How is power supplied to single unit PLCs?

How is power supplied to single unit PLCs?

• A. Externally
• B. Internally
• C. By the bus
• D. From an external battery

Answer: (B)

Power is supplied internally. A single unit (compact) PLC has its power supply built into the enclosure, so you provide the input voltage to the unit and it internally generates the voltages the processor and I/O need. This contrasts with modular systems, where a backplane bus carries data and a separate power supply module provides the power to the modules. An external battery may serve as a backup source, but it isn’t the normal primary supply for a single unit PLC.

Power is supplied internally. A single unit (compact) PLC has its power supply built into the enclosure, so you provide the input voltage to the unit and it internally generates the voltages the processor and I/O need. This contrasts with modular systems, where a backplane bus carries data and a separate power supply module provides the power to the modules. An external battery may serve as a backup source, but it isn’t the normal primary supply for a single unit PLC.