13.25
Date Code 20171006 Instruction Manual SEL-400 Series Relays
SELOGIC 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. Table 13.16 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 SELOGIC
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.
Table 13.17 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)
00000
00110
01000
01110
10000
10111
11011
11111
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