Omron C120 User guide

Optical Remote I/O
System Manual
Revised December 1999

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No. 6182
OMRON Corporation
Please read and understand this manual before using the product. Please consult your OMRON
representative if you have any questions or comments.
Read and Understand this Manual
Warranty and Limitations of Liability
WARRANTY
OMRON's exclusive warranty is that the products are free from defects in materials and workmanship for a
period of one year (or other period if specified) from date of sale by OMRON.
OMRON MAKES NO WARRANTY OR REPRESENTATION, EXPRESS OR IMPLIED, REGARDING NON-
INFRINGEMENT, MERCHANTABILITY, OR FITNESS FOR PARTICULAR PURPOSE OF THE
PRODUCTS. ANY BUYER OR USER ACKNOWLEDGES THAT THE BUYER OR USER ALONE HAS
DETERMINED THAT THE PRODUCTS WILL SUITABLY MEET THE REQUIREMENTS OF THEIR
INTENDED USE. OMRON DISCLAIMS ALL OTHER WARRANTIES, EXPRESS OR IMPLIED.
LIMITATIONS OF LIABILITY
OMRON SHALL NOT BE RESPONSIBLE FOR SPECIAL, INDIRECT, OR CONSEQUENTIAL DAMAGES,
LOSS OF PROFITS OR COMMERCIAL LOSS IN ANY WAY CONNECTED WITH THE PRODUCTS,
WHETHER SUCH CLAIM IS BASED ON CONTRACT, WARRANTY, NEGLIGENCE, OR STRICT
LIABILITY.
In no event shall the responsibility of OMRON for any act exceed the individual price of the product on which
liability is asserted.
IN NO EVENT SHALL OMRON BE RESPONSIBLE FOR WARRANTY, REPAIR, OR OTHER CLAIMS
REGARDING THE PRODUCTS UNLESS OMRON'S ANALYSIS CONFIRMS THAT THE PRODUCTS
WERE PROPERLY HANDLED, STORED, INSTALLED, AND MAINTAINED AND NOT SUBJECT TO
CONTAMINATION, ABUSE, MISUSE, OR INAPPROPRIATE MODIFICATION OR REPAIR.

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No. 6182
Application Considerations
SUITABILITY FOR USE
OMRON shall not be responsible for conformity with any standards, codes, or regulations that apply to the
combination of products in the customer's application or use of the products.
At the customer's request, OMRON will provide applicable third party certification documents identifying
ratings and limitations of use that apply to the products. This information by itself is not sufficient for a
complete determination of the suitability of the products in combination with the end product, machine,
system, or other application or use.
The following are some examples of applications for which particular attention must be given. This is not
intended to be an exhaustive list of all possible uses of the products, nor is it intended to imply that the uses
listed may be suitable for the products:
• Outdoor use, uses involving potential chemical contamination or electrical interference, or conditions or
uses not described in this manual.
• Nuclear energy control systems, combustion systems, railroad systems, aviation systems, medical
equipment, amusement machines, vehicles, safety equipment, and installations subject to separate
industry or government regulations.
• Systems, machines, and equipment that could present a risk to life or property.
Please know and observe all prohibitions of use applicable to the products.
NEVER USE THE PRODUCTS FOR AN APPLICATION INVOLVING SERIOUS RISK TO LIFE OR
PROPERTY WITHOUT ENSURING THAT THE SYSTEM AS A WHOLE HAS BEEN DESIGNED TO
ADDRESS THE RISKS, AND THAT THE OMRON PRODUCTS ARE PROPERLY RATED AND INSTALLED
FOR THE INTENDED USE WITHIN THE OVERALL EQUIPMENT OR SYSTEM.
PROGRAMMABLE PRODUCTS
OMRON shall not be responsible for the user's programming of a programmable product, or any
consequence thereof.

