Rockwell Automation AutoMax Enhanced Ladder Language Reference Manual - Manual (Page 19)

1Ć3
1.2 Normally Closed Contact (NCI)
Use this input instruction to examine whether a Boolean variable is on (1) or off (0).
When the variable is off, the instruction is true. Otherwise, the instruction is false.
The supported variables are:
D simple Boolean
D Boolean array element
D bitĆindexed integer or double integer
D bitĆindexed integer or double integer array element
D timer/counter status bits
Example of a Normally Closed Contact (NCI)
This rung shows that when switch1 is false, the
variable tank_fill is set true.