View Full Version : A/T disconnect offsets

08-02-2007, 08:48 AM
We've been busy getting autothrottles working and have had success! It's great to see those puppies move up an down.

Only thing we can't finish is the autothrottle disconnect. It works like it should but we can't find an offset to read that tells us if the A/T is engaged or not. We need this to provide some logic for SIOC code, otherwise the servo motors won't 'let go' after we disengage.

We tried various offsets from the lists - including 050A - but those offsets arent reading in any data that we coud see.

Anyone got any suggestions?


Bob Reed
08-02-2007, 10:45 AM
Hey Nic. How about when you disconnect, just cut the power to the drive unit? But there must be a offset. It is listed in FSUIPC so it has to be there. I will take a look at the doc and see if I spot it. I also have a friend that has his AT working I will see how he is reading disconnect.

08-02-2007, 03:31 PM
I actually had to use multiple conditions in SIOC (Opencockpits) to set an offset to AT On and Off, and then had Phidgets turn power on/off as required.

This was using the LDS 767 SDK offsets to look for (through FSCONV) and activated 0/0/4 Relay outputs if the offset combinations was ok.

I had a computer crash a couple of months ago, and haven't yet rebuilt my code, but i was looking at my beginning efforts and offsets used, and have put them below for reference:

Var 4540, name Autothr_stat, Link FSUIPC_IN, Offset $8BB2, Length 1 // Auto throttle Status
//&ISFLCH = TESTBIT &Autothr_sta2 10
&ISN1 = &Autothr_stat
c0 = &Autothr_stat = 0
c1 = &Autothr_stat > 1
c2 = &Autothr_stat < 9
CALL V4541

IF c0
if &ISFLCH = 1
&Auto_throttle = setbit 0
&Auto_throttle = CLEARBIT 0

IF &ISN1 = 9
&Auto_throttle = CLEARBIT 0

if c1 and c2
&Auto_throttle = setbit 0


Var 4541, name Autothr_sta2, Link FSUIPC_IN, Offset $8BAC, Length 4 // Auto throttle Status
&ISFLCH = TESTBIT &Autothr_sta2 10
&ISSPD = Testbit &Autothr_sta2 18
//&ISN1 = Testbit &Autothr_sta2 17
//&ISVNAV = Testbit &Autothr_sta2 9

Var 4542, name IsFLCH
Var 4543, name IsN1
Var 4544, name IsSPD
Var 4545, name IsVNAV

Var 4546, name Auto_throttle, Link FSUIPC_OUT, Offset $8BFF, Length 1 // Auto throttle active

Hope this at least gives you some idea of where to go.


08-02-2007, 03:48 PM
Hi Chris,

Unfortunately there is a bug in the Level-D SDK A/T status (not in FSCONV, but in the SDK).

In FLCH mode for instance it goes to zero... I have reported that to the Level-D team (being their beta tester for the SDK), they could not solve that for the FSX version because it would brake the Aerosoft MCP interface....

For the time being you have indeed to try to solve it with a combination of input signals. SIOC is powerful enough to that.

Nico Kaan

08-02-2007, 08:37 PM
Thanks guys, we have done a similar thing in code - assuming A/T is engaged if N1, SPD, VNAV, LVL-CHG or V/S are engaged.

Thought there must have been a simple offset for this condition ... but oh well :(