In a programmable controller circuit, to which type of terminal are relay coils typically connected?

In a programmable controller circuit, to which type of terminal are relay coils typically connected?

• A. Input
• B. Output
• C. Controller
• D. Feedback

Answer: (B)

Relays are actuators driven by the PLC. The output terminals are designed to supply the controlled voltage and current to external devices like relay coils. Input terminals read signals from sensors, not drive loads. The controller and feedback terminals are for internal logic or monitoring, not for energizing field devices. So, to energize or de-energize a relay coil under program control, you connect it to an output terminal, while ensuring the coil’s current matches what the output can deliver (and using a driver if needed).

Relays are actuators driven by the PLC. The output terminals are designed to supply the controlled voltage and current to external devices like relay coils. Input terminals read signals from sensors, not drive loads. The controller and feedback terminals are for internal logic or monitoring, not for energizing field devices. So, to energize or de-energize a relay coil under program control, you connect it to an output terminal, while ensuring the coil’s current matches what the output can deliver (and using a driver if needed).