NO and NC (Normally Open and Normally Closed) Proximity .
04/08/2017 · The most two common types of electrical failures are "opens" and "shorts," with opens being the most common. An open is an unwanted break in a circuit. Cuts, crushing, or other damage to the cable can cause an open. An example of a Normally Closed appliion: Emergency Stop. Modern factories are populated throughout with "EStop ...