
Date Code 20010625
M
IRRORED
B
ITS
™ Communications
I-3
SEL-311L Instruction Manual
Loopback Testing
Use the
LOO
command to enable loopback testing.
While in loopback mode, ROK
x
is deasserted, and another user-accessible flag, LBOK
x
will
assert and deassert based on the received data checks.
See
LOO Command
in
Section 10: Line Current Differential Communications and Serial Port
Communications and Commands
for more information.
Channel Monitoring
Based on the results of data checks described above, the relay will collect information regarding
the 255 most recent communications errors. Each record will contain at least the following
fields:
•
Dropout Time/Date
•
Pickup Time/Date
•
Time elapsed during dropout
•
Reason for dropout (See Message Decoding and Integrity Checks)
Use the
COM
command to generate a long or summary report of the communications errors.
There is only a single record for each outage, but an outage can evolve. For example, the initial
cause could be a data disagreement, but the outage can be perpetuated by framing errors. If the
channel is presently down, the COMM record will only show the initial cause, but the COMM
summary will display the present cause of failure.
When the duration of an outage exceeds a user-settable threshold, the relay will assert a user-
accessible flag, hereafter called RBAD
x
. Note: The user will typically combine RBAD
x
with
other alarm conditions using SEL
OGIC
control equations.
When channel unavailability exceeds a user-settable threshold, the relay will assert a user
accessible flag, hereafter called CBAD
x
. Note: The user will typically combine CBAD
x
with
other alarm conditions using SEL
OGIC
control equations.
M
IRRORED
B
ITS
P
ROTOCOL FOR THE
P
ULSAR
9600 B
AUD
M
ODEM
The user indicates that a Pulsar MBT modem is to be used by responding “MBT” to the
RTS/CTS setting prompt. When the user selects MBT, the baud rate setting will be limited 9600
baud.
The M
IRRORED
B
ITS
protocol compatible with the Pulsar MBT-9600 modem is identical to the
standard M
IRRORED
B
ITS
protocol with the following exceptions:
The relay injects a delay (idle time) between messages. The length of the delay is one relay
processing interval. Note: An idle processing interval guarantees at least 19 idle bits at 9600
baud in an SEL-321 Relay with the system frequency at 65 Hz.
Summary of Contents for SEL-311L
Page 6: ......
Page 8: ......
Page 26: ......
Page 54: ......
Page 144: ......
Page 216: ......
Page 252: ......
Page 302: ......
Page 338: ......
Page 480: ......
Page 484: ......
Page 486: ......
Page 502: ......
Page 532: ...12 28 Standard Event Reports and SER Date Code 20010625 SEL 311L Instruction Manual 4 ...
Page 552: ......
Page 554: ......
Page 574: ......
Page 576: ......
Page 596: ......
Page 602: ......
Page 628: ......
Page 656: ......
Page 662: ......
Page 664: ......
Page 688: ......
Page 700: ......
Page 716: ......
Page 722: ......
Page 734: ......