Omron SYSMAC C20P User manual

Cat. No. W168-E1-1B
C20P/C28P/C40P/C60P
SYSMAC
Programmable Controllers

P–type Programmable Controllers
OPERATION MANUAL
Revised January 1997

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ii
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 the product.
DANGER! Indicates information that, if not heeded, is likely to result in loss of life or serious injury.
WARNING Indicates information that, if not heeded, could possibly result in loss of life or serious injury.
Caution Indicates information that, if not heeded, could result in relatively serious or minor injury,
damage to the product, or faulty operation.
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 efficient and convenient operation
of the product.
1, 2, 3... 1. Indicates lists of one sort or another, such as procedures, checklists, etc.
OMRON, 1989
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.

iii
About this Manual:
The OMRON P-type Programmable Controllers offer an effective way to automate processing. man-
ufacturing, assembly, packaging, and many other processes can be automated to save time and
money. Distributed control systems can also be designed to allow centralized monitoring and supervi-
sion of several separate controlled systems. Monitoring and supervising can be done through a host
computer, connecting the controlled system to a data bank. It is thus possible to have adjustments in
system operation made automatically to compensate for requirement changes.
The P-type Units can utilize a number of additional Units including dedicated Special I/O Units that
can be used for specific tacks and Link Units that can be used to build more highly integrated sys-
tems.
The P-types are equipped with large programming instruction sets, data areas, and other features to
control processing directly. Programming utilizes ladder-diagram programming methods, which are
described in detail for those unfamiliar with them.
This manual describes the characteristics and abilities of the P-types, programming operations and
instructions, and other aspects of operation and preparation that demand attention. Before attempting
to operate the PC, thoroughly familiarize yourself with the information contained herein. Hardware
information is provided in detail in the
Installation Guide . A table of other manuals that can be used in
combination with this manual is provided at the end of
Section 1 Background .
Section 1 Precautions provides general precautions for using the Programmable Controller (PC).
The information contained in this section is important for the safe and reliable application of
the PC. You must read this section and understand the information contained before attempt-
ing to set up or operate a PC system.
Section 2 Background explains the background and some of the basic terms used in ladder-diagram
programming. It also provides an overview of the process of programming and operating a PC and
explains basic terminology used with OMRON PCs. Descriptions of peripheral devices used with the
P-types and a table of other manuals available to use with this manual for special PC applications are
also provided.
Section 3 Hardware Considerations explains basic aspects of the overall PC configuration and de-
scribes the indicators that are referred to in other sections of this manual.
Section 4 Memory Areas takes a look at the way memory is divided and allocated and explains the
information provided there to aid in programming. It also explains how I/O is managed in memory and
how bits in memory correspond to specific I/O points.
Section 5 Programming explains the basics of ladder-diagram programming, looking at the ele-
ments that make up the ‘ladder’ part of a ladder-diagram program and explaining how execution of
this program is controlled.
S
ection 6 Instruction Set then goes on to describe individually all of the instructions used in pro-
gramming.
Section 7 Program Execution Timing explains the scanning process used to execute the program
and tells how to coordinate inputs and outputs so that they occur at the proper times.
Section 8 Program Input, Debugging, and Execution explains how to convert a ladder diagram
into mnemonic code so that it can be input into the CPU through a Programming Console. This sec-
tion also provides the Programming Console procedures used to input and debug the program and to
monitor and control system operation.
Section 9 Troubleshooting provides information on system error indications and other means of re-
ducing system down time. Information in this section is also necessary when debugging a program.
The
Appendice s provide tables of standard OMRON products available for the P-types, reference
tables of instructions and Programming Console operations, and other information helpful in PC op-
eration.

