15.35
Date Code 20171006 Instruction Manual SEL-400 Series Relays
Communications Interfaces
SEL M
IRRORED BITS Communication
the send and receive communications channels to complete the path for the test.
While in loopback mode, ROKc is deasserted, and LBOKc asserts and deasserts
based on the received data checks.
Channel Monitoring
Based on the results of data checks (described above), the relay collects informa-
tion regarding the 255 most recent communications errors. Each record contains
at least the following fields:
➤ Dropout Time/Date
➤ Pickup Time/Date
➤ Time elapsed during dropout
➤ Reason for dropout
Use the COM command to generate a long or summary report of the communi-
cations errors.
NOTE: Combine error conditions
including RBADA, RBADB, CBADA, and
CBADB with other alarm conditions
using SEL
OGIC control equations. You
can use these alarm conditions to
program the relay to take appropriate
action when it detects a
communications channel failure.
There is a single record for each outage, but an outage can evolve. For example,
the initial cause could be a data disagreement, but framing errors can extend the
outage. 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 on Channel A or B exceeds a user-definable
threshold, the relay will assert a user-accessible flag, RBADA or RBADB. When
channel unavailability exceeds a user-definable threshold for Channel A or B, the
relay asserts a user-accessible flag, CBADA or CBADB.
MIRRORED BITS Communications Protocol for the Pulsar 9600-BPS Modem
NOTE: Use an SEL-C272 or SEL-C273
cable.
To use a Pulsar MBT modem, set setting MBT := Y. Setting MBT := Y hides set-
ting SPEED and forces it to 9600, and hides setting RTSCTS and forces it to a
value of N. The relay also injects a delay (idle time) of 3 ms between messages.
NOTE: You must consider the idle
time in the calculations of data
transfer latency through a Pulsar MBT
modem system.
The relay sets RTS to a negative voltage at the EIA-232 connector to signify that
M
IRRORED BITS communications matches this specification. Other relays may
set RTS to a positive voltage at the EIA-232 connector to signify usage of the R6
version or the R version of M
IRRORED BITS communications.
Settings
The port settings associated with MIRRORED BITS communications are shown in
Table 15.24 and Table 15.25.
Set PROTO := MBA or MBGA to enable the M
IRRORED BITS communications
protocol Channel A on this port. Set PROTO := MBB or MBGB to enable the
M
IRRORED BITS communications protocol Channel B on this port.
Table 15.24 General Port Settings Used With MIRRORED BITS Communications
(Sheet 1 of 2)
Name Description Range Default
PROTO Protocol None, SEL, DNP, MBA,
MBB, MBGA, MBGB,
RTD, PMU
SEL
MBT Enable Pulsar 9600 modem Y, N N
To Next Page
Loading...
