Rockwell Automation 1769-BOOLEAN Compact I/O Module Reference Manual - Manual (Page 12)

Publication 1769-RM016A-EN-P - July 2006
12 Module Operation
Boolean Expressions An expression is any legal combination of symbols that represents a value. An
expression that results in a value of either TRUE or FALSE is called a Boolean
expression. Every Boolean expression (except a null expression) consists of at
least one operand and can have one or more operators. Operands are values,
whereas operators are symbols that represent particular logical actions. For
example, in the expression
OUT = A AND B,
the value of OUT is either TRUE or FALSE and is determined by the value of
the expression “A AND B”. A and B are operands that also have a value of
TRUE or FALSE. The operator in the expression is the logical operator AND.
Other examples of logical operators are OR and XOR (exclusive-OR).
The 1769-BOOLEAN module outputs can be controlled based upon the
value of Boolean expressions configured by the program. An output state
(when in Boolean control mode) is determined by the state of that output’s
configured Boolean expression, with a value of TRUE corresponding to the
ON state and a value of FALSE corresponding to the OFF state.
Refer to Chapter 3, Module Data, Status, and Configuration on page 41, for
information on configuring control of the 1769-BOOLEAN module outputs
using Boolean expressions.