Normally Closed And Normally Open Contacts - GE PACSystems RX7i Cpu Programmer's Reference Manual

Chapter 4. Ladder Diagram (LD) Programming
4.4.5

Normally Closed and Normally Open Contacts

A normally closed contact (NCCON) acts as a switch that passes power flow if the BOOLV operand
is OFF (false, 0).
A normally open contact (NOCON) acts as a switch that passes power flow if the BOOLV operand
is ON (true, 1).
Operands
Parameter Description
BOOLV BOOLV may be a predefined system variable or a user-
defined variable.
NCCON:
If BOOLV is ON, the normally closed contact
does not pass power flow.
If BOOLV is OFF, the contact passes power
flow.
NOCON:
If BOOLV is ON, the normally open contact
passes power flow.
If BOOLV is OFF, the contact does not pass
power flow.
96 PACSystems* RX7i, RX3i and RSTi-EP CPU Programmer's Reference Manual
Allowed Operands
discrete variables in I, Q, M, T, S,
SA, SB, SC, and G memories;
symbolic discrete variables; bit-
in-word references on variables
in any non-discrete memory
(e.g., %L) or on symbolic non-
discrete variables.
Optional
No
GFK-2950C