A normally open limit switch is wired to an input module and programmed using XIO instruction. The instruction will be true when:
A)power is applied and the PLC is in the run mode.
B)the limit switch is closed.
C)the limit switch is open.
D)never.

Question

Quizplus · Accepted Answer

The XIO (Examine if Open) instruction is true when the input or contact it is examining is open. Since the limit switch is normally open, the XIO instruction will be true when the limit switch is in its normal (open) state.

A Normally Open Limit Switch Is Wired to an Input