OMRON CJ1W-DA08C Analog Output Module

The OMRON CJ1W-DA08C is a high‑precision analog output module designed for the CJ1 series programmable logic controllers. This module provides eight independent analog output channels, each configurable for voltage (±10 V, 0‑10 V, 0‑5 V) or current (4‑20 mA, 0‑20 mA) signals. It is used to control process actuators such as proportional valves, variable speed drives, and chart recorders, translating digital setpoints from the PLC into continuous analog signals.

Each channel features a 16‑bit digital‑to‑analog converter (DAC) for high resolution and low drift over temperature. The module includes output hold functions, which maintain the last value in case of communication loss, ensuring process safety. The CJ1W‑DA08C is isolated from the PLC backplane, preventing ground‑loop disturbances that could affect signal accuracy.

Technical Specifications

• Number of channels: 8 (analog outputs)

• Output signal ranges: ±10 V, 0‑10 V, 0‑5 V, 1‑5 V (voltage); 0‑20 mA, 4‑20 mA (current)

• Resolution: 16 bits (1/65536) for all ranges

• Accuracy: ±0.2% of full scale (at 25°C), ±0.3% over full temperature range

• Settling time: ≤ 1 ms (for step input change)

• Output impedance: ≤ 0.5 Ω (voltage), ≥ 1 MΩ (current)

• Isolation: Photo‑coupler isolation (between outputs and PLC bus)

• Internal power consumption: 5 V DC, 120 mA (from backplane)

• External power supply: 24 V DC (for current outputs)

• I/O allocation: 1 output word (control) and 2 input words (status) per channel grouping

• Dimensions: 90 x 65 x 85 mm (H x W x D)

• Operating temperature: 0°C to +55°C

• Storage temperature: -20°C to +75°C

Functional Capabilities

• Independent channel configuration: Each output can be set to voltage or current via software, without hardware jumpers.

• Hold function: In case of communication error with the CPU, outputs can hold the last value or go to a predefined safe state (user‑configurable).

• Diagnostic features: The module provides status flags for output overload, wiring disconnection (for current outputs), and power supply supervision.

• Scalable output: The PLC program can write values in engineering units (e.g., 0‑100%) and the module automatically scales to the selected output range.

Typical Applications

• Process control: Driving control valves, dampers, and variable frequency drives for flow, pressure, and temperature loops.

• Test and measurement: Generating reference voltages/currents for sensor calibration.

• Servo control: Providing analog torque or speed setpoints to servo amplifiers.

• Recording and display: Outputting signals to panel meters and chart recorders.

Integration with CJ1 PLC

The CJ1W‑DA08C mounts directly into the CJ1 rack and is automatically allocated memory addresses by the CPU. Using CX‑Programmer, the user configures the range for each channel and selects the hold mode. Writing a digital value to the corresponding output word updates the analog output. The module also provides status information (e.g., range error, open circuit) that can be read by the PLC program for diagnostics. For current outputs, an external 24 V DC power supply is required; the module does not source the loop power internally.

Wiring and Installation

Use shielded twisted‑pair cables for analog outputs to minimize noise pickup. Connect the shield to the ground terminal at the receiving device. The module uses removable terminal blocks; current outputs require connecting the load between the output terminal and the external 24 V DC supply’s negative terminal. Voltage outputs are connected directly between the output and the common terminal. All unused outputs should be left unconnected. Ensure the external power supply has adequate capacity for the total current loop load.

Compliance and Reliability

The CJ1W‑DA08C complies with EN 61131‑2, is CE marked, and UL recognized (cULus). It is rated for pollution degree 2 and is RoHS compliant.

Conclusion

The OMRON CJ1W‑DA08C analog output module offers a high‑density, high‑precision solution for generating analog signals in CJ1 PLC systems. Its flexibility, diagnostic features, and robust design make it an excellent choice for demanding industrial control applications.