JP2013110904A - Electric motor drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expand detector options to be used, by the provision of a communication unit and a detection program according to a plurality of communication protocol types on the drive device side.SOLUTION: A drive device obtains detection data of an encoder for detecting the position or the speed of a needle in an electric motor, through serial communication with the encoder, to drive the electric motor using the detection data. The drive device includes: a plurality of communication units 3331a, 3331b, 3331c capable of transmitting and receiving the detection data according to the plurality of communication protocol types provided in a plurality of encoders 2a, 2b, 2c; and a plurality of detection programs 3342a, 3342b, 3342c for processing the detection data received through the communication units. The drive device identifies the communication protocol of each encoder by the reception of a correct response data to a data request command transmitted according to each communication protocol.

Description

  The present invention relates to a driving device that performs serial communication with a detector such as an encoder that is attached to an electric motor and detects the position or speed of a mover, and drives the electric motor using the detected data.

FIG. 6 shows a general configuration example of a system for driving an electric motor using detection data from an encoder.
In FIG. 6, 1 is an electric motor, 2 is an encoder attached to the electric motor 1 and detects the position and speed of a mover (rotor), 3 is a driving device of the electric motor 1, and 4 is an output signal of the encoder 2. An encoder cable 5 to be sent to 3 is a power cable for supplying driving power from the driving device 3 to the electric motor 1.

  The drive device 3 includes a position / speed control circuit 31 to which a position / speed command is input from the host device, an inverter 32 that performs power conversion based on the output thereof, and supplies AC power to the motor 1, and an encoder 2. And an encoder communication processing unit 33 that converts the output signal into a detected position / velocity value and sends it to the position / velocity control circuit 31. The position / speed control circuit 31 performs a control operation on the inverter 32 so that the position / speed detection value follows the position / speed command.

Here, when the position of the mover is detected with high resolution or when the absolute position (absolute position) is detected, data transmission / reception between the driving device 3 and the encoder 2 is often performed by serial communication.
FIG. 7 shows details of the encoder communication processing unit 33 in FIG. The encoder communication processing unit 33 includes a connector 331, a communication transceiver 332, a custom LSI (ASIC: Application Specific IC) 333, and a CPU (including software) 334.
The communication transceiver 332 converts a differential signal transmitted / received to / from the encoder 2 via the connector 331 and the encoder cable 4 and a digital signal on the ASIC 333 side, and this digital signal is a communication circuit in the ASIC 333. 3331 performs serial / parallel conversion.

The CPU 334 instructs the communication circuit 3331 of the ASIC 333 to transmit a data request command using the installed position / speed detection program 3342. Upon receiving this instruction, the communication circuit 3331 transmits a data request command to the encoder 2 as serial data. The encoder 2 returns response data in response to the data request from the drive device 3 (encoder communication processing unit 33).
If the data request command from the driving device 3 requests position data, the encoder 2 returns position data as response data. The position / speed detection program 3342 of the CPU 334 receives the response data, calculates a position / speed detection value, and sends it to the position / speed control circuit 31 of FIG.

Here, general-purpose physical layers such as RS485 and RS442 are often used as serial communication standards, but the “communication protocol” such as transmission code, data format, clock synchronization method, etc. depends on the encoder manufacturer. Is different.
Therefore, the user needs to select a drive device based on the model information of the motor so as to conform to the communication protocol of the encoder mounted on the motor. For this reason, if the encoder mounted on the electric motor and the communication protocol of the driving device 3 that performs serial communication between the encoder and the encoder do not match, communication abnormality occurs and the electric motor cannot be driven.

  In Patent Document 1, as shown in FIG. 8, a plurality of types of communication formats (first to third communication formats) are included in an encoder circuit 120 that communicates the rotation detection signal from the rotation detection unit 110 to the outside according to the communication format. ) Using the communication circuits 121a to 121c and the selector 122, and selecting the desired communication format from the first to third communication formats via the EEPROM 130 and the selector 122 and transmitting the rotation detection signal to the outside. 100 is described.

  Further, in Patent Document 2, as shown in FIG. 9, in a serial communication system encoder 150 including a communication block 151 and an encoder signal processing circuit 152, a plurality of communication formats are stored in an external memory 160 connected to the communication block 151. And the encoder signal is serially communicated according to the communication format requested from the customer circuit 170.

