(1)
Interface with the clock The CFDIU is connected to the clock, located on the center instrument panel, which provides:
-GMT/Date
-elapsed time
-chronometer. The CFDIU permanently acquires GMT and the date and transmits these data on its output buses. The clock provides the date and the time at which faults occur. The time associated with the fault messages and the ECAM warnings enables the correlation between the ECAM warnings and the fault messages memorized by the CFDIU. In the event of loss of clock operation or incorrect operation detected by the CFDIU, the CFDIU takes over and calculates the time and the date using its internal clock. This transition does not require reinitialization if there is not a long power cutoff (> 200 ms). If there is a long power cutoff, the crew performs reinitialization using the MCDU. The CLOCK is declared failed or invalid (= incorrect operation) by the CFDIU when one of the labels of the GMT and DATE parameters is not refreshed or transmitted with incorrect parity or with SSM at NCD or FT confirmed over 1 minute.
(2)
Interface with the FWC In normal configuration (no fault) the CFDIU permanently reads the FWC1 bus and reads the FWC2 bus cyclicly for the reception of fault messages (label 356). When a fault occurs, or with incorrect FWC1 operation detected by the CFDIU, only FWC2 bus is read. The CFDIU returns to FWC1 bus after a long CFDIU power cutoff. The FWC provides the flight phases associated with ECAM warnings and used to generate the flight/ground conditions of the CFDIU and of type 1 systems.
NOTE : In addition to this parameter, it has been seen that the FWC
____
provides:
-the fault messages presented to the ECAM with label 357, using the same transmission protocol and the same transmission frequency as label 356 in Normal Mode. This label is permanently read by the CFDIU, message transmission is asynchronous and it is only emitted once for each warning
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-the fault messages generated by the BITE function which are transmitted by the FWC with label 356 using established protocol.
The FWC1 is declared failed by the CFDIU when "flight phase" label is not refreshed or transmitted with incorrect parity or with SSM at FW = 0, confirmed over 4 seconds. In this case, after the confirmation time on the FWC1, the CFDIU reads the FWC2 bus and uses this bus to retransmit the flight phases transmitted by the FWC2. The FWC1 is declared invalid (but not failed) by the CFDIU when "flight phase" label is transmitted with SSM at NCD = 01 or FT = 10, or with flight phase smaller than 1 or greater than 10, confirmed over 3 cycles. In this case, after the confirmation time on the FWC1, the CFDIU uses and retransmits at NCD = 01 the last correct flight phase received from the FWC1, i.e. received with SSM at NO = 11 and flight phase comprised between 1 and 10. If this last correct phase is no longer memorized, i.e. if moreover a CFDIU power cutoff occurs, after the confirmation time on the FWC1, the CFDIU uses and retransmits phase 1 at NCD = 01 by default. During the confirmation time the CFDIU does not retransmit anything. the FWC2 is declared failed or invalid (= incorrect operation), after a FWC1 failure, when "flight phase" label is not refreshed or transmitted with incorrect parity or with SSM at NCD = 01, FW = 00 or FT = 10, or with flight phase smaller than 1 or greater than 10. In this case, after the confirmation times on the FWC1 and the FWC2, the CFDIU uses and retransmits at NCD = 01 the last correct flight phase received from the FWC2 i.e. received with SSM at NO = 11 and phase comprised between 1 and 10. If this last correct phase is no longer memorized, i.e. if moreover a CFDIU power cutoff occurs, after the confirmation times on the FWC1 and on the FWC2, the CFDIU uses and retransmits phase 1 at NCD = 01 by default. During the confirmation times, the CFDIU does not retransmit anything.
NOTE : - During the confirmation times related to the invalid or
____ failed state, except in the case of CFDIU power cutoff, the CFDIU uses and retransmits at NO = 11 the last correct flight phase received.
-When the invalid or failed state disappears, the CFDIU resumes use and normal transmission of flight phases.
-The command label 227 (NULL/DC2/DC1) directly follows the value of the flight phase transmitted by the CFDIU, whether this phase is transmitted at NO or at NCD.
-After a power-up test of the CFDIU without FWCs, the CFDIU presents the Flight menu or the Ground menu depending on the
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本文链接地址：A320飞机维护手册 AMM 指示/记录系统INDICATING/RECORDING SYSTE(115)
