that has been handed over. That is, by changing the safety encoder, the feedback signal received by the servo control unit 42 is also the feedback signal received by the second receiving unit 51. By adopting this configuration, a common feedback signal is used between the servo control unit 42 and the safety control unit 52, and problems such as deviation in control timing caused by the change to the safety encoder 220 can be suppressed.

The method of adjusting the communication environment shown in Figure 3 ensures an optimal safety control environment for a motor using a safety encoder, while making it possible to change to a safety encoder with a different communication protocol without having to replace the servo driver 4.

<Other embodiments>
Another embodiment of the present disclosure will be described with reference to FIG. 5. FIG. 5 shows a schematic configuration of the servo system 100 after the safety encoder is changed from the configuration shown in FIG. 2. In this embodiment, the motor 2 is changed to the motor 20 as in the case shown in FIG. 4, and a safety encoder 221 is further attached. The safety encoder 221 is an encoder capable of detecting the displacement (rotation angle) of the ball screw 15 driven by the motor 20, and has two detectors for detecting the displacement therein, and has a duplicated circuit so that independent detection signals can be output by scanning simultaneously with the two detectors. Alternatively, a linear encoder capable of detecting the displacement of the table 16 driven and displaced by the motor 20 may be formed as the safety encoder 221. In this embodiment, the two safety encoders 220 and 221 are used to improve the accuracy of the position control of the table 16 and the safety function of the servo system 100.

Even in this embodiment in which the original safety encoder 22 is changed to multiple safety encoders (safety encoders 220, 221), communication between the multiple safety encoders after the change and the servo driver 4 can be established by applying communication protocol information corresponding to the safety encoders 220, 221 to the first receiving unit 41 and the second receiving unit 42 by the processing unit 63 according to the processing flow shown in FIG. 3. In this embodiment, the feedback signal from the safety encoder 221 is received by the second receiving unit 51, and the feedback signal is passed from the safety control unit 52 to the servo control unit 42 via the communication path L3.

<Appendix 1>
A motor control device (4) that servo-controls a motor (2, 20),
a receiving unit (41, 51) for receiving a detection signal from a safety encoder (22, 220) having a plurality of detectors for detecting a displacement of an output shaft of the motor (2, 20), the receiving unit (41, 51) being configured to be changeable according to communication protocol information for realizing communication between the safety encoder (22, 220) and the motor control device (4);
an acquisition unit (62) that acquires first communication protocol information corresponding to a first safety encoder (220) after the change when the safety encoder connected to the motor control device (4) is changed;
a processing unit (63) that performs a predetermined confirmation process to confirm whether a combination of the acquired first communication protocol information and the first safety encoder is appropriate, and that conforms the receiving unit (41, 51) to a configuration corresponding to the first safety encoder (220) according to the first communication protocol information;
A motor control device comprising:

<Appendix 2>
A method for adjusting a communication environment with a safety encoder (22, 220) in a motor control device (4) that servo-controls a motor (2, 20), comprising:
The motor control device (4) includes a receiving unit (41, 51) that receives a detection signal from a safety encoder (22, 220) having a plurality of detectors that detect a displacement of an output shaft of the motor (2, 20), the receiving unit (22, 220) being configured to be changeable according to communication protocol information for realizing communication between the safety encoder (22, 220) and the motor control device (4);
The method comprises:
When the safety encoder connected to the motor control device (4) is changed, a step (S103) of acquiring first communication protocol information corresponding to the changed first safety encoder (220);
A step (S105) of adapting the receiving unit (41, 51) to a configuration corresponding to the first safety encoder (220) according to the first communication protocol information after a predetermined confirmation process of confirming whether or not a combination of the acquired first communication protocol information and the first safety encoder is appropriate;
A method for adjusting a communication environment in a motor control device, comprising:

2 Motor 4 Servo driver 5 PLC
REFERENCE SIGNS LIST 10 External device 15 Ball screw 16 Table 22, 220, 221 Safety encoder 41 First receiving unit 42 Servo control unit 51 Second receiving unit 52 Safety control unit 61 Communication unit 62 Acquisition unit 63 Processing unit 100 Servo system

Claims (7)

