Sel 411L - Figure 14.10 F_TRIG Timing Diagram; Table 14.25 Comparison Operations

P.14.28
SEL-411L Relay Protection Manual Date Code 20151029
SELOGIC Control Equation Programming
SEL
OGIC Control Equation Operators
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
cycle duration (1/8th cycle). This pulse output asserts one processing interval
after the monitored element deasserts.
Pulse outputs should not be used in automation logic because the short
duration of the pulse may be missed during the longer automation processing
interval.
Figure 14.10 F_TRIG Timing Diagram
The argument of an F_TRIG statement must be a single bit within the relay.
An example of the relay detecting a falling edge of a calculated quantity is
shown in Example 14.12.
EXAMPLE 14.12 F_TRIG Operation
The SEL
OGIC control equation below shows an invalid use of the
F_TRIG operation.
ASV015 := F_TRIG (ASV001 AND ALT11) # Invalid statement, do not use
Use a SELOGIC control equation variable to calculate the quantity and
then use the F_TRIG operation on the result, as shown below.
ASV014 := ASV001 AND ALT11 # Calculate quantity in an intermediate result
variable
ASV015 := F_TRIG ASV14 # Perform an F_TRIG on the quantity
Comparison
Comparison is a mathematical operation that compares two numerical values
with a result of logical 0 or logical 1. AND and OR operators compare
Boolean values; comparison functions compare floating-point values such as
currents and other quantities. Comparisons and truth tables for operation of
comparison functions are shown in Table 14.25.
Math Operators
Use math operators when writing math SELOGIC control equations. Math
SEL
OGIC control equations manipulate numerical values and provide a
numerical base 10 result. Table 14.26 summarizes the operators available for
math SEL
OGIC control equations.
Relay Word bit A
F_TRIG A
F_TRIG A
Deasserts
F_TRIG A
Asserts
Relay Word bit A Changes
from 1 to 0
1
Processing
Interval
1
Processing
Interval
Table 14.25 Comparison Operations
A B A>B A>=B A=B A<>B A<=B A<B
6.357.00000111
5.105.10011010
4.254.00110100