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Cat. No. I55E-EN-03
Programmable Controller
SYSMAC CJ-series
CJ1W-MCH72
Motion Control Unit
OPERATION MANUAL
Notice
OMRON products are manufactured for use by a trained operator and only for the purposes described in this manual.
The following conventions are used to classify and explain the precautions in this manual. Always heed the information provided with them.
!WARNING Indicates information that, if not heeded, could possibly result in serious injury or loss of life.
!Caution Indicates information that, if not heeded, could possibly result in minor or relatively serious injury, damage to the product or faulty operation.
OMRON product references
All OMRON products are capitalized in this manual.
The first letter of the word Unit is also capitalized when it refers to an OMRON product, regardless of whether it appears in the proper name of the product.
The abbreviation PLC means Programmable Logic Controller.
Visual aids
The following headings appear in the left column of the manual to help you locate different types of information.
Note Indicates information of particular interest for efficient and convenient operation of the product.
iii
Trademarks and copyrights
MECHATROLINK is a registered trademark of Yaskawa Corporation. Trajexia is a registered trademark of OMRON.
All other product names, company names, logos or other designations mentioned herein are trademarks of their respective owners.
Copyright
Copyright © 2009 OMRON
All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form, or by any means, mechanical, electronic, photocopying, recording, or otherwise, without the prior written permission of OMRON.
No patent liability is assumed with respect to the use of the information contained herein. Moreover, because OMRON is constantly striving to improve its high-quality products, the information contained in this manual is subject to change without notice. Every precaution has been taken in the preparation of this manual. Nevertheless, OMRON assumes no responsibility for errors or omissions. Neither is any liability assumed for damages resulting from the use of the information contained in this publication.
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TABLE OF CONTENTS
Precautions |
vii |
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1 |
Intended audience .................................................................................................................................................... |
vii |
2 |
General precautions ................................................................................................................................................. |
vii |
3 |
Safety precautions.................................................................................................................................................... |
vii |
4 |
Operating environment precautions........................................................................................................................ |
viii |
5 |
Application precautions ............................................................................................................................................ |
ix |
6 Conformance to EC Directives ................................................................................................................................. |
xi |
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SECTION 1 |
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Introduction |
1 |
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1-1 |
Overview.................................................................................................................................................................... |
1 |
1-2 |
System philosophy..................................................................................................................................................... |
2 |
1-3 |
Motion control concepts ............................................................................................................................................ |
4 |
1-4 |
Servo system principles ........................................................................................................................................... |
13 |
1-5 |
Trajexia system architecture .................................................................................................................................. |
16 |
1-6 |
Cycle time ............................................................................................................................................................... |
17 |
1-7 |
Program control and multi-tasking .......................................................................................................................... |
22 |
1-8 |
Motion sequence and axes ....................................................................................................................................... |
23 |
1-9 |
Motion buffers ....................................................................................................................................................... |
31 |
1-10 |
Mechanical system................................................................................................................................................... |
33 |
1-11 |
Axis numbers ........................................................................................................................................................... |
34 |
SECTION 2 |
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Installation and wiring |
35 |
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2-1 |
Unit components ...................................................................................................................................................... |
35 |
2-2 |
Wiring ...................................................................................................................................................................... |
40 |
2-3 |
Installation ............................................................................................................................................................... |
50 |
2-4 |
Specifications........................................................................................................................................................... |
55 |
SECTION 3 |
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Data exchange |
59 |
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3-1 |
Introduction.............................................................................................................................................................. |
59 |
3-2 |
Memory areas........................................................................................................................................................... |
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3-3 |
Data.......................................................................................................................................................................... |
62 |
3-4 |
FINS commands ...................................................................................................................................................... |
65 |
SECTION 4 |
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BASIC commands |
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4-1 |
Categories ................................................................................................................................................................ |
73 |
4-2 |
All BASIC commands ............................................................................................................................................. |
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SECTION 5 |
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Examples |
267 |
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5-1 |
How-to’s ................................................................................................................................................................ |
268 |
5-2 |
Practical examples ................................................................................................................................................. |
320 |
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TABLE OF CONTENTS |
SECTION 6 |
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Troubleshooting |
347 |
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6-1 |
Items to Check First............................................................................................................................................... |
348 |
6-2 |
Error Indicators ...................................................................................................................................................... |
349 |
6-3 |
Troubleshooting Errors .......................................................................................................................................... |
350 |
6-4 |
Miscellaneous ........................................................................................................................................................ |
356 |
Revision history |
361 |
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vi
Intended audience |
1 |
Precautions
1 Intended audience
This manual is intended for the following personnel, who must also have knowledge of electrical systems (an electrical engineer or the equivalent).
•Personnel in charge of installing FA systems.
•Personnel in charge of designing FA systems.
•Personnel in charge of managing FA systems and facilities.
2 General precautions
The user must operate the product according to the performance specifications described in the operation manuals.
Before using the product under conditions which are not described in the manual or applying the product to nuclear control systems, railroad systems, aviation systems, vehicles, combustion systems, medical equipment, amusement machines, safety equipment, and other systems, machines, and equipment that may have a serious influence on lives and property if used improperly, consult your OMRON representative.
Make sure that the ratings and performance characteristics of the product are sufficient for the systems, machines, and equipment, and be sure to provide the systems, machines, and equipment with double safety mechanisms.