JP 2000-227344 A (paragraphs [0006] to [0010], FIG. 1 etc.) JP 2008-40582 A (paragraphs [0008] to [0012], FIG. 1 etc.)

  In the prior art shown in FIG. 6, normally, a life component such as an electrolytic capacitor is mounted on the drive device 3, and the drive device 3 including these components needs to be replaced after a predetermined period. At that time, the user must select a drive device that conforms to the communication protocol of the encoder 2. If this is wrong, the motor 1 cannot be driven, and the encoder 2 and the communication circuit in the drive device may be damaged. There was a fear.

Further, as described in Patent Document 1, when a plurality of communication formats are provided inside the encoder and switched, the motor (encoder) basically does not assume a setting change by the end user, so that the user There is no interface, and switching the communication format often involves disassembling the motor (such as removing the encoder cover).
In many cases, an electric motor or the like is complicatedly incorporated in a mechanical device, and when the electric motor is disassembled, the electric motor itself must first be removed from the mechanical device, which requires complicated and difficult work.

On the other hand, according to the prior art described in Patent Document 2, since a plurality of communication formats are built in the external memory, the problem as in Patent Document 1 can be solved temporarily.
However, since these communication formats are usually different for each encoder manufacturer, there is a problem that the drive devices that can be used are limited depending on the type of encoder on the user side, and there are fewer choices of drive devices. . In particular, the user may want to use an encoder of a specific communication format in consideration of functions such as resolution and response, performance, and cost, and the conventional technology of Patent Document 2 can sufficiently meet such a request. Can not.

  Therefore, the problem to be solved by the present invention is that a plurality of types of communication protocols are provided on the drive device side, and the communication protocol can be automatically selected according to a detector such as a connected encoder. An object of the present invention is to provide an electric motor drive device capable of increasing the number of options.

In order to solve the above-mentioned problem, the invention according to claim 1 acquires detection data by a detector that detects a position or speed of a mover of an electric motor by serial communication with the detector, and the detection data is obtained. In the driving device that drives the electric motor using,
A plurality of communication units capable of transmitting and receiving the detection data according to a plurality of types of communication protocols respectively possessed by the plurality of detectors; and a plurality of detection programs for processing the detection data received via these communication units. It is a thing.

  According to a second aspect of the present invention, in the motor drive device according to the first aspect, the drive device detects the data request command sequentially transmitted to the plurality of detectors according to a plurality of types of communication protocols by serial communication. When the response data from the detector is received and the correct response data is returned, an automatic selection program for automatically selecting the communication protocol of the detector connected to the drive device is executed, and the selected communication protocol To perform serial communication with the detector.

  According to a third aspect of the present invention, in the motor drive device according to the second aspect, the automatic selection program is executed a predetermined number of times when the detector is connected.

  According to a fourth aspect of the present invention, in the motor drive device according to the second aspect, the necessity of execution of the automatic selection program can be selected.

  According to a fifth aspect of the present invention, in the electric motor drive device according to any one of the second to fourth aspects, the detection program is stored in a low-speed nonvolatile memory, and corresponds to the selected communication protocol. The detection program is transferred from the nonvolatile memory to the high-speed memory and executed.

According to the first aspect of the present invention, the drive device includes a communication unit and a detection program corresponding to a plurality of communication protocols of the detector, so that the inventory of the drive device that a user or manufacturer has for maintenance can be minimized. It can be reduced to the limit.
According to the second aspect of the present invention, the drive device automatically selects the communication protocol, so that there is no erroneous connection, and the user connects the motor to the drive device without being aware of the communication protocol of the detector. Can be driven. In addition, since there is no communication protocol defect between the driving device and the detector, there is no possibility of causing deterioration of parts of the communication circuit.

According to the invention which concerns on Claim 3, when a user connects a drive device and a detector (electric motor) for the first time, a communication protocol can be selected automatically. For this reason, it is not necessary to switch the communication protocol when the machine in which the motor is incorporated is actually put into operation and driven, and the time from when the power is turned on until the motor can be operated can be shortened.
According to the fourth aspect of the invention, by enabling the selection of whether or not to execute the communication protocol automatic selection program, the user becomes aware of the communication protocol of the detector when the motor needs to be replaced. The electric motor can be replaced without any problems.
According to the fifth aspect of the present invention, only the portion corresponding to the communication protocol of the connected detector is transferred from the low-speed nonvolatile memory to the high-speed program execution memory and executed. The capacity can be used, and the cost can be reduced.

