Omron CQM1H-ADB21 Analog I/O Inner Board for CQM1H Series PLC

The Omron CQM1H-ADB21 is a high-resolution analog I/O inner board designed for the CQM1H programmable controller series. It provides four analog input channels and two analog output channels in a compact board that installs directly inside the CQM1H CPU chassis. This inner board expands the PLC’s analog processing capability without occupying external I/O slots, making it ideal for process control and monitoring applications requiring analog signal conditioning.

Analog Input Specifications

Number of input points: 4 channels, isolated from each other. Input signal ranges: selectable per channel via PC Setup settings. Voltage ranges: -10V to +10V (14-bit resolution, 5mV/1 LSB), 0V to 10V (12-bit resolution, 2.5mV/1 LSB), 1V to 5V. Current range: 4mA to 20mA (12-bit resolution, 5µA/1 LSB). Conversion speed: 1ms per point max. The converted value for each input is stored as a 4-digit hexadecimal value each cycle: -10V to +10V range corresponds to F800 to 07FF Hex; 0V to 10V and 0-20mA ranges correspond to 0000 to 0FFF Hex.

Analog Output Specifications

Number of output points: 2 channels. Output signal ranges: -10V to +10V (14-bit resolution, 1.22mV/1 LSB) or 0mA to 20mA (12-bit resolution, 5µA/1 LSB) depending on terminal connection. The setting for each output is written from the CPU as a 4-digit hexadecimal value. For -10V to +10V output: F800 to 07FF Hex. For 0 to 20mA output: 0000 to 07FF Hex. Output voltage/current is updated each cycle based on the value written to the output word.

Configuration and PC Setup

The CQM1H-ADB21 is configured through the CQM1H PC Setup area (DM 6611 and DM 6621). Parameters include input range selection for each of the four analog inputs, usage selection (enable/disable conversion per input), and output range selection. These settings are stored in the CPU Unit’s internal EEPROM and are reflected at power-on. For each input channel, the user can select: -10V to +10V, 0V to 10V, 0V to 5V, or 0mA to 20mA (distinguished by terminal connection). The board also supports scaling and averaging functions via setup.

Hardware Interface

The CQM1H-ADB21 physically mounts as an inner board in the CQM1H CPU chassis, occupying the slot-2 position. It does not occupy any external I/O slot address, preserving rack space for other modules. The board includes a 10-pin screw terminal block for field wiring connections. Inputs and outputs are accessed from the CPU via specific IR addresses: input data is allocated to IR 232 through IR 235, while output data is written to IR 236 through IR 237. Error and status flags are located in SR 254 (error flag) and AR 04 (range configuration flags).

Error Detection and Diagnostics

The board includes comprehensive diagnostic features. An inner board error flag (SR 254 bits) indicates any fault condition. Error codes stored in the CPU indicate specific fault types: 01 or 02 Hex indicates hardware error, 03 Hex indicates PC Setup error, 04 Hex indicates A/D or D/A conversion error. The user program can monitor these flags to trigger alarms or perform fail-safe actions when analog I/O problems are detected.

Electrical and Environmental

The CQM1H-ADB21 draws its power from the CQM1H CPU backplane; no external supply is required. Operating temperature: 0°C to 55°C. Storage: -20°C to 75°C. Humidity: 10% to 90% non-condensing. The board includes protection against reverse polarity and transient overvoltage on the signal lines. Isolation voltage: 500V AC between input channels and internal logic for 1 minute. Dielectric strength: 1,000V AC between balanced power supply line and input/ground for 1 minute.

Compatibility

The CQM1H-ADB21 is compatible with all CQM1H CPU models (CQM1H-CPU21, CPU51, CPU61) and can be used in combination with other inner boards such as the CQM1H-ADB41 (4 inputs only) or temperature control inner boards. It is also compatible with CQM1H expansion racks and all CQM1 series I/O modules. Multiple analog inner boards can be installed if the CPU provides multiple inner board slots.

Programming Considerations

The user program accesses analog input values using MOV instructions to read the IR words. For example, IR 232 contains analog input 1 converted value, IR 233 contains analog input 2, and so forth. Outputs are driven by writing values to IR 236 (output 1) and IR 237 (output 2). Programming examples in the operation manual show how to scale raw analog values to engineering units using ladder instructions or function blocks. The board supports both manual and automatic data update cycles.

Applications

Typical applications include temperature monitoring using thermocouple amplifiers connected as 0-10V signals, pressure and flow monitoring using 4-20mA transmitters, actuator control via analog outputs (e.g., proportional valve positioning), and analog setpoint control from HMIs.

Conclusion

The Omron CQM1H-ADB21 provides essential analog input and output capability for CQM1H PLCs in a compact inner board format. With four inputs, two outputs, and multiple voltage/current range selections, it is a versatile solution for process monitoring and control in legacy CQM1H systems.