JP2003122433A - Servo system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve good transmission even if the length of wiring interconnecting an encoder for detecting the position information of a rotating machine or the like and a controller controlling the position and speed of the rotating machine using the position information is varied when data are transmitted using Manchester codes between the encoder and the controller. SOLUTION: The encoder 11 and the controller 14 are provided with respective code conversion circuits capable of changing the phases of the Manchester codes. When the length of the wiring is changed, data with its phase modulated by the code conversion circuit are transmitted from the transmitting side, and the receiving side searches duty settings suited for data transmission, depending on whether or not reception of the modulated data is permitted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an encoder for detecting the position of a driving body that is rotationally driven or orthogonally driven, and a control device for the driving body, and more particularly to data transmission between the encoder and the control device. It is a thing.

[0002]

2. Description of the Related Art An encoder for detecting position information and speed information of a driving body is incorporated in a servo motor used for rotary drive or orthogonal drive of various machines.
In order to increase the amount of information to be detected and reduce the number of wiring in the machine, the data transmission by serial data is often used for information communication between the encoder and the control device that controls the position and speed of the driving body. ing.

An encoder and a control device in a conventional servo system will be described below.

FIG. 5 shows a conventional encoder 51 and control device 5.
4 shows a configuration of No. 4, 52 is a position detection unit that outputs position data indicating the absolute position of the driving body (motor) and abnormality information detected inside the encoder as parallel data, and 53 is a position detection unit 52 A data transmission unit that converts data into serial data and outputs the data, 55 a data reception unit that receives serial data from the encoder, converts the serial data into parallel data, and outputs the parallel data, and a drive unit 56 based on the encoder data from the data reception unit ( A motor drive unit that controls the position and speed of the motor.

FIG. 6 shows the configuration of a conventional data transmission section 53 and data reception section 55. Reference numeral 61 is a parallel-serial conversion section for converting transmission data composed of parallel data into serial data, and 62 is a parallel-serial conversion section. The code conversion unit 63 converts the NRZ code data output from the NRZ code data into the Manchester code data and outputs the code.
22. A transmission interface unit that transmits data according to the 22 standard, 64 is a reception interface unit that receives data according to the RS422 standard, and 65 is a code that converts Manchester code data from the reception interface unit into NRZ code data and outputs the converted data. The conversion unit 66 is a serial-parallel conversion unit that converts the serial data from the code conversion unit into parallel data.

FIG. 7 shows the configuration of serial communication between the encoder and the control device. The encoder 51 displays a command section for identifying the content of the transmission data and the position data and abnormality information detected by the position detection section 52. The data unit shown and the transmission error detection data unit generated from the command unit and the data unit are periodically and repeatedly transmitted to the control device 54. The control device 54 uses the received encoder data based on the received encoder data. It controls the position and speed of the driver and handles abnormalities.

FIG. 8 shows the NRZ code and the Manchester code handled by the code conversion unit, and the NRZ code is 1 bit.
While the "H" or "L" level is held in the section of, the Manchester code is a code in which the signal changes in the center of the section of 1 bit.

[0008]

However, in the above-described conventional configuration, when the distance of the transmission line between the encoder and the control device becomes a long distance, for example, 50 m or 100 m, the transmission is performed as shown in FIG. Due to waveform distortion due to cable characteristics and circuit threshold on the receiving side, the phase (duty) of the code on the transmitting side changed from 10% to 90% on the receiving side, resulting in serial data. However, there was a problem that it could not be received normally.

Further, in the conventional configuration, since data transmission is unidirectional from the encoder to the control device, in order to perform stable data transmission on an arbitrary transmission path, it is necessary to perform test transmission in advance and individually determine specifications. there were.

The present invention solves the above-mentioned conventional problems, and an object thereof is to provide a good serial transmission state even if the wiring length between the encoder and the control device varies.

[0011]

In order to solve the above problems, the present invention provides an encoder for detecting the position of a driver, receiving a request command consisting of serial data, and outputting the position data as serial data, and an encoder. To a control device that transmits a request command composed of serial data to and receives position data composed of serial data output from the encoder, and the data used for data communication between the encoder and the control device is a Manchester code. Further, the control device is provided with a code conversion unit capable of arbitrarily changing the duty of the Manchester code.

By the above means, it is possible to set the duty suitable for data transmission even if the duty variation due to the distortion of the transmission waveform occurs due to the variation of the wiring length of the wiring connecting the both.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a position detecting section for detecting the position of a driving body which is rotationally driven or orthogonally driven, and the position detecting section which receives a request command consisting of serial data. And an encoder including a first data communication unit that outputs the data as serial data,
A control device for controlling the position and speed of the driving body, the control device having a second data communication unit for transmitting a request command including serial data to the encoder and receiving position data including serial data output from the encoder; The data used for the data communication between the encoder and the control device is Manchester code, and the code conversion unit capable of arbitrarily changing the duty of the Manchester code is provided in the first data communication unit and the second data communication unit. It is a servo system.

