Which statement describes the default states of XIO and XIC?

Which statement describes the default states of XIO and XIC?

• A. XIO is normally closed; XIC is normally open
• B. XIO is normally open; XIC is normally closed
• C. Both are normally open
• D. Both are normally closed

Answer: (A)

The concept being tested is how ladder logic contacts behave in their resting state and how their names indicate that behavior. In ladder diagrams, a normally open contact is open when the input is not energized and closes when the input is energized. A normally closed contact is closed when the input is not energized and opens when the input is energized. XIC stands for Examine If Closed and is implemented as a normally open contact in practice; it remains open when the input is off and closes to pass current when the input is energized. XIO stands for Examine If Open and is implemented as a normally closed contact; it remains closed when the input is off and opens to stop current when the input is energized. So the default states align with the naming: XIO is normally closed, and XIC is normally open.

The concept being tested is how ladder logic contacts behave in their resting state and how their names indicate that behavior. In ladder diagrams, a normally open contact is open when the input is not energized and closes when the input is energized. A normally closed contact is closed when the input is not energized and opens when the input is energized.

XIC stands for Examine If Closed and is implemented as a normally open contact in practice; it remains open when the input is off and closes to pass current when the input is energized. XIO stands for Examine If Open and is implemented as a normally closed contact; it remains closed when the input is off and opens to stop current when the input is energized.

So the default states align with the naming: XIO is normally closed, and XIC is normally open.