Phoenix Contact 2979472 UMK-32 RM/MR-G24/1/PLC Active Interface Module

The Phoenix Contact 2979472 is a VARIOFACE output module designed to interface between sensitive control electronics and high-power industrial loads. This active module accepts low-level logic signals (typically 24V DC) from a PLC or microcontroller and uses them to energize integrated relays, which can switch external loads rated up to 3A and 250V AC. The module streamlines the interface between control and field circuits by consolidating 32 individual relays into a single, compact, ready-to-install assembly, which reduces wiring errors, saves panel space, and lowers installation time.

Key Specifications

• Model Number: UMK-32 RM/MR-G24/1/PLC

• Part Number: 2979472

• Number of Channels: 32, with 1 N/O (Normally Open) contact per channel

• Nominal Input Voltage: 24 V DC (for relay coil)

• Switching Capacity: Maximum 3A per contact

• Maximum Switching Voltage: 250 V AC, 125 V DC

• Contact Material: Silver Nickel (AgNi) with hard gold plating (2-layer double contact)

• Module Width: 202 mm

• Mounting Type: DIN rail mounting (NS 35/7,5 or NS 35/15)

• Connection Method: Screw terminal blocks

• Wire Size Range: 0.2 mm² to 4 mm²

• Status Indication: Green LED per signal path and supply voltage

• Protection: Freewheeling and polarity protection diodes per signal path

• Temperature Range: -20°C to 60°C (operating)

• Approvals: CE, UL Recognized (E238705), EAC

Design and Application

The UMK-32 RM/MR-G24/1/PLC is a universal interface solution for switching loads such as contactors, solenoids, valves, motors, and indicator lights. It is particularly useful when a PLC output module cannot directly supply the current or voltage required by industrial actuators. By placing this relay module between the PLC and the load, the sensitive control electronics are isolated from potential voltage spikes, current surges, and short circuits on the field side.

Relay Technology and Longevity

The pluggable miniature relays with 2-layer double contacts and hard gold plating guarantee reliable switching over a wide range of loads from 1 mA to 3 A. Gold-plated contacts maintain low contact resistance even with low voltages/currents, preventing oxide film buildup that causes field failures. The silver-nickel contact base ensures good weld resistance and arc extinction for higher current switching, resulting in a longer electrical life and consistent performance.

DIN Rail Mounting and Space Efficiency

The narrow design width of just 202 mm for 32 channels provides a high packing density without compromising on safety or performance. The module snaps directly onto standard DIN rails (NS 35/7,5 or NS 35/15), simplifying installation without additional mounting hardware. Screw-type terminal blocks on the field side provide secure, maintenance-friendly connections.

Status Indicators and Diagnostics

Green LED status indicators are provided for each signal path and supply voltage, allowing quick visual confirmation of relay coil energization and diagnostic checks. Freewheeling diodes clamp inductive voltage spikes during turn-off, protecting the upstream PLC output, while polarity protection diodes ensure the module is not damaged if the 24 V DC supply is accidentally reversed.

Conclusion

The Phoenix Contact 2979472 UMK-32 RM/MR-G24/1/PLC is a high-density, reliable interface module that simplifies the connection between a PLC and field devices. With 32 relay outputs, built-in protection, LED status indication, and a space-saving design, it is an essential component for any control cabinet requiring efficient load switching and signal isolation.