Watlow PM3 LEGACY ™ PID controller

Watlow PM3 LEGACY ™  PID controller

Product Core Information

Watlow PM3 LEGACY ™  PID is a 1/32 DIN panel mounted high-precision temperature controller that adopts universal input and multi output configurations, supports PID/switch control modes, and is suitable for industrial temperature regulation, process monitoring, and other scenarios. The product complies with the ISO 9001 standard, has an IP65 (NEMA 4X) protection level, supports multi country certifications such as CE, UL, CSA, etc., provides a 3-year warranty, and is equipped with dual four digit red and green LED displays. It is easy to operate and compatible with multiple communication protocols.

Core specification highlights:

Input type: compatible with J/K/T/N/E/R/S/B thermocouples, 2/3 wire RTD (100 Ω/1k Ω), thermistor, potentiometer, 0-10V voltage/0-20mA current and other process signals.

Output configuration: Supports switch DC, mechanical relay (5A), solid-state relay (0.5A), 4-20mA process output, and can be configured with heating, cooling, alarm, retransmission and other functions.

Control accuracy: Calibration accuracy ± 0.1% range (± 1 ° C @ 25 ° C environment), sampling rate 10Hz, display update rate 1Hz, temperature stability ± 0.1 ° C/° C environmental changes.

Key functions and features

（1） Control and tuning functions

PID control: supports P, PI, PD, PID, and switch control, with parameters including proportional band, integral (reset), and derivative (rate), which can be optimized through self-tuning or manual calibration; The switching difference of the switch control can be customized.

Self tuning and adaptive tuning:

Autotune: Based on 90% of the set value as a reference, the system characteristics are "learned" through 5 temperature cross tests. If not completed within 60 minutes, it will automatically exit. It supports three response modes: under damping, critical damping, and over damping.

TRU-TUNE+ ®  Adaptive tuning: Real time monitoring of process values, automatic adjustment of PID parameters to adapt to load changes, support for bandwidth and gain customization, suitable for dynamic process control.

Ramp/Soak: Supports 4 configuration files, with up to 40 steps per file. The heating rate (℃/minute/hour) and constant temperature time can be set, and the step types include heating, constant temperature, waiting for events/processes, jump cycles, etc., to meet the requirements of complex temperature control processes.

（2） Alarm and safety functions

Alarm type: Supports process alarm (absolute temperature threshold) and deviation alarm (relative to set value), 4 independent alarm channels, configurable high/low threshold and hysteresis (to avoid frequent alarms).

Alarm auxiliary function: supports locking/non locking mode (locking needs to be manually cleared), alarm mute, alarm blocking when starting/setting value changes. The alarm output logic can be set to "energize when alarm" or "de energize when alarm".

Fault protection: equipped with sensor open/short circuit detection, open-loop detection (monitoring process value deviation when output is 100%), input error handling (configurable to switch to manual mode or turn off output without disturbance).

（3） Auxiliary functions

Data storage: non-volatile memory, parameters are not lost after power failure, supports saving and restoring 2 sets of user configurations, and can quickly reuse parameter settings.

Display customization: Users can customize homepage parameters (up to 20), support display switching, automatic scrolling, and adapt to different operational scenarios.

Communication compatibility: Supports EIA-485, Modbus RTU, Bluetooth (optional), can be remotely configured and monitored through PC software (EZ-ZONE Configurator), supports networking with 247 Modbus nodes.

Installation and wiring

（1） Installation requirements

Panel incision size: 53.3mm (width) × 30.9mm (height), panel thickness: 1.53-9.52mm, fixed with snap on installation ring, IP65 protection needs to ensure that the sealing gasket is not twisted and installed in place.

Environmental restrictions: Operating temperature 0-65 ° C, storage temperature -40-85 ° C, relative humidity 0-90% (no condensation), suitable for Class I, Div.2 hazardous areas (some models).

（2） Wiring specifications

Power wiring: Supports 85-264V AC, 12-40V DC, or 20-28V AC, with built-in slow melting fuses (high voltage type 1A, low voltage type 2A), and must comply with NEC electrical standards.

Input wiring:

Thermocouple: The extension wire should be made of the same material as the thermocouple, and the positive and negative poles should be distinguished (red is usually the negative pole) to avoid polarity reversal.

RTD: The 3-wire system can compensate for lead resistance, and the three leads must have the same specifications (same wire diameter, same length), with a total lead resistance of ≤ 20 Ω.

Process signal: 0-20mA current input impedance of 100 Ω, 0-10V voltage input impedance of 20k Ω, ensuring that the signal source and controller are grounded together.

Output wiring: Inductive loads (such as relay coils) need to be paired with RC suppressors (Watlow part number 0804-0147-0000); It is recommended to extend the cycle of mechanical relays to reduce contact wear, while solid-state relays can shorten the cycle and improve control accuracy.