Further, the second data communication unit for outputting a request signal composed of a Manchester code set to an arbitrary duty, and the position data by the Manchester code composed of a preset basic duty when the request signal is normally received. Is a servo system including a first data communication unit that outputs

Further, a second data communication section which outputs a request signal including a duty setting by a Manchester code having a preset basic duty, and a duty setting included in the request signal when the request signal is normally received. Is a servo system including a first data communication unit that outputs position data using Manchester code.

A servo having a second data communication section for outputting a request signal composed of Manchester code set to an arbitrary duty and a first data communication section for directly outputting the request signal composed of Manchester code. System.

Further, the duty of the Manchester code is 50% as a basic duty, and the code is 1/4 or 1 /.
This is a servo system in which the duty can be changed at intervals of 8 or 1/16.

In this way, by modulating the transmission signal, data communication suitable for the transmission path can be realized.

Further, it is possible to search the duty setting suitable for the transmission path from the control device to the encoder.

Further, it is possible to search the duty setting suitable for the transmission path from the encoder to the control device.

Further, the duty setting suitable for the transmission path between the control device, the encoder and the control device can be searched regardless of the receiving operation of the encoder.

Furthermore, the duty setting can be set from coarse to fine depending on the circuit configuration of the code conversion unit.

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram of an encoder and a controller of a servo system according to an embodiment of the present invention, in which 11 is an encoder and 14 is a controller.

Reference numeral 12 is a position detecting section for outputting position data indicating the absolute position of the driving body (motor) and abnormality information detected inside the encoder as parallel data as in the conventional case, and 13 is for receiving serial data from the control device. The first data communication unit 15, which selects and outputs the data from the position detection unit 12 according to the received request signal, outputs the data necessary for controlling the motor to the encoder as a request signal,
A second data communication section 16 for receiving serial data from the encoder, and 16 is a second data communication section 15 as in the conventional case.
Drive unit (motor) based on the encoder data received by
Is a motor drive unit that controls the position and speed of the.

FIG. 2 shows the first data communication unit 13 and the second data communication unit 13.
2 shows a configuration of the data communication unit 15 in which 21 is a parallel-serial conversion unit that converts transmission data composed of parallel data into serial data, and 22 is NRZ code data from the parallel-serial conversion unit that is converted into Manchester code according to the duty setting. A transmission code conversion unit that variably outputs a signal change point, 23 is a transmission / reception interface unit that inputs / outputs transmission data and reception data as bidirectional serial data according to the RS422 or RS485 standard, and 24 is a Manchester code from the transmission / reception interface unit. Received N
A reception code conversion unit that converts RZ code data and measures the signal change point (duty) of the code using a reference clock and outputs the result. Reference numeral 25 is a serial conversion unit that converts serial data from the reception code conversion unit to parallel data. It is a parallel conversion unit.

FIG. 3 shows a configuration of serial communication between the encoder and the control device according to the embodiment of the present invention. The control device 14 transmits serial data including a command portion (request signal), and the encoder 11 transmits the serial data. When the data is normally received, the encoder 11 outputs serial data including a command part (request signal) and a data part (data detected by the position detection part 12), and this data is output to the control device 1
4, the control device 14 controls the position and speed of the driving body and performs abnormality processing based on the requested encoder data.

FIG. 4 is an operation waveform of the transmission code conversion section in the embodiment of the present invention, which has a configuration in which the change point of the Manchester code signal can be varied (modulated) according to the duty setting.

In the reception code converter 24, first, the signal change point of the Manchester code is detected, and the "L" level section from the falling change to the rising change and the "H" level from the rising change to the falling change are detected. Each section is counted using a reference clock, and the signal change point (duty) of the Manchester code is digitized from this count value.

The operation of the present invention will be described below with reference to FIGS.

First, an embodiment in which the duty change amount of the Manchester code caused by the influence of the transmission path is measured will be described.

As a method of measuring the amount of change, first, as shown in FIG. 3, serial data including the duty setting of the Manchester code is transmitted from the control device 14 to the encoder 11. Here, the duty of the Manchester code transmitted from the control device 14 can be arbitrarily changed. Encoder 1
In No. 1, encoder data is transmitted to the control device 14 by the received Manchester code set to the duty setting. In the control device 14, the signal conversion point (duty) is measured by the reception code conversion part 24 of the second data communication part 15, and the signal change point is changed based on the difference between the duty setting transmitted from the control device 14 to the encoder 11 and the received duty measurement value. The quantity can be calculated.

Next, correction of the signal conversion point of the Manchester code will be described.

If the duty change amount can be measured, the change point of the Manchester code is changed in the direction of correcting the change on the transmission side. That is, if the Manchester code change point is delayed from the center of the bit on the receiving side, the change point is shifted to the front of the center of the bit on the transmitting side, while the change point of the Manchester code is advanced from the center of the bit on the receiving side. If so, the transmitting side shifts the change point after the center of the bit.

In this way, the duty setting satisfying the operation is searched through the data transmission between the encoder and the control device, and the setting is set by the control device 14 by the encoder 11
When the encoder 11 transmits the data according to the duty setting, serial transmission suitable for the transmission path can be performed.