This manual provides information for using the CJ1W-MCH72. Be sure to read this manual before attempting to use the Unit and keep this manual close at hand for reference during operation.
!WARNING It is extremely important that the CJ1W-MCH72 and related devices be used for the specified purpose and under the specified conditions, especially in applications that can directly or indirectly affect human life. You must consult with your OMRON representative before applying the CJ1W-MCH72 and related devices to the above mentioned applications.
3 Safety precautions
!WARNING Never short-circuit the positive and negative terminals of the batteries, charge the batteries, disassemble them, deform them by applying pressure, or throw them into a fire.
The batteries may explode, combust or leak liquid.
!WARNING The CJ1W-MCH72 outputs will go off due to overload of the output transistors (protection). As a countermeasure for such problems, external safety measures must be provided to ensure safety in the system.
!WARNING The CJ1W-MCH72 will turn off the WDOG when its self-diagnosis function detects any error. As a countermeasure for such errors, external safety measures must be provided to ensure safety in the system.
!WARNING Never attempt to disassemble any Units while power is being supplied. Doing so may result in serious electric shock.
!WARNING Do not attempt to disassemble, repair, or modify any Units. Any attempt to do so may result in malfunction, fire, or electric shock.
!WARNING Never touch any of the terminals while power is being supplied. Doing so may result in serious electric shock.
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Operating environment precautions |
4 |
!WARNING Provide safety measures in external circuits (i.e., not in the Programmable Controller) to ensure safety in the system if an abnormality occurs due to malfunction of the PLC, malfunction of the CJ1W-MCH72, or external factors affecting the operation of the PLC or CJ1W-MCH72. Not providing sufficient safety measures may result in serious accidents.
•Emergency stop circuits, interlock circuits, limit circuits, and similar safety measures must be provided in external control circuits.
•The PLC will turn OFF all outputs when its self-diagnosis function detects any error or when a severe failure alarm (FALS) instruction is executed. As a countermeasure for such errors, external safety measures must be provided to ensure safety in the system.
•The PLC or CJ1W-MCH72 outputs may remain ON or OFF due to deposits on or burning of the output relays, or destruction of the output transistors. As a countermeasure for such problems, external safety measures must be provided to ensure safety in the system.
•When the 24 V DC output (service power supply to the PLC) is overloaded or shortcircuited, the voltage may drop and result in the outputs being turned OFF. As a countermeasure for such problems, external safety measures must be provided to ensure safety in the system.
•External safety measures must also be taken to ensure safety in the event of unexpected operation when connecting or disconnecting the connectors of the CJ1W-MCH72.
!Caution User programs written to the CJ1W-MCH72 will not be automatically backed up in the CJ1W-MCH72 flash memory (flash memory function).
!Caution Tighten the screws on the terminal block of the Power Supply Unit to the torque specified in this manual. Loose screws may result in burning or malfunction.
!Caution When positioning to a position determined using the teaching function, set the position designation setting in the positioning sequence to absolute positioning. If it is set to relative positioning, positioning will be performed to a position other than the one obtained with the teaching function.
!Caution Execute online edit only after confirming that no adverse effects will be caused by extending the cycle time. Otherwise, the input signals may not be readable.
!Caution Confirm the safety of the destination node before transferring a program to the node or changing the contents of I/O memory. Doing either of these without confirming safety may result in injury.
!Caution Do not save data into the flash memory during memory operation or while the motor is running. Otherwise, unexpected operation may be caused.
4 Operating environment precautions
!Caution Do not operate the control system in the following locations:
•Locations subject to direct sunlight.
•Locations subject to temperatures or humidity outside the range specified in the specifications.
•Locations subject to condensation as the result of severe changes in temperature.
•Locations subject to corrosive or flammable gases.
•Locations subject to dust (especially iron dust) or salts.
•Locations subject to exposure to water, oil, or chemicals.
•Locations subject to shock or vibration.
!Caution Take appropriate and sufficient countermeasures when installing systems in the following locations:
•Locations subject to static electricity or other forms of noise.
•Locations subject to strong electromagnetic fields.
viii
Application precautions |
5 |
•Locations subject to possible exposure to radioactivity.
•Locations close to power supplies.
!Caution The operating environment of the PLC System can have a large effect on the longevity and reliability of the system. Improper operating environments can lead to malfunction, failure, and other unforeseeable problems with the PLC System. Be sure that the operating environment is within the specified conditions at installation and remains within the specified conditions during the life of the system.
5 Application precautions
!WARNING Do not start the system until you check that the axes are present and of the correct type. The numbers of the axis will change if MECHATROLINK-II network errors occur during start-up or if the MECHATROLINK-II network configuration changes.
!WARNING Check the user program for proper execution before actually running it in the Unit. Not checking the program may result in an unexpected operation.
!WARNING Observe the following precautions when using the CJ1W-MCH72 or the PLC. Failure to abide by the following precautions could lead to serious or possibly fatal injury. Always heed these precautions.
•Always connect to a ground of 100 Ω or less when installing the Units. Not connecting to a ground of 100 Ω or less may result in electric shock.
•Always turn OFF the power supply to the PLC before attempting any of the following. Not turning OFF the power supply may result in malfunction or electric shock.
-Mounting or dismounting Power Supply Units, I/O Units, CPU Units, Memory Cassettes, or any other Units.
