CARD TYPE CODE (SEE BOTTOM OF PLACARD FOR DEFINITIONS)
PSEU CARD SLOT IDENTIFICATION (PHYSICAL LOCATION IN PSEU CHASSIS)
SENSORS WHICH INPUT TO THE PROX CARD
LEFT PLACARD SHOWN, RIGHT SIMILAR

A
PSEU Card Slot/Type Information Placards
Figure 2A

 32-09-03
 ALL  ú ú 01 Page 4 ú Sep 15/86
 
A

757
MAINTENANCE MANUAL

 (3)  
The prox card interprets a high voltage (13 volts), for target far, as logic 1 and a low voltage (0.3 volts), for target near, as logic 0 and sends these signals to the associated logic card.

 C.
Logic Card

__________
 (1)  
The logic card combines input signals from the prox cards such that output signals are provided according to specified combinations of input signals.

 (2)  
The two interchangable cards each contain logic for the landing gear, thrust reverser indication and thrust reverser auto restow systems. The cards are interchangable because logic for landing system 1 and 2 are identical as well as for the left and right engine thrust reversers.

 (3)  
The non-interchangable card contains logic for the door and cargo door control systems.

 D.
Driver Card

___________
 (1)  
Each driver card contains 38 driver channels. The card supplies appropriate open or ground signals to drive airplane indicating and control systems.

 (2)  
Type 1 drivers (of which there are 35 per card) supply a ground when powered and will fail to open with loss of power.

 (3)  
Type 2 drivers (of which there are 3 per card) provide an open or a ground when energized, depending on which contacts are wired to the user system. These drivers are relay type drivers and fail to corresponding inactive state with loss of power.

 E.
BITE Module

___________
 (1)  
The BITE module is a microprocessor based sytem that executes performance and diagnostic tests. The module consists of two unique BITE cards and a BITE control panel.

 (2)  
The BITE module reads test commands from panel controls and writes out data to panel displays and indicators. The microprocessor reads programs and test data from programmable-read-only-memory (PROM) and random-access-memory (RAM) and executes test programs to perform input/output operations with test data. During inflight testing faults are stored in RAM and can be recalled on the ground.

 F.
Proximity Sensors (Fig. 3)

_________________
 

 32-09-03
 ALL  ú ú 07 Page 5 ú Jun 15/87
 
A

757
MAINTENANCE MANUAL

 (1)  
The sensors provide the position sensing inputs to the PSEU. They are distributed to these systems:

 (a)  
Door System (Ref 52-71-00).

 (b)  
Thrust Reverser System (Ref 78-36-00).

 (c)  
Landing Gear System (Ref 32-09-02 and 32-61-00).

 (d)  
Cargo Door Control (Ref 52-34-00).

 (2)  
The sensor, a two-wire device connected to the PSEU prox card, is a magnetic field-producing coil-core combination. The sensor is contained in a non-magnetic stainless steel case. When a steel (magnet) target is brought near or moved away from the sensor face, the sensor inductance increases or decreases respectively.

 (3)  
Two types of sensor are used, round or rectangular. The round sensor is used for applications that do not allow the installation of the rectangular sensors due to physical constraints. Both sensors sense the proximity or distance of a steel (magnetic) target to its sensitive surface. The sensor actuation gap varies with types of sensor and sensor installation. Regardless of gap differences, all sensors provide same function and output to the prox card in the PSEU.
　
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 起落架 CHAPTER 32 - LANDING GEAR 1(46)