Omron CJ1W-ETN21 Ethernet Module for CJ Series Programmable Logic Controllers

Product Overview

The Omron CJ1W-ETN21 is an Ethernet communication module designed for the CJ series of programmable logic controllers. This module enables seamless integration of CJ PLCs into industrial Ethernet networks, supporting both EtherNet/IP protocol for real-time device-level communication and TCP/IP protocols for messaging and data exchange. The CJ1W-ETN21 is ideal for applications requiring high-speed data transfer, remote monitoring, and integration with SCADA systems, HMIs, and other networked devices. The module occupies a single slot in a CJ series rack and communicates with the CPU via the backplane bus.

Key Features of CJ1W-ETN21

The CJ1W-ETN21 features a 10/100BASE-TX auto-negotiating Ethernet port with RJ45 connector, supporting both full-duplex and half-duplex operation. It complies with the EtherNet/IP standard, enabling cyclic I/O data exchange with compatible devices such as remote I/O, drives, and vision systems. The module also supports socket services (UDP/TCP) for flexible message exchange with host computers and other Ethernet devices. It can act as a server or client for data transfer using FINS (Factory Interface Network Service) protocol, allowing communication with Omron PLCs over Ethernet.

The module includes a built-in web server for remote status monitoring and configuration via a standard web browser. It features LED indicators for link activity, network status, and error conditions. The CJ1W-ETN21 supports automatic address detection and configuration via DHCP or BOOTP, as well as static IP assignment. It can be used for programming and debugging over Ethernet, eliminating the need for a dedicated programming cable. The module operates from the CJ series backplane power supply and consumes 350 mA at 5 V DC. The operating temperature range is 0 to 55°C. It is certified for CE and UL standards.

Technical Specifications

• Manufacturer: Omron Corporation

• Part Number: CJ1W-ETN21

• Series: CJ1W

• Product Type: Ethernet Communication Module

• Communication Protocol: EtherNet/IP (implicit and explicit messaging), TCP/IP, UDP, FINS

• Connector: RJ45 (10/100BASE-TX, auto-negotiating)

• Max. Number of Connections: 32 (EtherNet/IP), 8 (socket services)

• Web Server: Yes (embedded)

• Configuration: Automatic (DHCP/BOOTP) or static IP

• Indicators: Link, activity, error LEDs

• Power Supply: 5 V DC from backplane (350 mA)

• Operating Temperature: 0 to +55 °C

• Storage Temperature: -20 to +75 °C

• Degree of Protection: IP20

• Dimensions (W x H x D): 35 mm x 90 mm x 85 mm

• Certifications: CE, UL

Functional Description

The CJ1W-ETN21 module acts as a gateway between the CJ CPU and Ethernet network. The CPU exchanges data with the module via the backplane using dedicated memory areas. In EtherNet/IP mode, the module can perform cyclic I/O data exchange with remote devices (e.g., Ethernet/IP adapters) without programming overhead. Socket services allow the PLC to send and receive data to/from any TCP/UDP device, enabling integration with PCs, printers, and other equipment. The built-in web server displays module status, error logs, and I/O information. The FINS protocol enables PLC-to-PLC communication and remote programming.

Applications

The Omron CJ1W-ETN21 is used in industrial automation systems requiring Ethernet connectivity for remote programming, data logging, SCADA integration, and machine-to-machine communication. Typical applications include packaging lines, material handling systems, and factory-wide control networks.