v
TABLE OF CONTENTS
PRECAUTIONS ix. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 Intended Audience x. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 General Precautions x. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 Safety Precautions x. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 Operating Environment Precautions x. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 Application Precautions xi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 1 – Background 1. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–1 Introduction 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–2 Relay Circuits: The Roots of PC Logic 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–3 PC Terminology 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–4 OMRON Product Terminology 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–5 Overview of PC Operation 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–6 Peripheral Devices 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–7 Available Manuals 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 2 – Hardware Considerations 9. . . . . . . . . . . . . . . . . . . . . . . . . . .
2–1 Introduction 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–2 Indicators 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–3 PC Configuration 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 3 – Memory Areas 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–1 Introduction 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–2 Data Area Structure 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–3 IR Area 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–4 SR Area 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–4–1 Battery Alarm Flag 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–4–2 Scan Time Error Flag 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–4–3 High-speed Drum Counter Reset 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–4–4 Clock Pulse Bits 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–4–5 Error Flag ER 25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–4–6 Always OFF and Always ON Flags 25. . . . . . . . . . . . . . . . . . . . . . . . . . .
3–4–7 First Scan Flag 25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–4–8 Arithmetic Flags 25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–5 DM Area 26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–6 HR Area 26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–7 TC Area 26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–8 TR Area 27. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 4 – Programming 29. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4–1 Introduction 30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4–2 Instruction Terminology 30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4–3 The Ladder Diagram 30. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4–3–1 Basic Terms 31. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4–3–2 Ladder Instructions 32. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4–3–3 Logic Block Instructions 33. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4–3–4 Branching Instruction Lines 34. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4–3–5 Jumps 39. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Table of contents
vi
4–4 Controlling Bit Status 40. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4–4–1 OUT and OUT NOT 40. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4–4–2 Differentiate Up and Differentiate Down 41. . . . . . . . . . . . . . . . . . . . . .
4–4–3 Keep 41. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4–4–4 Self-maintaining Bits 42. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4–5 The End Instruction 42. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4–6 Programming Precautions 43. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4–7 Program Execution 44. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 5 – Instruction Set 45. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–1 Introduction 46. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–2 Notation 46. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–3 Instruction Format 46. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–4 Data Areas, Definer Values, and Flags 47. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–5 Ladder Diagram Instructions 47. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–5–1 Load, Load NOT, AND, AND NOT, OR, and OR NOT 48. . . . . . . . . .
5–5–2 AND Load and OR Load 49. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–6 Bit Control Instructions 49. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–6–1 Output and Output NOT – OUT and OUT NOT 49. . . . . . . . . . . . . . . . .
5–6–2 Differentiate Up and Down – DIFU(13) and DIFD(14) 50. . . . . . . . . . .
5–6–3 Keep – KEEP(11) 51. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–7 Interlock and Interlock Clear – IL(02) and ILC(03) 53. . . . . . . . . . . . . . . . . . . . . .
5–8 Jump and Jump End – JMP(04) and JME(05) 55. . . . . . . . . . . . . . . . . . . . . . . . . . .
5–9 End – END(01) 56. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–10 No Operation – NOP(00) 56. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–11 Timer and Counter Instructions 56. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–11–1 Timer – TIM 57. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–11–2 High-speed Timer – TIMH(15) 61. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–11–3 Analog Timer Unit 61. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–11–4 Counter – CNT 64. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–11–5 Reversible Counter – CNTR(12) 67. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–11–6 High-speed Counter – HDM(98) 68. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–12 Data Shifting 77. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–12–1 Shift Register – SFT(10) 78. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–12–2 Word Shift – WSFT(16) 80. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–13 Data Movement 81. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–13–1 Move – MOV(21) 81. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–13–2 Move NOT – MVN(22) 82. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–14 Data Compare – CMP(20) 82. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–15 Data Conversion 84. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–15–1 BCD to Binary – BIN(23) 84. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–15–2 Binary to BCD – BCD(24) 85. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–15–3 4-to-16 Decoder – MLPX(76) 85. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–15–4 16-to-4 Encoder – DMPX(77) 87. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–16 BCD Calculations 89. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–16–1 BCD Add – ADD(30) 90. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–16–2 BCD Subtract – SUB(31) 92. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–16–3 Set Carry – STC(40) 93. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5–16–4 Clear Carry – CLC(41) 93. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
SECTION 6 – Program Execution Timing 95. . . . . . . . . . . . . . . . . . . . . . . . . .
6–1 Introduction 96. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6–2 Scan Time 96. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6–3 Calculating Scan Time 98. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6–3–1 Single PC Unit 98. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6–3–2 PC with Additional Units 99. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6–4 Instruction Execution Times 100. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
6–5 I/O Response Time 102. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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vii
SECTION 7 – Program Input, Debugging and Execution 105. . . . . . . . . . . . .
7–1 Introduction 106. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–2 Converting to Mnemonic Code 106. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–2–1 Program Memory Structure 106. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–2–2 Ladder Instructions 106. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–2–3 Logic Block Instructions 107. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–2–4 Coding Other Instructions 116. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–3 The Programming Console 121. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–3–1 The Keyboard 121. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–3–2 PC Modes 123. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–4 Preparation for Operation 124. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–4–1 Entering the Password 125. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–4–2 Clearing Memory 126. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–5 Inputting, Modifying, and Checking the Program 128. . . . . . . . . . . . . . . . . . . . . . . .
7–5–1 Setting and Reading from Program Memory Address 128. . . . . . . . . . . .
7–5–2 Inputting or Overwriting Programs 129. . . . . . . . . . . . . . . . . . . . . . . . . . .
7–5–3 Checking the Program 132. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–5–4 Displaying the Scan Time 133. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–5–5 Program Searches 134. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–5–6 Inserting and Deleting Instructions 136. . . . . . . . . . . . . . . . . . . . . . . . . . . 140
140
141
143
144
145
148
151
151
SECTION 8 – Troubleshooting 153. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8–1 Introduction 154. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8–2 Reading and Clearing Errors and Messages 154. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8–3 Error Messages 154. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
8–4 Error Flags 156. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appendix 157. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A – Standard Models 157. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
B – Programming Instructions 165. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
C – Programming Console Operations 171. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D – Error and Arithmetic Flag Operation 181. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
E – Binary–Hexadecimal–Decimal Table 183. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
F – Word Assignment Recording Sheets 185. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
G – Program Coding Sheet 191. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Glossary 193. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Index 207. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–6 Program Backup and Restore Operations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–8 Monitoring Operation and Modifying Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–6–2Restoring or Comparing Program Memory Data. . . . . . . . . . . . . . . .
7–7 Debugging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–8–1Bit/Digit Monitor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–8–3Hexadecimal/BCD Data Modification. . . . . . . . . . . . . . . . . . . . . . . .
7–6–1Saving Program Memory Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–8–2Force Set/Reset. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
7–8–4Changing Timer/Counter SV. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ix
PRECAUTIONS
This section provides general precautions for using the Programmable Controller (PC) and related devices.
The information contained in this section is important for the safe and reliable application of the PC. You must read
this section and understand the information contained before attempting to set up or operate a PC system.
1 Intended Audience x. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2 General Precautions x. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3 Safety Precautions x. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 Operating Environment Precautions x. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 Application Precautions xi. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

