Omron CJ1W-DA021 2-Channel Analog Output Module for CJ-Series PLCs
The Omron CJ1W-DA021 is a high-precision analog output module designed for the SYSMAC CJ-series programmable logic controller systems. This module provides two independent analog output channels that convert digital values from the PLC CPU into proportional voltage or current signals. The CJ1W-DA021 is ideal for industrial automation applications requiring precise analog control of field devices such as variable frequency drives, proportional valves, chart recorders, and process actuators. The module's compact dimensions of 31 × 90 × 65 mm (W × H × D) allow installation in space-constrained control cabinets.
Key Specifications
Model: CJ1W-DA021 Analog Output Unit
Product Series: CJ-series Special I/O Unit
Number of Analog Outputs: 2 channels
Output Signal Ranges: -10 to 10V, 0 to 10V, 0 to 5V, 1 to 5V, 4 to 20mA
Resolution: 1/4000 (full scale)
D/A Conversion Time: 1 ms per point
Output Impedance (Voltage): 0.5 Ω maximum
Maximum Output Current: 12 mA
Voltage Accuracy at 23°C: ±0.3% of full scale
Current Accuracy at 23°C: ±0.5% of full scale
External Power Supply: 24 VDC (+10%, -15%)
External Power Supply Current: 140 mA maximum
Current Consumption: 120 mA at 5V DC
External Connection: Removable terminal block
Isolation: Photocoupler between outputs and PLC signals (no isolation between outputs)
Dimensions (W × H × D): 31 × 90 × 65 mm
Weight: Approximately 0.11 kg (0.25 lbs)
Approvals: CE, UL, cUL, RoHS
Flexible Output Signal Ranges
The CJ1W-DA021 provides two independent analog output channels that can be configured for voltage or current output signals. Supported voltage ranges include -10 to 10V for bipolar applications, 0 to 10V and 0 to 5V for unipolar control, and 1 to 5V for applications requiring live zero detection. The 4 to 20 mA current output range provides compatibility with standard process control loops, offering long-distance signal transmission capability without voltage drop concerns. Each output channel can be independently configured for the appropriate signal range, providing flexibility for mixed-signal applications.
High Resolution and Accuracy
The CJ1W-DA021 delivers 1/4000 full-scale resolution, enabling precise control of analog output signals with fine granularity. This high resolution ensures smooth and accurate control of connected devices, eliminating step changes that could cause mechanical instability or process variation. The voltage output accuracy of ±0.3% of full scale at 23°C (±2°C) and current output accuracy of ±0.5% ensure that the output signal reliably represents the digital value written by the PLC program. The output impedance of 0.5 Ω maximum for voltage outputs ensures accurate signal delivery even with moderate cable lengths.
D/A Conversion Performance
The module features a D/A conversion time of 1 ms per point, supporting real-time control applications requiring rapid output updates. The fast conversion speed allows the PLC to update analog outputs at a rate suitable for closed-loop control applications such as PID regulation, motion control, and process control. The conversion is performed continuously and asynchronously to the PLC scan, ensuring that output signals are updated promptly when new values are written by the user program.
External Power Supply Requirements
The CJ1W-DA021 requires an external 24 VDC power supply (+10%, -15%) for analog output operation, separate from the PLC's internal power supply. This external power supply provides the current required to drive the output circuits and the connected field devices. The maximum external power supply current requirement is 140 mA, which should be considered when sizing the power supply for the control cabinet. The use of an external power supply isolates the analog output circuits from the PLC's internal power, improving noise immunity and protecting the PLC from field device faults.
Isolation and Noise Immunity
The CJ1W-DA021 provides photocoupler isolation between the analog output circuits and the PLC signals, protecting the controller from electrical noise and voltage transients from field devices. This isolation is particularly important in industrial environments where motors, drives, and welding equipment generate significant electromagnetic interference. The module does not provide isolation between individual output channels, but the overall isolation design ensures reliable operation in typical industrial control systems. The removable terminal block provides secure connections for field wiring.
PLC Programming and Data Transfer
The CJ1W-DA021 is controlled through the PLC user program using standard move instructions. The program writes digital values to the output words assigned to the module in the Special I/O Unit Area. These digital values are automatically converted by the module to the selected analog output range. The module supports scaling functions that allow the PLC to write engineering units directly, with the module handling conversion to the appropriate analog signal range. This scaling capability simplifies programming by eliminating the need for manual scaling calculations in the PLC program.
Process Control Applications
The CJ1W-DA021 is commonly used with PID control loops executed in the PLC program. The PID instruction reads an analog input from a process variable, calculates the required output to maintain setpoint, and writes the result to the analog output module. This closed-loop control architecture enables precise regulation of temperature, pressure, flow, level, and other process parameters. The analog output module's accuracy and resolution are critical to achieving stable control without oscillation or offset. In multi-loop applications, the CJ1W-DA021 can be combined with multiple analog input modules to provide complete process control solutions.
Motion and Drive Control Applications
In motion control applications, the CJ1W-DA021 provides speed references to servo drives and variable frequency drives for conveyor systems, hoists, and positioning tables. The analog output signals can be used to control motor speed in applications requiring smooth acceleration and deceleration. The wide range of output signal options (including -10 to 10V bipolar output) provides compatibility with drive inputs from various manufacturers. The module's fast conversion time supports real-time speed changes for dynamic motion applications.
Industrial Applications
The Omron CJ1W-DA021 analog output module is deployed across a wide range of industrial automation applications requiring precise analog control. In manufacturing, it controls VFD speed for conveyor systems, mixers, and extruders. In process control, it sends control signals to proportional valves for flow regulation, pressure control, and temperature management. In HVAC systems, it controls damper actuators, chilled water valves, and fan speed controllers. In test and measurement, it provides stimulus signals for device testing and calibration. The module's compact size and two-channel configuration make it suitable for applications where panel space is limited.
Conclusion
The Omron CJ1W-DA021 analog output module provides 2 channels of high-precision analog output with 1/4000 resolution, multiple signal ranges, and 1 ms conversion time for CJ-series PLCs. Its flexible output configuration, high accuracy, and compact dimensions make it a reliable solution for industrial automation applications requiring precise analog control of field devices.