It is a block diagram of the encoder communication process part in 1st Embodiment of this invention. It is a flowchart which shows the process of the automatic selection program in 1st Embodiment. It is a block diagram of the encoder communication process part in 2nd Embodiment of this invention. It is a flowchart which shows the process of the communication selection program in 2nd Embodiment. It is a block diagram of the encoder communication process part in 3rd Embodiment of this invention. It is a general block diagram of the system which drives the electric motor provided with the position detector. It is a figure which shows the detail of the encoder communication process part in FIG. It is a block diagram of the prior art described in patent document 1. FIG. It is a block diagram of the prior art described in patent document 2. FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows the configuration of the encoder communication processing unit 33X in the first embodiment of the present invention, and the same components as those in FIGS. 6 and 7 are denoted by the same reference numerals. The first embodiment corresponds to the inventions according to claims 1 and 2.
The encoder communication processing unit 33X in FIG. 1 is provided inside the drive device in the same manner as the encoder communication processing unit 33 in FIG. 6, but in FIG. 1, the entire drive device and the electric motor are not shown.

In FIG. 1, the main difference from FIG. 7 is the processing in the ASIC 333X and the CPU 334X.
Here, an example is shown in which the motor drive device corresponds to three types of encoders 2a, 2b, and 2c having different communication protocols. Hereinafter, these three types of encoders are referred to as encoders A, B, and C.
Note that the serial communication standards of the three types of encoders A, B, and C are all compliant with RS485 or RS422, and a common communication transceiver 332 and encoder cable 4 can be used. (Communication format, synchronization method, communication code, etc.) are different.

The communication circuit 3331X in the ASIC 333X in FIG. 1 is transmitted and received between the encoder communication unit 3331a, the encoder B communication unit 3331b, the encoder C communication unit 3331c, and these communication units and the communication transceiver 332. A changeover switch means 3332 for switching signals is incorporated. Note that the selector switch unit 3332 can be switched by an automatic selection program 3343 described later.
Here, each communication part 3331a, 3331b, 3331c is a circuit which converts the serial signal and parallel data of each communication protocol.

  On the other hand, the CPU 334X, in addition to the position / velocity detection program 3342a for the encoder A, the position / velocity detection program 3342b for the encoder B, and the position / velocity detection program 3342c for the encoder C, each of these programs and the ASIC 333X Switch means 3341a, 3341b, 3341c for turning on / off data transmission / reception with the communication parts 3331a, 3331b, 3331c, and these switch means 3341a, 3341b, 3341c and the changeover switch means 3332 are operated, and the encoder communication processing part 33X is operated. An automatic selection program 3343 for switching the communication protocol in accordance with the connected encoder A, B, or C. Note that the above programs and switch means are realized mainly by software.

Here, the position / speed detection program is a program that extracts data from a signal received from the ASIC 333X, converts the bits to the position data of the mover of the motor, and calculates the speed data. Further, when data transmission / reception is turned off by the switch means 3341a, 3341b, 3341c, the operation of the position / speed detection programs 3342a, 3342b, 3342c for the respective encoders is also stopped.
The automatic selection program 3343 sequentially instructs each of the communication units 3331a, 3331b, and 3331c in the ASIC 333X to transmit a data request command, and determines the communication protocol of the encoder connected to the driving device based on the response data received from the encoder. To do.

Next, processing of the automatic selection program 3343 will be described using the flowchart of FIG.
The automatic selection program 3343 operates immediately after the drive device is turned on. Since the encoder requires a predetermined time from when the power is supplied until the serial communication is started, the encoder first waits for activation of the encoder (step S01 in FIG. 6). Here, it is assumed that the encoders A, B, and C wait more than the start time of the encoder that takes the longest to start.

  When the predetermined waiting time described above has elapsed, a command to transmit a data request command for encoder A according to the communication protocol of encoder A is generated. The encoder A communication unit 3331a in the ASIC 333X receives the transmission command and transmits a data request command as serial data to the encoder connected to the driving device (step S02). At this time, the selector switch unit 3332 functions to connect the communication unit 3331 a and the communication transceiver 332.

