Side-by-Side Analysis: Omron CJ1 vs. CJ2 PLCs

Omron CJ1 PLCs Overview

Omron CJ1 PLCs are fast, flexible, and mid-sized modular programmable controllers that provide all the functions necessary for handling different types of automation applications, from simple sequence control to industrial process control.

These controllers feature a backplane-free structure in which the CJ1 modules connect module-to-module by use of simple locking connectors, doing away with the need for a bulky PLC rack. This simplifies system configuration while enhancing flexibility and lowering installation costs. A basic CJ1 system configuration comprises of a CPU unit, up to 10 standard I/O modules, special I/O and CPU bus units, a power supply, and an end cover.

Key Features:

The key features of the CJ1 Series include:

• Program capacity: 5k to 120k Steps
• Data memory capacity: 32k to 256k Words
• Basic LD instructions processing speed: ranges from 0.1µs (microseconds) to as low as 0.02µs per basic LD instruction.
• Compact Flash Memory cards of up to 48 MB for data storage and easy program transfers
• I/O capacity: Various CJ1 CPUs can control a maximum of  2560 I/O points
• I/O capability can be expanded with up to three CJ1 expansion racks
• Built-in peripheral ports and an integral RS-232C serial communication port
• Supports Controller Link, Ethernet, and DeviceNet communications
• CJ1 CPU models with –ETN suffix have a built-in 100Base-Tx Ethernet port for Ethernet-based communications
• Supports Omron’s FINS protocol – an industry-leading networking protocol that routes data across networks
• Programmed using Omron’s CX-Programmer software

CJ1-Series PLC Models

The CJ1 Series features three PLC models, namely:

CJ1H PLCs: CJ1H CPUs are designed to handle high-speed control tasks or large-scale automation applications that require a large memory capacity. They are characterized by the following attributes:

• Processing speed: 0.02µs (20 nanoseconds) per basic LD instruction
• Program capacity: up to 120k Steps
• Data memory capacity: up to 256k Words
• I/O capacity: can control up to  2560 I/O points
• A Serial Gateway that provides an easier link to various communication networks
• Integrated compact flash memory for no-battery operation
• Maximum number of supported I/O modules: up to 40 I/O modules, and 3 expansion racks
• Auxiliary flash memory: up to 64MB(Mbytes) for time-saving programming tasks
• Built-in RS-232C and peripheral ports
• Auto-tuning PID function for process control applications
• Supports structured PLC programming using Function Blocks

CJ1G PLCs: CJ1G CPUs are ideal for data management applications that require a large memory capacity. They include the following features: 

• Processing speed: 0.04µs (40 nanoseconds) per basic LD instruction
• Program capacity: up to 60k Steps
• Data memory capacity: up to 128k Words
• I/O capacity: 960 to 1280 I/O points
• Maximum number of supported I/O modules: up to 40 modules and three expansion racks. However, the CJ1G CPUs with an I/O capacity of 960 points can only support up to 30 modules and two expansion racks.
• Integrated compact flash memory for battery-less operation
• Auxiliary flash memory: supports up to 64MB of optional memory cards for time-saving programming tasks
• A Serial Gateway for connecting to different communication networks
• Built-in RS-232C and peripheral ports
• Auto-tuning PID function for process control applications
• Supports structured PLC programming using Function Blocks

CJ1M PLCs: CJ1M CPUs are designed for small-scale automation applications, such as inspection devices, automatic machines, etc. They feature the following:

• In terms of physical size, the CJ1M family is the smallest PLC model in the CJ1 Series; CJ1M-CPU11, CJ1M-CPU12 and CJ1M-CPU13 are just 1.25” wide.
• Processing speed: 0.1µs (100 nanoseconds) per basic LD instruction
• I/O capacity: supports 160 to 640 I/O points
• Maximum number of supported I/O modules: up to 20 modules and 1 expansion rack
• Data memory capacity: 32k Words (DM (Data Memory) only, no EM (Extended Data Memory))
• Auxiliary flash memory capacity: up to 64MB for time-saving programming
• Program capacity: 5k to 20k Steps
• Built-in pulse I/O. You can use a pulse I/O instruction to leverage the positioning capabilities in CJ1M-CPU21, CJ1M-CPU22, and CJ1M-CPU23.
• Utilizes a similar instruction set as the larger CJ1H/H and CJ1G/H CPUs; the only difference is that the CJ1M CPUs are not available with an Extended Data Memory(EM)
• CPU23, CPU22, and CPU21 CJ1M models incorporate built-in pulse catch inputs for detecting high-speed pulses that are faster than the CPU cycle time.
• An integrated high-speed counter in CJ1M-CPU21, CJ1M-CPU22, and CJ1M-CPU23 PLCs
• A Serial PLC Link that allows simple communication among nine (one master, eight slaves)  CJ1-Series PLCs
• A Serial Gateway for connecting easily to different communication networks
• Supports structured PLC programming using Function Blocks
• Includes a Terminal Block for easier connection of built-in I/O (in CPU23, CPU22, and CPU21).

