XIO stands for Examine If Open. What is the typical contact type for XIO when not energized?

XIO stands for Examine If Open. What is the typical contact type for XIO when not energized?

• A. Normally Open
• B. Normally Closed
• C. Extend Input
• D. Execute Input

Answer: (B)

XIO stands for Examine If Open, a ladder logic element that is true when the input is not energized. That behavior is implemented with a normally closed contact: it is closed when the input is off, allowing the rung to pass, and it opens when the input is energized, stopping the rung. So the typical contact type used with XIO is normally closed. The other options don’t describe a contact type used in this context, and normally open would be paired with a different instruction (XIC) rather than XIO.

XIO stands for Examine If Open, a ladder logic element that is true when the input is not energized. That behavior is implemented with a normally closed contact: it is closed when the input is off, allowing the rung to pass, and it opens when the input is energized, stopping the rung. So the typical contact type used with XIO is normally closed. The other options don’t describe a contact type used in this context, and normally open would be paired with a different instruction (XIC) rather than XIO.