  In response to the data request command, the encoder returns response data, and the automatic selection program 3343 reads the response data from the A communication unit 3331a and determines whether or not the response data has been received normally (step S03). If the response data received from the encoder is normal according to the communication protocol of the encoder A (Yes in step S03), it is repeated a predetermined number of times (n times, n is a plurality), that is, the received normal response data is If they match n times (step S04 Yes), the encoder A is selected (identified) as the encoder connected to the driving device (step S11).

If response data is not returned from the encoder or if a communication error occurs, it is determined that normal reception is not possible (No in step S03). Next, a command for transmitting the data request command of encoder B according to the communication protocol of encoder B is generated, and the data request command is transmitted (step S05).
Note that the above-mentioned communication abnormality is a case where a check for a specified data length, a disconnection check, a CRC (Cyclic Redundancy Check), a parity check, etc. are performed, and any of these is abnormal. .

  Next, when response data is returned from the encoder, and the response data is normal according to the communication protocol of encoder B (step S06 Yes), and the normal response data matches n times (step S07 Yes), The encoder B is selected as the encoder connected to the drive device (step S12).

  Similarly, when the encoder connected to the driving device is neither encoder A nor encoder B, the same processing (steps S08 to S10, S13) is executed for the communication protocol of encoder C, but the response from the encoder If it is determined that the data cannot be received normally (No at Step S09), an alarm is output as an encoder communication error (Step S14). In this case, the user recognizes that the encoder (electric motor) needs to be replaced because the communication protocol of the encoder connected to the drive device is other than A, B, and C.

In this embodiment, the data request command is transmitted in the order of the communication protocols of the encoders A, B, and C, and whether the response data is normal or abnormal is determined. This order is determined by the data transmission time of the data request command so that the request command data and the response data do not collide when the encoder returns the response data by mistake.
For example, when the transmission time of the data request command of the encoder B is longer than the transmission time of the data request command of the encoder A, when the encoder A is connected and the data request command of the encoder B is transmitted first, the drive While the apparatus is transmitting data, the encoder A may return response data, and the request command data and the response data may collide, leading to deterioration of the communication transceiver 332.
For this reason, the processing of FIG. 2 is periodically repeated from an encoder with a short data transmission time of the data request command, that is, in the order of encoders A → B → C.

Next, FIG. 3 is a block diagram of the encoder communication processing unit 33Y in the second embodiment of the present invention. The second embodiment corresponds to the invention according to claims 3 and 4.
The difference between FIG. 3 and FIG. 1 is that a communication selection parameter 3351 is provided in the EEPROM 335 which is a non-volatile memory in the driving device, and the CPU 334Y has the automatic selection program 3343 according to the communication selection parameter 3351. A communication selection program 3344 for executing or operating the switch means 3341a to 3341c and 3332 is mounted. Here, it is assumed that the communication selection program 3344 includes the automatic selection program 3343.

  FIG. 4 is a flowchart showing processing of the communication selection program 3344 in the second embodiment. Here, the communication selection parameter 3351 includes four parameters, “automatic selection” (execution of the automatic selection program 3343), “encoder A communication protocol”, “encoder B communication protocol”, and “encoder C communication protocol”. Then, the communication selection program 3344 performs processing according to any of these four parameters.

First, it is assumed that “automatic selection” is selected as the communication selection parameter 3351 in the factory-shipped state.
For this reason, when an electric motor and an encoder are connected to the drive device purchased by the user and the power is first turned on, the process branches to Yes in the first step SA1 in FIG. Therefore, the automatic selection program 3343 described above is executed by the communication selection program 3344 (step SA2).

  After executing the automatic selection program 3343, if it is determined that the above-described communication abnormality (step S14 in FIG. 2) (Yes in step SA4 in FIG. 4), by leaving the communication selection parameter 3351 as “automatic selection”, The automatic selection program 3343 will be executed again at the next power-on. The number of executions of this automatic selection program 3343 can be arbitrarily set.

On the other hand, if it is not determined that the communication is abnormal after executing the automatic selection program 3343 (step SA4 No in FIG. 4), the execution result of the automatic selection program 3343, that is, the communication protocol of any one of the encoders A, B, and C is used. The communication selection parameter 3351 is set (step SA5).
Therefore, after that, the communication protocol of the encoder connected to the driving device is selected as the communication selection parameter 3351, and in the next control cycle, the process branches to No in step SA1 in FIG. 3344 reads the communication selection parameter 3351 and selects a communication protocol (step SA3). Thereafter, the switch units 3341a to 3341c and 3332 are operated in accordance with the encoder A, B, or C corresponding to the communication protocol to perform communication with the encoder.