!
!
!
x
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 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 programming and operating OMRON PCs.
Be sure to read this manual before attempting to use the software and keep this
manual close at hand for reference during operation.
WARNING It is extreme important that a PC and all PC Units 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 a PC System to the abovementioned
applications.
3 Safety Precautions
WARNING Never attempt to disassemble any Units while power is being supplied. Doing so
may result in serious electrical shock or electrocution.
WARNING Never touch any of the terminals while power is being supplied. Doing so may
result in serious electrical shock or electrocution.
4 Operating Environment Precautions
Do not operate the control system in the following places.
•Where the PC is exposed to direct sunlight.
•Where the ambient temperature is below 0°C or over 55°C.
•Where the PC may be affected by condensation due to radical temperature
changes.
•Where the ambient humidity is below 10% or over 90%.
•Where there is any corrosive or inflammable gas.
•Where there is excessive dust, saline air, or metal powder.
•Where the PC is affected by vibration or shock.
•Where any water, oil, or chemical may splash on the PC.
Operating Environment Precautions 4

!
!
!
!
xi
Caution The operating environment of the PC System can have a large effect on the lon-
gevity and reliability of the system. Improper operating environments can lead to
malfunction, failure, and other unforeseeable problems with the PC System. Be
sure that the operating environment is within the specified conditions at installa-
tion and remains within the specified conditions during the life of the system.
5 Application Precautions
Observe the following precautions when using the PC.
WARNING Failure to abide by the following precautions could lead to serious or possibly
fatal injury. Always heed these precautions.
•Always ground the system to 100 Ωor less when installing the system to pro-
tect against electrical shock.
•Always turn off the power supply to the PC before attempting any of the follow-
ing. Performing any of the following with the power supply turned on may lead
to electrical shock:
•Mounting or removing any Units (e.g., I/O Units, CPU Unit, etc.) or memory
cassettes.
•Assembling any devices or racks.
•Connecting or disconnecting any cables or wiring.
Caution Failure to abide by the following precautions could lead to faulty operation or the
PC or the system or could damage the PC or PC Units. Always heed these pre-
cautions.
•Use the Units only with the power supplies and voltages specified in the opera-
tion manuals. Other power supplies and voltages may damage the Units.
•Take measures to stabilize the power supply to conform to the rated supply if it
is not stable.
•Provide circuit breakers and other safety measures to provide protection
against shorts in external wiring.
•Do not apply voltages exceeding the rated input voltage to Input Units. The
Input Units may be destroyed.
•Do not apply voltages exceeding the maximum switching capacity to Output
Units. The Output Units may be destroyed.
•Always disconnect the LG terminal when performing withstand voltage tests.
•Install all Units according to instructions in the operation manuals. Improper
installation may cause faulty operation.
•Provide proper shielding when installing in the following locations:
•Locations subject to static electricity or other sources of noise.
•Locations subject to strong electromagnetic fields.
•Locations subject to possible exposure to radiation.
•Locations near to power supply lines.
•Be sure to tighten Backplane screws, terminal screws, and cable connector
screws securely.
•Do not attempt to take any Units apart, to repair any Units, or to modify any
Units in any way.
Caution The following precautions are necessary to ensure the general safety of the sys-
tem. Always heed these precautions.
•Provide double safety mechanisms to handle incorrect signals that can be
generated by broken signal lines or momentary power interruptions.
•Provide external interlock circuits, limit circuits, and other safety circuits in
addition to any provided within the PC to ensure safety.
Application Precautions 5

1
SECTION 1
Background
1–1 Introduction 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–2 Relay Circuits: The Roots of PC Logic 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–3 PC Terminology 3. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–4 OMRON Product Terminology 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–5 Overview of PC Operation 4. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–6 Peripheral Devices 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1–7 Available Manuals 7. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2
1–1 IntroductionA Programmable Controller (PC) is basically a central processing unit (CPU)
containing a program and connected to input and output (I/O) devices (I/O
Devices). The program controls the PC so that when an input signal from an
input device turns ON, the appropriate response is made. The response nor-
mally involves turning ON an output signal to some sort of output device. The
input devices could be photoelectric sensors, pushbuttons on control panels,
limit switches, or any other device that can produce a signal that can be input
into the PC. The output devices could be solenoids, switches activating indi-
cator lamps, relays turning on motors, or any other devices that can be acti-
vated by signals output from the PC.
For example, a sensor detecting a product passing by turns ON an input to
the PC. The PC responds by turning ON an output that activates a pusher
that pushes the product onto another conveyor for further processing. An-
other sensor, positioned higher than the first, turns ON a different input to
indicate that the product is too tall. The PC responds by turning on another
pusher positioned before the pusher mentioned above to push the too-tall
product into a rejection box.
Although this example involves only two inputs and two outputs, it is typical of
the type of control operation that PCs can achieve. Actually even this exam-
ple is much more complex than it may at first appear because of the timing
that would be required, i.e., “How does the PC know when to activate each
pusher?” Much more complicated operations, however, are also possible.
The problem is how to get the desired control signals from available inputs at
appropriate times.
Desired control sequences are input to the P-type PCs using a form of PC
logic called ladder-diagram programming. This manual is written to explain
ladder-diagram programming and to prepare the reader to program and oper-
ate the P-type PCs.
1–2 Relay Circuits: The Roots of PC Logic
PCs historically originate in relay-based control systems. And although the
integrated circuits and internal logic of the PC have taken the place of the
discrete relays, timers, counters, and other such devices, actual PC opera-
tion proceeds as if those discrete devices were still in place. PC control, how-
ever, also provides computer capabilities and consistency to achieve a great
deal more flexibility and reliability than is possible with relays.
The symbols and other control concepts used to describe PC operation also
come from relay-based control and form the basis of the ladder-diagram pro-
gramming method. Most of the terms used to describe these symbols and
concepts, however, originated as computer terminology.
The terminology used throughout this manual is somewhat different from re-
lay terminology, but the concepts are the same. The following table shows
the relationship between relay terms and the PC terms used for OMRON
PCs.
Relay term PC equivalent
contact input or condition
coil output or work bit
NO relay condition
NC relay inverse condition
Relay vs. PC Terminology
Relay Circuits: The Roots of PC Logic Section 1–2

