Omron CJ1W-DA08C Analog Output Unit for CJ Series PLC

The Omron CJ1W-DA08C is an analog output unit designed for the CJ series programmable logic controllers (PLC). This unit provides eight analog output channels, each capable of delivering 4-20 mA current signals for precise control of field devices such as valve positioners, frequency inverters, and chart recorders. The CJ1W-DA08C is part of Omron's CJ1W I/O family, offering high-density analog output capability in a compact form factor suitable for industrial automation applications ranging from process control to machine automation.

Analog Output Specifications

The CJ1W-DA08C features eight independent analog output channels, each configurable for 4-20 mA current output. Each channel can be set separately to meet the specific requirements of connected field devices. The output resolution is 1/4,000, providing precise control of the output signal. Alternatively, the resolution can be set to 1/8,000 for applications requiring even finer granularity. The output range is 4-20 mA, corresponding to the standard industrial current loop signal widely adopted for analog control in manufacturing and process industries. The conversion time per unit is 4,000 ms, with an update period settable from 1.0 ms to 250 µs per point, allowing fast response to control loop demands.

Power Requirements and Connections

The CJ1W-DA08C requires a 24 V DC external power supply for operation, with a maximum inrush current of 20 A. The unit consumes up to 140 mA from the 5 V DC backplane and 170 mA from the 24 V DC external supply. The I/O connection type uses screw terminals, providing secure and reliable field wiring. Each output channel is accessible via the removable terminal block, which simplifies installation, maintenance, and replacement. The terminal base uses a removable terminal block design, allowing the module to be replaced without rewiring the field connections.

Physical and Environmental Specifications

The CJ1W-DA08C is designed for DIN rail mounting inside a control cabinet. Physical dimensions are 90 mm in height, 89 mm in depth, and the standard CJ series width. The unit is designed to operate within a temperature range suitable for industrial environments. The module is approved with UL and CE certifications, confirming compliance with safety and electromagnetic compatibility standards for industrial use.

Integration with CJ Series PLC Systems

The CJ1W-DA08C mounts directly to the CJ series backplane and is compatible with CJ1, CJ2, and CS1 series PLCs. The unit is configured using CX-Programmer or CX-Integrator software, where users can set output ranges, scaling parameters, and other configuration settings. The module occupies a position in the I/O table and is addressed as part of the PLC memory map. Data is transferred between the module and the CPU via the backplane bus, with status and diagnostic information accessible to the user program. The unit supports both normal and synchronous I/O refreshing modes, allowing optimization of update timing for specific application requirements.

Applications in Industrial Automation

The CJ1W-DA08C is suitable for a wide range of analog output applications where precise control of 4-20 mA signals is required. Typical uses include controlling proportional valves in hydraulic and pneumatic systems, providing setpoint signals to variable frequency drives (VFDs) for speed control, driving chart recorders and panel meters, and controlling process actuators such as electric actuators and positioners. Industries employing this module include packaging, material handling, automotive assembly, food and beverage processing, and general factory automation.

Diagnostic Features and Reliability

The module includes diagnostic capabilities to assist with commissioning and system maintenance. Status indicators on the front panel provide visual confirmation of power, operation, and error conditions. Output channel status can be monitored through the PLC, allowing the control program to detect open-circuit conditions or wiring faults. The screw terminal design ensures reliable electrical connections resistant to vibration typically encountered in industrial equipment.

Conclusion

The Omron CJ1W-DA08C analog output unit delivers eight channels of 4-20 mA output capability for CJ series PLC systems. Its high resolution, configurable per-channel settings, and integration with CJ series controllers make it a suitable choice for precision analog control in industrial automation applications.