The Omron CJ1W-PRT21 is a analog output unit designed for use with Omron’s CJ-series programmable logic controllers (PLCs). Although the description initially mentions “input points,” the unit is actually an analog output module that converts binary data from the PLC into analog voltage signals. It features 8 output points, each individually configurable for signal range selection, allowing for maximum flexibility in diverse industrial applications.

### Signal Range and Resolution

The unit supports four selectable voltage output ranges: 1 to 5 V, 0 to 5 V, 0 to 10 V, and –10 to +10 V. Each of the 8 points can be set to a different range independently. The standard resolution is 1/4000 (12-bit equivalent), but it can also be set to 1/8000 (13-bit equivalent) for higher precision. This enables fine-grained control in applications such as valve positioning, motor speed control, or analog instrumentation.

### Conversion Speed and Accuracy

The conversion speed is 1 ms per point under normal settings, with the option to reduce it to 250 μs or less per point for high-speed applications. The unit offers a comprehensive accuracy of ±0.3% of full scale, ensuring reliable and repeatable analog output performance.

### Key Functions

●Output Hold Function: Maintains the last output value even if the PLC CPU stops or a communications error occurs, ensuring process safety.

●Measurement Function: Allows monitoring of the actual output value for diagnostic purposes.

●Offset/Gain Adjustment: Supported on most models (except CJ1W-DA042V) for fine-tuning output characteristics.

●Scaling Function: Enables conversion of engineering units directly, supported on CJ1W-DA08V, DA08C, and DA042V models.

### High-Speed Direct Conversion

A special variant, CJ1W-DA042V, offers direct conversion with a 20 μs/point D/A conversion speed, making it suitable for ultra-fast control loops. This model also supports consistent millisecond total processing capability, ideal for synchronous multi-axis control or high-speed data acquisition systems.

### Physical and Connectivity

The unit uses a removable terminal block for easy wiring and maintenance. It is designed for rack-mounted installation in CJ-series PLC systems, providing a compact and scalable solution for up to eight analog outputs per module.

### Application Areas

Typical applications include process control, temperature regulation, speed control of drives, valve actuation, and analog signal generation for test and measurement systems. The combination of multiple output ranges, adjustable resolution, and high-speed options makes this unit versatile for both general-purpose and high-performance automation tasks.