Issue setting offset 0x07D4 (Autopilot AltitudeHoldVar)

[Fabio Drago]

Hi all,

I'm building my custom panel and I'm trying to set the hold altitude.
At the moment it works fine for the positive values only. When it goes negative the altitude go wild 🙂

I'm using .net client 3 and FSUIPC7 and this is the relevant code:

//Offset declaration
private Offset<Int32> _autopilotAltitudeHoldVar = new Offset<Int32>(0x07D4);

// Add the increment
var actual = _autopilotAltitudeHoldVar.Value;
var newalt = (Int32)(actual + diff * 0.3048 * 65536); (diff can be +100 or -100)
_autopilotAltitudeHoldVar.Value = newalt;

 

When I turn into negative altitude (actual=0 and diff=-100) then newalt is -1997537.
The displayed altitude goes to 99900 and if I readback the offset the value is 1995539712.

If I set the hold altitude with the simulator panel (-100)  the offset value is  -1997536.

I'm going crazy with it.

Thaks,
Fabio

 

[Paul Henty]

Hi Fabio,

Your code looks okay.

I've tried it here with FSX, but that sim doesn't seem to support negative altitudes for the autopilot at all. You can't set them on the panels of any aircraft.

If negative hold altitudes are now supported in MSFS (on default aircraft) then my guess is that FSUIPC7 and/or SimConnect hasn't been changed to support this.

Maybe @John Dowson can shed some light on this.

Paul

[Fabio Drago]

Thanks Paul,

it also seems strange to me that negative values can be entered. Waiting John feedback I have set to zero all negatives values.

Fabio