Omron CJ1W-EIP21 EtherNet/IP Unit for CJ-Series PLCs

The Omron CJ1W-EIP21 is a CPU bus unit that adds EtherNet/IP communication capability to CJ-series programmable logic controllers. It supports high-performance tag data links with a capacity of 180,000 words or more, enabling efficient real-time data exchange with other EtherNet/IP devices such as PLCs, HMIs, drives, and remote I/O systems. This unit is designed for machine control and factory automation networks requiring high-speed periodic communication.

Communication Specifications

Physical interface: 100Base-TX (100 Mbit/s Ethernet) with baseband modulation and CSMA/CD media access method. Transmission media: Shielded twisted-pair (STP) cable, Category 5, 5e or higher with 100 ohm impedance. Transmission distance: 100 meters maximum between node and switching hub. Star form topology. Baud rate: 100 Mbit/s (fast Ethernet). Auto-negotiation supported.

Tag Data Link Features

The CJ1W-EIP21 performs cyclic communication known as tag data links. Number of connections: 256 maximum. Packet interval (refresh cycle): adjustable from 0.5 ms to 10,000 ms in 0.5 ms increments, settable independently for each connection. Allowed communications bandwidth per unit: 6,000 to 12,000 packets per second. Number of tag sets: up to 256. Tag types available: CIO Area, DM Area, EM Area, Holding Area, Work Area, and user-defined network symbols. Maximum link data size per node is highly scalable.

Compatible PLCs

The CJ1W-EIP21 is compatible with NJ-series, CJ-series (CJ1, CJ2 including CJ2H and CJ2M), CP1H, and NSJ-series PLCs. Up to 8 units can be mounted in a CJ-series system (including expansion racks). For CJ2H-CPU6[]-EIP, up to 7 EtherNet/IP units can be connected. For CJ2M CPU units, up to 2 EtherNet/IP units can be connected. For CP1H systems, up to 2 EtherNet/IP units maximum.

Memory Allocation

The CJ1W-EIP21 utilizes allocated CIO Area words: 25 words per unit for control bits, flags, target node operating and error information, and communications status. Allocated DM Area words: 100 words per unit containing the IP address display and settings area. The user can also designate any usable data area words for tag data links. Unlike standard Ethernet units, the CJ1W-EIP21 stores its configuration in non-volatile memory within the unit itself, not in the CPU Bus Unit Setup Area.

Supported Services

In addition to tag data links, the CJ1W-EIP21 supports CIP (Common Industrial Protocol) message services for explicit messaging between devices. The unit can act as a CIP client or server, reading and writing data to other CIP devices using MSG instructions in the PLC ladder program. FINS/TCP and FINS/UDP messaging are also supported for communication with Omron PLCs and HMIs using the FINS protocol over Ethernet.

Configuration Software

Configuration is performed using the Network Configurator software (included with CX-One or available separately). This software is used for building, setting, and controlling multi-vendor EtherNet/IP networks. It enables IP address assignment, tag data link connection setup, and real-time network monitoring. The software supports automatic network discovery and conflict detection. For CJ2-series PLCs, configuration can also be performed through the PLC’s built-in web server or using CX-Programmer.

Hardware Specifications

Dimensions: 31 mm width x 90 mm height x 65 mm depth (CJ-series standard dimensions). Current consumption: 410 mA maximum at 5V DC from the CPU backplane. Weight: 94 g maximum. Mounting: Plugs into any CJ-series CPU rack or expansion rack slot. The unit has a single RJ45 Ethernet connector on the front panel with link/activity and network status indicators. Communication LED indicators include RUN, ERC, ERH, and 100/LINK for network diagnostics.

Environmental Specifications

Operating temperature: 0°C to 55°C. Storage temperature: -20°C to 75°C. Humidity: 10% to 90% non-condensing. Vibration resistance: 2g at 10 to 57 Hz. Shock resistance: 15g for 11 ms. Conforms to CJ-series general specifications. The unit is CE marked, UL/cUL recognized, and RoHS compliant.

Diagnostic Features

The CJ1W-EIP21 provides extensive diagnostics including Ethernet link status, network traffic monitoring, tag data link error detection, and connection timeout management. Error information is reported to the CPU and can be read using status bits in the allocated CIO words. The unit also supports SNMP (Simple Network Management Protocol) for integration with network management systems.

Applications

Typical applications include high-speed machine-to-machine data sharing, coordination of multiple PLCs on a production line, connection to EtherNet/IP-enabled remote I/O (such as Omron NX series), and data exchange with robot controllers, VFDs, and vision systems using CIP protocol. The tag data link mechanism is ideal for systems requiring deterministic periodic data updates.

Conclusion

The Omron CJ1W-EIP21 provides full EtherNet/IP connectivity for CJ-series PLCs with exceptionally high tag data link capacity. Its compact size, extensive diagnostic capabilities, and compatibility with major industrial Ethernet standards make it a versatile communication solution for factory automation networks.