10.18
SEL-587Z Instruction Manual Date Code 20020903
Testing and Troubleshooting
Relay Self-Tests
ROM Failure checksum Yes Latched Performs a checksum
test on the relay program
memory every 0.2 seconds.
CR_RAM Failure checksum Yes Latched Performs a checksum
test on the active copy of
the relay settings every 0.2 sec-
onds.
EEPROM Failure checksum Yes Latched Performs a checksum test
on the nonvolatile copy of
the relay settings every 0.2 sec-
onds.
Microprocessor
Crystal
a
Failure Yes Latched The relay monitors the
microprocessor crystal. If
the crystal fails, the relay displays
“CLOCK STOPPED” on the LCD
display. The test runs continuously.
Microprocessor
a
Failure Yes Latched The microprocessor examines
each program instruction, memory
access, and interrupt. The relay dis-
plays “VECTOR nn” on the LCD
upon detection of an invalid
instruction, memory access, or spu-
rious interrupt. The test runs con-
tinuously.
+5 V PS Under/
Overvoltage
a
Failure +4.65 V
+5.95 V
Yes Latched A circuit on the
SEL-587Z main
board monitors the +5 V
power supply. Upon detection
of a failure, the circuit forces
the microprocessor to reset.
a
The following self-tests are performed by dedicated circuitry in the microprocessor and the SEL-587Z main board. Failures in these tests
shut down the microprocessor and are not shown in the STATUS report.
Table 10.6 Relay Self-Tests (Sheet 2 of 2)
Self-Test Condition Limits
Protection
Disabled
ALARM Output Description
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