Omron CJ2 PLCs Overview

As the natural successor of the CJ1 Series, the CJ2 Series not only inherits every feature of the CJ1 Series but also offers a wider choice of CPUs, greater performance, better processing speed, more memory capacity, faster I/O response, a wider variety of communication interfaces, and extreme scalability. Also, networking, programming, and debugging are faster and easier in CJ2 PLCs.

In addition, because of its high flexibility in configuration, the CJ2 Series is an ideal solution for a wide array of industrial automation applications, including food and beverage processing, packaging, automotive manufacturing, simple/advanced machine automation, quality inspection, advanced information processing, etc.

Key Features:

A CJ2 CPU can directly replace any preceding generation CJ1 CPU but with greater performance and improved functionality offered by the following features:

• Increased program capacity: varying from 5k to 400k. Steps
• More data memory capacity: ranging from 64k to 832k Words
• Greater CPU processing performance, with better processing speed for basic LD instructions, ranging from 0.04µs/step to as low as 0.016µs/step
• Incorporates new PLC instructions that provide instant access to fast Input/Output data
• Includes high-speed I/O modules, such as analog input modules with 20 µs conversion time
• Instant I/O refreshing and faster program execution, which enables flexible machine control
• Most CJ2 CPU models are available with a built-in multifunctional Ethernet port that has EtherNet/IP Data Link functionality for high-speed data communication between I/O devices, PACs, other PLCs, and HMIs.
• Tag programming: CJ2 CPU models featuring the built-in Ethernet port use a common tag access database between controllers and HMIs, greatly reducing development time.
• Multi-axes synchronous control with up to 4 axes of Pulse Train Output(PTO) I/O line driver for advanced motion control
• Supports an optional RS-485/RS-422A or RS-232C serial board
• A standard built-in USB port that allows plug-and-play accessibility to CJ2 PLCs
• CJ2 CPUs with the Ethernet port can easily connect to MicroLogix, CompactLogix, and ControlLogix controllers from Rockwell Automation
• Extreme scalability: The CJ2 control platform allows users to select a wide variety of compatible CJ1-Series I/O units to handle different control needs, whether the application requires 16 I/O units or 5000 I/O units.

CJ2-Series PLC Models

Omron CJ2-Series PLCs are subdivided into two performance classes, namely:

CJ2H PLCs: These are high-speed, high-capacity modular controllers well suited for advanced machine automation applications, such as in high-speed sorting conveyors and visual inspection of electrical components. They include the following features:

• High program capacity: from 50k to 400k. Steps
• More data memory capacity: from 160k to 832k Words
• Basic logic instructions (LD) execution time: 16ns/step (0.016µs/step)
• Symbol, Comment Memory: 3.5MB
• Supports up to 2560 Input/Output points
• Immediate basic I/O refreshing that ensures improved real-time processing
• Faster response and higher precision for better processing quality and advanced machine operation
• Advanced motion control function: You can achieve synchronized control with CJ2H PLCs on up to 20 axes of motion by simply using five high-speed position control units.
• CJ2H-CPU6-EIP units feature an integral multi-functional Ethernet port that incorporates EtherNet/IP Data link function
• All CJ2H CPU models include an RS-232C serial communication port
• Available with a high-speed interrupt function
• Easier accessibility through a standard inbuilt USB port
• Provides Synchronous Unit Operation in combination with a CJ1-Series position control unit (Catalog No. CJ1W-NC4)

CJ2M PLCs: These are high-performance modular controllers that are ideal for general machine automation and packaging needs. They feature the following:

• A wide variation of program capacities: from 5k to 60k. Steps
• Data storage capacity: 64k to 160k Words
• 20k Steps of dedicated Function Block execution memory, which allows structured, object-oriented PLC programming even in entry-level CJ2M CPUs using Function Block software modules.
• Comment, symbol memory: 1MB
• Basic logic instructions (LD) execution time: 40ns/step (0.04µs/step)
• Any CJ2M CPU unit can support a maximum of 40 I/O modules, and control up to 2560 I/O points
• A built-in USB port on all CJ2M CPU models that allows direct connection of Support Software through a standard USB cable.
• CJ2M-CPU3 units include a general-purpose built-in Ethernet port that supports tag-based EtherNet/IP Data Links, FTP data transfers, communications between different PLCs, connection to Support Software, and more.
• A choice of RS-485/422/232C and Ethernet interfaces on any CJ2M CPU
• CJ2M CPU models with unit version 2.0 or later do support optional pulse I/O modules that are controlled by dedicated positioning instructions.
• By mounting the pulse I/O add-on modules, users can extend the functionalities of any CJ2M CPU(version 2.0 or later) with:
• Pulse width control outputs
• Incremental encoder inputs
• Pulse frequency control outputs
• Quick-response inputs
• Interrupt inputs
• High-speed counters
• Up to 2 pulse I/O add-on modules can be mounted on a given CJ2M CPU, enabling direct control of 4 axes of motion.
• Compatibility with all existing CJ1-Series I/O, control, communication, and power supply units
• CJ2M-CPU3 models support an optional serial board to add RS-485/422A or RS-232C communications ports

Omron CJ1 vs. CJ2 PLCs

Having discussed the key features and the different PLC models offered in the Omron CJ1 and CJ2 Series, let’s now explore the specific comparisons between the two PLC Series based on their key features.

