The Q64TCRTBWN is Mitsubishi Electric’s 4-channel RTD-input bidirectional temperature control module for the MELSEC-Q programmable controller series, providing closed-loop PID temperature control for four independent zones using resistance temperature detector (RTD) sensors — delivering the superior measurement accuracy of Pt100 and Pt1000 RTDs with full heating and cooling bidirectional control capability in a single intelligent function slot. As the RTD-dedicated counterpart to the Q64TCTTBWN dual-input module, the Q64TCRTBWN is specified for precision temperature control applications where all zones are instrumented with RTD sensors and the highest available measurement accuracy in the 0°C to 850°C range is required. In stock at Atlantech Drives. Request your quote within 24-48 hours with worldwide shipping and 12-month warranty.
What Is the Q64TCRTBWN?
The Q64TCRTBWN is a MELSEC-Q series intelligent function module combining four RTD input channels with four corresponding analogue output channels under independent PID control with bidirectional heating and cooling capability. Each channel accepts a 3-wire Pt100, Pt1000, or JPt100 RTD sensor and operates as a complete closed-loop temperature controller — reading the RTD resistance, converting it to a temperature value with built-in lead resistance compensation, comparing it against the stored setpoint, executing the PID algorithm with independent heating and cooling parameter sets, and generating proportional analogue output signals to the heating and cooling actuators. The «BW» suffix denotes bidirectional (heating and cooling) control with separate PID tuning for each direction, enabling precise temperature regulation in processes where both heating and cooling are required to maintain the setpoint — such as environmental test chambers, reaction vessels requiring exothermic control, and precision thermal conditioning systems. The module operates autonomously without loading the CPU scan cycle, communicating with the CPU via FROM/TO instructions or GX Works2 auto-refresh.
Key Technical Specifications
- Model: Q64TCRTBWN
- Control Channels: 4 (independent bidirectional PID per channel)
- Input Type: RTD — Pt100 (3-wire), Pt1000 (3-wire), JPt100 (3-wire)
- Temperature Range: Pt100/JPt100: -200°C to +850°C; Pt1000: -200°C to +850°C
- Input Resolution: 0.1°C
- Input Accuracy: ±0.5°C at 25°C ambient (±1.0°C over full operating temperature range)
- Lead Resistance Compensation: Built-in (3-wire connection)
- Control Algorithm: PID with autotuning, bidirectional heating/cooling
- Output Type: Voltage (0–5 VDC, 0–10 VDC, 1–5 VDC) or Current (4–20 mA, 0–20 mA) per channel
- Output Resolution: 12-bit
- Sampling Period: 500 ms per channel
- Current Consumption (5 VDC internal bus): 0.65 A
- External Power Supply: 24 VDC ±10%, 0.45 A (required)
- Operating Temperature: 0°C to 55°C
- Weight: Approx. 0.28 kg
Series Comparison & Selection Guide
Mitsubishi Electric’s MELSEC-Q temperature control module range covers thermocouple-only, RTD-only, and dual-input configurations in both standard (heating-only) and bidirectional (heating/cooling) variants. The Q64TCRTBWN occupies the RTD-only bidirectional position in this range, making it the correct selection when all four temperature zones use RTD sensors AND bidirectional heating/cooling control is required. For thermocouple installations requiring bidirectional control, the Q64TCRTN (heating-only) or Q64TCTTBWN (dual-input bidirectional) should be specified depending on whether RTD flexibility is also needed. For heating-only RTD applications, the Q64TCRT (RTD-only heating) module is appropriate. The Q64TCRTBWN provides better measurement accuracy than thermocouple-based modules in the 0°C to 500°C range — Pt100 RTDs in this range typically achieve ±0.3°C sensor accuracy compared to ±0.5–1.5°C for type K thermocouples — making the Q64TCRTBWN the preferred choice for pharmaceutical batch processing, laboratory environmental chambers, and precision material testing equipment where temperature uniformity specifications are tighter than ±1°C.
Maintenance Tips
RTD sensors connected to the Q64TCRTBWN should be inspected annually for lead resistance changes that could affect measurement accuracy. The module’s 3-wire connection compensates for uniform lead resistance, but if the three leads develop significantly different resistances (due to partial corrosion, mechanical damage to one conductor, or connection loosening), the compensation becomes inaccurate and a temperature measurement offset develops. Verify lead resistance balance by measuring the resistance of each of the three conductors individually with a low-resistance ohmmeter — all three should measure within 0.1 Ω of each other for accurate compensation. For high-vibration installations, re-torque the RTD terminal connections annually to prevent resistance increases from loose connections. The Q64TCRTBWN’s PID parameters are stored in the module’s internal non-volatile memory and are retained across power cycles without battery backup — however, if the module is replaced, the PID parameters must be re-entered or re-loaded from a GX Works2 project backup. Maintain a GX Works2 project file containing the current PID parameter values for all channels as part of the plant maintenance documentation, enabling rapid module replacement without the need to re-run autotuning in a production environment.
Frequently Asked Questions
Q: What is the difference between the Q64TCRTBWN and the Q64TCRT, and when should bidirectional control be specified?
A: The Q64TCRT is a heating-only RTD temperature control module, while the Q64TCRTBWN adds bidirectional (heating and cooling) control with independent PID parameter sets for each direction. Bidirectional control is required in any process where both heating and cooling actuators are present and the module must manage both — such as environmental test chambers (heater + refrigeration compressor), continuous chemical reactors (heater + cooling water valve), and precision thermal platforms (heating element + Peltier cooler). For simple heating-only processes such as industrial ovens, injection moulding heater bands, and process fluid heating, the Q64TCRT is sufficient and more cost-effective.
Q: Can the Q64TCRTBWN’s autotuning function be run while the process is already at operating temperature?
A: Yes, but with caution. The autotuning algorithm applies a step change to the control output and observes the process response to calculate PID parameters. If autotuning is initiated while the process is already at setpoint, the step change will cause a deliberate temperature deviation from setpoint — this may be acceptable in a test or commissioning scenario but is undesirable in a production environment. For production systems, it is recommended to run autotuning during a dedicated commissioning run before the first production batch, or during a planned maintenance shutdown when the process temperature deviation caused by autotuning will not affect product quality.
Q: Does the Q64TCRTBWN support alarm outputs for over-temperature and under-temperature conditions?
A: Yes. The Q64TCRTBWN provides upper and lower process alarm thresholds for each channel, configurable via buffer memory parameters in GX Works2. When the measured temperature exceeds the upper alarm threshold or falls below the lower threshold, the corresponding alarm bit in the buffer memory is set to ON, which can be read by the CPU program to trigger an alarm output or initiate a safe-shutdown sequence. Both deviation alarms (triggered by a defined offset from setpoint) and absolute alarms (triggered at fixed temperature thresholds) are supported.
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