452 Electrical Power Systems Technology
When the response of a particular input module is programmed, it
may be identified as a relay contact. In this regard, the symbol may be
a NC contact or a NO contact. The coil or actuating member of the con-
tact takes on the same numbering assignment as the coil. The coil, how-
ever, is identified as a circle on the diagram, and the contacts are identi-
fied by the standard contact symbol. The contacts can be programmed
to achieve either the NO or NC condition, according to their intended
functions.