OMRON CQM1H‑MAB42 Analog I/O Module for CQM1H PLC

The OMRON CQM1H‑MAB42 is a specialised analog input/output slave module designed for the CQM1H programmable logic controller platform. It features four analog input channels and two analog output channels, each with 12‑bit resolution (0‑4095 counts). This module enables the CQM1H CPU to interface with sensors, transmitters, and analog actuators such as proportional valves or chart recorders, extending the PLC’s ability to handle process variables.

Analog Input Specifications

The four inputs are individually configurable for voltage (±10 V, 0‑10 V, 0‑5 V) or current (4‑20 mA, 0‑20 mA) using DIP switches on the module’s side panel. Input impedance is 1 MΩ for voltage ranges and 250 Ω for current ranges. Conversion speed is 2 ms per channel (maximum scan time 8 ms for all four). Resolution is 12 bits (1.22 mV for 0‑5 V range, 4.88 μA for 4‑20 mA). Absolute accuracy is ±0.5% full scale at 25 °C. Each input has a built‑in low‑pass filter (1 kHz cutoff), and input protection against 30 V overvoltage is provided.

Analog Output Specifications

The two outputs can be set to 0‑10 V, ±10 V, or 4‑20 mA (selectable per channel). Output settling time is 1 ms for voltage and 2 ms for current. Load impedance: minimum 2 kΩ for voltage, maximum 600 Ω for current. Output resolution remains 12 bits (2.44 mV for 0‑10 V, 4.88 μA for 4‑20 mA). Short‑circuit protection and overcurrent limiting are integrated. The output holds its last value when the PLC is in STOP mode, configurable to either clamp or hold via CX‑Programmer settings.

Data Exchange and Addressing

The CQM1H‑MAB42 occupies two I/O words in the CQM1H’s internal address space. Input data is mapped to consecutive input words (e.g., IR 010 for channel 1‑4) while output data uses one output word. Setup parameters (range selection, filter enable) are stored in the DM area of the CPU, typically using DM 6600‑6699. The module does not require external 24 V power; it draws 150 mA from the PLC backplane at 5 V DC.

Installation and Configuration

Physically, the module mounts on the right side of the CQM1H CPU as any standard expansion unit. Maximum number of analog modules in a system is limited by the total I/O capacity (up to 11 slots for CQM1H). Configuration is performed via the CX‑One software (version 9.0 or later) or via a handheld programmer. Scaling functions can be programmed using ladder instructions: SCL(194) or APR(69). The module supports interrupt inputs for high‑speed analog triggering if used with CQM1H‑CPU51/CPU61.

LED Indicators and Diagnostics

Front panel LEDs indicate RDY (ready), ERR (error), and each I/O channel’s activity. The ERR LED illuminates if a range setting conflicts or if an output exceeds specified limits. Diagnostic information can be read from special auxiliary words A434‑A437. The module also incorporates self‑diagnosis of A/D and D/A converters via a cyclic software test.

Typical Applications

Applications include temperature monitoring (with 0‑10 V thermocouple transmitters), pressure control in hydraulic presses, speed reference for DC drives, and position feedback from linear potentiometers. The CQM1H‑MAB42 is widely used in retrofitting older machines requiring analog control without migrating to new PLC families.