-Assembling the Units.
-Setting DIP switches or rotary switches.
-Connecting cables or wiring the system.
-Connecting or disconnecting the connectors.
!Caution Be sure that all mounting screws, terminal screws, and cable connector screws are tightened to the torque specified in this manual. Incorrect tightening torque may result in malfunction.
!Caution Wire correctly. Incorrect wiring may result in burning.
!Caution Mount the Unit only after checking the terminal block completely.
!Caution Resume operation only after transferring to the new CJ1W-MCH72 Unit the contents of the VR and table memory required for operation. Not doing so may result in an unexpected operation.
!Caution When replacing parts, be sure to confirm that the rating of a new part is correct. Not doing so may result in malfunction or burning.
!Caution Use the dedicated connecting cables specified in operation manuals to connect the Units. Using commercially available RS-232C computer cables may cause failures in external devices or the Unit.
!Caution Outputs may remain on due to a malfunction in the built-in transistor outputs or other internal circuits. As a countermeasure for such problems, external safety measures must be provided to ensure the safety of the system.
!Caution Failure to abide by the following precautions may lead to faulty operation of the PLC, the CJ1W-MCH72 or the system, or could damage the PLC or CJ1W-MCH72. Always heed these precautions.
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Application precautions |
5 |
•Fail-safe measures must be taken by the customer to ensure safety in the event of incorrect, missing, or abnormal signals caused by broken signal lines, momentary power interruptions, or other causes.
•Interlock circuits, limit circuits, and similar safety measures in external circuits (i.e., not in the Programmable Controller) must be provided by the customer.
•Install external breakers and take other safety measures against short-circuiting in external wiring. Insufficient safety measures against short-circuiting may result in burning.
•Install the PLC Unit as far as possible from sources of strong harmonic noise.
•Lock the sliders securely until they click into place when connecting the Power Supply Unit, CPU Unit, I/O Units, Special I/O Units, or CPU Bus Units. Functions may not work correctly if the sliders are not locked properly.
•Always attach the End Cover provided with the CPU Unit to the Unit on the right end of the PLC. The CJ-series PLC will not operate properly if the End Cover is not attached.
•Always use the power supply voltages specified in the operation manuals. An incorrect voltage may result in malfunction or burning.
•Take appropriate measures to ensure that the specified power with the rated voltage and frequency is supplied in places where the power supply is unstable. An incorrect power supply may result in malfunction.
•Use crimp terminals for wiring. Do not connect bare stranded wires directly to terminals. Connection of bare stranded wires may result in burning.
•Leave the label attached to the Unit when wiring. Removing the label may result in malfunction if foreign matter enters the Unit.
•Remove the label after the completion of wiring to ensure proper heat dissipation. Leaving the label attached may result in malfunction.
•Do not apply voltages to the Input Units in excess of the rated input voltage. Excess voltages may result in burning.
•Do not apply voltages or connect loads to the Output Units in excess of the maximum switching capacity. Excess voltage or loads may result in burning.
•Check the user program for proper execution before actually running it on the Unit. Not checking the program may result in an unexpected operation.
•Be sure that the terminal blocks, Memory Units, expansion cables, and other items with locking devices are properly locked into place. Improper locking may result in malfunction.
•Double-check all wiring and switch settings before turning ON the power supply. Incorrect wiring may result in burning.
•Disconnect the LR and GR terminals when performing insulation resistance or withstand voltage tests. Not disconnecting the functional ground terminal may result in burning.
!Caution Confirm that no adverse effect will occur in the system before attempting any of the following. Not doing so may result in an unexpected operation.
•Changing the operating mode of the PLC (including the operating mode at power up).
•Force-setting/force-resetting any bit in memory.
•Changing the present value of any word or any set value in memory.
!Caution Do not pull on the cables or bend the cables beyond their natural limit. Doing either of these may break the cables.
!Caution Do not place objects on top of the cables or other wiring lines. Doing so may break the cables.
!Caution Resume operation only after transferring the system parameter data to the CJ1WMCH72 and saving the data to flash memory. Not doing so may result in an unexpected operation.
!Caution Confirm that set parameters and data operate properly.
!Caution Check the pin numbers before wiring the connectors.
x
Conformance to EC Directives |
6 |
!Caution Perform wiring according to specified procedures.
!Caution Before touching a Unit, be sure to first touch a grounded metallic object in order to discharge any static build-up. Not doing so may result in malfunction or damage.
!Caution Do not drop the Unit or subject it to abnormal shock or vibration.
!Caution Confirm the safety of the destination node before transferring a program to the node or changing the contents of I/O memory. Doing either of these without confirming safety may result in injury.
6 Conformance to EC Directives
6-1 Applicable directives
• EMC Directives
6-2 Concepts
OMRON devices that comply with EC Directives also conform to the related EMC standards so that they can be more easily built into other devices or machines. The actual products have been checked for conformity to EMC standards (see the following note). Whether the products conform to the standards in the system used by the customer, however, must be checked by the customer.
EMC-related performance of the OMRON devices that comply with EC Directives will vary depending on the configuration, wiring, and other conditions of the equipment or control panel in which the OMRON devices are installed. The customer must, therefore, perform final checks to confirm that devices and the overall machine conform to EMC standards.