No. 6182
3
Disclaimers
CHANGE IN SPECIFICATIONS
Product specifications and accessories may be changed at any time based on improvements and other
reasons.
It is our practice to change model numbers when published ratings or features are changed, or when
significant construction changes are made. However, some specifications of the products may be changed
without any notice. When in doubt, special model numbers may be assigned to fix or establish key
specifications for your application on your request. Please consult with your OMRON representative at any
time to confirm actual specifications of purchased products.
DIMENSIONS AND WEIGHTS
Dimensions and weights are nominal and are not to be used for manufacturing purposes, even when
tolerances are shown.
PERFORMANCE DATA
Performance data given in this manual is provided as a guide for the user in determining suitability and does
not constitute a warranty. It may represent the result of OMRON's test conditions, and the users must
correlate it to actual application requirements. Actual performance is subject to the OMRON Warranty and
Limitations of Liability.
ERRORS AND OMISSIONS
The information in this manual has been carefully checked and is believed to be accurate; however, no
responsibility is assumed for clerical, typographical, or proofreading errors, or omissions.

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Notice:
OMRON products are manufactured for use according to proper procedures by a qualified operator
and only for the purposes described in this manual.
The following conventions are used to indicate and classify precautions in this manual. Always heed
the information provided with them. Failure to heed precautions can result in injury to people or dam-
age to property.
DANGER Indicates an imminently hazardous situation which, if not avoided, will result in death or
serious injury.
WARNING Indicates a potentially hazardous situation which, if not avoided, could result in death or
serious injury.
Caution Indicates a potentially hazardous situation which, if not avoided, may result in minor or
moderate injury, or property damage.
OMRON Product References
All OMRON products are capitalized in this manual. The word “Unit” is also capitalized when it refers
to an OMRON product, regardless of whether or not it appears in the proper name of the product.
The abbreviation “Ch,” which appears in some displays and on some OMRON products, often means
“word” and is abbreviated “Wd” in documentation in this sense.
The abbreviation “PC” means Programmable Controller and is not used as an abbreviation for any-
thing else.
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 ef ficient and convenient operation
of the product.
1, 2, 3... 1. Indicates lists of one sort or another, such as procedures, checklists, etc.
OMRON, 1990
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 permis-
sion 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 informa-
tion contained in this publication.

vi

TABLE OF CONTENTS
vii
PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 Intended Audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 General Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 Operating Environment Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 Application Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1-1 Remote I/O Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1-2 Optical Remote I/O Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 2
System Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-1 Basic System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-2 Multilevel Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-3 C20, P-type, and K-type Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-4 C120 Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-5 C500 Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-6 C1000H and C2000H Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-7 C200H System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-8 Combined Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2-9 Connection Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 3
Operations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-1 Block Diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-2 I/O Link Unit Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-3 Unit Number and I/O Word Allocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3-4 I/O Word Allocation Examples . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 4
Unit Components and Switch Settings . . . . . . . . . . . . . . .
4-1 Remote I/O Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-2 I/O Link Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-3 Optical I/O Units . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4-4 Switch Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 5
System Installation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5-1 Dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5-2 Optical Fiber Cable . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5-3 Wiring .................................................................
SECTION 6
I/O Response Times . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-2 C500 Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-3 C1000H and C2000H Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6-4 C200H Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

