Schneider Electric TM171PDM27R Modicon M171 27 I/O Controller

TM171PDM27R: Modicon M171 programmable controller, 27 I/O

The TM171PDM27R is a Schneider Electric Modicon M171/M172 programmable controller (HVAC and pumping solution) with 27 I/O. This is the only flush-mounting controller in this group, with an integral display: a 160 × 96 mm front with a 128 × 64 pixel LCD, aimed at HVAC and pumping applications where the operator interface sits in a panel door. It runs from 24 V AC/DC or from 48 V DC, has no Ethernet port, and talks Modbus serial over RS485. This unit is supplied from 24 V ±20 % AC/DC or 48 V ±20 % DC, so the first thing to confirm is the control supply of the panel. Seven Star LLC supplies the TM171PDM27R in Oman and the GCC as an independent supplier based in Muscat.

The datasheet confirms the variant as programmable, with a built-in real-time clock, a display and the communication ports listed in the specifications below. Reading the reference, TM171 identifies the M171 family and PDM the blind or display body style, but this is our interpretation and not a published ordering table.

Technical specifications of the TM171PDM27R

Inputs, outputs and communications of the TM171PDM27R

The discrete inputs are 8 (sink or source, 24 V AC/DC and 48 V DC, 2.5 mA, 20 kΩ). The analogue inputs are 6 (2 NTC plus 4 configurable), with the analogue input types listed as 0–5 V ratiometric, 0–10 V, 4–20 mA, resistance ranges, NTC probes, and Pt 1000 up to 800 °C, plus one high-speed counter input.

Outputs: 7 relay outputs: 3 SPST on one common, 2 SPST on a second common, 2 SPDT with independent commons; 5 A SPST, 8 A SPDT. Analogue outputs: 5 (3 voltage/current, 4–20 mA or 0–10 V; 2 open-collector, 1 kHz, 12 V, 35 mA). The unit can power sensors directly with 5 V DC at 50 mA and 12 V DC at 150 mA. As relays, the outputs suit contactor coils, valve actuators and signalling, and they are not intended for fast switching; use an analogue or open-collector output where the datasheet provides one for modulating duties.

Communications

The datasheet lists these ports: CAN, USB type A, USB mini-B, RS485 (Modbus serial). The RS485 port is listed for Modbus serial link only, so integration is by serial network, with CAN available for expansion or network use.

Selection checklist for the TM171PDM27R

• Confirm the supply: 24 V ±20 % AC/DC or 48 V ±20 % DC.
• Count channels by type: 8 discrete inputs, 7 relay outputs: 3 SPST on one common, 2 SPST on a second common, 2 SPDT with independent commons; 5 A SPST, 8 A SPDT relays, 6 analogue inputs.
• Check that the relay ratings cover the load.
• Check that Modbus serial over RS485 is enough for your supervisory link; there is no Ethernet port.
• Check the width of the housing (160 mm) against the panel layout.

Typical uses of the TM171PDM27R in Oman and the GCC

In the Gulf, cooling load dominates building and plant energy use, which is why HVAC controllers of this class are common. This unit fits cooling-tower and heat-recovery sequences, fan-coil and ventilation zone control and chilled-water and air-handling-unit control. The serial-only communication suits stand-alone panels or small serial networks. Facilities contractors, OEM panel builders and utility service teams specify this family for packaged plant and retrofit work.

Supply, size and environment

Supply is 24 V ±20 % AC/DC or 48 V ±20 % DC, with a consumption of 5 W at 24–48 V AC/DC. The housing is 160 mm wide, 96 mm high, weighing 0.32 kg; mounting is flush mounting. Storage temperature is −20 to 85 °C and humidity 10–90 % non-condensing; protection is IP20, so the unit belongs inside a cabinet. Operating range is −10 to 55 °C.

In Oman and the wider Gulf, a controller panel on a plant roof or in a plant room routinely meets temperatures above the upper limits. Plan cabinet ventilation or cooling, and where the datasheet specifies derating, apply it to the actual cabinet air temperature rather than the room temperature.

Installation and maintenance of the TM171PDM27R

Mount the unit (Flush mounting) in a clean cabinet and keep low-voltage signal wiring away from relay-output cabling. Check that the supply is 24 V ±20 % AC/DC or 48 V ±20 % DC before energising, since the 48 V DC and 24 V ranges differ between family members. Commission outputs with loads disconnected, then enable each channel in turn, and record the final configuration so that a spare unit can be configured in the same way.

Probe lines should be screened where lengths are long, and the sensor-supply capability (listed in the specifications) must not be exceeded. During maintenance, check terminal tightness, cabinet temperature and dust, and keep the controller programme and parameters backed up. A new TM171PDM27R on the shelf is the fastest recovery if the panel runs a critical HVAC or pumping duty.

How the TM171PDM27R compares with related Modicon M171/M172 references

The nearest relatives of the TM171PDM27R from the datasheets we have read are listed below. Controllers and expansion modules share the housing family but differ in channels, display and Ethernet.

Information to send with an RFQ for the TM171PDM27R

• Exact reference TM171PDM27R and quantity.
• Control supply voltage available in the panel.
• Channel count by type and the communication protocol required.
• Load types on the relays.
• Delivery location and project deadline.

Documents and quotation

The manufacturer datasheet for the TM171PDM27R is attached on this page and includes the specification summarised above. Check the revision date against your project requirements.

Send us the reference TM171PDM27R, quantity and delivery location and Seven Star LLC will reply to your RFQ. We supply as an independent supplier based in Muscat.