Cross-Channel Discretes; Ascb Engage Logic Data - Honeywell SPZ-8000 Maintenance Manual

de-energized. The servo switching monitor in the FGC validates
different engaged states against allowed states. Anytime an
unallowed state is detected, such as AP engaged without YD
(relay K2 energized but not K3), the servo switching monitor
will cause the servo power control relay to de-energize,
causing the system to disengage and the FGC to become invalid.
The servo switching monitor is discussed in detail in
section 4.
3. B. (4) (d) Cross-Channel Discretes
The status of one FGC is conveyed to the cross-channel FGC via
the cross-channel discretes. The cross-side servo power off
output from OR gate "A" will be active whenever the servo power
control relay is open, thus removing power from all clutches,
and power to the clutches is switched off. Whenever this
output is active, the FGC is invalid and will not engage the
system should the cross-channel FGC fail. The servo disconnect
output from AND gate "H" will be active whenever the FGC does
not have AP, YD, and trim engaged. As long as this output is
not active, this FGC is the priority channel and AP, YD, or
trim is engaged. The FGC also outputs the AP and YD power
valids to the cross-channel FGC.
(e) ASCB Engage Logic Data
The cross-channel engage status data listed below is used for
engage synchronization and channel prioritization. All ASCB
output data is controlled and formatted by the "A" processor.
AP/YD/Trim Engage Status (Word 2)
- Off/Invalid
- Off/Standby
- Selected/Standby
- Selected/Engaged
. Channel Priority Status (Word 1)
. AFCS Status to Fault Warning Computer (Word 37)
- TCS Status
- AP/YD/Trim Status
- Channel Priority
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