Note Applicable EMC (Electromagnetic Compatibility) standards are as follows:
•EMS (Electromagnetic Susceptibility): EN61000-6-2
•EMI (Electromagnetic Interference): EN61000-6-4 (Radiated emission: 10-m regulations)
6-3 Conformance to EC Directives
The CJ1W-MCH72 complies with EC Directives. To ensure that the machine or device in which a CJ1W-MCH72 is used complies with EC Directives, the CJ1W-MCH72 must be installed as follows:
1The CJ1W-MCH72 must be installed within a control panel.
2Reinforced insulation or double insulation must be used for the DC power supplies used for the communications and I/O power supplies.
3Units complying with EC Directives also conform to the Common Emission Standard (EN61000-6-4). With regard to the radiated emission (10-m regulations), countermeasures will vary depending on the devices connected to the control panel, wiring, the configuration of the system, and other conditions. The customer must, therefore, perform final checks to confirm that devices and the overall machine conform to EC Directives.
xi
Conformance to EC Directives |
6 |
6-4 Installation within Control Panel
Unnecessary clearance in cable inlet or outlet ports, operation panel mounting holes, or in the control panel door may cause electromagnetic wave leakage or interference. In this case, the product may fail to meet EC Directives. In order to prevent such interference, fill clearances in the control panel with conductive packing. (In places where conductive packing comes in contact with the control panel, ensure electrical conductivity by removing the paint coating or masking these parts when painting.)
xii
Overview |
Section 1-1 |
SECTION 1
Introduction
1-1 Overview
The CJ1W-MCH72 is a Trajexia-style motion control unit that can be connected to a CJ1-series PLC. It acts as an interface between PLC systems and Trajexia-style motion control systems.
Trajexia is the OMRON motion platform that offers you the performance and the ease of use of a dedicated motion system. It maximum flexibility and scalability. At the heart of Trajexia lies the TJ1 multi-tasking motion coordinator. Powered by a 32-bit DSP, it can do motion tasks such as e-cam, e-gearbox, registration control and interpolation, all using simple motion commands.
The CJ1W-MCH72 has the following features:
•A MECHATROLINK-II connection for a MECHATROLINK-II network with up to 30 axes. The motion cycle time is selectable: 0.5 ms, 1 ms, 2 ms or 4 ms.
•An Encoder Interface connection. It supports the main absolute encoder protocols allowing the connection of an external encoder to the system.
•The possibility to exchange analogue and digital input and output data with the PLC CPU.
•A wide choice of rotary, linear and direct-drive servos as well as Inverters are available to fit your needs in compactness, performance and reliability. The Inverters connected to the MECHATROLINK-II are driven at the same update cycle time as the Servo Drivers.
Note The Trajexia system supports 3 kinds of MECHATROLINK-II slaves: Servo Drivers, Inverters and I/Os.
The CJ1W-MCH72 only supports 2 kinds of MECHATROLINK-II slaves: Servo Drivers and Inverters. It does not support I/Os.
1
System philosophy |
Section 1-2 |
1-2 System philosophy
CJ1W-MCH72 |
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AXIS CONTROL LOOP |
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Bufferff |
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AXIS TYPE |
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Positioniti |
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Program Buffer |
profilefile |
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gereratort |
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ENC |
BASIC PROGRAMS |
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All other |
Process 1 |
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Servo |
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Process 2 |
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Servo Driver |
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Process 3 |
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Positioniti |
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Loop |
MOTOR |
Process 14 |
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Speed Loop |
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Torque |
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Comms |
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Loop |
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I/O |
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BUILT-IN TJ1-PLC interface
The system philosophy is centred around the relationship between:
•System architecture
•Cycle time
•Program control and multi-tasking
•Motion sequence and axes
•Motion buffers
A clear understanding of the relationship between these concepts is necessary to obtain the best results for the Trajexia system.
1-2-1 Glossary
1-2-1-1 Motion sequence
The Motion Sequence is responsible for controlling the position of the axes.
1-2-1-2 Servo period
Defines the frequency at which the Motion Sequence is executed. The servo period must be set according to the configuration of the physical axes. The available settings are 0.5 ms, 1 ms, 2 ms or 4 ms.
1-2-1-3 Cycle time
Is the time needed to execute one complete cycle of operations in the CJ1WMCH72. The cycle time is divided in 4 time slices of equal time length, called "CPU Tasks". The cycle time is 1ms if SERVO_PERIOD = 0.5 ms or SERVO_PERIOD = 1 ms, 2 ms if the SERVO_PERIOD = 2 ms and 4 ms if the
SERVO_PERIOD = 4 ms
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System philosophy |
Section 1-2 |
1-2-1-4 CPU tasks |
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The operations executed in each CPU task are:
CPU task |
Operation |
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First CPU task |
Motion Sequence |
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Low priority process |
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Second CPU task |
High priority process |
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Third CPU task |
Motion Sequence (only if SERVO_PERIOD = 0.5 ms) |
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LED Update |
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High priority process |
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Fourth CPU task |
External Communications |
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1-2-1-5 Program
A program is a piece of BASIC code.
1-2-1-6 Process
Is a program in execution with a certain priority assigned. Process 0 to 12 are Low priority processes and Process 13 and 14 are High priority processes. First the process priority, High or Low, and then the process number, from high to low, will define to which CPU task the process will be assigned.
