Schweitzer Engineering Laboratories SEL-751 - Table 7.49 Front-Panel Leds and the TAR 0 Command; Table 7.50 TEST DB Commands

7.54
SEL-751 Relay Instruction Manual Date Code 20170927
Communications
Communications Protocols
The elements are represented as Relay Word bits and are listed in rows of
eight, called Relay Word rows. The first four rows, representing the front-
panel operation and target LEDs, correspond to Table 7.49. All Relay Word
rows are described in Table K.1 and Table K.2.
Relay Word bits are used in SEL
OGIC control equations. See Appendix K:
Relay Word Bits.
The TAR command does not remap the front-panel target LEDs, as is done in
some previous SEL relays.
TEST DB Command
Use the TEST DB command to temporarily force the relay to send fixed
analog and/or digital values over communications interfaces for protocol
testing.
The TEST DB command provides a method to override Relay Word bits or
analog values to aid testing of communications interfaces. The command
overrides values in the communications interfaces (ASCII, SEL Fast Message,
DNP, Modbus, IEC 60870-5-103, and IEC 61850) only. The actual values
used by the relay for protection and control are not changed. However, remote
devices may use these analog and digital signals to make control decisions.
Ensure that remote devices are properly configured to receive the overridden
data before using the TEST DB command.
To override analog data in a communications interface, enter the following
from Access Level 2 or higher:
Table 7.49 Front-Panel LEDs and the TAR 0 Command
LEDs 7 6 5 4 3 2 1 0
TAR 0 ENABLED TRIP_LED TLED_01 TLED_02 TLED_03 TLED_04 TLED_05 TLED_06
Table 7.50 TEST DB Commands
Command Description Access Level
TEST DB Displays the present status of digital and
analog overrides.
2
TEST DB A name value Forces the protocol analog element name to
override value.
2
TEST DB D name value Forces the protocol digital element name to
override value.
2
TEST DB name OFF Clears (analog or digital) override for ele-
ment name.
2
TEST DB A OFF Clears all analog overrides. 2
TEST DB D OFF Clears all digital overrides 2
TEST DB OFF Clears all analog and digital overrides. 2
=>>TEST DB A name value <Enter>
WARNING
To reduce the chance of a false
operating decision when using the
TEST DB command, ensure that
protocol master device(s) flag the data
as “forced or test data”. One possible
method is to monitor the TESTDB
Relay Word bit.