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13.25
Date Code 20171006
Instruction Manual
SEL-400 Series Relays
SEL
OGIC
Control Equation Programming
SEL
OGIC
Control Equation Operators
Boolean Operators
Use Boolean operators to combine values with a resulting Boolean value. The
arguments of the operator may be either numbers or Boolean values, but the
result of the operation must be a Boolean value. Combine the operators to form
statements that evaluate complex Boolean logic.
contains a summary
of Boolean operators available in SEL-400 series relays.
Parentheses
Use paired parentheses to control the execution order of operations in a SEL
OGIC
control equation. Use as many as 14 nested sets of parentheses in each SEL
OGIC
control equation. The relay calculates the result of the operation on the innermost
pair of parentheses first and then uses this result with the remaining operations.
is a truth table for an example operation that illustrates how paren-
theses can affect equation evaluation.
AND
Boolean AND
OR
Boolean OR
Table 13.15
Operator Precedence From Highest to Lowest (Sheet 2 of 2)
Operator
Description
Table 13.16
Boolean Operator Summary
Operator
Description
( )
Parentheses
NOT
Logical inverse
AND
Logical AND
OR
Logical OR
R_TRIG
Rising-edge trigger
F_TRIG
Falling-edge trigger
>, <, =, <=, >=, <>
Comparison of values
Table 13.17
Parentheses Operation in Boolean Equation
A
B
C
A AND B OR C
A AND (B OR C)
0
0
0
0
0
0
0
1
1
0
0
1
0
0
0
0
1
1
1
0
1
0
0
0
0
1
0
1
1
1
1
1
0
1
1
1
1
1
1
1
Summary of Contents for SEL-421-4
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