PFC Digital Avionics, Altitude Pre Selector

[Frank.O]

Hi Pete,

this is not a big thing and I can well live with it. I'm asking just out of curiosity. The altitude set by the altitude pre selector on the Digital Avionics can be increased or decreased in steps of 100 feet (1000 feet if you turn the knob faster). In former versions of PFC.dll this resulted in round values in the FS autopilot or the altitude pre selector on the panel (500, 2800 or 5000 for instance). This is now different. The FS values are always like 499, 2799 or 4999. I think this started with one of the 1.8X releases (can't say exactly when because I rarely use the AP). Where does this come from?

Best regards,

Frank

[Pete Dowson]

In former versions of PFC.dll this resulted in round values in the FS autopilot or the altitude pre selector on the panel (500, 2800 or 5000 for instance). This is now different. The FS values are always like 499, 2799 or 4999. I think this started with one of the 1.8X releases (can't say exactly when because I rarely use the AP). Where does this come from?

No change on my part, not in the several years of my PFC driver's existence. Sounds more like the specific panel you are using. Altitudes internally are all in metres and some gauges don't round correctly. Either that, or perhaps you re-programmed the knob on the PFC avionics, perhaps?

I've just checked here and the values shown on, for example, the default 737 MCP are always multiples of 100. I've also looked at the code where I operate the increment and that is not only the same as it has been for at least 20 months, it takes great care to correct any reading it gets from FS which isn't a multiple of 100.

Regards,

Pete

[Frank.O]

Good morning Pete,

thanks for your reply.

No change on my part, not in the several years of my PFC driver's existence. Sounds more like the specific panel you are using. Altitudes internally are all in metres and some gauges don't round correctly. Either that, or perhaps you re-programmed the knob on the PFC avionics, perhaps?

Hm..., can't be anything of that I think. The panel is the standard Baron panel from which I removed the panel DME and inserted the altitude pre selector of the Cessna Grand Caravan instead. That hasn't changed ever since I started to use PFC equipment (2 years). And the knob isn't reprogrammed also. I'm sure it was still good when I started to use FS9.

I've just checked here and the values shown on, for example, the default 737 MCP are always multiples of 100. I've also looked at the code where I operate the increment and that is not only the same as it has been for at least 20 months, it takes great care to correct any reading it gets from FS which isn't a multiple of 100.

Strange, isn't it?

He he he, computers do have an inner life and a personality as well, don't they?

May be I should go and learn XML so I can make my own altitude pre selector.

Anyway, thank you Pete.

Regards,

Frank

[Pete Dowson]

The panel is the standard Baron panel from which I removed the panel DME and inserted the altitude pre selector of the Cessna Grand Caravan instead. That hasn't changed ever since I started to use PFC equipment (2 years).

The gauge in the Grand Caravan is most definitely the culprit. Compare the very same altitude there with the one in the standard Bendix-type radio stack (the Altitude display is the value above the VS display in the autopilot at the bottom of the stack). It is evidently not converting metres to feet correctly -- probably rounding down instead of rounding to the nearest. :(

I'll look at increasing the value in metres just a tad, see if that helps. I really can't say why it changed -- possibly it is related to the re-compilation of the PFC DLL with version 7 of the MSVC compiler -- I was using version 6 until recently. Certainly that part of the source code hasn't been changed.

Whatever I do, the main priority is to keep the main A/P and MCP displays correct, which they certainly are still. MS evidently have different conversion code in the Grand Caravan selector gauge.

Regards,

Pete

[Frank.O]

Hi again,

The gauge in the Grand Caravan is most definitely the culprit.

that's absolutely right. After your first reply I made some more tests with standard panels and found the same (the good thoughts are allways a bit late :oops: ).

I'll look at increasing the value in metres just a tad, see if that helps.

No, please don't. As I said initially it's not a big deal. No work necessary here.

BTW I've sorted it out on my own. Had a look at the XML code for the respective gauges on the 747 and found it pretty easy to make my own altitude pre selector. It's just a display of the values set and uses the same bitmap as in the Caravan but that's all I need and it works like a charm :) .

Took me about two hours and was very funny without any knowledge about XML :lol: .

I am pretty proud of myself :wink:

Thanks for taking the time to look at it.

Regards,

Frank

[Pete Dowson]

I'll look at increasing the value in metres just a tad, see if that helps.

No, please don't.

Ahtoo late. After experimenting with different values via FSInterrogate, I found that adding 256 to the value (which is in 1/65536's of a metre) did the trick, without messing up the good values. 256 is equivalent to 0.0039 metres (i.e. 1/256th).

The result is PFC DLL version 1.831 which is being released as I write this -- I have sent a copy of the DLL (only) to yuo (too big to attach here).

BTW I've sorted it out on my own. Had a look at the XML code for the respective gauges on the 747 and found it pretty easy to make my own altitude pre selector. It's just a display of the values set and uses the same bitmap as in the Caravan but that's all I need and it works like a charm :) .

Took me about two hours and was very funny without any knowledge about XML :lol: .

I am pretty proud of myself :wink:

I am not surprised, you ought to be! I've had a brief glance at XML from time to time and can't make head nor tail of it! Looks nothing like any sort of programming language I've ever used and doesn't look something I'd want to mess with! :) :o :? :?

Regards,

Pete

[Frank.O]

The result is PFC DLL version 1.831 which is being released as I write this -- I have sent a copy of the DLL (only) to yuo (too big to attach here).

It has arrived, thanks a lot.

Frank