Which statement best describes a programming device's function?

• A. It is used to enter the desired program into the PLC
• B. It is used to run the plant at full speed
• C. It is used to terminate PLC communications
• D. It is used to cool the PLC cabinet

Answer: (A)

The main idea is how a programming device interacts with the PLC to bring the control logic into use. A programming device is the tool you use to create or edit the control program and transfer that program into the PLC’s memory so the CPU can execute it. Without loading the program, the PLC has nothing to run. This is why the function described—entering the desired program into the PLC—is what the programming device is for.

The other activities described aren’t about loading or preparing the program. Running the plant at full speed happens during operation after the program is loaded, driven by the PLC’s execution of the logic. Terminating PLC communications would be a network or protocol management task, not the job of loading the program. Cooling the PLC cabinet is a hardware concern related to physical protection rather than programming.