If a programmable controller manages a motor, what connects the motor to the PLC?

A relay is commonly used to connect a motor to a programmable logic controller (PLC). This device acts as an electromechanical switch that can open or close a circuit in response to signals from the PLC. When the PLC sends a command, the relay activates, allowing the electrical current to flow and powering the motor.

Relays provide several benefits in this context: they can handle significant loads while being controlled by low-voltage signals from the PLC, which ensures the safety and functionality of the system. They also serve as a means to isolate the PLC from high voltage and high current situations, protecting the controller from damage caused by electrical surges or faults.

The other options, such as capacitors, switches, and sensors, have their specific roles in electrical and automation systems, but they do not serve the same function as relays in the context of directly connecting a motor to a PLC. Capacitors are usually used for power factor correction or to smooth out voltage fluctuations. Switches are typically used for manual control and do not provide the same level of integration and automation that relays do. Sensors are used for monitoring parameters and providing data back to the PLC, but they do not connect a motor to a PLC for operational control.