OMRON CQM1‑TC101 2‑Loop Thermocouple Temperature Control Unit
The OMRON CQM1‑TC101 is a dedicated temperature control module for the CQM1 series PLC. It supports two independent temperature control loops, each accepting thermocouple inputs (type K or J) and providing PID output via time‑proportional (ON/OFF) or PWM signals. This unit is ideal for extrusion machines, injection moulding, heat treatment ovens, and packaging sealing bars, where precise temperature regulation is critical.
Input Specifications
Each loop can be configured for K or J thermocouples via DIP switches. Input range: K type -200 to 1300 °C; J type -100 to 850 °C. Cold junction compensation is automatic internal. Input impedance is >1 MΩ. Resolution: 0.1 °C in display, 12‑bit (approx. 0.3 °C for K type) for control. Sampled every 0.5 second per channel. Absolute accuracy: ±0.3% of full scale ±1 °C. The module provides open thermocouple detection (burnout) and indicates sensor break as an error flag.
PID Control Features
Each loop executes independent PID control with auto‑tuning and self‑tuning capability. Auto‑tuning (AT) uses the limit cycle method to calculate proportional band (P), integral time (I), and derivative time (D) during initial setup. Self‑tuning continuously adjusts PID parameters when load changes. The unit supports manual reset and output limiting. Control output can be either ON/OFF (hysteresis adjustable) or time‑proportional PWM with a cycle time from 1 to 99 seconds. Output signals are 24 V DC, 50 mA per channel, typically driving solid state relays (SSR).
Data Exchange with CQM1 CPU
The TC101 occupies 4 I/O words. Input words contain current temperature values (binary or BCD selectable), alarms (high/low limits), and error codes. Output words set the setpoint, PID parameters, and output mode. Each loop can store up to 8 setpoint profiles (ramp/soak programs), each with time step and target temperature. The module’s internal memory retains parameters without battery using EEPROM.
Alarms and Diagnostics
Two alarm points per loop can be defined: absolute high, absolute low, deviation high/low, or hysteresis alarm. Alarm outputs are available as bits in the input word, and can also drive physical outputs via the PLC’s discrete I/O if needed. Diagnostic LEDs on the front panel: RUN, ERR, TC1, TC2. The ERR LED flashes if any loop has a sensor break or output short. Hysteresis for ON/OFF control is adjustable from 0 to 999 °C.
Installation and Compatibility
The module mounts on the CQM1 CPU expansion rack (right side). It is compatible with CQM1 CPU11, CPU21, CPU41, and CPU44. Power consumption: 200 mA from 5 V backplane, plus external 24 V DC (50 mA) for the thermocouple reference junction. External wiring uses a detachable 10‑pin screw terminal block, accepting AWG 22‑16. Thermocouple extension wire should be used to maintain accuracy.
Applications
Typical installations include plastic thermoforming machines, soldering stations, lab reactors, and food frying equipment. The two independent loops can control two separate heating zones (e.g., barrel zones of an extruder). By using auto‑tuning, commissioning time is reduced, and the PID algorithm maintains ±1 °C stability in well‑insulated systems.
