Omron CJ1W-ETN21 Ethernet Unit

The Omron CJ1W-ETN21 is a high-performance Ethernet Unit designed for the CJ Series programmable logic controllers. This CPU bus unit provides organic connectivity between production sites and management information systems through standard Ethernet networks. Supporting both 100BASE-TX and 10BASE-T communication standards, the CJ1W-ETN21 enables PLC data exchange with host computers, workstations, other PLCs, and Ethernet-enabled field devices. The unit implements the FINS (Factory Interface Network Service) communications service over TCP/IP and UDP/IP protocols, as well as FTP server functions, socket services, and mail transmission capabilities, making it a versatile solution for industrial network integration.

Technical Specifications

Key Features and Benefits

• FINS Communications Service: The Ethernet Unit provides FINS messaging over TCP/IP and UDP/IP protocols, allowing seamless data exchange between CJ Series PLCs and host computers across Ethernet networks. FINS commands can read and write CIO, DM, and EM area data, execute PLC control operations, and retrieve status information without requiring complex socket programming.

• FTP Server Functions: The built-in FTP server enables remote file access to the PLC's Memory Card. Users can upload or download program files, data logs, and configuration files from any FTP client, simplifying program transfer and data collection for production reporting and quality analysis systems.

• Socket Services: Direct socket services allow custom TCP/IP and UDP/IP communication programming using user-defined protocols. This feature enables the CJ1W-ETN21 to communicate with non-Omron devices, barcode readers, printers, and other Ethernet-equipped instruments using proprietary or industry-standard application protocols.

• Mail Transmission Services: The unit can automatically send email messages to specified recipients when predefined conditions occur, such as alarm events or production milestones. The mail function supports both transmission and reception, with remote command reception allowing external systems to trigger PLC operations via email commands.

Functional Overview

The CJ1W-ETN21 operates as a CPU bus unit mounted on the CJ Series CPU rack or expansion rack. The unit requires node address assignment via the front-panel rotary switches and network configuration using CX-Programmer or dedicated network configuration tools. During operation, the unit autonomously manages TCP/IP and UDP/IP communications, delivering FINS messages to the CPU via the backplane bus and generating responses to external requests.

Compatibility and Integration

The CJ1W-ETN21 is compatible with Omron CJ Series CPUs including CJ1, CJ1M, CJ2, and CS1 Series PLCs. Up to four Ethernet Units can be connected to a CPU rack. The unit supports automatic adjustment of the PLC's built-in clock via SNTP, server and host name specifications for flexible network configuration, and automatic clock synchronization with time servers.

Installation and Configuration

The CJ1W-ETN21 mounts in any I/O slot of the CJ Series CPU rack or expansion rack. Node number selection is set using the front-panel rotary switches. Initial configuration includes IP address assignment, subnet mask, and FINS network address settings using CX-Programmer or the unit's built-in web server. The unit supports automatic network settings through BOOTP. RJ45 connection uses standard category 5 or 5e twisted-pair cabling with 100-meter maximum segment length. No external power supply is required as the unit draws 5 VDC power from the PLC backplane.

Maintenance and Reliability

The CJ1W-ETN21 is designed for long-term reliability with maintenance-free operation under normal conditions. The unit includes diagnostic LED indicators for power (PWR), network link/activity (LNK/ACT), and unit status (RUN, ERC, ERH). Self-diagnostic functions detect network disconnection, duplicate IP address conflicts, and communication errors. The unit consumes 370 mA at 5 VDC with low heat generation.

Conclusion

The Omron CJ1W-ETN21 Ethernet Unit provides a comprehensive solution for connecting CJ Series PLCs to Ethernet networks. With FINS communications, FTP server functions, socket services, and mail transmission capabilities, the unit addresses the requirements of factory data collection, remote monitoring, and inter-controller networking, making it a versatile communication module for system integrators and automation engineers.