OMRON CQM1‑AD042 4‑Channel Analog Input Unit for CQM1 PLC
The OMRON CQM1‑AD042 is a dedicated analog input slave module for the CQM1 series programmable logic controllers. It provides four independent analog input channels, each configurable for either voltage (0‑10 V DC) or current (4‑20 mA) signals. With 12‑bit resolution (0‑4095 counts), this module enables the CQM1 CPU to read process variables such as pressure, temperature (via transmitters), flow, and position from analog sensors.
Analog Input Specifications
Each of the four channels can be individually set via DIP switches on the module side panel. Voltage range: 0‑10 V DC (input impedance 1 MΩ). Current range: 4‑20 mA (input impedance 250 Ω). The conversion speed is 2.5 ms per channel, meaning a full scan of all four channels takes 10 ms. Resolution: 12 bits (2.44 mV for voltage, 4.88 μA for current). Absolute accuracy: ±0.5% of full scale at 25 °C, with temperature drift ±0.02%/°C. The module includes input filtering (1 kHz cutoff) and overvoltage protection up to 30 V.
Data Format and Addressing
The CQM1‑AD042 occupies four input words in the PLC’s I/O memory, one per channel. Data is stored as binary values (0‑4095) representing 0‑10 V or 4‑20 mA. A conversion formula (scaling) can be implemented in ladder logic using the SCL(194) instruction. Optionally, the module can be configured to output data in BCD format (0‑2000), useful for direct display on numeric indicators. The module does not require external 24 V power; it draws 150 mA from the backplane at 5 V DC.
Installation and Configuration
The module mounts on the right side of any CQM1 CPU (models CPU11, CPU21, CPU41, CPU44) as a standard expansion unit. Maximum number of analog modules is limited by total I/O points (max 11 slots). Configuration is performed using the CX‑Programmer software (version 5.0 or later) or a handheld programmer. DIP switches on the front set the input type per channel. The module automatically detects the presence of an input signal and reports an error if the signal is outside the valid range (e.g., sensor break for 4‑20 mA).
Diagnostics and LED Indicators
Front panel LEDs: POWER (green) indicates backplane power; RUN (green) indicates normal operation; ERR (red) flashes if a channel is overloaded or misconfigured. Each channel has a yellow LED that blinks when the input value exceeds the set threshold (programmable via the PLC). The module performs a self‑diagnosis at power‑up, checking A/D converter calibration values stored in EEPROM.
Environmental and Compliance
Operating temperature: 0‑55 °C, storage: -20‑75 °C. Humidity: 35‑85% non‑condensing. Vibration resistance: 2 G (10‑150 Hz). The module meets UL 508, CSA C22.2 No. 142, and EN 61131‑2 standards. CE marking for EMC (EN 61131‑2:2007).
Typical Applications
The CQM1‑AD042 is commonly used in plastic injection moulding (pressure monitoring), water treatment (flow rate), HVAC (damper position feedback), and packaging (fill level detection). Its four channels allow monitoring of multiple analog sensors without occupying excessive rack space. When combined with a CQM1‑TC101 temperature module, a complete process control system can be assembled.