TABLE OF CONTENTS
viii
SECTION 7
Error Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7-1 Self-diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7-2 SR and AR Area Flags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7-3 Locating Transfer Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appendices
A Standard Models . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
C Power Supply Wiring Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D Using the C200H-RM001-PV1 with CS1-series PCs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ix
About this Manual:
Basic OMRON PC Systems can be expanded to include Optical Remote I/O Systems. These flexible,
distributed control systems which use optical fiber cable to provide rapid data transmission over long
distances, free from external noise.
This manual has been prepared to explain how to incorporate Optical Remote I/O Systems into C120,
C200H, C500, C1000H, and C2000H PC Systems. It provides the necessary information, such as
system configuration, settings, and I/O word allocation, for connecting Remote I/O Master Units, Re-
mote I/O Slave Units, I/O Link Units, and/or Optical I/O Units.
Before attempting to install or operate an Optical Remote I/O System, be sure to thoroughly familiar-
ize yourself with the information contained herein.
Section 1 introduces Optical Remote I/O Systems and describes their advantages and characteris-
tics.
Section 2 describes the components that go together to construct an Optical Remote I/O System and
the factors required to design a System.
Section 3 describes the LR area used in data transfer between the PCs, the method used to allocate
it to the PCs, and the polling process used to actually transfer data.
Section 4 provides details on Optical Remote I/O Systems and the main Units used to build these
Systems. Parts of the Units, switch setting, and examples of switch settings are provided.
Section 5 provides details on Unit dimensions and optical fiber cable.
Section 6 offers details on response times.
Section 7 describes error indications and error processing. Both indicator lights and dedicated error–
related flags are provided.
Appendix A provides a list of the basic specifications and complete model numbers of products used
in Optical Remote I/O Systems.
Appendix B provides technical specifications.
WARNING Failure to read and understand the information provided in this manual may result in
personal injury or death, damage to the product, or product failure. Please read each
section
in its entirety and be sure you understand the information provided in the section
and related sections before attempting any of the procedures or operations given.
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xi
PRECAUTIONS
This section provides general precautions for using the Optical Remote I/O System and related devices.
The information contained in this section is important for the safe and r eliable application of the Optical Remote I/O
System. Y ou must r ead this section and understand the information contained befor e attempting to set up or operate
the Optical Remote I/O System.
1 Intended Audience . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 General Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 Safety Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 Operating Environment Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 Application Precautions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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3Safety Precautions
xii
1 Intended Audience
This manual is intended for the following personnel, who must also have knowl -
edge 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 relevant 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 ma-
chines, 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 programming and operating the System.
Be sure to read this manual before attempting to use the System and keep this
manual close at hand for reference during operation.
WARNING It is extremely important that the Optical Remote I/O System 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 Optical Remote I/O System to the
above-mentioned applications.
3 Safety Precautions
WARNING Do not attempt to take any Unit apart while the power is being supplied. Doing so
may result in electric shock.
WARNING Do not touch any of the terminals or terminal blocks while the power is being
supplied. Doing so may result in electric shock.
Caution Tighten the screws on the terminal block of the AC Power Supply Unit to the
torque specified in the operation manual. The loose screws may result in burning
or malfunction.
Caution Execute online edit only after confirming that no adverse ef fects will be caused
by extending the cycle time. Otherwise, the input signals may not be readable.
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 Provide safety measures in external circuits (i.e., not in the Programmable
Controller),
including the following items, in order to ensure safety in the system
if an abnormality occurs due to malfunction of the PC or another external factor
affecting the PC operation. Not doing so may result in serious accidents.

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5Application Precautions
xiii
•Emergency stop circuits, interlock circuits, limit circuits, and similar safety
measures must be provided in external control circuits.
•The PC will turn OFF all outputs when its self-diagnosis function detects any
error or when a severe failure alarm (F ALS) instruction is executed. As a coun -
termeasure for such errors, external safety measures must be provided to en -
sure safety in the system.
•The PC outputs may remain ON or OFF due to deposition 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.
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 tempera -
ture.
•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 suf ficient countermeasures when installing systems in the
following locations:
•Locations subject to static electricity or other forms of noise.
•Locations subject to strong electromagnetic fields.
•Locations subject to possible exposure to radioactivity.
•Locations close to power supplies.
Caution The operating environment of the Optical Remote I/O System can have a large
effect on the longevity and reliability of the system. Improper operating environ -
ments
can lead to malfunction, failure, and other unforeseeable problems with
the System. Be sure that the operating environment is within the specified condi -
tions at installation and remains within the specified conditions during the life of
the System.
5 Application Precautions
Observe the following precautions when using the Optical Remote I/O System.
WARNING Always heed these precautions. Failure to abide by the following precautions
could lead to serious or possibly fatal injury.
•Always ground the system to 100 Ω or less when installing the Units. Not con -
necting to a ground of 100 Ωor less may result in electric shock.
•Always turn OFF the power supply to the PC before attempting any of the fol -
lowing. Not turning OFF the power supply may result in malfunction or electric
shock.
•Mounting or dismounting I/O Units, CPU Units, Memory Units, or any other
Units.

