K. Roll Channel Analog Interface (Fig. 26)
(1) The analog interface diagram illustrates the various LRU's which are associated with the generation and implementation of signals used during roll channel modes of operation. All of the input signals are converted from analog form to digital for internal use by the computer. In addition, all of the output signals are converted from digital to analog prior to going to their respective destinations.
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R/T NO 1 (E2-4) M924 FLIGHT CONTROL COMPUTER A (E1-2)
Roll Channel Analog Interface Block DiagramFigure 26
(2)
(3)
(4)
A
737-300/400/500MAINTENANCE MANUAL
Logic Inputs
(a)
The R3 load control center relay is used as a logic input to indicate to the flight control computer that a bus transfer has occurred.
(b)
R44 NAV XFR Relay-1 provides a logic input to the flight control computer which indicates if a NAV transfer or EFIS transfer has been made. As the NAV XFR signal is routed through the EFIS switching relay-1. VOR/LOC super flag is open when NAV transfer is made.
(c)
The VOR/LOC super flag is required prior to capturing the VOR or LOC beams. After capture it is not monitored unless the FCC is in the approach on course (AOC) mode. Loss of the super flag while in AOC will disengage the A/P. The ILS DC is required for LOC capture and for antenna switching.
(d)
The R315 ILS relay 1 indicates whether the forward LOC antenna has been selected. This will normally happen when an ILS frequency is selected and either the VOR/LOC or APP pushbutton is pressed. If the forward antenna has not been selected the localizer cannot be captured when in the APP mode.
Command input signals are used for computer or feedback control.
(a)
The aileron position sensor input is used to synchronize the A/P roll channel output to the actual aileron position prior to engaging.
(b)
The VOR/LOC deviation input is the prime guidance signal used during the two radio modes of operation. VOR deviation during a VOR mode and localizer deviation during a LOC or approach mode.
(c)
The aileron crossfeed input from FCC B provides a comparison of the aileron actuators (A and B) for use during approach.
(d)
The aileron actuator position feedback is a signal from the A actuator to indicate the amount of command received from the FCC valve amplifier and the actuators response.
(e)
The roll control wheel steering input is a command input signal used in the RCWS mode whenever the output of the "out of detent" sensor is exceeded.
(f)
The spoiler position feedback signal is summed with the aileron actuator feedback when the flaps are set at 27 degrees or greater.
(g)
The A/P-A/T radio altimeter drive signal is used during final approach for gain control, flare control, GA logic, and dual engage logic.
Logic outputs provide annunciation, engage sequence, F/D control and bar bias plus self test inhibit.
(a)
The actuator detent signal is sent to the aileron actuator at engagement to hydraulically lock the detent piston against the internal output crank.
(b)
The ILS test inhibit signal is used to energize a relay in the flight instrument accessory unit or integrated flight system accessory unit which prevents testing of the ILS functions in the VHF NAV RCVR after LOC capture.
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本文链接地址：737-300 400 500 AMM 飞机维护手册 自动飞行 AUTOFLIGHT 1(107)