  If the electric motor connected to the driving device is exchanged together with the encoder, the user may select “automatic selection” in the communication selection parameter 335 and perform the communication protocol automatic selection operation again.

Next, FIG. 5 is a configuration diagram of the encoder communication processing unit 33Z in the third embodiment of the present invention. The third embodiment corresponds to the invention according to claim 5.
The major difference between FIG. 5 and FIGS. 1 and 3 is that the position / speed detection program 3342a for encoder A, the position / speed detection program 3342b for encoder B, and the position / speed detection program 3342c for encoder C are external to the CPU 334Z. The point stored in the flash ROM 336 as a low-speed non-volatile memory provided in the memory and any one of these position / speed detection programs are selected by the changeover switch means 337 and transferred to the RAM in the CPU 334Z, The speed detection program 3342 is that the operation of any one of the communication units 3331a to 3331c is validated via the changeover switch unit 3341. Here, the RAM in the CPU 334Z, which is the transfer destination of the position / speed detection program 3342, functions as a high-speed program execution memory.

  As shown in FIG. 5, when the encoder A is connected to the drive device (encoder communication processing unit 33Z), the communication protocol for encoder A is selected in the communication selection parameter 3351 by executing the automatic selection program. Therefore, as a result of referring to the communication selection parameter 3351, the communication selection program 3344 controls the changeover switch means 337 to read the encoder A position / speed detection program 3342a in the flash ROM 336, and the position / speed detection program 3342a It is transferred to the internal RAM of the CPU and operates as a position / speed detection program 3342.

At the same time, the selector switch 3341 is controlled by the communication selection program 3344, and the position / speed detection program 3342, that is, the encoder A position / speed detection program 3342a is executed to process the transmission / reception data of the encoder A communication unit 3331a. is there.
At this time, the changeover switch unit 3332 is connected to the communication unit 3331a side by the communication selection program 3344.

  As described above, according to each embodiment, the drive device includes a communication unit and a detection program corresponding to a plurality of communication protocols of the encoder, so that the user does not need to prepare a drive device for each communication protocol. It is possible to reduce the burden on equipment management and cost, and it is possible to automatically establish an appropriate communication protocol simply by connecting an encoder, and to prevent failure of circuit components due to communication protocol mismatch. Can do.

2a, 2b, 2c: Encoder 4: Encoder cable 33X, 33Y, 33Z: Encoder communication processing unit 331: Connector 332: Communication transceiver 333X: ASIC
3331X: Communication circuit 3331a, 3331b, 3331c: Communication unit 3332: Changeover switch means 334X, 334Y, 334Z: CPU
3341: Changeover switch means 3341a, 3341b, 3341c: Switch means 3342, 3342a, 3342b, 3342c: Position / speed detection program 3343: Automatic selection program 3344: Communication selection program 335: EEPROM
3351: Communication selection parameter 336: Flash ROM
337: Changeover switch means

Claims (5)

In the drive device for detecting the detection data by the detector for detecting the position or speed of the mover of the electric motor by serial communication with the detector, and driving the electric motor using the detection data,
A plurality of communication units capable of transmitting and receiving the detection data according to a plurality of types of communication protocols respectively possessed by a plurality of detectors; a plurality of detection programs for processing the detection data received via these communication units;
An electric motor drive device comprising: In the electric motor drive device according to claim 1,
The driving device receives response data from the detector in response to a data request command sequentially transmitted to a plurality of detectors according to a plurality of types of communication protocols by serial communication, and the driving device is returned when correct response data is returned. An electric motor drive device, wherein an automatic selection program for automatically selecting a communication protocol of the detector connected to the device is executed, and serial communication is performed with the detector according to the selected communication protocol. In the motor drive device according to claim 2,
An electric motor driving device, wherein the automatic selection program is executed a predetermined number of times when the detector is connected. In the motor drive device according to claim 2,
An electric motor drive device characterized in that the necessity of execution of the automatic selection program can be selected. In the electric motor drive device according to any one of claims 2 to 4,
The detection program is stored in a low-speed nonvolatile memory;
A drive device for an electric motor, wherein the detection program corresponding to the selected communication protocol is transferred from the nonvolatile memory to a high-speed memory and executed.

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