The Q64TCRT is a 4-channel RTD temperature control module from Mitsubishi Electric for the MELSEC-Q series, combining RTD temperature measurement and PID control output in a single intelligent function module — eliminating the need for separate temperature controllers for up to 4 independent process temperature loops. Available now at Atlantech Drives with worldwide express delivery and 12-month warranty — complete our quote form for pricing and availability.
What Is the Mitsubishi Q64TCRT?
The Q64TCRT is an intelligent function module that integrates 4-channel RTD input measurement with on-board PID temperature control and transistor control output, all within a single MELSEC-Q base slot. Unlike the Q64RD (measurement-only RTD module), the Q64TCRT executes PID algorithms internally at the module level — independent of the CPU scan cycle — delivering consistent control period performance regardless of CPU load. Each of the 4 channels operates as an independent temperature control loop with configurable setpoint, PID parameters, alarm limits, and output mode. The transistor control output per channel drives an external solid-state relay or heater contactor, making the Q64TCRT a complete temperature control solution requiring only RTD sensors and SSR/contactor interface hardware.
Key Technical Specifications
- Number of control channels: 4
- Sensor input type: RTD (Pt100, JPt100)
- Measurement range (Pt100): –200 to +850°C
- Temperature resolution: 0.1°C
- Control output type: Transistor (open collector, NPN)
- Control output voltage: 12/24 V DC
- Control output current: 0.1 A max per channel
- Control method: PID, PI, PD, P, ON/OFF (selectable per channel)
- Control period: 0.5 s (standard), configurable
- Auto-tuning: Yes (AT function per channel)
- Alarm outputs: Upper/lower limit, deviation alarm per channel
- Isolation: Optical isolation between input/output and internal bus
- Number of occupied I/O points: 32
- Power consumption: 5 V DC, 0.52 A; 24 V DC, 0.10 A (external)
- Operating temperature: 0 to 55°C
Series Comparison & Selection Guide
Within the MELSEC-Q temperature control module range, the Q64TCRT occupies a specific position distinct from both measurement-only and thermocouple-input variants:
- Q64TCRT vs Q64RD: The Q64RD is a measurement-only module — it converts RTD resistance to temperature values for the CPU to read, but performs no control output. The Q64TCRT adds on-board PID control and transistor output, making it a self-contained controller. Choose Q64RD when temperature values feed into custom ladder-based control logic; choose Q64TCRT when standard PID temperature control with direct output is required.
- Q64TCRT vs Q64TCTTBWN: The Q64TCTTBWN is a thermocouple-input temperature control module. The Q64TCRT accepts RTD inputs (Pt100/JPt100) only. Select based on the sensor type installed in the application — RTDs for higher accuracy and long-term stability below 600°C; thermocouples for high-temperature or fast-response requirements.
- Q64TCRT vs Q64TCRTN: The Q64TCRTN adds a manual output mode and enhanced alarm functions compared to the Q64TCRT. For applications requiring manual output percentage control for commissioning or override purposes, specify the Q64TCRTN.
Expert Tips
- Use the Q64TCRT’s auto-tuning (AT) function during commissioning to calculate initial PID parameters automatically. Trigger AT from the buffer memory AT command bit (BFM #26, bit 0 per channel) via a FROM/TO instruction or GX Works2 auto-refresh. AT works by introducing a step change in output and measuring the process response — ensure the process is at a stable initial temperature and the setpoint is at the target operating temperature before starting AT, as an incorrect starting condition produces unreliable PID parameters.
- The Q64TCRT’s transistor control output is designed to drive solid-state relays (SSRs) directly — connect the output terminal to the SSR control input positive and COM to the SSR control input negative. Select an SSR with a DC control input range compatible with 12/24 V DC and a minimum control current below 10 mA to ensure reliable switching from the Q64TCRT’s 0.1 A output.
- For multi-zone furnace or oven control where zone interactions cause PID tuning difficulties, enable the cascade control function available in the Q64TCRT buffer memory parameters. Cascade control uses the outer loop (zone temperature) setpoint to generate the inner loop (heater power) setpoint dynamically, improving disturbance rejection in thermally coupled zones.
- Monitor the Q64TCRT’s channel error status flags (BFM #29) in the CPU ladder program to detect RTD disconnection, sensor short-circuit, or output overcurrent conditions — these faults do not automatically generate a CPU error and will only be visible in the module’s own error register unless explicitly read by the ladder program.
Frequently Asked Questions
Q: Can the Q64TCRT control output directly switch a resistance heater without an SSR?
A: No. The transistor control output is rated at 0.1 A maximum and is designed exclusively for driving SSR control inputs or similar low-current control signals. Resistance heaters draw several amperes and must be switched by an SSR or contactor rated for the heater load — the Q64TCRT output drives the SSR/contactor control circuit only.
Q: Does the Q64TCRT PID control continue operating if the MELSEC-Q CPU is in STOP mode?
A: No. When the CPU enters STOP mode, the Q64TCRT control outputs are turned OFF as part of the controlled stop sequence. PID execution within the module continues internally, but the output is inhibited until the CPU returns to RUN mode. For applications requiring heater output to be maintained during CPU STOP (e.g. process hold temperature), implement an external output hold relay circuit independent of the Q64TCRT output.
Q: How are the Q64TCRT PID parameters accessed and modified?
A: PID parameters (proportional band, integral time, derivative time, setpoint) are stored in the Q64TCRT buffer memory and accessed via FROM/TO instructions in the CPU ladder program, or via GX Works2 intelligent function module monitor/test dialog. Parameters can be modified online without stopping the CPU, allowing real-time PID tuning adjustments during process operation.
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