Instrument data polling rate

[Hemsk]

Hi Pete!

I have a problem with a homebuilt manifold pressure gauge using a RC-servo pluged into Opencokpits servocard.

The gauge moves to it´s correct position, but it moves jerky.

Not with a smooth movement.

I have the exact same problem when I connect my homebuilt manifold pressure gauge to my Simkits interface card.

Simkits also use FSUIPC to read and write data to and from MS flightsimulator.

Are all microsoft flightsimulator instrument values read by FSUIPC updated at same rates?

Are the instrument values inside MS flightsimulator calculated at same rates? Or do some instruments have priority over others?

I have a wild idea that the value for manifold pressure provided in offset Offset 08C0 through FSUIPC is updated at a too low speed.

Can you do something in FSUIPC to improve the data rate coming out if it is that whitch is causing my problem?

I have tryed several servos. No mechanical problem.

I use a powered USB hub for my Simkits interface card, to avoid voltage drop to my servos.

As suggested by Simkits.

[Pete Dowson]

I have a problem with a homebuilt manifold pressure gauge using a RC-servo pluged into Opencokpits servocard. The gauge moves to it´s correct position, but it moves jerky.

Not with a smooth movement.

I have the exact same problem when I connect my homebuilt manifold pressure gauge to my Simkits interface card. Simkits also use FSUIPC to read and write data to and from MS flightsimulator.

Are all microsoft flightsimulator instrument values read by FSUIPC updated at same rates?

No. If you are talking about FS2004 or before, there are priorities, to avoid affecting FS performance.

Are the instrument values inside MS flightsimulator calculated at same rates? Or do some instruments have priority over others?

No, I think they are mostly the same. But even FS's own gauges are a little jerky. If you enlarge them you can see this. They get away with it because they are normally too small to notice. Programs like Project Magenta, and well-programmed add-on aircraft, tend to use their own smoothing (interpolation) to make the displayed gauge values change nice and smoothly.

I have a wild idea that the value for manifold pressure provided in offset Offset 08C0 through FSUIPC is updated at a too low speed.

Well, I can check to see if it is one of the lower priority items.

Can you do something in FSUIPC to improve the data rate coming out if it is that whitch is causing my problem?

I have just had a look. The Manifold Pressure values are part of a large group updated at a second (not top) priority, which rates it at a little over 4 updates per second -- a quarter of the normal update rate (18.2 per second).

FSUIPC has had this rate built in for these values for its whole life, 8 years now. Odd that itr should only now be seen as a problem?

Anyway, seeing as PCs are several times more powerful now than they were 8 years ago, I guess I could relax some of those timings. Are there any others whilst I'm at it?

Regards

Pete

[Pete Dowson]

Anyway, seeing as PCs are several times more powerful now than they were 8 years ago, I guess I could relax some of those timings. Are there any others whilst I'm at it?

Try version 3.761, from here:

http://fsuipc.simflight.com/beta/FSUIPC3761.zip

Let me know. It can't get those values any faster.

Regards

Pete

[Hemsk]

Thanks Pete!

Wow you are fast!

Well on Opencockpits forum I found 2 people with the same problem as I have with RC-servo instruments and jerky movement of the needle.

One who is building a manifold pressure instrument, like me.

And a fellow, who built a flap gauge, and a speedbrake movement, what ever that is?

So ill make a few trials with the old FSUIPC first to see if there are more gauges that behaves jerky, and then I´ll let you known as soon as possible.

The reason why it´s only now begun to be a problem is that the RC-servo card at Opencockpits haven´t been around for so long. Its relatively new, and people haven´t used it much yet I guess. Or it´s been used for other instruments or functions that aren´t affected by this jerky movement behaviour.

[Hemsk]

Hi Pete!

Just wanted to say we successfully programmed the Manifold pressure gauge and RPM gauge.

We used the FSUIPC V. 3761 you provided, and it works great, The RC-servos move very much smoother than before.

Totally acceptable.

I havent been able to test if other instruments behave jerky as I promised to do.

Maybe someone else can inform us of problems they are havin with RC-servo instruments using SIMKITS or Opencockpits IOcards here?

[awhitlock]

FSUIPC beta v3.761 download link shown by Peter earlier, seems no longer to be valid.

Can anyone make available to me a copy of beta v3.761 ??

thanks and regards

Alan

[Thomas Richter]

FSUIPC beta v3.761 download link shown by Peter earlier, seems no longer to be valid.

Can anyone make available to me a copy of beta v3.761 ??

thanks and regards

Alan

Hi

Just download the latest v3.766

http://fsuipc.simflight.com/beta/FSUIPC3766.zip

[awhitlock]

Thank you

Alan

[awhitlock]

Thanks to Hemsk and EW321 for helping with beta files.

For everyones information I loaded FSUIPC3766 on my system and confirm that the smoothness of Simkits servo Manifold Press and RPM gauges are much improved. Fantastic.

:D :D

regards

Alan

[dimon2kgb]

Oh, i have this problem too. The pointer of my flaps gauge don't move smoothy, but jerky. Should I rewrite my SIOC, or there is a promlem with gettings data from MSFX? :)

Video: http://www.youtube.com/watch?v=MQEi-hcVCx4 - Video!

[dimon2kgb]

Just does the 4.30 FSUIPC version have enough resolution for servo gauges? I can't make it work in the right way. :(

[Pete Dowson]

Just does the 4.30 FSUIPC version have enough resolution for servo gauges? I can't make it work in the right way. :(

4.30 is out of date. The current version is 4.40.

When you ask about resolution you need to state which quantity you are talking about else I cannot possibly answer.

Regards

Pete

[dimon2kgb]

Oh, of course, sorry, just i've forgotten about it. :) I'm using Offset $0BE0 for Flaps indication and servo flaps indicator from OC with 10bit resolution.

P.S. Maybe 4.40 version can help me? :)

[Pete Dowson]

Oh, of course, sorry, just i've forgotten about it. :) I'm using Offset $0BE0 for Flaps indication and servo flaps indicator from OC with 10bit resolution.

0BE0 is merely a copy of the SimConnect variable "TRAILING EDGE FLAPS LEFT PERCENT", scaled to scaled to the FS98-compatible 0 to 16384 range.

So, its potential resolution is 1 in 16384 for full flaps. That's 14 bit. Of course you won't be able to read it fast enough to get every possible value, and nor will FSUIPC receive every possible value because of the asynchronous data passing mechanism used by SimConnect. However, you should be able to read it often enough to give smooth enough values, and if you are driving servos the motion needs of the mechanism itself will surely interpolate the parts between.

If you want to observe the values it is providing simply go to FSUIPC's Logging page, put 0BE0 in the first Offset slot on the right-hand sde, select type "U16", then check the "FS Window" option below. You will get a real-time readout on FSX's screen.

P.S. Maybe 4.40 version can help me? :)

There's no difference in offset 0BE0 in any version of FSUIPC4. I don't think FSX's SimConnect changed it in either of the SP1 or SP2 updates, and it is merely a read-out from the Sim's own value (from the Sim1.DLL engine).

I only mentioned you were out of date because I do not support old versions.

Regards

Pete