A motor control device that servo-controls a motor,
a receiving unit that receives a detection signal from a safety encoder having a plurality of detectors that detect a displacement of an output shaft of the motor, the receiving unit being configured to be changeable according to communication protocol information for realizing communication between the safety encoder and the motor control device;
an acquisition unit that acquires, when the safety encoder connected to the motor control device is changed, first communication protocol information corresponding to the changed first safety encoder;
a processing unit that performs a predetermined confirmation process to confirm whether a combination of the acquired first communication protocol information and the first safety encoder is appropriate, and that conforms the receiving unit to a configuration corresponding to the first safety encoder according to the first communication protocol information;
a servo control unit that is communicatively connected to the safety encoder via a first communication path and that executes servo control of the motor based on a detection signal of the safety encoder obtained via the first communication path;
a safety control unit that is communicatively connected to the safety encoder via a second communication path different from the first communication path, and that executes safety control regarding an operation of the motor based on a detection signal of the safety encoder obtained via the second communication path;
Equipped with
After the processing unit has adapted the receiving unit to a configuration corresponding to the first safety encoder according to the first communication protocol information,
The safety control unit executes the safety control based on a detection signal of the first safety encoder obtained via the second communication path,
The servo control unit is prohibited from acquiring a detection signal from the first safety encoder via the first communication path, and the safety control unit receives a detection signal obtained via the second communication path from the safety control unit, and executes the servo control based on the received detection signal.
Motor control device. A storage unit that stores one or more pieces of communication protocol information corresponding to one or more safety encoders of a type that the receiving unit can support,
The acquisition unit acquires the first communication protocol information from the one or more pieces of communication protocol information stored in the storage unit.
The motor control device according to claim 1 . A communication unit is further provided for communicatively connecting an external device that holds one or more pieces of communication protocol information corresponding to one or more safety encoders of a type that the receiving unit can support,
The acquisition unit acquires the first communication protocol information from the one or more pieces of communication protocol information held by the external device.
The motor control device according to claim 1 . The communication unit is configured to permit communication between the external device and the motor control device when a predetermined security signal is input from the external device.
The motor control device according to claim 3. The processing unit requests a user to input information on a communication protocol corresponding to the changed safety encoder, and executes, as the predetermined confirmation process, a process of comparing the information input by the user with the first communication protocol information acquired by the acquisition unit.
The motor control device according to any one of claims 1 to 4. When the safety encoder connected to the motor control device is changed to a plurality of safety encoders including the first safety encoder,
The acquisition unit acquires predetermined communication protocol information corresponding to the plurality of safety encoders after the change,
the processing unit performs the predetermined confirmation process to confirm whether the combination of the acquired predetermined communication protocol information and the plurality of safety encoders is appropriate, and adapts the receiving unit to a configuration corresponding to the plurality of safety encoders according to the predetermined communication protocol information.
The motor control device according to any one of claims 1 to 5 . A method for adjusting a communication environment with a safety encoder in a motor control device that servo-controls a motor, comprising:
the motor control device includes a receiving unit that receives a detection signal from a safety encoder having a plurality of detectors that detect a displacement of an output shaft of the motor, the receiving unit being configured to be changeable according to communication protocol information for realizing communication between the safety encoder and the motor control device;
a servo control unit that is communicatively connected to the safety encoder via a first communication path and that executes servo control of the motor based on a detection signal of the safety encoder obtained via the first communication path;
a safety control unit that is communicatively connected to the safety encoder via a second communication path different from the first communication path, and that executes safety control regarding an operation of the motor based on a detection signal of the safety encoder obtained via the second communication path;
Equipped with
The method comprises:
When the safety encoder connected to the motor control device is changed, acquiring first communication protocol information corresponding to the changed first safety encoder;
a step of performing a predetermined confirmation process for confirming whether a combination of the acquired first communication protocol information and the first safety encoder is appropriate, and adapting the receiving unit to a configuration corresponding to the first safety encoder according to the first communication protocol information;
After adapting the receiving unit to a configuration corresponding to the first safety encoder according to the first communication protocol information, permit the safety control unit to execute the safety control based on a detection signal of the first safety encoder obtained via the second communication path, prohibit the servo control unit from acquiring a detection signal from the first safety encoder via the first communication path, and cause the safety control unit to receive the detection signal obtained via the second communication path from the safety control unit and execute the servo control based on the received detection signal.
allowing;
A method for adjusting a communication environment in a motor control device, comprising:

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