3
Actually there is not a total equivalence between these terms, because the
term condition is used only to describe ladder diagram programs in general
and is specifically equivalent to one of certain basic instructions. The terms
input and output are not used in programming per se, except in reference to
I/O bits that are assigned to input and output signals coming into and leaving
the PC. Conditions and inverse conditions are explained in
4–3 The Ladder
Diagram
.
1–3 PC Terminology
Although also provided in the Glossary at the back of this manual, the follow-
ing terms are crucial to understanding PC operation and are thus explained
here as well.
When we refer to the PC, we are generally talking about the CPU and all of
the Units directly controlled by it through the program. This does not include
the I/O devices connected to PC inputs and outputs.
If you are not familiar with the terms used above to describe a PC, refer to
2
Hardware Considerations
for explanations.
A device connected to the PC that sends a signal to the PC is called an input
device; the signal it sends is called an input signal. A signal enters the PC
through terminals or through pins on a connector on a Unit. The place where
a signal enters the PC is called an input point. This input point is allocated a
location in memory that reflects its status, i.e., either ON or OFF. This mem-
ory location is called an input bit. The CPU in its normal processing cycle
monitors the status of all input points and turns ON and OFF corresponding
input bits accordingly.
There are also output bits in memory that are allocated to output points on
Units through which output signals are sent to output devices, i.e., an out-
put bit is turned ON to send a signal to an output device through an output
point. The CPU periodically turns output points ON and OFF according to the
status of the output bits.
These terms are used when describing different aspects of PC operation.
When programming, one is concerned with what information is held in mem-
ory, and so I/O bits are referred to. When describing the Units that connect
the PC to the controlled system and the places on these Units where signals
enter and leave the PC, I/O points are referred to. When wiring these I/O
points, the physical counterparts of the I/O points, either terminals or connec-
tor pins, are referred to. When describing the signals that enter or leave the
system, reference is made to input signals and output signals, or sometimes
just inputs and outputs.
The Control System includes the PC and all I/O devices it uses to control an
external system. A sensor that provides information to achieve control is an
input device that is clearly part of the Control System. The controlled system
is the external system that is being controlled by the PC program through
these I/O devices. I/O devices can sometimes be considered part of the con-
trolled system, e.g., a motor used to drive a conveyor belt.
PC
Inputs and Outputs
Controlled System and
Control System
PC Terminology Section 1–3

4
1–4 OMRON Product Terminology
OMRON products are divided into several functional groups that have ge-
neric names. A
ppendix A Standard Models list products by these groups.
The term Unit is used to refer to all OMRON PC products, depending on the
context.
The largest group of OMRON products is I/O Units. I/O Units come in a vari-
ety of point quantities and specifications.
Special I/O Units are dedicated Units that are designed to meet specific
needs. These include Analog Timer Units and Analog I/O Units.
Link Units are used to create Link Systems that link more than one PC or
link a single PC to remote I/O points. Link Units include I/O Link Units that
are used to connect P-type PCs to Remote I/O Systems controlled by a larg-
er PC (e.g. C1000H) and Host Link Units.
Other product groups include Programming Devices, Peripheral Devices,
and DIN Rail Products.
1–5 Overview of PC Operation
The following are the basic steps involved in programming and operating a
P-type PC. Assuming you have already purchased one or more of these
PCs, you must have a reasonable idea of the required information for steps
one and two, which are discussed briefly below. This manual is written to ex-
plain steps three through six, eight, and nine. The section(s) of this manual
that provide relevant information are listed with each of these steps.
1. Determine what the controlled system must do, in what order, and at
what times.
2. Determine what Units will be required. Refer to the
Installation Guide . If
a Link System is required, refer to the required
System Manual(s) .
3. On paper, assign all input and output devices to I/O points on Units and
determine which I/O bits will be allocated to each. If the PC includes
Special I/O Units or Link Systems, refer to the individual
Operation
Manuals
or System Manuals for details on I/O bit allocation. ( Section 3
Memory Areas)
4. Using relay ladder symbols, write a program that represents the se-
quence of required operations and their inter-relationships. Be sure to
also program appropriate responses for all possible emergency situ-
ations. (
Section 4 Programming, Section 5 Instruction Set, Section 6
Program Execution Timing)
5. Input the program and all required operating parameters into the PC.
(
Section 7 Program Input, Debugging, and Execution )
6. Debug the program, first to eliminate any syntax errors and then to elim-
inate execution errors. (
Section 7 Program Input, Debugging, and Exe-
cution
and Section 8 Troubleshooting )
7. Wire the PC to the controlled system. This step can actually be started
as soon as step 3 has been completed. Refer to the
Installation Guide
and to Operation Manuals and System Manuals for details on individual
Units.
8. Test the program in an actual control situation and fine tune it if required.
(
Section 7 Program Input, Debugging, and Execution and Section 8
Troubleshooting
)
9. Record two copies of the finished program on masters and store them
safely in different locations. (
Section 7 Program Input, Debugging, and
Execution
)
1, 2, 3...
Overview of PC Operation Section 1–5

