Ladder Logic Elements and Instructions
406 870 USE 101 10 V.2
Standard Ladder Logic Elements

Introduction This section provides a glossary of standard ladder logic symbols and instructions.

Ladder Logic

Symbols The table below provides the meaning of standard ladder logic symbols.

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Symbol Meaning Nodes Consumed
Normally open (N.O.) contact 1
Normally closed (N.C.) contact 1
Positive transitional (P.T.) contact 1
Negative transitional (N.T.) contact 1
Normal coil 1
Memory-retentive or latched coil; the
two symbols mean the same thing, and
the user may select the preferred
version for online display.
1
Horizontal short 1
Vertical short 0