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Date Code 20020129
Metering and Monitoring
5-17
SEL-387E Instruction Manual
Critical RAM
The particular area of RAM where the settings are stored is deemed Critical RAM. It is verified
by computing a checksum. This must agree with a previously stored checksum value, or the
relay will declare a Critical RAM (CR_RAM) failure. There is no warning for the test.
EEPROM
EEPROM is checked by computing a checksum. If the computed value does not agree with the
stored value, the relay declares an EEPROM failure. There is no warning for the test.
Interface Boards
The relay checks the interface board ID register against a stored value. If any values differ, the
relay declares an I/O_BRD failure. There is no warning state for this test. Use the
INITIO
<ENTER>
command to reset the stored value for the new interface board configuration.
Self-Test Alarm Limits
Table 5.2 summarizes the limits for issuing warning or failure alarms during self-testing. The
power supply and temperature alarms list the values below or above which the stated alarm is
issued.
Table 5.2: Self-Test Alarm Limits
Self-Test
Warning Limits
Failure Limits
Channel Offset
30 mVdc
NA
+5 V Power Supply
4.80/5.20 Vdc
4.65/5.40 Vdc
+5 V Regulated
4.75/5.20 Vdc
4.50/5.40 Vdc
–5 V Regulated
–4.75/–5.25 Vdc
–4.50/–5.40 Vdc
+12 V Power Supply
11.50/12.50 Vdc
11.20/14.00 Vdc
–12 V Power Supply
–11.50/–12.50 Vdc
–11.20/–14.00 Vdc
+15 V Power Supply
14.40/15.60 Vdc
14.00/16.00 Vdc
–15 V Power Supply
–14.40/–15.60 Vdc
–14.00/–16.00 Vdc
Temperature
–40/+85
C
–50/+100
C
RAM NA
Cannot
READ/WRITE
Flash ROM
NA
Bad Checksum
A/D NA
Slow
Conversion
Critical RAM
NA
Bad Checksum
EEPROM NA
Bad
Checksum
IO_BRD
NA
Incorrect Interface Board Value