Contact

Definition

A ladder instruction that tests a memory bit. Examine-if-closed is true when the bit is on; examine-if-open is true when it is off.

A contact in a program is not a contact in the field. Whether the bit is on depends on how the device is wired and whether the field contact is normally open or normally closed, and confusing the two is a common commissioning error.

Also known as: examine if closed, examine if open, XIC, XIO.

Definition

See also