These rotary selector switches have three stable positions. Each position activates a ground to the DMC inputs (discretes) or to the DU inputs.
-pushbutton switches 9WT1 and 9WT2 These pushbutton switches enable the Captain and the First Officer to exchange the EFIS displays. They have one stable position and one unstable position. The unstable position activates a ground to the DMC inputs.
-PFD potentiometers 7WT1 and 7WT2 and ND potentiometers 8WT1 and 8WT2 These potentiometers are provided with an end of travel switch which generates a ground to the DMC at the OFF position.
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-ECAM/UPPER DISPLAY potentiometer and ECAM/LOWER DISPLAY potentiometer These potentiometers are of the same type as the PFD and ND potentiometers. Their end of travel switch generates a ground to the DMC at the OFF position. They are included in the ECAM control panel.
(Ref. Fig. 014)
(2) Switching inside the DMC
Switching is achieved by software: the DMC provides several busses to
the DUs with only two normally validated by two booleans on the bus.
The other busses are validated in case of reconfiguration.
Furthermore, each active DMC receives the output busses from the
DMC3, the active DMC replaces its output busses by the incoming DMC3
busses, to ensure data supply to the DUs when the active DMC has
failed.
(Ref. Fig. 015)
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DU Input addressing
Figure 014
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INTENTIONALLY BLANK
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EIS - Switching direct and return lines
Figure 015 (SHEET 1)
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EIS - Switching direct and return lines
Figure 015 (SHEET 2)
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(3) DMC software process
The software process related to the reconfiguration is implemented in
the DMC general application software program in a dedicated memory
inside the DMC and accessible by the data loader.
It includes the addressing process which validate the relevant output
busses A629 according to the reconfiguration status.
(Ref. Fig. 014)
-
the exchange of the PFD and the ND used for the EFIS transfer (Ref. Fig. 014)
-
the exchange of the two ECAM displays used to save the EWD in case of a DU failure
-
the computation of the ECAM single display mode used in case of an ECAM DU failure.
(4)
Direct line switching (Ref. Fig. 015) This figure represents the direct lines: from the DMC to the DU, and the return lines from the DU to the DMC.
(5)
Return line switching Each DMC receives a return line from all the DUs it can potentially drive. The switching of these lines depends on the reconfiguration status.
(Ref. Fig. 015)
The comparison between the return line and the direct line is as
follows:
------------------------------------------------------------------------------RETURN the DMC compares by software computation with:
LINE ------------------------------------------------------------------------------PFD1 the PFD output if the DMC drives the CAPT PFD DU PFD2 the PFD output if the DMC drives the F/O PFD DU ND1 the ND CAPT output if the DMC drives the CAPT ND DU ND2 the ND F/O output if the DMC drives the F/O ND DU EWD1 the EWD output if the DMC drives the EW DU EWD2 the EWD output if the DMC(ECAM) drives the ND (capt or f/o) SD1 the SD output if the DMC drives the SD SD2 the SD output if the DMC(ECAM) drives the ND(capt or f/o)
together with EW DU invalid
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(6)
Output busses
Two output buses are generated by the active DMCs, as follows:
- one general high speed data bus
- one general low speed data bus
(7)
The general high speed output bus of the Captain side is issued to control:
-
the FWC1 and the FWC2
-
the ECAM Control Panel
-
the DMU
-
the FDIU.
-
the DFDR.
-
the PVI (optional) or
-
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