3
Motion control concepts |
Section 1-3 |
1-3 Motion control concepts
The CJ1W-MCH72 offers these types of positioning control operations:
1Point-to-Point (PTP) control
2Continuous Path (CP) control
3Electronic Gearing (EG) control.
This section introduces some of the commands and parameters used in the
BASIC programming of the motion control application.
Coordinate system
Positioning operations performed by the CJ1W-MCH72 are based on an axis coordinate system. The CJ1W-MCH72 converts the position data from either the connected Servo Driver or the connected encoder into an internal absolute coordinate system.
The engineering unit that specifies the distances of travelling can be freely defined for each axis separately. The conversion is performed through the use of the unit conversion factor, which is defined by the UNITS axis parameter. The origin point of the coordinate system can be determined using the DEFPOS command. This command re-defines the current position to zero or any other value.
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MOVEABS(30) |
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MOVE(60) |
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MOVEABS(50) |
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MOVE(50) |
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MOVE(30) |
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A |
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A move is defined in either absolute or relative terms. An absolute move takes the axis (A) to a specific predefined position with respect to the origin point. A relative move takes the axis from the current position to a position that is defined relative to this current position. The figure shows an example of relative (command MOVE) and absolute (command MOVEABS) linear moves.
1-3-1 PTP control
In point-to-point positioning, each axis is moved independently of the other axis. The CJ1W-MCH72 supports the following operations:
•Relative move
•Absolute move
•Continuous move forward
•Continuous move reverse.
4
Motion control concepts |
Section 1-3 |
1-3-1-1 Relative and absolute moves
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MOVEABS(100) AXIS(0) |
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MOVEABS(50) AXIS(1) |
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To move a single axis either the command MOVE for a relative move or the command MOVEABS for an absolute move is used. Each axis has its own move characteristics, which are defined by the axis parameters.
Suppose a control program is executed to move from the origin to an axis no. 0 (A) coordinate of 100 and axis no. 1 (B) coordinate of 50. If the speed parameter is set to be the same for both axes and the acceleration and deceleration rate are set sufficiently high, the movements for axis 0 and axis 1 will be as shown in the figure.
At start, both the axis 0 and axis 1 moves to a coordinate of 50 over the same duration of time. At this point, axis 1 stops and axis 0 continues to move to a coordinate of 100.
The move of a certain axis is determined by the axis parameters. Some relevant parameters are:
Parameter |
Description |
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UNITS |
Unit conversion factor |
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ACCEL |
Acceleration rate of an axis in units/s2 |
DECEL |
Deceleration rate of an axis in units/s2 |
SPEED |
Demand speed of an axis in units/s |
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Defining moves
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DECEL=10 |
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SPEED=10 |
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MOVE(40) |
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5
Motion control concepts |
Section 1-3 |
The speed profile in this figure shows a simple MOVE operation. Axis A is the time, axis B is the speed. The UNITS parameter for this axis has been defined for example as meters. The required maximum speed has been set to 10 m/s. In order to reach this speed in one second and also to decelerate to zero speed again in one second, both the acceleration as the deceleration rate have been set to 10 m/s2. The total distance travelled is the sum of distances travelled during the acceleration, constant speed and deceleration segments. Suppose the distance moved by the MOVE command is 40 m, the speed profile is given by the figure.
B |
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ACCEL=5 |
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DECEL=10 |
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SPEED=10 |
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MOVE(40) |
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A |
6 |
The two speed profiles in these figures show the same movement with an acceleration time respectively a deceleration time of 2 seconds. Again, Axis A is the time, axis B is the speed.
B |
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ACCEL=10 |
10 |
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DECEL=5 |
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SPEED=10 |
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MOVE(40) |
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A |
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Move calculations
The following equations are used to calculate the total time for the motion of the axes.
•The moved distance for the MOVE command is D.
•The demand speed is V.
•The acceleration rate is a.
•The deceleration rate is d.
Acceleration time |
= |
Acceleration distance |
= |
Deceleration time |
= |
6
Motion control concepts |
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Section 1-3 |
Deceleration distance |
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Constant speed distance |
= |
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Total time |
= |
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1-3-1-2 Continuous moves
The FORWARD and REVERSE commands can be used to start a continuous movement with constant speed on a certain axis. The FORWARD command moves the axis in positive direction and the REVERSE command in negative direction. For these commands also the axis parameters ACCEL and SPEED apply to specify the acceleration rate and demand speed.
Both movements can be cancelled by using either the CANCEL or RAPIDSTOP command. The CANCEL command cancels the move for one axis and RAPIDSTOP cancels moves on all axes. The deceleration rate is set by DECEL.
1-3-2 CP control
Continuous Path control enables to control a specified path between the start and end position of a movement for one or multiple axes. The CJ1W-MCH72 supports the following operations:
•Linear interpolation
•Circular interpolation
•CAM control.
1-3-2-1 Linear interpolation
3
2 |
1 |
B
A
7
Motion control concepts |
Section 1-3 |
In applications it can be required for a set of motors to perform a move operation from one position to another in a straight line. Linearly interpolated moves can take place among several axes. The commands MOVE and MOVEABS are also used for the linear interpolation. In this case the commands will have multiple arguments to specify the relative or absolute move for each axis.
