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13.27
Date Code 20171006
Instruction Manual
SEL-400 Series Relays
SEL
OGIC
Control Equation Programming
SEL
OGIC
Control Equation Operators
The argument of an R_TRIG statement must be a single bit within the relay. An
example of the relay detecting a rising edge of a calculated quantity is shown in
F_TRIG
F_TRIG is a time-based function that creates a pulse when another value
changes, as shown in
. Use F_TRIG to sense when a value
changes from logical 1 to logical 0 and take action only after the value changes
state. The F_TRIG output is a pulse of one protection processing interval dura-
tion (typically 1/8th cycle). This pulse output asserts one processing interval after
the monitored element deasserts.
Figure 13.9
R_TRIG Timing Diagram
Example 13.10
R_TRIG Operation
The SEL
OGIC
control equation below is invalid.
PSV15 :=
R_TRIG (PSV01 AND PSV23)
# Invalid statement, do not use
Use a SEL
OGIC
control equation variable to calculate the quantity and then
use the R_TRIG operation on the result, as shown below.
PSV14 :=
PSV01 AND PSV23
# Calculate quantity in an intermediate
result variable
PSV15 :=
R_TRIG PSV14
# Perform an R_TRIG on the quantity
Relay Word bit A
R_TRIG A
R_TRIG A
Deasserts
R_TRIG A
Asserts
Relay Word bit A Changes
from 0 to 1
1
Processing
Interval
1
Processing
Interval
Summary of Contents for SEL-421-4
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