Sel SEL-421 - Aliases; Assigning and Removing Aliases

R.3.24
SEL-421 Relay Reference Manual Date Code 20111215
SELOGIC Control Equation Programming
SELOGIC Control Equation Elements
breaker opens. The OR combination of PSV01 and PSV02 contains a
rising edge for each circuit breaker operation, open or closed, that
Protection Counter 1 counts.
# Example protection counter programming
#
# This example counts how many times a three-pole circuit breaker operates
either open or closed
#
# Detect OPEN and CLOSE and combine
PSV01 := R_TRIG 52AA1 # Pulse for each close
PSV02 := F_TRIG 52AA1 # Pulse for each open
PSV03 := PSV01 OR PSV02 # Pulse for each open or close
#
# The counter automatically resets every 1,000 operations
PCN01PV := 1000
PCN01R := PCN01Q
PCN01IN := PSV03 # Count open and close operations
PSV04 := PCN01CV >900 # PSV04 signals impending reset
Aliases
Although the SEL-421 provides extensive programming facilities and
opportunity for comments, troubleshooting customized programs is
sometimes difficult. Aliases provide an opportunity to assign more meaningful
names to the generic variable names in order to improve the readability of the
program. Example 3.10 provides examples of assigning aliases.
EXAMPLE 3.10 Assigning and Removing Aliases
The following free-form math SEL
OGIC control equations show you
how to create aliases.
# Assign the alias names with the SET T command
SET T
PMV01,THETA # Assign the alias “THETA” to PMV01
PMV02,TAN # Assign the alias “TAN” to PMV02
Use the alias names “THETA” and “TAN “ in a free-form SELOGIC
control equation:
# Calculate the tangent of THETA
TAN := SIN(THETA)/COS(THETA)
To remove the alias from the alias setting, issue the SET T command
and press <Enter> until the alias appears; then type DELETE <Enter>:
SET T
nn: PMV01,THETA # (where nn = line number)
DELETE
Assign as many as 200 alias names to any Relay Word bit or analog quantity,
using the SET T command. The maximum length of an alias is seven
characters. Valid characters are 0–9, A–Z (only uppercase) and _ (underscore).
Make sure no Relay Word bit or analog quantity appears more than once in the
alias settings. Each alias name must be unique, i.e., you cannot use the name
of an existing Relay Word bit or analog quantity. If you remove the alias
name, all settings that referenced that alias revert to the original name.