Next, an embodiment of serial transmission suitable for the transmission path will be described.

In the first embodiment, the Manchester code (request signal) set to an arbitrary duty is transmitted from the control device 14 to the encoder 11, and is preset when the transmission data is normally received by the encoder 11. Control device 14 with Manchester code consisting of basic duty
The data is transmitted to the encoder, and the duty of the Manchester code that can be used in the transmission path can be determined depending on the presence or absence of data transmission (reply to the request signal) from the encoder.

In the second embodiment, data (request signal) including the duty setting is transmitted to the encoder 11 by the Manchester code having the basic duty preset by the control device 14, and the transmission data is transmitted to the encoder 11.
Is normally received, the data is transmitted to the control device 14 by the Manchester code including the duty setting included in the request signal, and is used in the transmission path depending on whether or not the encoder transmits data (replies to the request signal). A determination of the possible Manchester code duty can be made.

In the third embodiment, the control unit 14 transmits the Manchester code set to an arbitrary duty to the encoder 11, and the encoder 11 re-outputs the request signal composed of the Manchester code as it is, The re-output Manchester code is received by the control device 14 again, and the duty of the Manchester code that can be used in the transmission path can be determined regardless of whether the encoder 11 normally receives the code.

Next, an embodiment for setting the resolution of the Manchester code signal change will be described.

As for the variable resolution of the signal change point (duty) of the Manchester code, the circuit scale can be made smaller by counting and generating the change point by counting the reference clock in decimal number and generating the change point in binary number. Considering that the total circuit scale of the code conversion unit is not increased, the Manchester code has a 1-bit width of 2 ^N reference clocks (N = 2,
3, 4), and variable duty resolution (variable interval) is 1
/ 4 bit, 1/8 bit, or 1/16 bit.

If there is no restriction on the circuit scale, it is not necessary to limit to the above resolution setting.

The above is the description of the configuration and operation in the present embodiment. Whether or not serial data can be received via the transmission path or the duty measurement value of serial data at the time of reception with respect to changes in the serial data caused by the transmission path. With the configuration for feeding back, it becomes possible to set the serial data suitable for the transmission path.

As described above, the present invention realizes the transmission condition suitable for the transmission path by providing the structure capable of easily searching the degree of change of the serial data with respect to the arbitrary transmission path, and drives the motor stably. Can be provided.

[0045]

As is apparent from the above embodiments, the present invention has the function of modulating the transmission code and searches the duty setting of the data code suitable for the transmission path, thereby transmitting distance, transmission line material, and circuit. The change can be corrected for the change in the transmission code caused by the configuration, etc., and highly reliable data transmission can be realized.

Since the setting suitable for the transmission path can be searched and corrected as in the present invention, it is possible to realize sharing without providing an encoder or a control device corresponding to each transmission line length, and to manually perform data A highly reliable drive system can be provided without evaluating the transmission state.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a servo system according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of first and second data communication units according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of serial data according to the embodiment of this invention.

FIG. 4 is a data code diagram of the embodiment of the present invention.

FIG. 5 is a block diagram of a conventional servo system

FIG. 6 is a block diagram of a conventional data transmitter and data receiver.

FIG. 7 is a configuration diagram of conventional serial data.

FIG. 8 is a conventional data code diagram.

FIG. 9 is a conventional serial data transmission waveform diagram.

[Explanation of symbols]

11 encoder 12 Position detector 13 First data communication unit 14 Control device 15 Second data communication unit 16 Motor drive 21 Parallel-to-serial converter 22 Transmit Code Converter 23 Transmission / reception interface section 24 Received Code Converter 25 Serial-parallel converter

Claims (5)

[Claims] 1. A first data communication for detecting a position of a driving body that is rotationally driven or orthogonally driven, and first data communication for receiving a request command including serial data and outputting the data of the position detection unit as serial data. And a second data communication unit that transmits a request command including serial data to the encoder and receives position data including serial data output from the encoder, and controls the position and speed of the driving body. The data used for data communication between the encoder and the control device is a Manchester code, and a code conversion unit that can arbitrarily change the duty of the Manchester code is provided in the first data communication unit and the second data communication unit. Servo system installed in the data communication section of. 2. A second data communication unit for outputting a request signal composed of a Manchester code set to an arbitrary duty, and position data by a Manchester code composed of a preset basic duty when the request signal is normally received. The first data communication unit for outputting
The described servo system. 3. A second data communication unit which outputs a request signal including a duty setting by a Manchester code having a preset basic duty, and a duty setting included in the request signal when the request signal is normally received. To output position data in Manchester code consisting of
2. The servo system according to claim 1, which comprises the data communication unit. 4. A second data communication section for outputting a request signal composed of a Manchester code set to an arbitrary duty, and a first data communication section for outputting the request signal composed of this Manchester code as they are. The servo system described in 1. 5. The Manchester code duty is 50%.
The servo system according to claim 1, wherein the duty is variable at intervals of ¼, ⅛, or 1/16 with the reference duty as.