VIDEO
R
V4
U DUGENERATOR
DU ANOMALY U.
INPUTS
DU FAIL DISPLAYFORMAT
LOWER
SYNC
1
FORMAT
G
L DU
DU
NC
LWR DU OVHT
TO TOP
LOGIC FORMAT
DRIVER
EICAS TOP DISPLAY
B DISPLAY IND
STROKE/
TO BOTTOM
L DU BEAM TEST FAILSWITCHING MODULE
X
(SHT 2) (SHT 2)
C
VIDEO
LWR DU
DISPLAY IND
SPARE
GENERATOR NC
TO BOTTOM
L DU ANOMALY
Y
FAIL6 DU
C EPR, N1, N3,
DISPLAY IND
DRIVER
X
(SHT 2)
MISC
FUEL FLOW
ENGINE
TO FMC
SIGNAL
Y
TO FMC
ANALOG TO
H
TMC
SOURCE
DATA DIGITAL
TMC
DFDAU LOGIC
NC
OUTPUT DATASELECTION
2
V0
TO BOTTOM DISPLAY
K
K ARINC
DISCRETE DATA
SWITCHING
V1
ANALOG TO
TO BOTTOM 429
DIGITAL
H
CROSSTALK
DISPLAY CONFIG DATA
V2
DISPLAY
SWITCHING
AIDS
V3
RIGHT COMPUTER VALID COMPUTER VAL-WRAPAROUND
DATA TX IDITY MONITOR
V4
CROSSTALK
WRAPAROUND
SYNC
WORD
RIGHT EICAS COMPUTER
WRAPAROUND
GENERATOR
INTERNALS
SAME AS
UPPER
J
LEFT EICAS COMPUTER
DISPLAY
SWITCHING
MODULE
C 1 CONTROL RELAY SWITCHES 11 DPDT. RELAYS, OF WHICH 8 ARE USED FOR DISPLAY SWITCHING
2 1 SET OF DPDT CONTACTS SHOWN, OTHERS SIMILAR
3
USED AS AIR/GND FOR ALL COMPUTER FUNCTIONS (SHT 2)
4 INHIBITS MCL + AURAL WHEN BOTH ENGINES ARE SHUTDOWN ON THE GROUND
D
E D
5
DELAYS MCL + AURAL, OR REMOVES THEM IF ALREADY PRESENT, DURING TAKEOFF FROM 80KTS TO 400 FT OR
20 SECS AFTER NOSEWHEEL LIFTOFF, WHICHEVER OCCURS FIRST
(SHT 2)
EICAS BOTTOM DISPLAYTO DISPLAYSWITCHING MODULE
6
HARDWARE EXISTS FOR THIRD DU DRIVE BUT SOFTWARE NOT IMPLEMENTED
SELECT PANEL
EICAS RELAY PANEL
EICAS Outputs Schematic
Figure 12 (Sheet 1)
ú
31-41-00
ALL ú ú 08 Page 40 ú Jan 28/02
A
757
MAINTENANCE MANUAL
ú
31-41-00
ALL ú ú 11 Page 41 ú Jan 28/02
A
757
MAINTENANCE MANUAL
(a) Analog Discrete Outputs 1) Two output discretes control operation of the master CAUTION light and owl aural. Each computer sends a discrete to both master CAUTION light/switches to turn on the light. A separate discrete is routed to the WEU from each computer to enable the caution owl aural. 2) The master CAUTION light/switches are turned on and the caution owl aural is sounded when level B alert messages are displayed, unless inhibited as follows: a) Master CAUTION lights will not come on when Air/Ground systems 1 or 2 indicate the airplane is on the ground and both fuel control switches are at cutoff. Any level B message present when the inhibit is removed will not turn on the lights. b) During takeoff, the master CAUTION lights will not come on when computed airspeed is greater than 80 knots and radio altitude is less than 400 feet, unless 20 seconds has elapsed. The 20 second timer starts at nose wheel lift-off. Any non-reset condition present when the inhibit is removed will turn on the lights. c) The output to the WEU for caution owl aural tone generation is inhibited in the same manner as the master CAUTION lights. 3) Each computer sends a computer fail discrete to the other EICAS computer. In addition, the left computer fail discrete is sent to the display select panel for automatic display switching. 4) An SEI enable discrete is sent by both computers to the Standby Engine Indicator. This enable will be set to an open circuit whenever both pilots display units are faulty, both computers are faulty, the BITE Test Format has been selected, or a single display has failed and the Status page is being displayed. 中國航空網 m.k6050.com 航空翻譯 www.aviation.cn 本文鏈接地址：757 AMM 飛機維護手冊 儀表 CHAPTER 31 - INSTRUMENTS 2(36)
