Specifications

Engineering Standard –NSW
Signalling SMS 02
Cerberus Level Crossing Monitor Equipment
March 2005 Version 1.2 © Australian Rail Track Corporation Page 86 of 118
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B
or as a Boolean expression
C = A + B
C will be true when either A or B are true.
7.1.2.7.3 NOT Operator
The logical NOT operation is represented by the "!"
character. Examples of logical NOT operations are as
follows: Either as relay logic by:
A C
or as a Boolean expression
by: C = !A
C will be true when A is not true.
7.1.2.7.4 Combinations of logic Operations
The logical operators AND, OR, and NOT can be combined using
brackets [, and ] to form any required Boolean expression.
An example of a combinational logical operations
is: Either as relay logic by: