HVAC Controller with 28 I/O
The TM172PDG28SI is a Modicon M171/M172 series programmable controller built for HVAC control, carrying 28 total I/O: 8 digital inputs (24 V AC/DC, sink or source), 8 analog inputs configurable by pair for NTC, Pt1000, 0–10 V, or 4–20 mA, 4 analog outputs (2 voltage, 2 voltage/current/PWM), and 8 digital outputs (3 A relay SPDT/SPST and 0.5 A isolated SSR). Onboard communications include one Ethernet port (Modbus TCP and BACnet IP with webserver), two RS485 ports (Modbus serial or BACnet MS/TP), one CAN port, and USB ports for programming and data transfer. Backlit LCD 128×64 display provides local HMI for status and parameter adjustments without an external panel.
Mounting & Environmental Fit
Dimensions: 5.7 x 4.3 x 2.4 in (144 x 110 x 60.5 mm). IP20 rating keeps it inside a clean enclosure; pollution degree 2 fits typical control panels. Operating ambient -4 to +149 °F (-20 to +65 °C) with a 5 to 95% non-condensing humidity range. When mounted horizontally and listed to UL 60730-1, the maximum ambient derates to 131 °F (55 °C). Rated supply voltage 24 V ±10% AC or 20–38 V DC; draws 12 W typical. Sensor power outputs: 5 V DC at 50 mA and 24 V DC at 150 mA, derived from the controller.
Analog Input Flexibility & Accuracy
Eight analog inputs configurable by pair. Accepts NTC 103AT-2 and NK103, Pt1000, PTC, 0–10 V, 0–5 V, 0–20 mA, 4–20 mA, and high-ohm resistance measurements. Input impedance 10 kΩ for voltage, <150 Ω for current. Measurement accuracy: ±1 °C for NTC and Pt1000 ranges (50–100 °C band), ±1% of full scale for 4–20 mA and 0–10 V, ±2% for 0–4 mA. Built-in real-time clock drifts ≤30 s/month over -20 to +65 °C. Discrete inputs draw 2.5 mA at 24 V AC/DC; logic selectable sink or source for wiring flexibility.
Compliance & Sourcing
Certified to CSA 60730-1, UL 60730-1, EN 60730-1, EN 60068-2-27 (shock), EN 60068-2-6 (vibration), and meets IEC 61000-4-x EMC immunity levels. Material flammability rated UL94 V-0. Compliant with EU EMC Directive 2014/30/EU and Low Voltage Directive 2014/35/EU. Overvoltage category II, pollution degree 2.