Schweitzer Engineering Laboratories SEL-421-4 - Page 1192

13.26
SEL-400 Series Relays Instruction Manual Date Code 20171006
SELOGIC Control Equation Programming
SEL
OGIC Control Equation Operators
NOT
Use NOT to calculate the inverse of a Boolean value according to the truth table
shown in Table 13.18.
AND
Use AND to combine two Boolean values according to the truth table shown in
Table 13.19.
OR
Use OR to combine two Boolean values according to the truth table shown in
Table 13.20.
R_TRIG
R_TRIG is a time-based function that creates a pulse when another value
changes, as shown in Figure 13.9 Use R_TRIG to sense when a value changes
from logical 0 to logical 1 and take action only once when the value changes. The
R_TRIG output is a pulse of one protection processing interval duration (typi-
cally 1/8th cycle). This rising-edge pulse output asserts one processing interval
after the monitored element asserts.
Ta b l e 1 3.1 8 N OT Op e rat o r Tr u t h Ta b le
Value A NOT A
01
10
Table 13.19 AND Operator Truth Table
Value A Value B A AND B
000
010
100
111
Table 13.20 OR Operator Truth Table
Value A Value B A OR B
000
011
101
111