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5Application Precautions
xiv
•Assembling the Units.
•Setting DIP switches or rotary switches.
•Connecting cables or wiring the system.
•Connecting or disconnecting the connectors.
Caution Failure
to abide by the following precautions could lead to faulty operation of the
Optical Remote I/O System, or could damage the PC or PC Units. Always heed
these precautions.
•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.
•Always use the power supply voltages specified in this manual. 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. Be particularly careful in places where the
power supply is unstable. An incorrect power supply may result in malfunction.
•Install external breakers and take other safety measures against short-circuit -
ing in external wiring. Insuf ficient safety measures against short-circuiting may
result in burning.
•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.
•Disconnect
the functional ground terminal when performing withstand voltage
tests. Not disconnecting the functional ground terminal may result in burning.
•Be sure that all the mounting screws, terminal screws, and cable connector
screws are tightened to the torque specified in this manual. Incorrect tighten -
ing torque may result in malfunction.
•Leave the label attached to the Unit when wiring. Removing the label may re -
sult in malfunction if foreign matter enters the Unit.
•Remove
the label after the completion of wiring to ensure proper heat dissipa -
tion. Leaving the label attached may result in malfunction.
•Double-check all wiring and switch settings before turning ON the power sup -
ply. Incorrect wiring may result in burning.
•Mount Units only after checking terminal blocks and connectors completely.
•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.
•Check the user program for proper execution before actually running it on the
Unit. Not checking the program may result in an unexpected operation.
•Confirm
that no adverse ef fect 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 PC.
•Force-setting/force-resetting any bit in memory.
•Changing the present value of any word or any set value in memory.
•Resume
operation only after transferring to the new CPU Unit the contents of
the DM Area, HR Area, and other data required for resuming operation. Not
doing so may result in an unexpected operation.
•Do
not pull on the cables or bend the cables beyond their natural limit. Doing
either of these may break the cables.
•Do not place objects on top of the cables or other wiring lines. Doing so may
break the cables.

5Application Precautions
xv
•Use crimp terminals for wiring. Do not connect bare stranded wires directly to
terminals. Connection of bare stranded wires may result in burning.
•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.
•Before touching a Unit, be sure to first touch a grounded metallic object in order
to discharge any static built-up. Not doing so may result in malfunction or dam -
age.

1
SECTION 1
Introduction
1-1 Remote I/O Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1-2 Optical Remote I/O Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1-1SectionRemote I/O Systems
2
1-1 Remote I/O Systems
Assembly lines are often extremely long, making it difficult if not impossible to
wire all I/O devices directly from CPU Racks or Expansion I/O Racks. A Remote
I/O System can be used to solve this problem. In a Remote I/O System, a Rack
can be located farther from the CPU Rack than is possible with Expansion I/O
Racks connected directly to the CPU Rack.
By locating a Rack farther from the CPU Rack, a Remote I/O System eliminates
the time and mess in wiring (or changing wiring) to many devices that are sepa -
rated from the CPU Rack. Although all I/O points must ultimately be wired indi -
vidually,
the question is one of distance: Do you want to wire dozens of terminals
all the way across a factory complex or do you want to run a single cable for most
of the distance and then wire individual terminals locally?
The following diagram illustrates how a simple Remote I/O System would be set
up. Slave Racks, described below , are controlled by the CPU through the Mas -
ter. The dotted circles show the devices that would be controlled through the
Units on each Rack.
Processing
machine Processing machine
Processing
machine
Processing
machine
Sensor Sensor Sensor
CPU Rack
Master
Slave Rack
Slave
Slave Rack
Slave
Assembly line
Wiring distance could also be reduced by placing an independent CPU Rack
near every location that required control, but in doing so, each PC would have to
be programmed independently and the activities of all the PC programs would
need to be coordinated, a very dif ficult job. Here too, a Remote I/O System sim -
plifies
the task by allowing a single CPU, and thus a single program, to integrate
control of the entire process. A Remote I/O System thus has these two advan -
tages: Racks can be located a greater distance from the CPU Rack and coordi -
nating control actions is simplified because all control is exerted by one program.
A third advantage of Remote I/O Systems is reduced noise interference. This is
the result of the single cable that replaces the otherwise numerous wires that
would be required all the way from the CPU and Expansion I/O Racks to the I/O
devices.
A Remote I/O System directly involves only one PC and the program in it.
Through
it, a large number of I/O points can be controlled a greater distance from

