Omron CJ1W-SCW22 Serial Communication Unit for CJ Series PLC

The Omron CJ1W-SCW22 is a serial communication unit designed for the CJ1, CJ2, and CS1 series programmable logic controllers (PLCs). It provides two independent serial ports: one RS-232C and one RS-422/485 (selectable). This unit enables the PLC to communicate with a wide range of serial devices such as barcode readers, weigh scales, printers, and third-party controllers.

Port Specifications

Port 1 is a 9-pin D-sub RS-232C interface supporting baud rates up to 115.2 kbps. Port 2 can be configured as either RS-232C (via the same connector) or RS-422/485 (via a removable terminal block), with baud rates up to 115.2 kbps. Both ports support data bits: 7 or 8; parity: none, even, odd; stop bits: 1 or 2.

Protocol Support

The unit supports Omron’s Host Link (SYSMAC WAY), protocol macros, Modbus RTU (master/slave), and no-protocol (general serial) modes. Protocol macros allow users to create custom communication sequences for non-standard devices using CX-Protocol software. Up to 100 protocol macros can be stored onboard.

Communication Modes

Each port can operate independently in one of the following modes: Host Link (command/response), protocol macro, Modbus master/slave, or serial gateway. The unit supports full-duplex and half-duplex operation, with flow control (RTS/CTS or XON/XOFF) available on the RS-232C port.

Integration with CJ PLC

The CJ1W-SCW22 mounts directly on the CJ-series CPU rack or an expansion rack. It does not require an external power supply, drawing all necessary power from the backplane (350 mA at 5V). The unit is configured via the CX-Programmer software, where users assign unit numbers (0 to 95) and set communication parameters.

Diagnostics and LEDs

Front panel LEDs indicate power, unit ready, each port’s transmit/receive activity, and error status. The unit can trigger a CPU alarm on communication time-out. Self-diagnostic functions check for memory errors and parameter misconfiguration.

Mechanical and Environmental

Dimensions: 31 x 90 x 64 mm (W x H x D). Operating temperature: 0°C to 55°C; storage: -20°C to 75°C. Humidity: 10% to 90% non-condensing. The unit is rated IP20 and must be installed in a cabinet. A detachable terminal block is provided for RS-422/485 connections.

Applications

Typical uses include connecting PLC to legacy serial instruments, remote terminal units (RTUs), variable frequency drives, and operator panels. It is also used for data collection from weigh scales and barcode scanners in packaging lines.

Conclusion

The Omron CJ1W-SCW22 serial communication unit provides flexible, two-port connectivity for CJ-series PLCs. With support for protocol macros and Modbus, it simplifies integration with diverse serial devices.