Consider the three axis move in a 3-dimensional plane in the figure. It corresponds to the MOVE(50,50,50) command. The speed profile of the motion along the path is given in the diagram. The three parameters SPEED, ACCEL and DECEL that determine the multi axis movement are taken from the corresponding parameters of the base axis. The MOVE command computes the various components of speed demand per axis.
A is the time axis, B is the speed axis.
1-3-2-2 Circular interpolation
50
-50 |
0 |
50 |
It may be required that a tool travels from the starting point to the end point in an arc of a circle. In this instance the motion of two axes is related via a circular interpolated move using the MOVECIRC command.
Consider the diagram in the figure. It corresponds to the MOVECIRC(-100,0,- 50,0,0) command. The centre point and desired end point of the trajectory relative to the start point and the direction of movement are specified. The MOVECIRC command computes the radius and the angle of rotation. Like the linearly interpolated MOVE command, the ACCEL, DECEL and SPEED variables associated with the base axis determine the speed profile along the circular move.
1-3-2-3 CAM control
B
A
8
Motion control concepts |
Section 1-3 |
Additional to the standard move profiles the CJ1W-MCH72 also provides a way to define a position profile for the axis to move. The CAM command moves an axis according to position values stored in the CJ1W-MCH72 Table array. The speed of travelling through the profile is determined by the axis parameters of the axis.
The figure corresponds to the command CAM(0,99,100,20). A is the time axis, B is the position axis.
1-3-3 EG control
Electronic Gearing control allows you to create a direct gearbox link or a linked move between two axes. The MC Unit supports the following operations.
•Electronic gearbox
•Linked CAM
•Linked move
•Adding axes
1-3-3-1 Electronic gearbox
B |
2:1 |
1:1 |
1:2 |
A |
The CJ1W-MCH72 is able to have a gearbox link from one axis to another as if there is a physical gearbox connecting them. This can be done using the CONNECT command in the program. In the command the ratio and the axis to link to are specified.
In the figure, A is the Master axis, and B is the CONNECT axis.
Axes |
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Ratio |
CONNECT command |
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1 |
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1:1 |
CONNECT(1,0) AXIS(1) |
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2:1 |
CONNECT(2,0) AXIS(1) |
1:2 |
CONNECT(0.5,0) AXIS(1) |
9
Motion control concepts |
Section 1-3 |
1-3-3-2 Linked CAM control |
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B
A
Next to the standard CAM profiling tool the CJ1W-MCH72 also provides a tool to link the CAM profile to another axis. The command to create the link is called CAMBOX. The travelling speed through the profile is not determined by the axis parameters of the axis but by the position of the linked axis. This is like connecting two axes through a cam.
In the figure, A is the Master axis (0) position, and B is the CAMBOX Axis (1) position.
1-3-3-3 Linked move
B |
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C |
D |
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A |
The MOVELINK command provides a way to link a specified move to a master axis. The move is divided into an acceleration, deceleration and constant speed part and they are specified in master link distances. This can be particularly useful for synchronizing two axes for a fixed period.
The labels in the figure are:
ATime axis.
BSpeed axis.
CMaster axis (1).
DSynchronized.
EMOVELINK axis (0).
10
Motion control concepts |
Section 1-3 |
1-3-3-4 Adding axes
B
BASE(0)
ADDAX(2)
FORWARD MOVE(100) AXIS(2) MOVE(-60) AXIS(2)
A
B
A
B |
A |
It is very useful to be able to add all movements of one axis to another. One possible application is for instance changing the offset between two axes linked by an electronic gearbox. The CJ1W-MCH72 provides this possibility by using the ADDAX command. The movements of the linked axis will consists of all movements of the actual axis plus the additional movements of the master axis.
In the figure, A is the time axis and B is the speed axis.
1-3-4 Other operations
1-3-4-1 Cancelling moves
In normal operation or in case of emergency it can be necessary to cancel the current movement from the buffers. When the CANCEL or RAPIDSTOP commands are given, the selected axis respectively all axes will cancel their current move.
1-3-4-2 Origin search
The encoder feedback for controlling the position of the motor is incremental. This means that all movement must be defined with respect to an origin point. The DATUM command is used to set up a procedure whereby the CJ1WMCH72 goes through a sequence and searches for the origin based on digital inputs and/or Z-marker from the encoder signal.
11
Motion control concepts |
Section 1-3 |
1-3-4-3 Print registration |
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The CJ1W-MCH72 can capture the position of an axis in a register when an event occurs. The event is referred to as the print registration input. On the rising or falling edge of an input signal, which is either the Z-marker or an input, the CJ1W-MCH72 captures the position of an axis in hardware. This position can then be used to correct possible error between the actual position and the desired position. The print registration is set up by using the REGIST command.
The position is captured in hardware, and therefore there is no software overhead and no interrupt service routines, eliminating the need to deal with the associated timing issues.
1-3-4-4 Merging moves
B
MERGE=0
A
B
MERGE=1
A
If the MERGE axis parameter is set to 1, a movement is always followed by a subsequent movement without stopping. The figures show the transitions of two moves with MERGE value 0 and value 1.
In the figure, A is the time axis and B is the speed axis.
1-3-4-5 Jogging
Jogging moves the axes at a constant speed forward or reverse by manual operation of the digital inputs. Different speeds are also selectable by input. Refer to the FWD_JOG, REV_JOG and FAST_JOG axis parameters.
