Error Message "System Failure; "System Failure" In Switch Position"Automatic - Raytheon 138-119 Operator's And Service Manual

4.4

Error message "System Failure"

4.4.1

"System Failure" in switch position"Automatic"

If the Distribution Unit 1 fails, an error message, which leads to a switch--over in the
Change Over Box, is output from the DU 1.
Condition for that is a normal operating mode of the Compass systems and a switch posi-
tion "Automatic" of the Change Over Switch.
Cause of an error message can be below mentioned disturbances:
1. Internal CAN bus of the DU 1 failed.
2. Voltage drop of two monitored voltages (extern, output) in the DU 1.
3. Complete breakdown of the DU 1.
All above mentioned errors or combinations thereof, will lead to a "System Failure"
in the DU 1.
This "System Failure" activates a closing of a relay contact in the DU 1.
By this an electrical circuit is closed in the Change Over Box and all relays are connected
to 24 V DC switching potential. All relays of the Switch over Box are caused to activate and
switch--over the output from DU 1 to DU 2.
Edition: April 06, 2005
Change Over Box
138- -119
NOTE!
A failure in the compass system 2 and a generation of an
error message in the Distribution Unit does not lead to a
switch--over of the Change Over Box.
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