Phoenix Contact PLC-RSC-24DC/21-21AU Relay Module Gold

PLC-RSC-24DC/21-21AU: relay module with gold contacts for low-level signals, 2 changeover

The Phoenix Contact PLC-RSC-24DC/21-21AU (order no. 2967125) is a PLC-INTERFACE module with two changeover contacts coated with hard gold, driven by a 24 V DC coil. AU in the code refers to gold. The module is 14 mm wide, 80 mm high and 94 mm deep. The coil range is 20.2 to 33.6 V DC at 20 degrees C.

Seven Star LLC supplies the PLC-RSC-24DC/21-21AU as an independent supplier in Muscat for projects in Oman and the GCC, quoted against the exact part number shown here.

Technical specifications of the PLC-RSC-24DC/21-21AU

How the PLC-RSC-24DC/21-21AU works

The PLC-RSC-24DC/21-21AU is a PLC-INTERFACE module: a narrow basic terminal block with screw terminals on which a miniature plug-in relay is fitted. The block carries the coil input with its protective circuit and a yellow LED that shows when the coil is energised, and routes the contact(s) to separate screw terminals. Because the relay is plugged in, it can be replaced without rewiring. The coil side and the contact side are electrically isolated, with the test voltage in the table, which lets a low-voltage controller output switch a load on a different voltage level.

Gold contacts are meant for low signal levels. The datasheet lists a limiting continuous current of only 50 mA and a maximum switching voltage of 30 V AC or 36 V DC, so this module is intended for signal-level circuits, not power loads. The material is AgNi with hard-gold plating.

Where the PLC-RSC-24DC/21-21AU fits in a system

Modules like this are placed between a PLC output card (or a field sensor) and a load that the controller cannot drive directly: solenoids, contactors, signal lamps, small motors. They also give isolation and a replaceable wear element, so a failed contact does not mean rewiring a whole output card. In the PLC-RSC range, the choice of coil voltage, number of changeover contacts and contact material is what separates the variants.

Use the PLC-RSC-24DC/21-21AU to switch analogue-like or low-current signals, such as inputs to a PLC card, feedback circuits or measurement lines. Do not use it for coils or lamps, for which the standard 2967060 is correct.

Selection and ordering checklist

• Confirm the coil voltage of the PLC-RSC-24DC/21-21AU against the controller output: DC or AC, and the tolerance range in the table.
• Check that the PLC output can supply the typical input current.
• Confirm the load voltage and current are within the switching data, including inrush.
• Check the contact material (standard or gold-plated) against the load level, because small signals need gold.
• Check the number of changeover contacts needed.
• Consider the divider plate and bridging accessories for neighbouring modules at higher voltages.
• Check that your load is a signal-level circuit under 50 mA and 30 V.

Installation, commissioning and maintenance of the PLC-RSC-24DC/21-21AU

Clip the PLC-RSC-24DC/21-21AU on a 35 mm DIN rail, wire the coil and contact terminals with screwdriver torque of 0.6 to 0.8 Nm and insert the relay. Check polarity on DC coils. At commissioning, switch each channel and confirm with the LED that the coil is energised, then measure the contact state.

Because the gold layer is thin, never switch inductive or lamp loads through these contacts, even once, since that can damage the plating and ruin the low-level capability. Keep the load within 50 mA and 30 V AC or 36 V DC.

Typical applications in Oman and the GCC

In Oman and the GCC, relay interface modules are used in pump, valve and compressor control panels, in lighting control and in building management systems. The temperature range in the table covers most indoor cabinets, but outdoor panels with strong solar load should be checked against the upper limit.

Signal switching in instrument cabinets and I/O marshalling panels across the Gulf benefit from gold contacts, which resist the oxidation that raises contact resistance at small currents.

Comparison with related PLC-INTERFACE relay modules

Information to send with an RFQ

• Full part number PLC-RSC-24DC/21-21AU and quantity.
• Coil voltage and type (DC or AC).
• Load voltage, current and type (resistive, inductive or lamp).
• Number of changeover contacts needed.
• Cabinet ambient temperature.
• Delivery location and date.

Documents and quotation

Send us the part number PLC-RSC-24DC/21-21AU and the quantity you need, and we will confirm which official documents are available for this device. Seven Star LLC is an independent supplier in Muscat and quotes for projects across Oman and the GCC; we do not act on behalf of the manufacturer.

Please also tell us the delivery location and required timeline so that availability can be checked before you commit to a project schedule.