5
Designing the Control System is the first step in automating any process. A
PC can be programmed and operated only after the overall Control System is
fully understood. Designing the Control System requires a thorough under-
standing of the system that is to be controlled. The first step in designing a
Control System is thus determining the requirements of the controlled sys-
tem.
The first thing that must be assessed is the number of input and output points
that the controlled system will require. This is done by identifying each device
that is to send an input signal to the PC or which is to receive an output sig-
nal from the PC. Keep in mind that the number of I/O points available de-
pends on the configuration of the PC. Refer to
3–3 IR Area for details on I/O
capacity and assigning I/O bits to I/O points.
Next, determine the sequence in which control operations are to occur and
the relative timing of the operations. Identify the physical relationships be-
tween the I/O devices as well as the kinds of responses that should occur
between them.
For instance, a photoelectric switch might be functionally tied to a motor by
way of a counter within the PC. When the PC receives an input from a start
switch, it could start the motor. The PC could then stop the motor when the
counter has received five input signals from the photoelectric switch.
Each of the related tasks must be similarly determined, throughout the entire
control operation.
The actual Units that will be mounted must be determined according to the
requirements of the I/O devices. This will include actual hardware specifica-
tions, such as voltage and current levels, as well as functional considera-
tions, such as those that require Special I/O Units or Link Systems. In many
cases, Special I/O Units or Link Systems can greatly reduce the program-
ming burden. Details on these Units and Link Systems are available in indi-
vidual
Operation Manuals and System Manuals.
Once the entire Control System has been designed, the task of program-
ming, debugging, and operation as described in the remaining sections of
this manual can begin.
Control System Design
Input/Output Requirements
Sequence, Timing, and
Relationships
Unit Requirements
Overview of PC Operation Section 1–5

6
1–6 Peripheral Devices
The following peripheral devices can be used in programming, either to input/
debug/monitor the PC program or to interface the PC to external devices to
output the program or memory area data. Model numbers for all devices
listed below are provided in
Appendix A Standard Models . OMRON product
names have been placed in bold when introduced in the following descrip-
tions.
A Programming Console is the simplest form of programming device for OM-
RON PCs. Although a Programming Console Adapter is sometimes re-
quired, all Programming Consoles are connected directly to the CPU without
requiring a separate interface. The Programming Console also functions as
an interface to output programs to a standard cassette tape recorder.
Various types of Programming Console are available, including both
CPU-mounting and Hand-held models. Programming Console operations are
described later in this manual.
A Peripheral Interface Unit is required to interface the GPC to the PC.
The GPC also functions as an interface to output programs directly to a stan-
dard cassette tape recorder. A PROM Writer, Floppy Disk Interface Unit, or
Printer Interface Unit can be directly mounted to the GPC to output pro-
grams directly to an EPROM chip, floppy disk drive, or printing device.
LSS is designed to run on IBM AT/XT compatibles to enable nearly all of the
operations available on the GPC. It also offers extensive documentation ca-
pabilities.
A Host Link Unit is required to interface a computer running LSS to the PC.
The FIT is an OMRON computer with specially designed software that allows
you to perform all of the operations that are available with the GPC or LSS.
Programs can also be output directly to an EPROM chip, floppy disk drive, or
printing device without any additional interface units. The FIT has an EPROM
writer and a 3.5” floppy disk drive built in.
A Peripheral Interface Unit or Host Link Unit is required to interface the
FIT to the PC. Using an Optical Host Link Unit also enables the use of optical
fiber cable to connect the FIT to the PC. Wired Host Link Units are available
when desired. (Although FIT does not have optical connectors, conversion to
optical fiber cable is possible by using Converting Link Adapters.)
Other than its applications described above, the PROM Writer can be
mounted to the PC’s CPU to write programs to EPROM chips.
Other than its applications described above, the Floppy Disk Interface Unit
can be mounted to the PC’s CPU to interface a floppy disk drive and write
programs onto floppy disks.
Other than its applications described above, the Printer Interface Unit can be
mounted to the PC’s CPU to interface a printer or X–Y plotter to print out pro-
grams in either mnemonic or ladder-diagram form.
Programming Console
Graphic Programming
Console: GPC
Ladder Support Software:
LSS
Factory Intelligent Terminal:
FIT
PROM Writer
Floppy Disk Interface Unit
Printer Interface Unit
Peripheral Devices Section 1–6

