Rockwell Automation 1769-BOOLEAN Compact I/O Module Reference Manual - Manual (Page 15)

Publication 1769-RM016A-EN-P - July 2006
Module Operation 15
Control Outputs Using
Boolean Expressions You can configure the 1769-BOOLEAN module outputs to be controlled by
Boolean expression (Boolean control mode).
Format of Boolean Expression
Each output is controlled with a separate expression. The fixed format of each
Boolean expression is assumed to be of the form:
Output State = (A x B) y C
where A, B, and C are operands and x and y are logical operators you select.
The location of the parentheses in the fixed format indicates that the logical
operation represented by x is performed on operands A and B first, with the
result of that operation then used as the first operand for the logical operation
represented by y (with C being the second operand).
The parameter names assigned in the 1769-BOOLEAN module configuration
file that correspond to the operands and operators of the fixed format
Boolean expression above are:
A: Operand_A_#
B: Operand_B_#
C: Operand_C_#
x: Operator_1_#
y: Operator_2_#
where the # symbol indicates the module output (OUT0 through OUT3).
Boolean Expression
Configuration Restrictions The Boolean expressions controlling the output states have default values
assigned to each operand and operator. These default values assign “None” to
each operand and operator resulting in a “Null” expression. A “Null”
expression will be accepted by the module but will result in an output that will
always be in the OFF state.
The module will only accept the following variations of Boolean expressions
as valid (based on the fixed format expression (A x B) y C).