Phoenix Contact PLC-BPT-24DC/1/SEN Solid‑State Relay Module

The Phoenix Contact PLC-BPT-24DC/1/SEN (article number 2900262) is a solid‑state relay module from the PLC-INTERFACE family. Designed for industrial automation, this 6.2 mm wide terminal block houses a solid‑state relay that provides a reliable, maintenance‑free switching solution for PLC output circuits. The module features a 24 V DC nominal input voltage and is equipped with push‑in connection technology for rapid wiring. A key differentiator is the integrated sensor supply voltage distribution (BB), enabling the module to simultaneously switch a load while providing a 24 V DC supply to a connected sensor. The solid‑state design offers high switching frequency, no contact wear, and silent operation, making it suitable for applications with frequent switching cycles or where mechanical relays would be prone to failure.

Technical Specifications

The PLC-BPT-24DC/1/SEN operates with a nominal input voltage of 24 V DC (range 19.2 V to 28.8 V). Input current is typically 4 mA. The output is a solid‑state relay, 1 normally open contact, designed for AC load switching. Output voltage range: 24 V AC to 240 V AC, output continuous current: 0.5 A to 3 A depending on ambient temperature. Surge current capability up to 10 A for 20 ms. The module has a maximum power dissipation of 0.6 W. Push‑in connection terminals accept solid conductors from 0.14 mm² to 1.5 mm² and flexible conductors with ferrules from 0.14 mm² to 1.5 mm². Stripping length is 8 mm. The module occupies 6.2 mm width on a DIN rail (NS 35/7.5). Operating temperature range: -20°C to +60°C. Storage temperature: -40°C to +85°C. Protection rating: IP20. The housing is made of polyamide (PA) insulating material with V0 flammability rating.

Key Features

• Solid‑state relay with 1 normally open contact for AC loads

• 24 V DC input (coil side) compatible with standard PLC outputs

• Push‑in connection technology for fast, tool‑free wiring

• Integrated sensor supply voltage distribution (BB) for powering sensors

• 6.2 mm wide, space‑saving design for high‑density control cabinets

• No mechanical wear, suitable for high‑frequency switching

• Built‑in protective circuitry against overvoltage and reverse polarity

• LED indicator for input state (yellow)

• Removable labeling strip for circuit identification

• Certified for industrial applications (CE, UL, RoHS)

Solid‑State Relay Technology

Unlike electromechanical relays that use physical contacts, the solid‑state relay in the PLC-BPT-24DC/1/SEN uses semiconductor switching elements (typically a triac or thyristor) to switch AC loads. This offers several advantages: no contact arcing, no contact wear, silent operation, and the ability to switch at much higher frequencies (up to several kHz). The input and output are optically isolated, providing galvanic separation between the PLC logic side and the load circuit. The module includes internal snubber circuits to reduce electrical noise and protect against voltage spikes. The solid‑state relay is suitable for loads such as solenoid valves, contactor coils, indicator lamps, and small heaters, provided the load current and voltage ratings are respected. For inductive loads, derating may be required.

Sensor Supply Distribution (BB)

The "SEN" suffix in the product name indicates the inclusion of a sensor supply distribution terminal (BB). This allows the module to not only switch the load but also provide a 24 V DC supply to a connected sensor via the same module. This is particularly useful in PLC control cabinets where a digital input sensor (e.g., proximity switch) needs to be powered from the same voltage rail as the PLC output. The BB terminal distributes the auxiliary voltage (typically 24 V DC from the power supply) to the sensor without passing through the relay contacts. This simplifies wiring, reduces the number of terminal blocks needed, and creates a cleaner, more organized control panel design.

Applications

The PLC-BPT-24DC/1/SEN is widely used in industrial automation for switching AC loads from a DC PLC output. Typical applications include controlling small AC contactors and motor starters (up to 3 A), switching indicator lamps and signal lights, interfacing with solenoid valves in pneumatic or hydraulic systems, providing a clean interface between a PLC and a heating element, and powering sensors directly from the module's BB terminal. The module is also used in building automation for lighting control, in packaging machinery for solenoid activation, and in test equipment for signal switching. Its solid‑state design makes it particularly valuable in high‑cycle applications such as high‑speed counting or pulsed output control.

Installation and Wiring

Mount the PLC-BPT-24DC/1/SEN on a 35 mm DIN rail (NS 35/7.5) by snapping it onto the rail. The push‑in connection terminals allow solid wires to be inserted directly; for flexible wires, use a ferrule and push it into the terminal. The stripping length is 8 mm. Connect the PLC output to the input terminals A1 (+) and A2 (-). Connect the load circuit to the output terminals (13, 14). For the sensor supply distribution, connect the 24 V DC supply to the BB (+) terminal and 0 V to the BB (-) terminal. Then connect the sensor to the same BB terminals. The relay is polarized on the input side; observe correct polarity for DC operation. The LED indicator (yellow) will illuminate when the input voltage is applied. The module does not require additional cooling under normal conditions but should be mounted with sufficient clearance from other heat‑generating components.

Maintenance and Diagnostics

The solid‑state relay module is maintenance‑free due to its non‑mechanical design. However, periodic visual inspection should be performed to ensure no overheating or discoloration of the housing. The LED indicator provides immediate status of the input. If the load does not switch when the LED is on, check the load wiring and verify that the load current and voltage do not exceed the module's ratings. If the load continues to draw current after the input is de‑energized, the solid‑state relay may have failed shorted (rare). The module cannot be repaired; replacement of the entire module is required in case of failure. The module's protective circuitry includes overvoltage suppression, but external fuses are recommended for the load circuit to protect against short circuits.

Environmental and Compliance

The PLC-BPT-24DC/1/SEN is CE, UL, and RoHS compliant. It meets EN 61000‑6‑2 (industrial immunity) and EN 61000‑6‑4 (emissions). Operating temperature: -20°C to +60°C (with derating above 50°C for output current). Humidity: 10‑95% non‑condensing. Vibration resistance: 2g (10‑55 Hz). The module is rated IP20 and must be installed in a control cabinet. It is designed for pollution degree 2 environments. The housing is self‑extinguishing according to UL 94 V‑0.

Conclusion

The Phoenix Contact PLC-BPT-24DC/1/SEN solid‑state relay module combines the benefits of semiconductor switching with the convenience of push‑in wiring and sensor supply distribution. Its compact 6.2 mm width, reliable switching up to 3 A AC, and maintenance‑free operation make it an excellent choice for PLC output interfacing in industrial automation, particularly where high switching frequency or silent operation is required.