JP3186490B2 - Multiplex encoder - Google Patents

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 an absolute rotation angle of a rotating body, and more particularly to an encoder for detecting an absolute rotation angle of a rotating body.
The present invention relates to a rotary encoder used in a device incorporated in a servomotor and used in a plurality of configurations.

[0002]

2. Description of the Related Art A brushless DC servomotor and a brushless A servomotor are used for driving various machines.
There is a C servo motor (DC brushless servo motor), and in recent years, demand for an AC servo motor has been increasing due to easy motor maintenance.

There are various types of position detectors for servo systems, and in recent years, rotary encoders incorporated and used in servo motors have become widespread. Encoders incorporated in AC servomotors are broadly classified into incremental encoders and absolute encoders. The output signal of the incremental encoder is as shown in FIG.
A and B two-phase signals having a phase difference of 90 degrees in electrical angle with each other so that the rotation direction can be determined, a reference Z signal of one pulse per rotation, and commutation signals U and V for switching the energized phase of the AC servomotor. , W are generally provided. An absolute encoder is an encoder that can recognize the absolute position within one rotation immediately after turning on the power. The absolute position, which is the operation of aligning the machine position with the controller immediately after turning on the power required in a control system using an incremental encoder, is performed. Since a return operation is not required, it is becoming widespread in servomotors for large robots such as articulated robots, and many of them are multi-rotation absolute encoders equipped with a motor rotation number counting function.

[0004] A conventional multi-rotation type absolute encoder will be described below. FIG. 9 shows functional blocks of a conventional multi-rotation type absolute encoder.
In FIG. 9, reference numeral 91 denotes an original signal detector for detecting an incremental signal and an absolute signal; 92, a multi-turn counter; 93, a backup circuit; 94, a conversion circuit;
Is an output IC.

FIG. 10 is a block diagram of the original signal detector of FIG. 9, which comprises a light emitting element 101, a rotating slit plate 102, a light receiving element 103, and a waveform shaping circuit 104, and converts a signal received by the light receiving element into a pulse waveform. Make the conversion.

The operation of the multi-rotation type absolute encoder configured as described above will be described with reference to FIG. First, when the main power supply is turned on, the A and B signals having a phase difference of 90 degrees from the original signal detector 91 corresponding to the rotational position of the encoder and the Z signal generated once per rotation and the resolution of one rotation are supported. and outputs the 2 ⁰ 2 ^K-1 of 1 rotation absolute signal K bits and. The multi-rotation counter 92 counts the number of rotations using the upper two bits 2 ^K−1 and 2 ^K−2 of the absolute signal output. The conversion circuit 94 converts the one-rotation absolute data and the multi-turn count data, which are parallel data, into serial data and transmits the serial data to a driver or an NC system.

On the other hand, when the main power supply is turned off, the backup circuit 93 detects the 2 ^K-1 and 2 ^K-2 signals of the upper 2 bits of the absolute signal output and the multi-rotation counter 92
And always working. As a result, even when the main power is turned on again, the number of rotations is retained without resetting,
In addition, the number of rotations changed when the main power supply is turned off can be detected.

[0008]

However, in the above-mentioned conventional configuration, when a plurality of encoders are used, the number of output lines from the encoders is required independently for each encoder, so that the number of lines increases, and However, there are problems such as wiring space and workability, and disconnection and reliability of output lines.

An object of the present invention is to solve the above-mentioned conventional problems, and an object of the present invention is to provide an encoder that can share an encoder output line and reduce the number of wires in a device even in a plurality of configurations.

[0010]

In order to achieve this object, a multiplex transmission type encoder according to the present invention comprises:
One-rotation data detector that detects the position within rotation, multi-rotation data detector that counts the number of rotations in the forward and reverse directions of the rotating machine, and status that holds abnormality detection information in the encoder
A signal detection unit comprising a detection unit;
A data output circuit that converts data into a serial data string and outputs it, a data input circuit that receives commands from a higher-level system that determines the timing of outputting data from the data output circuit, and a switch between the data input circuit and the data output circuit A data input / output unit comprising a bidirectional buffer, a backup circuit for operating the multi-rotation data detection unit when the main power is OFF, and a power ON / OFF detection circuit for monitoring the ON / OFF state of the main power. Power supply control unit consisting of 4 and commands from the upper system, etc. are received by the data input / output unit and identification information such as encoder number
And a circuit section for storing the
Share the input and output signal lines of the
When the main power supply is turned on, the output form of the encoder signal after the main power supply is turned on may be a form in which a plurality of encoders sequentially output identification information in response to a request from the host system, or the main power supply may be turned on regardless of a request from the host system. Then, the data is output in a form of sequentially and sequentially outputting the encoder identification information . Also, multiple servo motors
I / O signal lines for encoders mounted on
When the main power is turned on, the output form of the encoder signal after the main power is turned on is output in a one-to-one manner for each encoder in response to a request from the host system. A form in which information is output in order of the main power supply O regardless of the request from the host system
When N, one output mode can be selected based on the encoder identification information from the three modes of sequentially and sequentially outputting the encoder identification information . Ma
In addition, the encoder identification information for identifying the encoder of each servo motor is an encoder number and output order information of the encoder data in the multiplex transmission, and the encoder has a function of transmitting and receiving serial data. appropriate time that encoder becomes the transmission state, the other encoder than those adapted to the timing control order waiting data output by monitoring the output data from the other encoders Ensure a reception state is there. In addition, the configuration of the signal output from the encoder is such that the encoder identification information is combined with any one of the data of the one-rotation data detection unit, the multi-rotation data detection unit, and the status detection unit and output.
Things. In addition, identification information such as encoder number
The writing operation of the circuit section for storing is performed by the command provided in the rotating machine.
Write control signal line using connector or cable
Is what you choose through.

[0011]

With this configuration, it is possible to obtain an encoder in which the wiring can be reduced and the signal lines can be shared as compared with the conventional multi-rotation type absolute encoder, so that the device can be easily reduced in size and multi-axis.

[0012]

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

FIG. 1 is a functional block diagram of one embodiment of the present invention. In FIG. 1, reference numeral 11 denotes a signal detection unit, which is composed of a one-rotation data detection unit 12, a multi-rotation data detection unit 13, and a status detection unit 14. It performs the operations of counting the number of times, detecting voltage abnormalities in the encoder, detecting signal abnormalities, and retaining abnormal data. Reference numeral 15 denotes a data input / output unit, and a data output circuit 1
6. A data input circuit 17 and a bidirectional buffer circuit 18 for converting data from the signal detector into a serial data string and outputting the data, receiving a data request signal from a host system, and transmitting serial data.・ Reception switching operation is performed. Reference numeral 19 denotes a power control unit, which comprises a backup circuit 20 and a power ON / OFF detection circuit 21, monitors the state of main power ON / OFF, controls the operation switching of the data input / output unit, and detects multi-rotation data when the main power is OFF. It backs up the operation of the unit, status detection unit, and identification information storage circuit unit.

The identification information storage circuit section 22 is a circuit for storing encoder identification information such as each encoder number and data output order (priority order) via a data input / output section, and is used when a plurality of encoders are used. The writing of the identification information is performed by designating the encoder to be stored by the control signal.

Here, the signals output from the one-rotation data detector 12 and the multi-rotation detector 13 in FIG. 1 are detected by the same configuration as in FIGS. 9 and 10 shown in the conventional example.

FIG. 2 is a configuration diagram when the present encoder is incorporated in a servomotor and used in a plurality of configurations. The main power supply, the operation backup battery, and the serial data line are all configured to be commonly connected.

FIG. 3 is a diagram showing a configuration of a write control signal of identification information of the present encoder. FIG. 3A shows an example in which a control signal line is taken out via a connector, and the writing operation of identification information can be selected by shorting or opening the connector.

FIG. 3B shows an example in which a control signal line is taken out through a lead wire. The write operation of identification information can be selected by shorting or opening the lead wire, connecting to a main power supply or GND, or the like. Has become.

FIG. 4A shows an example of a write sequence of identification information of an encoder using a write control signal line.
When the control signal is set to 5 V, the serial data is in a state of transmitting identification information from the host system or the like to the encoder, and when the control signal is set to 0 V, the state is in a high impedance state.

FIG. 4B is a diagram showing an example of an operation switching sequence of the encoder transmission / reception. When the encoder is in the reception mode, the serial data is in a request state from the host system or the like, and when the encoder is in the transmission mode. Means that the serial data is output from the encoder.

FIGS. 5, 6, and 7 are diagrams showing a data transmission / reception sequence between the host system and the encoder when used in a plurality of encoder configurations, and show a case of a three-axis configuration as an example.

The operation when the multiplex transmission type encoder having the above configuration is used in a plurality of configurations as shown in FIG. 2 will be described.

In the present encoder, since the encoder input / output operation is set by the encoder identification information, it is necessary to write the identification information when the encoder is used for the first time.

First, the writing operation of the encoder identification information will be described with reference to FIGS.

When the encoder main power is turned on, since the identification information has not been set, the data input / output unit 15 enters an input mode. Here, the identification information is input from a serial data line using an identification information setting machine or a host system. Then, the data is input and stored in the identification information storage circuit unit 22 via the bidirectional buffer circuit 18 and the data input circuit 17.

When the encoders are connected and used in a plurality of configurations as shown in FIG. 2, the above-mentioned writing operation is performed simultaneously for all the encoders. Encoder 1 by control signal line
The writing operation is performed by designating each unit.

An embodiment at this time is shown in FIG. In this example, the control signal line is set to 5 V, an encoder is specified, and identification information is written from a host system.

On the other hand, when the writing operation is performed by the encoder alone, it is not necessary to specify the encoder by using the control signal line because it is not necessary to specify the encoder.

When the encoder main power supply is turned off, the identification information storage circuit section 2 is powered by the power supply ON / OFF detection circuit 21, the backup circuit 20, and an externally connected battery.
The contents of No. 2 are retained, and after the next main power ON, the input / output operation (transmission / reception operation) is performed in the encoder operation according to the contents of the identification information storage circuit unit.

Next, a description will be given of the switching of the transmission / reception operation of the encoder and the data transmission / reception sequence with the host system with reference to FIGS.

When the encoder main power supply is turned on, the encoder enters the reception mode as shown in FIG. 4B and waits for a signal request from the host system, depending on the contents of the identification information storage circuit section 22. Here, when the host system outputs the number of the encoder axis as the data request signal, the encoder receives the request signal at the data input / output unit 15, and only the encoder corresponding to the number enters the transmission mode, and the encoder transmits its own encoder identification information. The data output circuit 16 converts the data of the encoder 11 and the data of the signal detector 11 into a serial data string and outputs the data. Upon completion of the data output, the encoder returns to the reception mode, waits for a request signal from the host system, and thereafter repeats the above operation.

Here, except for the axis specified by the request signal, the operation in the reception mode is performed. At this time, the serial data of the axis specified by the request signal is received, and the next data output sequence wait and timing wait are performed. are doing.

Next, a data transmission / reception sequence between the encoder and the host system will be described with reference to FIGS.

FIG. 5 shows an example in which the host system and a plurality of encoders correspond one-to-one, in which the host system performs one-to-one data transmission and reception only on the axis for which the encoder number is specified.

FIG. 6 shows an example in which a host system and a plurality of encoders correspond in a one-to-many configuration. When the host system designates an encoder number, the plurality of encoders sequentially output in an output order based on identification information. This is an example in which the operation is repeatedly performed in response to a request from the next system.

FIG. 7 shows the main power supply O regardless of the host system.
In this example, a plurality of encoders sequentially and repeatedly output data in an output order based on identification information after N.

The sequences shown in FIGS. 5, 6, and 7 can be selected by encoder identification information.

As described above, by transmitting and receiving data between encoders and timing the data, it is possible to eliminate collision between input and output data in a plurality of configurations, and to realize highly reliable multiplex transmission. can do.
Further, by making it possible to select a transmission / reception sequence with the upper system based on encoder identification information, it is possible to realize a system construction and a multi-axis system in accordance with the controllability of the device.

[0039]

As described above, the present invention has a plurality of encoders by providing an encoder identification function, selection of a data output sequence according to a use, and data monitoring / input / output switching function between encoders. Even if used, the input and output signals of the encoder can be shared, and multiplex transmission with stable data switching can be realized.
It is possible to realize an encoder that can easily reduce wiring and increase the number of axes.

[Brief description of the drawings]

FIG. 1 is a block diagram of a multiplex transmission encoder according to an embodiment of the present invention.

FIG. 2 is a configuration diagram when the multiplex transmission system encoder is used in a plurality of configurations.

FIG. 3 is a configuration diagram of an identification information write control signal of the multiplex transmission type encoder.

FIG. 4 is a timing chart showing switching of the operation of the multiplex transmission encoder.

FIG. 5 is a diagram showing an operation of a data transmission / reception sequence for one-to-one correspondence in the multiplex transmission system encoder.