12
Servo system principles |
Section 1-4 |
1-4 Servo system principles
The servo system used by and the internal operation of the CJ1W-MCH72 are briefly described in this section.
1-4-1 Semi-closed loop system
The servo system of the CJ1W-MCH72 uses a semi-closed or inferred closed loop system. This system detects actual machine movements by the rotation of the motor in relation to a target value. It calculates the error between the target value and actual movement, and reduces the error through feedback.
1-4-2 Internal operation of the CJ1W-MCH72
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Inferred closed loop systems occupy the mainstream in modern servo systems applied to positioning devices for industrial applications. The figure shows the basic principle of the servo system as used in the CJ1W-MCH72.
1The CJ1W-MCH72 performs actual position control. The main input of the controller is the Following Error, which is the calculated difference between the demand position and the actual measured position.
2The Position Controller calculates the required speed reference output determined by the Following Error and possibly the demanded position and the measured position. The speed reference is provided to the Servo Driver.
3The Servo Driver controls the rotational speed of the servo motor corresponding to the speed reference. The rotational speed is proportional to the speed reference.
4The rotary encoder generates the feedback pulses for both the speed feedback within the Servo Driver speed loop and the position feedback within the CJ1W-MCH72 position loop.
The labels in the figure are:
ACJ1W-MCH72.
BServo system.
CDemand position.
DPosition control.
ESpeed reference.
FSpeed control.
GMotor.
HEncoder.
IMeasured speed.
JMeasured position.
13
Servo system principles |
Section 1-4 |
1-4-3 Motion control algorithm
The servo system controls the motor by continuously adjusting the speed reference to the Servo Driver. The speed reference is calculated by the motion control algorithm of the CJ1W-MCH72, which is explained in this section.
Kvff ∑
Kp
A B
C
Ki ∑
Kd ∆ |
Kov ∆ |
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D
The motion control algorithm uses the demand position (A), the measured position (D) and the Following Error (B) to determine the speed reference. The Following Error is the difference between the demanded and measured position. The demand position, the measured position and the Following Error are represented by the axis parameters MPOS, DPOS and FE. Five gain values have been implemented for the user to be able to configure the correct control operation for each application.
C is the output signal.
•Proportional gain
The proportional gain Kp creates an output Op that is proportional to the Following Error E.
Op = Kp · E
All practical systems use proportional gain. For many just using this gain parameter alone is sufficient. The proportional gain axis parameter is called
P_GAIN.
•Integral gain
The integral gain Ki creates an output Oi that is proportional to the sum of the Following Errors that have occurred during the system operation.
Oi = Ki · ΣE
Integral gain can cause overshoot and so is usually used only on systems working at constant speed or with slow accelerations. The integral gain axis parameter is called I_GAIN.
•Derivative gain
The derivative gain Kd produces an output Od that is proportional to the change in the Following Error E and speeds up the response to changes in error while maintaining the same relative stability.
Od = Kd · ∆E
Derivative gain may create a smoother response. High values may lead to oscillation. The derivative gain axis parameter is called D_GAIN.
•Output speed gain
The output speed gain Kov produces an output Oov that is proportional to the change in the measured position Pm and increases system damping.
Oov = Kov · ∆Pm
14
Servo system principles |
Section 1-4 |
The output speed gain can be useful for smoothing motions but will generate high Following Errors. The output speed gain axis parameter is called OV_GAIN.
•Speed feed forward gain
The speed feedforward gain Kvff produces an output Ovff that is proportional to the change in demand position Pd and minimizes the Following Error at high speed.
Ovff = Kvff · ∆Pd
The parameter can be set to minimise the Following Error at a constant machine speed after other gains have been set. The speed feed forward gain axis parameter is called VFF_GAIN.
The default settings are given in the table along with the resulting profiles.
Fractional values are allowed for gain settings.
Gain |
Default value |
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Proportional gain |
0.1 |
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Integral gain |
0.0 |
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Derivative gain |
0.0 |
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Output speed gain |
0.0 |
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Speed feedforward gain |
0.0 |
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15
Trajexia system architecture |
Section 1-5 |
1-5 Trajexia system architecture
The system architecture of the Trajexia is dependant upon these concepts:
•Program control
•Motion Sequence
•Motion buffers
•Communication
•Peripherals
These concepts depend upon the value set in the SERVO_PERIOD parameter. The relationship between the value of SERVO_PERIOD and the different concepts of the system architecture are describes as follows.
1-5-1 Program control
Programs make the system work in a defined way. The programs are written in a language similar to BASIC and control the application of the axes and modules. 14 Programs can be executed in parallel. The programs can be set to run at system power-up, started and stopped from other programs and executed from Trajexia Studio.
Programs execute commands to move the axes, control inputs and outputs and make communication via BASIC commands.
1-5-2 Motion sequence
The motion sequence controls the position of all 32 axes with the actions as follows:
•Reading the Motion buffer
•Reading the current Measured Position (MPOS)
•Calculating the next Demanded Position (DPOS)
•Executing the Position loop
•Sending the Axis reference
•Error handling
1-5-3 Motion buffers
Motion buffers are the link between the BASIC commands and the Axis control loop. When a BASIC motion command is executed, the command is stored in one of the buffers. During the next motion sequence, the profile generator executes the movement according to the information in the buffer.
