PLC Board with Finder 44.52 Relay Module

This PLC board is an industrial control printed circuit board pre-fitted with a Finder 44.52 series relay module. The Finder 44.52 is a compact, 6 A electromechanical relay with two changeover (2 CO) contacts, rated for 250 V AC / 30 V DC. The board integrates the relay as an output or interface element for programmable logic controllers, enabling safe switching of loads such as contactors, solenoid valves, indicator lights, and small motors. The design is intended for DIN rail or panel mounting in industrial control cabinets, offering a ready-to-use solution for adding relay outputs to PLC systems or for replacing failed relay boards in existing machinery. The board is typically used in applications where galvanic isolation between the PLC output and the field device is required, or where the PLC's built-in outputs have insufficient current or voltage rating.

Technical Specifications of Finder 44.52 Relay

The Finder 44.52 relay installed on this board features 2 form C (2 changeover) contacts. Contact rating: 6 A at 250 V AC (resistive load), 6 A at 30 V DC (resistive load). Maximum switching voltage: 400 V AC / 300 V DC. Maximum switching current: 6 A. Maximum switching power: 1500 VA / 150 W. Contact material: AgNi (silver-nickel). Coil voltage: varies by model; typical coil voltages include 12 V DC, 24 V DC, 48 V DC, 110 V DC, 24 V AC, 110 V AC, and 230 V AC. The relay has a mechanical life of 20 × 10⁶ operations and an electrical life of 100 × 10³ operations at rated load. Coil power consumption: approximately 0.4 W to 0.8 W depending on coil voltage. Insulation between coil and contacts: 4000 V AC (1 minute). Operating temperature range: -40°C to +85°C. Relay dimensions: 29 mm × 12.4 mm × 25 mm. The board includes the relay socket (Finder 44.52 series socket) which provides secure connection to the relay and PCB mounting pins.

Key Features

• 2 changeover (DPDT) relay contacts rated at 6 A / 250 V AC

• High switching capacity suitable for industrial loads

• Coil voltages available for both AC and DC control signals

• 4000 V AC isolation between coil and contacts for safety

• Industrial operating temperature range (-40°C to +85°C)

• PCB-mounted socket for easy relay replacement

• LED indicator across the coil for visual status (optional, depends on board design)

• Suppression components (diode or RC snubber) may be included on the board

• DIN rail mounting ears or panel mounting holes provided

Function in PLC Systems

In a programmable logic controller system, outputs are often limited to low-power signals (e.g., 24 V DC, 0.5 A transistor outputs) or small relay outputs. When the application requires switching higher currents or voltages (e.g., 230 V AC motor contactors, heaters, or pumps), an external relay interface is necessary. This PLC board with the Finder 44.52 relay serves exactly that purpose. The PLC output (e.g., 24 V DC) energizes the relay coil, and the relay contacts switch the load circuit. The board can also be used to isolate different voltage domains (e.g., 5 V logic from 230 V AC). The two changeover contacts allow the user to implement both normally open and normally closed functions, or to switch two independent circuits simultaneously. The board is often placed in the control cabinet near the PLC I/O rack, with the PLC output terminals wired to the relay coil terminals and the load circuits wired to the contact terminals.

Applications

This relay board is used in industrial automation applications such as: controlling motor contactors for pumps, fans, and compressors; switching solenoid valves in hydraulic and pneumatic systems; interfacing with heating elements and lamps; signal conversion between different voltage levels; isolating PLC outputs from noisy field circuits; and providing additional output capacity when the PLC's built-in outputs are insufficient. Typical industries include manufacturing, packaging, material handling, HVAC, water treatment, and automotive assembly. The board is also suitable for retrofitting older machines where original relay boards have failed.

Installation and Wiring

The board is designed to be mounted on a 35 mm DIN rail (EN 60715) or directly on a panel using screws. Ensure adequate clearance around the relay for heat dissipation. Connect the PLC output signal to the relay coil terminals (A1 and A2). Observe polarity for DC coils (A1 positive, A2 negative). Connect the load circuit to the common (C), normally open (NO), and normally closed (NC) terminals as required. If the board includes an LED indicator, it will illuminate when the coil is energized. For inductive loads (contactors, solenoids), it is recommended to install a suppression diode (for DC) or RC snubber (for AC) across the load to protect the relay contacts. The board's terminals are typically screw or spring-clamp type, accepting wire sizes up to 2.5 mm². The board should be installed inside an IP20 or higher rated control cabinet to protect against dust and moisture.

Maintenance and Replacement

The relay is socketed, allowing easy replacement without soldering. If the relay fails due to contact welding or coil burnout, it can be unplugged from the socket and a new Finder 44.52 relay inserted. The board itself requires no routine maintenance beyond periodic visual inspection for loose wires or overheated terminals. The relay's electrical life is limited by switching cycles; for high-cycle applications, consider derating the load or using a solid-state relay alternative. The relay contacts may wear over time; if contact resistance increases or the relay fails to switch, replacement is recommended.

Environmental and Compliance

The Finder 44.52 relay is RoHS compliant and meets IEC 61810-1 standards. The board is typically CE marked as part of an assembly. Operating temperature: -40°C to +85°C for the relay, but the board may be limited to 0°C to 55°C due to other components. Storage temperature: -40°C to +85°C. Humidity: 10-95% non-condensing. The board is intended for use in pollution degree 2 environments (control cabinets).

Conclusion

This PLC board with the Finder 44.52 relay module provides a convenient, robust solution for extending the output capabilities of programmable logic controllers. Its 6 A switching capacity, dual changeover contacts, and socketed relay design make it suitable for a wide range of industrial switching tasks, from small signal switching to moderate power control applications.