*
 present position (PPOS)

 *
 true heading (HDG)

 *
 status of selected system (STS)

 *
 track and ground speed (TK/GS)

 *
 test values (TEST)

 -
a SYS DISPLAY selector switch with four positions: OFF, 1, 2, 3. The OFF position disables the display of the CDU but the mode control of the ADIRUs remains active

 -an ON BAT annunciator.
 The CDU contains three identical connectors referenced J1, J2 and J3.
 (Ref. Fig. 006)
 No cooling air is provided to the CDU.
 The CDU is supplied with 28VDC from the selected ADIRU to drive internal
 circuits and the data display. The 28VDC inputs are isolated from each
 other. The aircraft supplies 5VAC power for panel lighting/LCD
 backlighting and for annunciator lighting.

 B. ADIRU (Ref. Fig. 007)
 (1) General The ADIRU is contained in a 4 MCU case as defined in ARINC 600. The ADIRU has to be aligned on a special shelf in the avionics compartment in accordance with the installation design described in ARINC 738. This installation involves modification of the ARINC 600 standard to include three alignment pins and a floating connector. Pins 12 and 13 of the bottom plug have been modified with a reducer to accept power input instead of coax input as defined in ARINC 738. All input discretes are electrically isolated by an in-line diode or an equivalent device. The discrete outputs are protected by means of diodes to permit a wired OR circuit with other outputs.
R 1EFF : 001-049, 101-105, 151-199, 201-203, 1 34-12-00Page 24 1 1 Config-1 May 01/05 1 1 1CES 1

 ADIRS CDU - Internal Block Diagram
 Figure 006

R 1EFF : 001-049, 101-105, 151-199, 201-203, 1 34-12-00Page 25 1 1 Config-1 May 01/05 1 1 1CES 1

 ADIRU - General View
 Figure 007

R 1EFF : 001-049, 101-105, 151-199, 201-203, 1 34-12-00Page 26 1 1 Config-1 May 01/05 1 1 1CES 1 As each ADIRU is a common point to all engines installed on the aircraft, special care is taken to make impossible any electrical disturbance to propagate through the ADIRU/engine interface to other inputs/outputs dedicated to engines. The ADIRU is designed to reach a high level of protection for lightning and Electromagnetic Interference (EMI). The lightning protection circuitry is made up of high-powered Zener diode type semiconductors called Transzorbs on I/O connector pins. Power supply inputs are protected by Mov or by Zener type suppressor mounted adjacent to I/O connector. A 80960 microprocessor is shared between the ADR and IR functions to perform computations, BITE and input/output. The ADIRU contains an ADR and an IR portion supplied by a common power (115VAC, 28VDC).

 (2)
 ADR portion (Ref. Fig. 008) Five resolvers can be used for the analog baro-correction and the AOA inputs. The ADR provides eight ARINC 429 low-speed output buses (buses 5 to 8 are reserved for engine control). Each bus can drive twenty ARINC bus loads.

 (3)
 IR portion (Ref. Fig. 008) A DSP (Digital Signal Processing) C25 microprocessor is used to interface between the sensor block and the 80960 microprocessor. The gyros/accel sensors block contains three accels and three gyros mounted along each axis. This sensor block is supplied by a high voltage power supply provided by the IR portion. The IR provides four ARINC 429 High-Speed output buses. Each bus can drive twenty loads.

R 1EFF : 001-049, 101-105, 151-199, 201-203, 1 34-12-00Page 27 1 1 Config-1 May 01/05 1 1 1CES 1

 ADIRU - Block Diagram
 Figure 008

R 1EFF : 001-049, 101-105, 151-199, 201-203, 1 34-12-00Page 28 1 1 Config-1 May 01/05 1 1 1CES 1

 AIR DATA/INERTIAL REFERENCE SYSTEM (ADIRU & CDU) - DESCRIPTION AND OPERATION
____________________________________________________________________________
 1. General
_______ The Air Data/Inertial Reference System (ADIRS) provides the main air data and heading/attitude/navigation data to the aircraft systems. The main computers of the ADIRS are the three Air Data/Inertial Reference Units (ADIRU) which are controlled by the ADIRS Control and Display Unit (CDU). The ADIRS is a three channel system. Each channel is isolated from the others and provides independent information as defined in ARINC 738. Each ADIRU contains:
 -
an Air Data Reference (ADR) portion. Its operation is described in 34-13

 -
an Inertial Reference (IR) portion. Its operation is described in 34-14. Power supply is common for ADR and IR and described in 34-11.

 2. Component Location
__________________
 (Ref. Fig. 001, 002)
 The three ADIRUs are installed in the avionics compartment.
　
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