Switch Position "Automatic - Raytheon 138-119 Operator's And Service Manual

2.1.1

Switch position "Automatic"

In the normal mode (switch position "Automatic") the switching--over of the output signals of
compass system 1 are carried out of the Distribution Box (DU1) via the Change Over Box
(see Figure 4).
All relays of the Change Over Box are dropped out. The DUs of both compass systems
communicate via the CAN bus. But only the DU1 is "active" and its output signals ("A In1",
"B In2" etc.) are switched to the connected receiver ("A Out", "B Out" etc.).
If a fault is detected in the DU1 ("System Failure"), the Change Over Box switches over to
the DU2 automatically. This is affected by closing the contact of relay "System Failure" in
the DU1. Thus the 24 V DC switching voltage is switched to the Change Over Box via the
Change Over Switch.
All relays of the Change Over Box operate and switch the outputs of the Change Over Box
from the signal outputs of the DU1 (for example "A In1") to the signal outputs of the DU2
(for example "A In2").
At the same time the error message "System Failure" can be detached as a 24 V DC po-
tential from the Change Over Switch for external applications.
This switch--over function is not activated by a fault in the Distribution Unit 2.
After repair and setting into operation again the output signals of the compass system 1 are
switched to the output of the Change Over Box, No additional measures are necessary.
Edition: April 06, 2005
Change Over Box
138- -119
ATTENTION!
It can happen that there is a desynchronisation of the
6--steps/degree signal after switching--over -- either
manual or automatically.
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