L-1011 Trainer Installation: ARCIN 429 for Altimeter and Audio Side Panel

L-1011 Altimeter ARINC 429 Integration Tests

Today Jim Blasco and myself worked on doing ARINC 429 label integration tests with the Altimeter. The Altimeter uses Label 204 and due to the fact that it uses a slightly different variant of a ARINC 429 compatible protocol it has to run on it's own bus. The 204 Label for the Altimeter uses a 32bit word that does not have a SSM field or Parity Bit.

The short demo video bellows shows data being sent to the ADI, HSI, VSI and ALT.  The next steps will be to send actual simulator from X-Plane to the instruments. 

Besides the tests with the Altimeter we also installed the first of two audio side panels. The L-1011 Cockpit Procedure Trainer did not come with these side panels and we got them from an actual (British Airways) L-1011. The audio side panels provide the hookups for the headset (boom and headset) as well as a connector for the hand microphone. The side panel also has room to store the headset in.

L-1011 Audio Side-Panel Installation

Avionics Bending: Honeywell VSI/TRA

Honeywell VSI/TRA Display from TCAS-2000 System on the L-1011

Many of the L-1011's got upgraded with TCAS during their service time. The most commonly installed TCAS system on the L-1011 is the Honeywell TCAS-2000. I recently got my hands on a pair of Honeywell 4067644 VSI/TRA displays. The displays are vintage 1990s and will make the L-1011 simulator a lot more authentic, and, they are a lot of fun to work with. They take ARINC 429 input for both the VSI data as well as the TACAS data. The image above shows the VSI/TRA without any data sent to it, therefore, it indicates both TCAS and VSI as FAIL.

Here is a short demo of the VSI/TRA receiving Vertical Speed data from the ARINC 429 Primary bus

From: Honeywell TCAS-2000 Installation Manual

The VSI/TRA display runs off 115V 400Hz power and can take both ARINC 429 data as well as ARINC 575 ADC data. The 575 stuff is purely analog so not so interesting for working with the flight simulator, but the ARINC 429 stuff comes in very handy. Also, the VSI/TRA comes in a 41pin as well as a 55pin version. The ones that I have are the 41 pin version; and, here is the pinout for the 41pin VSI/TRA:

J1-1	VS +DC REF	ARINC 575
J1-2	VS DC RATE	ARINC 575
J1-3	VS -DC REF	ARINC 575
J1-4	Primary VS (HI)	ARINC 565
J1-6	Primary VS (LO)	ARINC 565
J1-5	VS 26 VAC Ref (Hi)	ARINC 565
J1-7	Not Used
J1-21	Not Used
J1-8	VSI Valid Flag	ARINC 575/565
J1-9	5V Lamp Dimming (LO)
J1-10	5V Lamp Dimming (HI)
J1-11	TCAS TA/RA (B)	ARINC 429
J1-26	TCAS TA/RA (A)	ARINC 429
J1-12	VS No 1 (B)	ARINC 429
J1-27	VS No 1 (A)	ARINC 429
J1-13	Not Used
J1-14	VS No 2 (B)	ARINC 429
K1-30	VS No 2 (A)	ARINC 429
J1-15	Config Common
J1-16	VS 26 VAC Ref (C)
J1-17	CS3	Configuration Bit
J1-18	PTM Common
J1-19	PTM PWR Out -15VDC
J1-20	PTM PWR Out +15VDC
J1-22	Chassis Ground
J1-23	115VAC 400Hz (C)
J1-24	Remote Light Sensor (LO)
J1-25	Remote Light Sensor (HI)
J1-28	Not Used
J1-29	RA Valid Out
J1-31	Source Select In
J1-32	CS0	Configuration Bit
J1-33	CS1	Configuration Bit
J1-34	CS2	Configuration Bit
J1-35	CS4	Configuration Bit
J1-36	CS5	Configuration Bit
J1-37	CS6	Configuration Bit
J1-38	CS7	Configuration Bit
J1-39	DC Ground
J1-40	115VAC 400Hz (H)
J1-41	CS8	Configuration Bit

The Vertical Speed input label for the VS 1 and VS 2 sources is Label 212.

Avionics Bending: Vertical Speed Indicator - VSI (Analysis)

Compared to the Airspeed Indicator from the previous posing, the Vertical Speed Indicator used with the Sperry Avionics packaged is a rather simple device. The indicator shows the aircraft's vertical speed in thousands of feet per minute ranging from 6000 fpm down to 6000 fpm up.

Here is a short video showing the basic performance of the VSI by simply using an ADC, an H-bridge and a simple micro-controller for data input.

The instrument an instrument-case is held together by two screws on the backside of the VSI.



Just like the Airspeed Indicator, the VSI has a gear portion in the front, one motor and one potentiometer that is used for position resolution, and a number of on-board electronics.





The "OFF" flag is actuated with about 12V DC and the motor in the instrument can be driven all the way to 47V DC.





The gear mechanism in the instrument is very basic and consists of a large gear attached to the motor and the potentiometer. The indicator is directly attached to the main shaft.

The large potentiometer reads zero resistance at 170 degrees of shaft angle.