OMRON CJ1H‑CPU66H V4.0 High‑Performance CPU Unit for CJ Series PLC

The OMRON CJ1H‑CPU66H V4.0 is a high‑end CPU unit within the CJ1H family of programmable logic controllers. It is designed for large‑scale control systems requiring fast scan times, extensive I/O capacity, and advanced features such as built‑in Ethernet and high‑speed counters. The V4.0 firmware revision adds enhanced security, improved motion control functions, and compatibility with newer CJ2 expansion modules. This CPU supports up to 1280 I/O points and 120K steps of user program memory.

Performance Specifications

Processing speed: basic instructions (LD, OUT) execute in 0.02 µs, application instructions (MOV, ADD) in 0.12 µs. The CPU uses a 32‑bit RISC processor running at 80 MHz. Program capacity: 120K steps (standard) expandable to 160K steps via memory cassette. Data memory: 128K words (DM), 64K words (EM) with battery backup. The CPU includes a real‑time clock with a calendar accuracy of ±2 minutes per month, backed by a lithium battery (life approx. 5 years). Scan time for a typical 20K step program plus I/O refresh is under 5 ms.

Built‑in I/O and Special Functions

The CJ1H‑CPU66H integrates 16 digital inputs (24 V DC, 4 mA) and 8 transistor outputs (sink, 0.5 A per point). Additionally, it features two high‑speed counters (100 kHz each) that can be configured as up/down, phase differential, or pulse + direction. Four interrupt inputs with a response time of 0.1 ms are included. The CPU also provides two pulse outputs (100 kHz) for direct stepper motor control without external positioning modules. These built‑in I/O are accessible via a removable 24‑pin connector on the front of the CPU.

Built‑in Ethernet Port

An integrated Ethernet port (RJ45, 10/100Base‑T) supports the EtherNet/IP protocol. This allows the CPU to act as a tag data server/client, enabling communication with HMIs, SCADA systems, and other PLCs via cyclic (implicit) or explicit messaging. The port also supports FTP server for file transfer, SMTP for email alerts, and SNMP for network management. Up to 32 simultaneous connections are possible. The IP address is configured via the CX‑Programmer software or by using the CPU’s DIP switches (BOOTP or static).

Memory and Data Retention

Program memory is flash ROM, requiring no battery for program storage. Data memory (DM, EM) is battery‑backed SRAM. A memory cassette slot on the front accepts optional memory cards (CJ1W‑MExx series) for program backup, auto‑boot, or additional file storage (up to 4 MB). The CPU also supports a built‑in EEPROM for parameter storage. The battery (CJ1W‑BAT01) can be replaced without removing the CPU. An LED indicator on the front panel warns when the battery voltage is low.

Expansion and Configuration

The CJ1H‑CPU66H is the master unit in a CJ series backplane (CJ1W‑BCxxx). It can control up to 1280 I/O points across a maximum of 40 I/O modules or 80 special units (analog, temperature, motion, etc.). It also supports up to 20 remote I/O racks via optical or electrical SYSMAC BUS cables. The CPU has two peripheral ports: a USB 2.0 type‑B port for programming (compatible with CX‑One) and a 9‑pin RS‑232C port for serial communication (host link, no‑protocol, Modbus RTU).

Diagnostics and Safety

The CPU includes a self‑diagnosis function that checks for CPU errors, memory errors, I/O bus errors, and battery errors. Errors are indicated by front‑panel LEDs (RUN, ERR/ALM, INH, PRPHL) and can be read via auxiliary area bits. The CPU supports two safety features: a watchdog timer (programmable from 10 to 2000 ms) and a built‑in password protection for program read/write. The V4.0 firmware adds support for PLCopen motion blocks and user authentication via Active Directory.

Typical Applications

The CJ1H‑CPU66H V4.0 is used in large packaging lines, automotive body assembly, printing presses, and material handling systems. Its high speed and large I/O capacity make it suitable for controlling multiple axes, coordinating with vision systems, and managing complex data logging. The integrated Ethernet simplifies integration into factory networks.