Compare the operation of a standard examine-on contact instruction with that of an off-to-on transitional contact. the transitional off-to-on contact will close for only one program scan whenever the trigger signal goes from off-to-on, even though the triggering signal may stay on. a standard examine if open contact will stay on as long as the trigger signal is on. the transitional off-to-on contact will close for only one program scan whenever the trigger signal goes from on-to-off, even though the triggering signal may stay on. a standard examine if closed contact will stay on as long as the trigger signal is on. the transitional off-to-on contact will close for only one program scan whenever the trigger signal goes from off-to-on, even though the triggering signal may stay on. a standard examine if closed contact will stay on as long as the trigger signal is on. the transitional off-to-on contact will close for only one program scan whenever the trigger signal goes from on-to-off, even though the triggering signal may stay on. a standard examine if open contact will stay on as long as the trigger signal is on.