How can an Input Device reference multiple Input Instructions?

How can an Input Device reference multiple Input Instructions?

• A. By wiring to multiple PLCs
• B. By using a separate IO module per instruction
• C. By using different tag addresses for each instruction
• D. By using the same tag address for all instructions

Answer: (D)

In PLC programming, a physical input is represented in the program by a tag (an address that maps to that input). An input device can be referenced by many input instructions by pointing each instruction to the same tag. That way every instruction sees exactly the same real-world signal at the same time, so the device can drive multiple logic paths or checks without duplicating hardware or wiring. Using different tags would split the connection into separate signals, which isn’t needed here, and wiring to other PLCs or adding separate IO modules would add hardware rather than address the software reference. So, referencing the same tag address for all instructions is the way to have one input device serve multiple instructions.

In PLC programming, a physical input is represented in the program by a tag (an address that maps to that input). An input device can be referenced by many input instructions by pointing each instruction to the same tag. That way every instruction sees exactly the same real-world signal at the same time, so the device can drive multiple logic paths or checks without duplicating hardware or wiring. Using different tags would split the connection into separate signals, which isn’t needed here, and wiring to other PLCs or adding separate IO modules would add hardware rather than address the software reference. So, referencing the same tag address for all instructions is the way to have one input device serve multiple instructions.