-
the other UP selection signal from the L/G control-lever
-
the other DOWN selection signal from the L/G control-lever
-all of the L/G system Complementary signals from the proximity conditioning cards
-and an enable or disable signal from the microprocessor card.
The L/G control-logic processes these input signals and when:
-each of the two logic parts supply the correct output signal
-the microprocessor controlled enable/disable line supplies an enable signal.
Then the L/G control-logic will let a 28V d.c. output and an earth return to be supplied to the (L/G or door selector-valve) solenoid-windings.
The L/G system retraction and extension cycles are controlled by electrical power applied to the (L/G and door selector-valve) solenoid-windings in the correct sequence.
A separate logic circuit controls the L/G position indicator lights. This logic uses only the L/G-system Normal-signals from the proximity conditioning cards. The output signals from this logic supply the indicator-light relays. These relays are located on the Annunciator-Light Test and Interface Board (9LP).
NOTE : Only the logic of the LGCIU in SYSTEM No1 controls the
____ three indicator lights. The logic is not affected by the change in control of the L/G.
(c) Interface Cards
The Interface cards provide L/G position-information, (i.e L/G downlocked, shock absorber compressed) to the interfaced aircraft systems Ref. 32-62-00. One of these cards also contains the logic circuitry for control of the Cargo-Door Open/Closing System.
The Interface cards process L/G-system Complementary input-signals and supply L/G position-information output-signals in discrete form.
(d) OBRM/Microprocessor card
The main components of the OBRM/Microprocessor card are:
-
an On Board Replaceable Memory Module (OBRM) which contains an Electronically Erasable Programmable Read Only memory (EEPROM)
-
an Intel 8031 microcontroller
-a Harris 3282 ARINC 429 transceiver
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-an Intel 8251 RW232C interface device
-a Non Volatile Random Access Memory (NOVOL RAM)
-Random Access Memory (RAM).
Contained in the OBRM is the software used by the microcontroller. The software is mainly programmed in Intel PL/M-51 high level programming language and has specific routines programmed in ASM-51 Assembly language.
The software performs these main functions:
1_ System Status (position) Information
The software prepares and transmits LGCIU system status data
(ie L/G downlocked, LH flap disconnected) on the ARING 429
output data buses. This data is transmitted to:
- the FWC (for ECAM display)
- the SFCC
- the CFDS
- other systems (Ref. 32-62-00).
Those systems that require high integrity data either receive
discrete data alone (Interface cards) or receive discrete data
against which ARINC 429 data is checked.
2_ 'Active'/'Standby' Determination
In a serviceable LGCIU the software receives input signals
from the L/G control-lever and the other LGCIU. From these
signals the software (changeover logic) makes the decision if
the LGCIU should be 'Active' (in control of the L/G system) or
'On Standby'.
When the decision is 'Active' the software transmits:
- an enable signal to the L/G control-logic (Output/Control
and Indication card) so that the L/G and door selector-valve
solenoid-windings can be energized
- an 'Active' signal to the other LGCIU.
When the decision is 'On Standby' the software transmits:
- a disable signal to the L/G control-logic so that the L/G
and door selector-valve solenoid-windings can not be
energized.
- an 'On Standby' signal to the other LGCIU.
With both LGCIU systems serviceable, LGCIU 1 Active and LGCIU
2 ON Standby:
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3
_
-a de-selection of DOWN will cause LGCIU 1 to become 'On Standby' and LGCIU 2 to become 'Active' (and take control of the L/G system) 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：A320飞机维护手册 AMM LANDING GEAR 起落架4(49)
