If the contact on a PLC ladder logic rung is an examine off type, then
A) the field device must be a NO type of contact.
B) power flows in the contact if the input pin associated with the examine off contact has zero volts present.
C) the field device must be a NC type of contact.
D) power flows in the examine off contact if the field device is a NC contact type and the contacts are in their normal position.
E) None of the above

Question

Quizplus · Accepted Answer

An examine off contact in PLC ladder logic is true (allows power to flow) when the input signal is low (zero volts), which corresponds to the condition described in choice B.

If the Contact on a PLC Ladder Logic Rung Is