User manual

Magelis B - 23
1. Introduction: Display unit operating concepts
B
 Display unit self-tests
 Self-test on power-up
When the display unit is powered up, the following self-tests are
performed:
 Continuous self-test
A continuous self-test checks that the program is operating correctly
(watchdog).
NOTE: If a problem is detected, which prevents operation of the product,
the display unit turns off all its indicator lights, stops working and
displays an error number (if the detected fault permits it to do so).
If the same problem appears after the display unit is switched back
on, inform the maintenance department of this error number.
ELEMENT
TESTED
TEST
PRINCIPLE
FAILURE
CRITERION
ACTION IN
EVENT OF
FAILURE
The working
memory
(RAM)
Writing/reading
Value read different
from value written
Operation
impossible:
STOP
The firmware Checksum
calculation and
checking
Calculated
checksum <> Stored
checksum
Operation
impossible: STOP
The application
memory
Checksum
calculation and
checking
Calculated
checksum <> Stored
checksum
Operation
impossible:
Transfer
compulsory
XBT ref. Note
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