Avionics Bending: Attitude Director Indicator - ADI (Analysis and Pinout)

First power up of the two pilot side instruments. Without the ARINC 429 data the flags will not clear, however, the measurements on the power supplies show that they are intact. I am really curious to see if the instruments will work after being on the line for over 6800 hours, having been parked in the Arizona desert for 10+ years and being rough handled during de-install ... we will see over the next few weeks. The next step here will be to write the ARINC bridge between xPlane and the avionics buses.

So, just like the HSI from yesterday's post, the SFENA (Thales Group) ADI is a truly awesome instrument and shows some very clever mechanical engineering. Both the N32 and the N33 are very much a complete computer in a box that does both the ARINC 429 handling as well as all of the servo channel handling.

The main subsystems of the ADI are:

1. Input Processor
2. Central Processing Unit
3. A/D Converter
4. Attitude Servo Channels
5. Pointer and Command Bar Servomechanism
6. Failure Warning Indicators
7. Output Processor
8. Power Supply / Lighting

The ADI actually ingests fewer ARING 429 labels than the HSI does. The N33 HSI receives data on 8 ARINC buses, while the N32 ADI only receives data on 5 of the ARINC avionics buses. Here is a list of the buses and the respective ARINC lablels:

Bus 1 - FAST/SLOW (Label 142)
Bus 2 - Not used
Bus 3 - Localizer (Label 173), Glideslope (Label 174)
Bus 4 - Reciprocal ADI - Sin/Cos Recopy (Label 325), Sin/Cos Recopy (Label 324)
Bus 5 - Roll Angle (Label 325) and Pitch Angel (Label 324)
Bus 6 - Flight Director Commands - Roll Command (Label 141), Pitch Command (Label 140) and Yaw Command (Label 143)

All of the buses above run either at 12 Kb/s or 100 Kb/s ... Bus1 and Bus4 are 100 Kb/s buses.

Here is the pin-out for the SFENA N32 ADI J1 connector:

q	Remote Test	Switch Input
A	115V 400 Hz	Power
B	115V 400 Hz	Power
P	BUS 1	ARINC 429
R	BUS 1	ARINC 429
y	BUS 3	ARINC 429
w	BUS 3	ARINC 429
a	BUS 4	ARINC 429
b	BUS 4	ARINC 429
T	BUS 5 Primary	ARINC 429
U	BUS 5 Primary	ARINC 429
X	BUS 5 Alternate	ARINC 429
Y	BUS 5 Alternate	ARINC 429
V	Bus 5 Alternate and Primary Switch	Switch Input
K	BUS 6 - Flight Director Channel 1	ARINC 429
L	BUS 6 - Flight Director Channel 1	ARINC 429
G	BUS 6 - Flight Director Channel 2	ARINC 429
H	BUS 6 - Flight Director Channel 2	ARINC 429
FF	Pin Program CPT/FO	Logic
M	FD/A Flag	Logic
HH	F/S Flag	Logic
AA	G/S Flag	Logic
GG	LOC Flag	Logic
EE	FD Flag	Logic
z	Monitor Bus - Reciproacl ADI	ARINC 429
y	Monitor Bus - Reciproacl ADI	ARINC 429
e	Decision Height Warning Light
f	Decision Height Warning Light
D	Integral Ligthing	5V
E	Integral Ligthing	5V
g	Validity Output Glideslope
h	Validity Output Flight Director
m	Validity Output Fast/Slow

To see the ADI in check this blog posting: SFENA ADI Working with XPlane