OMRON CJ Series PLC Practical Guide

OMRON CJ series PLC system: Engineer's practical manual from unit version management to troubleshooting

In industrial automation sites, OMRON CJ series programmable logic controllers (PLCs) are widely used for control from single machine equipment to complex production lines due to their compact size, high performance, and flexible scalability. However, facing multiple sub series such as CJ1H, CJ1M, CJ1, as well as constantly updated Unit Versions, engineers often encounter challenges in selection, system integration, and maintenance: what are the functional differences between different versions? How to determine which instructions the CPU unit supports based on the unit version? How to quickly locate I/O allocation faults? What are the precautions for battery replacement? This article is based on the official technical information of CJ series PLC, providing engineers with a complete set of engineering practice guidelines from unit version management, system configuration, memory allocation, troubleshooting to daily maintenance.

Unit version: "Invisible ID Card" for CJ series CPUs

The CJ series CPU units have introduced a "unit version" management mechanism to distinguish the set of functions possessed by CPU units produced in different periods. This concept is crucial for determining program compatibility and functional support.

1.1 How to identify unit versions

The unit version is marked on the right side of the batch number on the CPU unit nameplate, in the format of "Ver. □□". For example, the version of CJ1H-CPU67H-R unit may be 4.2, 4.1, or 4.0. For CPU units produced before November 4, 2003, the nameplate does not display the version (referred to as Pre Ver. CPU unit).

1.2 Starting point for versions of different models

CJ1H-CPU □□ H-R (high-speed type): version starting from 4.0

CJ1H-CPU □□ H/CJ1G-CPU □□ H/CJ1M-CPU □□: Version starting from 2.0

CJ1G-CPU □□ P (Loop Control CPU): CPU unit component version 3.0 or higher, LCB component version 2.0

After understanding the starting point of the version, engineers must confirm the compatibility of the new and old units when replacing the CPU or upgrading the system, otherwise it may cause the program to fail to download or run incorrectly.

1.3 Relationship between Unit Version and Function Support

New features in version 4.0 and above (requires CX Programmer 7.0 or higher):

Function block online editing

Input/output variables in functional blocks (supporting large amounts of data transfer)

Text string support in function blocks (ST language programming)

New features in version 3.0 (requires CX Programmer 5.0 or higher):

Function block (compliant with IEC 61131-3 standard)

Serial gateway (converts FINS commands to CompoWay/F)

Annotation memory (storing symbol tables, annotations, etc. in internal flash memory)

Simple backup data extension (supports annotation backup)

Free running timer (A000: 10ms increments, A001: 100ms increments)

New features in version 2.0 (requires CX Programmer 4.0 or higher):

Upload/download of individual tasks

Improved password read protection (can protect individual tasks)

Write protection through network FINS commands

Online network connection without the need for an I/O table

Up to 8 levels of network communication (formerly 3 levels)

Connect PLC online through NS series PT

Slot header setting (up to 64 groups)

Power on automatic transmission without parameter files (REPLACE. OBJ)

Operation start/end time record (A515~A520)

New application instructions: MILH/MILR/MILC, TPO, GRY, PRV2, combination instructions (TKY/HKY/DSW/MTR/7SEG), time comparison instructions, explicit message instructions, extension block comparison BCMP2, etc

Important notice: If a program containing features specific to a higher version is downloaded to a lower version CPU unit, compilation will encounter an error and download will fail. If passed When transferring OBJ files, program errors may occur and the CPU will stop running during startup or execution of related functions.

CPU Unit Selection Guide: How to Choose CJ1H, CJ1M, CJ1

The CJ series is mainly divided into three categories of CPU units, each suitable for different performance requirements.

2.1 CJ1H CPU Unit (High Performance Type)

Model, Program Capacity, Data Memory (DM+EM), Basic Instruction Execution Time, Extended Rack Count

CJ1H-CPU67H-R 250K Step 448K Word 0.016 μ s 3

CJ1H-CPU66H-R 120K steps 256K words 0.016 μ s 3

CJ1H-CPU65H-R 60K steps 128K words 0.016 μ s 3

CJ1H-CPU64H-R 30K steps 64K words 0.016 μ s 3

High speed type (- R) features: basic instruction 0.016 μ s, special instruction 0.048 μ s, floating-point calculation 0.24 μ s (about 33 times faster than standard CJ1H). The interrupt response time is 40 μ s, and the I/O refresh time is halved (1.4 μ s for 16 point input units). Supports three types of timed interrupt units: 0.1ms, 1ms, and 10ms.

Standard type (CJ1H-CPU □□ H): Basic instruction 0.02 μ s, special instruction 0.06 μ s.

2.2 CJ1M CPU unit (compact built-in I/O type)

Model Built in I/O Program Capacity Pulse Output PWM Output Expansion Rack

CJ1M-CPU23 has 20K steps, 2 channels, 100kHz, 2 channels, and 1 channel