JP2005276121A - Serial encoder conversion apparatus and network servo system comprising same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a serial encoder conversion apparatus for a network servo capable of eliminating the delay of feedback data. <P>SOLUTION: A network servo system which drives a motor 3 via a servo amplifier 2 in response to a command from a controller 1, includes one or more receivers 5 for branching and directly receiving pulse data 6 output from an encoder including a pulse count function, and a serial encoder conversion apparatus 4 including a pulse data monitor function for converting the received pulse data into general contact signal type digital data 7 and outputting the data to the controller. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an amplifier serial encoder conversion device applied to a servo drive which is a mechatronic device and a network servo system including the same.

As a conventional network servo, for example, a “servo control system” disclosed in Patent Document 1 can be cited. FIG. 4 is an explanatory diagram of the servo control system, which includes a controller 101, servo amplifiers 104a to 104d, and motors 103a to 103d. The controller 101 and the servo amplifier 104 are connected by a network having a predetermined transmission cycle.
The servo amplifier 104 coupled with the controller 101 via a network in this way is called a network servo. In the network servo, the servo amplifier 104 receives a drive command for the motor 103 from the controller 101 via the network, and transmits position information obtained from the motor 103 to the controller 101.
The motor 103 includes an encoder for position detection, and the servo amplifier 104 obtains an encoder signal from each encoder. When the encoder of the motor 103 is a serial encoder, the servo amplifier 104 needs to include a serial pulse conversion circuit that converts serial data into parallel data.
The output of the serial pulse conversion circuit is an analog command from the controller 101 or a servo feedback pulse for the pulse train command. Conventionally, a tachometer was used to detect the rotational speed of the motor. Recently, a method of extracting a speed feedback pulse from a position feedback pulse of a position detecting encoder has been frequently used, and a pulse corresponding to the actual speed of the motor 103 is output.
FIG. 3 is a configuration diagram of a “servo control system” according to Patent Document 1, in which a speed monitoring system of the motor 103 is configured. The servo amplifier 102 in FIG. 3 is different from the servo amplifier 104 in FIG. Network servos 102a to 102d each having a serial pulse conversion circuit (not shown) therein. Therefore, when monitoring the speed of the motor 103, the speed monitor 105 can monitor the speed of the motor 103 by monitoring a feedback pulse with little delay.

JP 2002-354859 A (FIGS. 1 and 2) JP 2002-304201 A

However, in an environment using a conventional network servo as in Patent Document 1, feedback pulses are transmitted and received as communication data. However, since the network is a network, the feedback data is delayed by the transmission cycle or is dedicated to the network. IC and protocol were required.
Also, since it was necessary to prepare a CPU to convert the feedback data, the processing of the serial pulse conversion circuit via the CPU further causes a delay in the software processing cycle and increases the delay of the feedback data. There was a problem that was causing it.
Also, as disclosed in Patent Document 2, there is an attempt to eliminate the delay of feedback data by having a pulse output function in the network servo. However, this method requires a pulse counter to be prepared in terms of cost and size. There was a problem.

  The present invention has been made in view of such problems, and by branching feedback data to the controller without passing through the CPU, by making a plurality of feedback data into general-purpose input signals, It is an object of the present invention to provide a serial encoder conversion apparatus having a monitoring function of a serial encoder that can realize an environment not limited to a specific protocol or network, and a network servo system including the same.

To achieve the above object, the serial encoder conversion device according to claim 1 is a serial encoder conversion device used in a network servo system that drives a motor via a servo amplifier in response to a command from a controller, One or more receiving devices that directly receive pulse data output from the encoder, and the pulse data received by the receiving device is converted into digital data by a general-purpose contact signal method and output to the controller. It has a monitor function.
According to a second aspect of the present invention, in the serial encoder conversion device according to the first aspect, the received serial encoder information is converted into a bit string and converted into a contact signal corresponding to a switch input, and the contact signal is converted into a network I / O. It is characterized by having a function of reflecting on the input data of the apparatus.
According to a third aspect of the present invention, there is provided a network servo system according to the first or second aspect, a controller for receiving a digital signal from the serial encoder converter, a motor in response to a command from the controller. In a network servo system comprising a servo amplifier for driving, a motor driven by the servo amplifier, and an encoder fixed to the motor and having a pulse count function, a serial data signal from the encoder is transmitted to the serial encoder The positioning completion determination is performed by sending feedback data to the converter and the servo amplifier.

According to the present invention, the controller can acquire position data that is newer and earlier than the position data that the network servo outputs as network data, and can confirm the completion of positioning in the position control earlier than via the network. As a result, the position control performance can be improved.
Furthermore, since it can be handled as a general-purpose input signal, it can be handled as general-purpose communication data by combining multi-axis feedback data, and there is an effect that both performance and wiring saving can be achieved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration diagram of a serial encoder conversion apparatus having a monitoring function of a serial encoder according to the present invention.
In FIG. 1, reference numeral 1 denotes a controller, which sends control commands to the motors 3a to 3c via a network, and receives feedback pulses 7 converted into a contact signal format from a serial encoder converter to perform control. . Reference numerals 2a to 2c denote servo amplifiers that drive the motors 3a to 3c based on commands from the controller 1 and receive signals from the motors via the receiving ICs 8a to 8c. Reference numeral 4 denotes a serial encoder conversion device which directly receives and monitors serial data 6 from the motors 3a to 3c via the receiving ICs 5a to 5c, converts them into contact signals, and outputs them to the controller.