1-1SectionRemote I/O Systems
3
the PC. This is achieved by mounting a Remote I/O Master Unit to the CPU
Rack to control I/O points located possibly many kilometers away . Each Master
serves as a ‘switching point’ for controlling all of the I/O points accessed through
it. These I/O points are accessed through the Master , not controlled by it. All I/O
control comes from the program in the CPU.
More than one Master can be mounted to a single PC, with each Master forming
the starting point of a Remote I/O Subsystem, i.e., a Remote I/O Subsystem
includes one Master plus all of the Remote I/O Units controlled through it.
The Remote I/O Units that can be included in each Subsystem depend on the
specifications of the Master. Masters are available either with optical or wire
specifications. Optical Remote I/O Systems transfer data through optical fi-
ber
cables to enable the greatest transmission distance and the greatest resis -
tance to electrical noise. Wired Remote I/O Systems use wire cables which
don’t
of fer as great a distance as Optical Subsystems, but do greatly reduce the
burden of wiring remote I/O and afford greater resistance to noise than inde-
pendently wired I/O points. Both types of Master can be mounted to the same PC
to meet specific distance and noise-resistance requirements.
Master
on Rack
Label printer
Remotely Controlled I/O Devices
Glue coater
PC
Optical and
Wired Masters
on Rack Auto welder
Conveyer Packing machine
Optical Subsystem
Wired Subsystem
Polisher
PC
All Remote I/O Systems consist of at least one Remote I/O Master Unit con-
nected in series to one or more Units accessed through it. One of these Units
that is common to most Remote I/O Systems is a Remote I/O Slave Unit.
A Master is mounted to the CPU Rack or an Expansion I/O Rack; a Slave is
mounted
to a Backplane to form what is called a Slave Rack . T o a Slave Rack is
mounted the same other Units as those mounted to the CPU or Expansion I/O
Rack, with only a few exceptions (e.g., Link Units other than Slaves cannot be
mounted to Slave Racks). The advantage of a Slave Rack is that it can be lo-
cated
a considerable distance from the CPU Rack with the only connection re -
quired being a cable running from the Master to the Slave. The actual distance a
Slave Rack can be removed from the Master , as well as the other Units used to
configure a Remote I/O System, depends on the type of Remote I/O System be -
ing
used. Collectively , all of the Units connected in a Remote I/O System are re -
ferred to as Remote I/O Units.
This manual describes Optical Remote I/O Systems. Wired Remote I/O Units
are described in the
Wired Remote I/O System Manual .

1-2SectionOptical Remote I/O Systems
4
1-2 Optical Remote I/O Systems
Optical Remote I/O Systems are flexible, distributed control systems which can
be customized as necessary by adding or eliminating various Units. They are
easy to design and adjust and have a very short downtime even in the unlikely
event of system failure.
Optical Remote I/O Systems consist of one or more Remote I/O Master Units
together with one or more of the following Units: I/O Link Units, I/O Slave Unit,
and Optical I/O Units.
I/O Link Unit
PC
I/O bus
Optical I/O Unit
PC
Master
Slave
I/O Units
An I/O Link Unit mounted to a CPU Rack or an independent I/O Link Rack is
used to create an I/O Link between two CPUs. An I/O Link allows one CPU to
directly input and/or output one or two words of data from and to another CPU.
This enables coordination of CPU activities. Although this is an exception to the
basic ‘one-program’ concept of Remote I/O Systems, it can be very effective
when
one part of an operation requires a separate program but also requires in -
tegration with another PC. With the smaller (e.g., P-type and K-type) PCs, I/O
Links are also the only way to connect to a Remote I/O System.
An
I/O Link can also be set up as the only element of an Optical Remote I/O Sys -
tem, i.e., without any Optical I/O Units or Slave Racks. Such a System would be
a like a PC Link System on a very limited scale, but it would employ I/O bits in the
IR area and not the LR area.
An
Optical I/O Unit is used when it is necessary to control only a few I/O points in
one location. It is not mounted to a Rack; rather , it is located by itself in series with
the rest of the Units in the System. In this respect, an Optical I/O Unit is the Opti -
cal System equivalent of a Remote Terminal. Unlike a Remote Terminal, how-
ever, an Optical I/O Unit has fixed I/O terminals, not replaceable relays. In ap-
pearance, it looks much like an I/O Unit or Special I/O Unit.
A Remote I/O Subsystem consists of a single Remote I/O Master Unit and all
Remote I/O Units controlled through it.
In this manual, the term “Remote I/O Subsystem” always refers to an Optical
System unless specifically designated as a Wired System. For convenience,
Remote I/O Master Units and Remote I/O Slave Units are referred to respec-
tively as simply “Masters” and “Slaves”. These terms, as well, always refer to
Optical
Units unless otherwise specified. The term “Slave Rack” is used to refer
to a Backplane with a Slave mounted to it. “PC” always means Programmable
Controller.
C500 Masters and C500 Slaves are used for the C500, C1000H, and C2000H.
C500 Masters and C500 Slaves can also be used for the C120, although a C120
Master and C120 Slave are available
An Optical Remote I/O System provides a number of advantages, as indicated in
the following table.
Features of Optical
Remote I/O Systems

1-2SectionOptical Remote I/O Systems
5
Advantages of Optical Remote I/O Systems
Reduced wiring burden and easier wiring changes
Greater transmission distance from CPU Rack
Coordination of control facilitated by use of a single program
I/O Links enable direct transfer of data between PCs
Rapid data transmission
High responsiveness and fidelity
Free from the adverse effects of external noise
Optical fiber cable is used for communication lines. As a result, wiring is signifi -
cantly simplified and the system can be easily expanded as necessary.
Either All-plastic Fiber (APF), Plastic-clad Fiber (PCF), or Quartz Crystal (AGF)
can be used for the optical fiber cables in a an Optical Remote I/O System. APF
cable is especially instrumental in simplifying wiring and reducing cost.
A variety of basic Systems and Subsystems can be constructed and combined
in many ways to meet a wide range of control requirements. Throughout this
manual, particular terms are used to refer to these basic systems, and they are
defined as follows.
A
Control System is the extended system, including all external devices such as
stepping motors, mechatronic modules, and control components (solenoids,
sensors, switches, etc.).
A
PC System is a system which includes a Programmable Controller (PC) and
all it controls up to, but not including, any external devices.
A Remote I/O System includes all the Optical and Wired Remote I/O subsys-
tems under the control of a single PC. These systems can perform distributed
control
actions, such as remote operation of several large machines, by execut -
ing a program in the memory of a single PC’
s CPU.
Model numbers have been shortened. For example, a C200H-RT001 Remote
I/O Slave Unit is called simply a “C200H Slave.” See Appendix A for a complete
list of all products covered in this manual, along with their model numbers.
Terminology