7.55
Date Code 20170927 Instruction Manual SEL-751 Relay
Communications
Communications Protocols
where value is a numerical value and name is an analog label from Tab le L.1,
Analog Quantities, with an “x” in the DNP, Modbus, Fast Meter, IEC 60870-
5-103, or IEC 61850 column. For example, the TEST DB command can be
used to force the value of the A-phase current magnitude transmitted to a
remote device to 100 amperes:
To override digital data in an SEL ASCII, SEL Fast Message, Modbus, DNP,
IEC 60870-5-103, or IEC 61850 communications interface, enter the
following from Access Level 2 or higher:
where name is a Relay Word bit (see Table K .1) and value is 1 or 0. For
example, if Relay Word bit 51P1T := logical 0, the TEST DB command can
be used effectively to test the communications interface by forcing the
communicated status of this Relay Word bit to logical 1:
Values listed in the SER triggers SER1, SER2, SER3, and SER4 cannot be
overridden.
When the relay is not in Test Mode, the relay responds to either the digital or
analog override request with the following message:
The relay responds:
Relay Word bit TESTDB will also assert to indicate that Test Mode is active. If the
relay is already in the test mode (overrides are already active), the relay responds:
The TEST DB command alone displays the present status of digital and
analog overrides. An example TEST DB response after two analogs follows:
=>>TEST DB A IA_MAG 100 <Enter>
=>>TEST DB D name value <Enter>
=>>TEST DB D 51P1T 1 <Enter>
WARNING: TEST MODE is not a regular operation.
Communication outputs of the device will be overridden by simulated values.
Are you sure (Y/N)? Y <Enter>
Test Mode Active. Use Test DB OFF command to exit Test Mode.
Override Added
Override Added
NOTE: When using the TEST DB
command to generate values for Fast
Meter testing, you may need to
override all current and voltage
angles (IA_ANG, VA_ANG, etc.) to
ensure the expected phase
relationship.
NOTE: When using the TEST DB
command, specifying a negative value
may yield an unexpected display in
some instances.
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