OMRON CQM1-AD041 Analog Input Unit for CQM1 PLC

The OMRON CQM1-AD041 is a high-resolution analog input module designed for the compact CQM1 programmable logic controller series. It provides four independent analog input channels, each configurable for voltage or current signals, enabling direct connection to sensors, transmitters, and other analog field devices. The module offers 12-bit resolution and high accuracy for process measurement applications.

Input Signal Ranges

Each channel can be individually set via software or DIP switches to one of the following ranges: 0 to 10 V, 0 to 5 V, 1 to 5 V, 0 to 20 mA, or 4 to 20 mA. Input impedance is 1 MΩ for voltage and 250 Ω for current. The module supports both single-ended and differential configurations (jumper-selectable).

Resolution and Accuracy

Resolution is 12 bits (1/4096) for all ranges. Overall accuracy is ±0.5% of full scale at 25°C, with a temperature drift of ±0.02% per °C. Conversion time is 2 ms per channel (all channels scanned sequentially). The module also provides averaging function (up to 8 samples) for noise reduction.

Data Transfer to PLC

The converted digital values are stored in dedicated input words (IR area) accessible by the CPU. Scaling can be performed in the PLC user program using standard arithmetic operations. The module also outputs a status flag indicating overrange or underrange conditions.

Wiring and Connection

Field wiring is connected via a removable terminal block with screw clamps, accepting wires up to 1.5 mm². Each channel has two terminals (positive and negative). A common terminal is provided for current-loop connections. Shielded cables are recommended for signal integrity.

Configuration and Setup

Configuration is done through the PLC programming software (CX-Programmer or SYSMAC-CPT). Users can assign input ranges, enable/disable channels, and set averaging parameters. The module's DIP switches allow basic range selection without software.

Diagnostics and Indicators

An LED indicates power and communication status. The module performs self-diagnostics on power-up, checking for A/D converter errors. A fault is reported to the CPU via a dedicated flag.

Environmental and Electrical Ratings

Operating temperature: 0 to 55°C, storage: -20 to 75°C. Power supply: 5 VDC from backplane (250 mA) and 24 VDC external (50 mA) for current inputs. Isolation: 500 VAC between input and PLC.

Compatibility

Compatible with all CQM1 CPUs (CQM1, CQM1H). Up to three analog units can be installed in a single rack (depending on CPU capacity).

Applications

Used for temperature measurement (thermocouples via transmitters), pressure, flow, level, and other process variables in small to medium-scale industrial systems.

Maintenance and Calibration

No routine calibration required; the module uses stable reference sources. Periodic cleaning of terminals and inspection of wiring is recommended.

In summary, the OMRON CQM1-AD041 analog input module delivers reliable and accurate signal conditioning for CQM1 PLC systems, supporting a wide range of industrial sensors.