Supervisory Functions
143
7SS52 V4 Manual
C53000-G1176-C182-3
Figure 5-33 Characteristic for measured value monitoring
Memory supervi-
sion
The memory modules of the central unit and the bay units are periodically tested for
faults.
•
A checksum is formed for the program memory (Flash EPROM) during start-up and
cyclically during operation.
•
For the RAM, a data pattern is written during start-up and read again. Write and
read results are compared.
•
For the parameter and configuration data memory (EEPROM), the checksum of the
stored quantities is formed and compared with the checksum calculated during
each new writing process.
•
For the dual-port RAM of the slave modules, the stored parameters and configura-
tion data are compared with the data on the master module.
5.5.1.4
Output Trip Supervision
The output trip channels of the bay unit are controlled via two trip channels and one
release channel. The trip output channels are checked in connection with the cyclic
protection test (Chapter 5.5.1.7, page 144).
5.5.1.5
Battery Monitoring
The central unit and the bay units are equipped with buffer batteries to ensure that
LED states, date and time, operational and fault events as well as fault records are
maintained in case of an auxiliary power failure. As soon as the battery voltage drops
below a certain threshold, an alarm "
Batt. superv CU
" (
FNo. 10422/CU
) or
”
BattSuperv $00
” (
FNo. 176.1174/CU
) is output.
5.5.1.6
Supervision in Maintenance Mode
Isolator
supervision
While a bay is in maintenance, settable with the parameter
(
XX12/CU
),
there is no monitoring of the isolator status checkback signals, nor a plausibility check.
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