Processing Speed

CJ2 CPUs offer greater processing performance, with their basic LD instruction execution time ranging from 0.04µs (microseconds) to as low as 0.016µs per basic LD instruction. On the other hand, the basic LD instructions processing speed of the CJ1 CPUs varies from 0.1µs (microseconds) to 0.02µs per basic instruction.

Program Capacity

CJ2 CPUs provide a wider variation of program capacities, from 5k to 400k Steps, compared to the CJ1 CPUs, whose available program capacities range from 5k to 120k Steps.

Data Memory Capacity

The available data memory capacities of the CJ1 CPUs range from 32k to 256k Words. In contrast, CJ2 CPUs offer more data memory capacities, ranging from 64k to 832k Words.

I/O Capacity

Various CJ1 CPU models and all CJ2 CPUs have the capability to support up to 40 I/O modules and to control a maximum of  2560 I/O points. This I/O capacity is expandable with up to three CJ-Series expansion racks. Even so, some CJ1 CPU models, such as the CJ1M-CPU11, CJ1M-CPU21, CJ1M-CPU12, and CJ1M-CPU22, can only support 10 I/O modules without an option of extending the I/O capability with expansion racks. Also, other models like the CJ1M-CPU13 and CJ1M-CPU23 can only support 20 I/O modules and one expansion rack, while the CJ1G-CPU42H and CJ1G-CPU43H units can support 30 I/O modules and up to 2 expansion racks.

Pulse I/O Modules 

In the CJ1 Series, CJ1M-CPU21, CJ1M-CPU22, and CJ1M-CPU23 PLC models are available with built-in pulse I/O modules. However, CJ2 PLCs do not have inbuilt pulse I/O modules; instead, CJ2M CPU models (with unit version 2.0 or later) are capable of incorporating optional pulse I/O add-on modules that are controlled by dedicated positioning instructions. You can mount up to 2 pulse I/O add-on modules on any CJ2M CPU (version 2.0 or later) for direct control of up to 4 axes of motion.

Programming Software

All Omron CJ1 and CJ2 PLCs are programmed using Omron’s CX-Programmer software. In addition, all CJ1 CPU models support structured PLC programming using Function Blocks. However, in the CJ2 Series, only CJ2M CPUs support structured, object-oriented PLC programming using Function Blocks; the CJ2M CPU models have a 20k Steps program memory dedicated to Function Block execution.

Communication and Networking

Omron CJ1 and CJ2 PLCs support both standardized open network interfaces and cost-effective, high-speed, high-bandwidth proprietary network links. This enables effective communication and interaction between the two PLC Series (CJ1 and CJ2 Series) and with other PLCs, compatible HMIs, sensors, actuators, SCADA systems, and other industrial devices.

For example, data links between CJ1 and CJ2 PLCs, or to higher-level automation systems can be made using Ethernet or Serial links or via Omron’s Controller Link network – a powerful, deterministic, and easy-to-use communications network designed for high-speed transmission of large amounts of data.

Essentially, CJ1 PLCs support the following communications protocols:

• Ethernet
• Controller Link
• Profibus-DP
• DeviceNet
• CompoBus/S
• Serial communication via built-in RS-232C ports, a Serial Gateway, or through a Serial PLC Link
• Fully user-configurable CAN (Controller Area Network)-based communication

On the other hand, CJ2 PLCs support more communication protocols and networking technologies, including:

• Ethernet-based communications such as FL-net
• Serial communications via a built-in USB port and/or over RS-485, RS-422, and RS-232C interfaces
• EtherNet/IP Data Link communications supported by a built-in multi-functional Ethernet port
• Major open Fieldbus protocols: PROFIBUS-DP, Modbus TCP, PROFINET, Modbus RTU, DeviceNet, and CANopen (based on Controller Area Network)
• EtherCAT network communications using an EtherCAT interface
• Motion control networks such as MECHATROLINK-II
• CompoBus/S for high-speed I/O control
• Fully user-configurable CAN (Controller Area Network)-based communication

In summary:

Omron CJ2 PLCs inherit and optimize all the CJ1 features while also adding EtherNet/IP with Data Link function as a standard feature for high-capacity, high-speed Ethernet-based communications and networking.

This entry was posted on February 12th, 2024 and is filed under Uncategorized. Both comments and pings are currently closed.