7
1–7 Available Manuals
The following table lists other manuals that may be required to program and/
or operate the P-type PCs.
Operation Manuals and/or Operation Guides are
also provided with individual Units and are required for wiring and other
specifications.
Name Cat. no. Contents
Installation Guide W167 Hardware specifications
GPC Operation Manual W84 Programming procedures for the GPC (Graphics Program-
ming Console)
FIT Operation Manual W150 Programming procedures for using the FIT (Factory Intelligent
Terminal
LSS Operation Manual W113 Programming procedures for using LSS (Ladder Support Soft-
ware)
Printer Interface Unit Operation Guide W107 Procedures for interfacing a PC to a printer
PROM Writer Operation Guide W155 Procedures for writing programs to EPROM chips
Floppy Disk Interface Unit Operation Guide W119 Procedures for interfacing a PC to a floppy disk drive
Optical Remote I/O System Manual W136 Information on building an Optical Remote I/O System to en-
able remote I/O capability
Host Link System Manual W143 Information on building a Host Link System to manage PCs
from a ‘host’ computer
K-type Analog I/O Units Operation Guide W122 Hardware and software information on using Analog I/O Units
with the P-type PCs.
Available Manuals Section 1–7

9
SECTION 2
Hardware Considerations
2–1 Introduction 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–2 Indicators 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
2–3 PC Configuration 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

10
2–1 IntroductionThis section provides information on hardware aspects of P-type PCs that
are relevant to programming and software operation. These include indica-
tors on the CPU and basic PC configuration. This information is covered in
detail in the
Installation Guide .
2–2 Indicators CPU indicators provide visual information on the general operation of the
PC. Using the flags and other error indicators provided in the memory data
areas, although not a substitute for proper error programming, provides
ready confirmation of proper operation.
CPU indicators are located on the front right hand side of the PC adjacent to
the I/O expansion slot and are described in the following table.
Indicator Function
POWER Lights when power is supplied to the CPU.
RUN Lights when the CPU is operating normally.
ERR Lights when an error is discovered in system error diagnosis op-
erations. When this indicator lights, the RUN indicator will go off,
CPU operation will be stopped, and all outputs from the PC will
be turned OFF.
ALARM Lights when an error is discovered in system error diagnosis op-
erations. PC operation will continue.
2–3 PC Configuration
The Units from which P-type PCs can be built are shown below.
Unit type Name Words
occupied Inputs provided Outputs provided
CPU C20P 2 12 points 8 points
C28P 2 16 points 12 points
C40P 4 24 points 16 points
C60P 4 32 points 24 points
Expansion I/O Unit C4K 2 4 input points or 4 output points
C20P 2 12 points 8 points
C28P 2 16 points 12 points
C40P 4 24 points 16 points
C60P 4 32 points 24 points
Special I/O Units Analog Timer Unit 2 4 timer inputs
C4K Analog Input Unit 2 4 analog inputs
C1K Analog Input Unit 2 1 analog input
Analog Output Unit 2 1 analog output
I/O Link Unit 2 16 input and 16 output bits
Each PC is connected in series starting with a CPU and, if required, continu-
ing on with Expansion I/O or Special I/O Units. All other Units are connected
in series following the CPU and can be in any order desired except for the
I/O Link Unit, which must always come last. Up to five Units, including the
CPU can be connected as long as the total number of words occupied does
not exceed ten. Refer to
Section 3–3 IR Area for configuration examples.
CPU Indicators
PC Configuration Section 2–3

11
SECTION 3
Memory Areas
3–1 Introduction 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–2 Data Area Structure 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–3 IR Area 15. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–4 SR Area 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–4–1 Battery Alarm Flag 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–4–2 Scan Time Error Flag 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–4–3 High-speed Drum Counter Reset 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–4–4 Clock Pulse Bits 24. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–4–5 Error Flag ER 25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–4–6 Always OFF and Always ON Flags 25. . . . . . . . . . . . . . . . . . . . . . . . . . .
3–4–7 First Scan Flag 25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–4–8 Arithmetic Flags 25. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–5 DM Area 26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–6 HR Area 26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–7 TC Area 26. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
3–8 TR Area 27. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .