Contacts & Coils Part 2

Another set of basic contacts and coils that can be used in Ladder Logic are the Normally Closed Contact and the Normally Closed Coil. These work just like their normally open counterparts – only in the opposite.

Contact Normally ClosedWhen “solved” the referenced input is examined for an OFF condition. If the status is OFF (logical 0) power (logic) will flow from left to right. If the status is ON, power will not flow.

Ladder Logic Normally Closed Coil When “solved” if the coil is a logical 0, power will be turned on to the device. If logical 1, power will be OFF.