FIG. 6 is a diagram showing an operation of a data transmission / reception sequence corresponding to one-to-multi-axis in the multiplex transmission system encoder.

FIG. 7 is a diagram showing an operation of a data transmission / reception sequence for sequential output in the multiplex transmission system encoder.

FIG. 8 is a timing chart of an output signal of a conventional incremental encoder.

FIG. 9 is a block diagram of a conventional multi-rotation type absolute encoder.

FIG. 10 is a block diagram of an original signal detector of a conventional multi-rotation type absolute encoder.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Signal detection part 12 One rotation data detection part 13 Multi rotation data detection part 14 Status detection part 15 Data input / output part 16 Data output circuit 17 Data input circuit 18 Bidirectional buffer circuit 19 Power supply control part 20, 93 Backup circuit 21 Power supply ON / OFF detection circuit 22 identification information storage circuit unit 91 original signal detection unit 92 multi-turn counter 94 conversion circuit 95 output IC 101 light emitting element 102 rotating slit plate 103 light receiving element 104 waveform shaping circuit

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G08C 19/00 G01D 5/245

Claims (5)

(57) [Claims] 1. A one-rotation data detector for detecting a position within one rotation of a rotary machine, a multi-rotation data detector for counting the number of rotations of a rotary machine in forward and reverse directions, and abnormality detection information in an encoder.
A signal detection unit including a status detection unit that holds information, a data output circuit that converts data of the signal detection unit into a serial data string and outputs the data, and a higher-level system that determines the timing of outputting data of the data output circuit. And a data input / output unit comprising a bidirectional buffer for switching between the data input circuit and the data output circuit, and a backup circuit for operating the multi-rotation data detection unit when the main power supply is turned off. A power supply control unit comprising a power ON / OFF detection circuit for monitoring the ON / OFF state of the main power supply, and receiving a command from a host system by a data input / output unit and storing identification information such as an encoder number. circuit
And a part, the encoder output of which is attached to a plurality of servomotors
When the signal line is used in common, the output form of the encoder signal after the main power is turned on is the form in which a plurality of encoders sequentially output the identification information in response to the request from the host system, or the request from the host system. A multiplex transmission type encoder which outputs in the form of sequentially and sequentially outputting the encoder identification information when the main power is turned on regardless of the main power supply. 2. One time for detecting a position within one rotation of a rotating machine.
Rotation data detector and counts the number of rotations of the rotating machine in the forward and reverse directions
Multi-rotation data detector and error detection information in the encoder
Signal detection unit consisting of a status detection unit that holds information
And converts the data of the signal detection unit into a serial data string and outputs it.
Data output circuit and the data output circuit data
Commands from a host system that determines when to apply
A data input circuit, a data input circuit and data
Data consisting of a bidirectional buffer that switches the output circuit
The data input / output unit and the multi-rotation data detection unit are operated when the main power is turned off.
Monitor ON / OFF status of backup circuit and main power supply
Power control unit comprising a power ON / OFF detection circuit
And commands from the host system etc. by the data input / output unit
A circuit for receiving and storing identification information such as an encoder number
And a part, the encoder output of which is attached to a plurality of servomotors
When the signal line is used in common, the output form of the encoder signal after the main power is turned on is output one-on-one for each encoder individually in response to a request from the upper system, and in response to a request from the upper system. One output form is identified by encoder identification from three forms: a form in which a plurality of encoders sequentially output in the order of identification information, and a form in which the main power is turned on regardless of a request from a higher-level system, and the output is sequentially and sequentially output in the order of encoder identification information. A multiplex transmission type encoder that can be selected based on information. 3. An encoder identification information for identifying an encoder of each servo motor is an encoder number and output order information of encoder data in multiplex transmission, and the encoder has a function of transmitting and receiving serial data.
When the output order of each encoder falls under the transmission state, the other encoders are set to the reception state and the output data from the other encoders are monitored by monitoring the output data from the other encoders. The multiplex transmission system encoder according to claim 1 or 2, wherein: 4. of the signal outputted from the encoder configuration, encoder identification information and 1 rotation data detector, rotation data detection unit, and to output a combination of any of the data in the status detection unit according Item 1 to Claim
The multiplex transmission system encoder according to any one of claims 3 to 7 . 5. Storing identification information such as an encoder number.
The writing operation of the circuit part is performed by the connector provided in the rotating machine.
Or via a write control signal line using a cable
2. The multiplex transmission method encoder according to claim 1, wherein the encoder is selected.