When the movement is finished, the motion command is removed from the buffer.
1-5-4 Communication
The CJ1W-MCH72 can exchange data with memory areas in the PLC. This enables the CJ1W-MCH72 to use the inputs and outputs connected to the PLC. Also, programs in the CJ1W-MCH72 and PLC programs can exchange control and status data.
For more information on communication and data exchange, refer to chapter 3.
1-5-5 Peripherals
All inputs and outputs are used with the set of parameters (IN, OP, AIN, AOUT). The inputs and outputs are automatically detected and mapped in Trajexia. Inverters are considered a peripheral device and have a set of BASIC commands to control them.
16
Cycle time |
Section 1-6 |
1-6 Cycle time
All processes in the Trajexia system are based on the cycle time. The cycle time is divided into four CPU tasks:
•250 s time intervals for a SERVO_PERIOD of 0.5 and 1.0 ms
250 s
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Cycle time = 1ms
•500 s time intervals for a SERVO_PERIOD of 2.0 ms
500 s
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Cycle time = 2 ms
•1 ms time intervals for a SERVO_PERIOD of 4.0 ms
1 ms
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Cycle time = 4 ms
The processes that can be carried out in each time interval depends on the
SERVO_PERIOD that is set.
The operations executed in each CPU task are:
CPU task |
Operation |
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First CPU task |
Motion Sequence |
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Low priority process |
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Second CPU task |
High priority process |
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Third CPU task |
Motion Sequence (only if SERVO_PERIOD=0.5ms) |
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LED Update. |
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High priority process |
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Fourth CPU task |
External Communications |
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Note The Motion sequence execution depends on setting of the SERVO_PERIOD parameter.
1-6-1 Servo period
The SERVO_PERIOD can be set at 0.5, 1, 2 or 4 ms. The processes that take place within the cycle time depend on the setting of the SERVO_PERIOD parameter. The SERVO_PERIOD parameter is a Trajexia parameter that must be set according to the system configuration.
The factory setting is 1ms (SERVO_PERIOD=1000). A change is set only after a restart of the CJ1W-MCH72.
17
Cycle time |
Section 1-6 |
Note Only the Sigma-III Servo Driver and the Sigma-V Servo Driver support the 0.5 ms transmission cycle.
1-6-1-1 Servo period 0.5 ms
CPU task 1 |
Motion sequence |
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Low priority task (0,1,2,3...) |
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CPU task 2 |
High priority task (13,14) |
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CPU task 3 |
Motion sequence |
1ms |
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LED refresh |
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High priority task (13,14) |
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CPU task 4 |
Communication |
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The SERVO_PERIOD has a value of 0.5ms and the motion sequence is executed every 0.5ms.
1-6-1-2 Servo period 1 ms
CPU task 1 |
Motion sequence |
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Low priority task (0,1,2,3...) |
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CPU task 2 |
High priority task (13,14) |
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CPU task 3 |
LED refresh |
1ms |
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High priority task (13,14) |
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CPU task 4 |
Communication |
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The SERVO_PERIOD has a value of 1ms and the motion sequence is executed every 1ms. As the motion sequence is not executed during CPU task 3, there is more time for the program execution. High priority programs run faster.
1-6-1-3 Servo period 2 ms
CPU task 1 |
Motion sequence |
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Low priority task (0,1,2,3...) |
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CPU task 2 |
High priority task (13,14) |
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CPU task 3 |
LED refresh |
2ms |
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High priority task (13,14) |
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CPU task 4 |
Communication |
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The SERVO_PERIOD has a value of 2ms and the motion sequence is executed every 2.0ms.
18
Cycle time |
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Section 1-6 |
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1-6-1-4 Servo period 4 ms |
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CPU task 1 |
Motion sequence |
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Low priority task (0,1,2,3...) |
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CPU task 2 |
High priority task (13,14) |
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CPU task 3 |
LED refresh |
4ms |
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High priority task (13,14) |
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CPU task 4 |
Communication |
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The SERVO_PERIOD has a value of 4ms and the motion sequence is executed every 4.0ms.
1-6-1-5 Servo period rules
The number of axes and MECHATROLINK-II slaves in the Trajexia system determines the value of the SERVO_PERIOD system parameter.
There are 2 types of MECHATROLINK-II slaves that are supported by the CJ1W-MCH72 units:
•Servo Drivers
The CJ1W-MCH72 considers Servo Drivers as axes.
•Inverters
The CJ1W-MCH72 does not consider Inverters as axes.
You should comply with the most restrictive rules when you set the SERVO_PERIOD parameter. An incorrect value of the SERVO_PERIOD parameter results in an incorrect detection of the MECHATROLINK-II slaves.
The most restrictive rules are given in the tables below. For each unit the table lists the maximum number of slaves the unit can control at the given
SERVO_PERIOD setting.
SERVO_PERIOD |
Total number |
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Number of |
Total number of |
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of axes |
MECHATROLINK-II |
MECHATROLINK-II |
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stations |
stations |
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axes |
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inverters |
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0.5 ms |
8 |
4 |
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4 |
4 |
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1.0 ms |
16 |
8 |
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8 |
8 |
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2.0 ms |
16 |
16 |
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8 |
16 |
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4.0 ms |
32 |
30 |
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8 |
30 |
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