Next, the operation will be described.
Most recent servo control systems extract speed data pulses using position data pulses from the encoder without using a small generator (tachometer) for speed detection. As a method for extraction, for each sample period from the A phase, B phase, and Z phase signals from the position encoder, a method for obtaining speed data from the number of pulses P and the sample period time TS by CPU calculation using a counter, or AB2 phase The position data pulse of the digital signal is converted into analog speed data by using a conversion circuit from the position data and output as analog speed data. The position data pulse is directly taken as position data into the controller, and the analog speed data is converted into an A / D converter, Or processing such as digitized by differential processing and taken in as speed data Are we.

In the present invention, in order to improve the point that speed data extraction processing from such position data requires complicated processing and a conversion device, and to simplify these and enhance versatility, input and output of relays and other sensors are performed. The contact point signal system of the input / output circuit to be used is introduced to process the speed feedback pulse.
First, when an analog or pulse train command is sent from the controller 1 to the servo amplifiers 2a to 2c, the servo amplifier 2 drives the motor 3 based on the command. Position data by the serial encoder of the motor 3 is received by the receiving ICs 8a to 8c of the servo amplifier 2 and simultaneously branched and received by the receiving ICs 5a to 5c of the serial encoder conversion device 4.

The serial encoder conversion device 4 includes a simple contact input processing circuit (not shown) and performs position data conversion processing. The contact input circuit is an existing circuit that processes on / off input / output of a relay or the like, and is compared with a simple pulse input unit using an insulating element such as a pulse transformer or a photocoupler and a threshold value. It has a simple circuit configuration including a voltage adjusting unit and a contact signal pulse output unit.
When a position pulse from the encoder of the motor 3 is input, the serial encoder conversion device 4 generates and outputs a pulse signal in a contact signal format by an on / off process by a contact input circuit. The controller 1 processes the contact signal (digital signal) from the serial encoder conversion device 4 in the general-purpose contact signal format in the same manner as other sensor inputs such as relays, and extracts them based on the position data and the position data. Perform feedback processing based on speed data. The servo speed control unit calculates the difference between the speed command and the feedback speed pulse to create a current command to perform servo control.
In this way, encoder data without delay can be fed back as a simple hardware contact input regardless of the network transmission cycle and CPU software processing.
In addition, by simplifying and generalizing the signal format, it is possible to consolidate operation commands and the like, thereby simplifying processing and speeding up, and eliminating data transmission delays.

  FIG. 2 is a configuration diagram of a serial encoder conversion device having a monitoring function of a serial encoder according to another embodiment. By reflecting a switch signal in input data of a network I / O device, a feedback pulse to the controller 1 is shown. It can be applied to positioning completion determination in other multi-axis links as an I / O station on the network. it can.

According to the present invention, the controller can acquire position data that is newer and earlier than the position data that the network servo outputs as network data, and can confirm the completion of positioning in the position control earlier than via the network. As a result, the position control performance can be improved.
Furthermore, since it can be handled as a general-purpose input signal, it can be handled as general-purpose communication data by combining multi-axis feedback data, and there is an effect that both performance and wiring saving can be achieved.

It is a block diagram of the serial encoder converter which has the monitoring function of the serial encoder which concerns on this invention. It is a block diagram of the serial encoder converter which has the monitoring function of the serial encoder which concerns on other embodiment of this invention. It is a block diagram of the conventional servo control system. It is explanatory drawing of the servo control system shown in FIG.

Explanation of symbols

1 Controller 2 Servo Amplifier 3 Motor 4 Serial Encoder Converter 5, 8 Receiving IC
6 Serial data 7 Contact signal

Claims (3)

  A serial encoder conversion device used in a network servo system for driving a motor via a servo amplifier in response to a command from a controller, wherein the one or more receiving devices directly receive pulse data output from the encoder, and the reception A serial encoder conversion device comprising a monitoring function of the pulse data, wherein the pulse data received by the device is converted into digital data by a general-purpose contact signal system and output to the controller.   2. A function of converting received serial encoder information into a bit string and converting it into a contact signal corresponding to a switch input, and a function of reflecting the contact signal in input data of a network I / O device. Serial encoder converter.   The serial encoder conversion device according to claim 1, a controller that receives a digital signal from the serial encoder conversion device, a servo amplifier that drives a motor according to a command from the controller, and a motor that is driven by the servo amplifier And an encoder fixed to the motor and having a pulse count function, a serial data signal from the encoder is fed back to the serial encoder conversion device and the servo amplifier. A network servo system characterized by positioning completion judgment.

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