Sel 411L - Figure 14.9 R_TRIG Timing Diagram; Table 14.24 or Operator Truth Table

P.14.27
Date Code 20151029 Protection Manual SEL-411L Relay
SELOGIC Control Equation Programming
SEL
OGIC Control Equation Operators
OR
Use OR to combine two Boolean values according to the truth table shown in
Table 14.24.
R_TRIG
R_TRIG is a time-based function that creates a pulse when another value
changes, as shown in Figure 14.9. 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 cycle
duration (1/8th cycle). This rising-edge pulse output asserts one processing
interval after the monitored element asserts.
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 14.9 R_TRIG Timing Diagram
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 Example 14.11.
EXAMPLE 14.11 R_TRIG Operation
The SEL
OGIC control equation below is invalid.
PSV15 := R_TRIG (PSV01 AND PSV23) # Invalid statement, do not use
Use a SELOGIC 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
F_TRIG
F_TRIG is a time-based function that creates a pulse when another value
changes, as shown in Example 14.11. Use F_TRIG to sense when a value
Table 14.24 OR Operator Truth Table
Value A Value B A OR B
000
011
101
111
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