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MAINTENANCE MANUAL
SPEED BRAKE LVDTS
1A 1B 2B
2A
3A 3B
CAPTAIN'S
FIRST OFFICER'S
CONTROL WHEEL
CONTROL WHEEL
RVDTS
RVDTS
SPOILER PCA RVDTS
* = BAD RVDT
A = ACTIVE SUB-CHANNEL B = STANDBY SUB-CHANNEL C = MODEL SUB-CHANNEL
= SUB-CHANNEL DETECTING ERROR
Redundancy Management
Figure 9
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MAINTENANCE MANUAL
SPEED BRAKE LVDTS
* = BAD RVDT A = ACTIVE SUB-CHANNEL B = STANDBY SUB-CHANNEL C = MODEL SUB-CHANNEL
NOTE:
COMPARATOR OUTPUT = 1 IF INPUTS DISAGREE
Maintenance Monitor Transducer Failure Detection Figure 10
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MAINTENANCE MANUAL
SPEED BRAKE LVDTs 1
1A 2B 1B
2A
3A 3B
CAPTAIN'S
FIRST OFFICER'S
1
CONTROL WHEEL
CONTROL WHEEL
RVDTs
RVDTs
CSEU-L (EXAMPLE)
* = BAD RVDT
A = ACTIVE SUB-CHANNEL
B = STANDBY SUB-CHANNEL
C = MODEL SUB-CHANNEL
THESE COMPONENTS HAVE EQUIVALENT CIRCUIT CONNECTIONS TO THE SCMs AS THE CAPTAIN'S CONTROL WHEEL RVDTs
Maintenance Monitor Transducer Failure Detection
Figure 10A
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MAINTENANCE MANUAL
2) The comparator produces a logic one if the two inputs disagree and a logic zero if they agree. Output (X, Y, and Z in Fig. 10) is fed to all three SCMs. In the example above, SCM 1L compares RVDTs #1 and #2 which produces a logic one at X since the two signals disagree. SCM 2L compares RVDTs #1 and #3. Since both agree, the comparator outputs a logic zero at Y. SCM 3L, comparing RVDTs #2 and #3, produces a logic one at Z since the two do not agree.
3) The required input for the voting logic is 1-1-0 on the three leads to the AND gate. The logic used to set the faultball is a VOTE FAIL and a "switch" decision. This condition is met, in the example, only in SCM 3L. Therefore, the RVDT faultball (CW XDCR) is set on this SCM.
4) The faultball will always be set on the SCM whose active subchannel, A, is receiving input from the faulty transducer (RVDT or LVDT). Table 1 identifies which control wheel or speedbrake lever transducer is at fault when a given faultball is set.
Table 1: Control Wheel and Speedbrake Lever Faultballs
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