Asked by Maria Arias on Jul 14, 2024
Verified
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.
Normally Open
A term describing a contact or switch that is disconnected in its default state and requires activation to close the connection.
XIO Instruction
An instruction used in PLC programming representing "Examine if Off", used to check if a specific input or bit is off or false.
- Differentiate the categories of contacts and coils employed in ladder logic diagrams.
Verified Answer
JF
javier fernandezJul 16, 2024
Final Answer :
C
Explanation :
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.
Learning Objectives
- Differentiate the categories of contacts and coils employed in ladder logic diagrams.