Response time

[VFRJON]

Ive been playing with FSUIPC using VB6 and modifying the SDK example. What I have noticed is that there seems to be a delay of anything up to a second before I see a change in my 'UIPCHello.exe' window.

For example if I display the active COM1 freq, and then hit the Stby Swap button on my radio panel, it takes a little whille for it to change form say 122.80 to 120.50 in my exe.

Is this normal, or would it be something in the code of the UIPCHello.exe that causes this?

Jon

[Pete Dowson]

Ive been playing with FSUIPC using VB6 and modifying the SDK example. What I have noticed is that there seems to be a delay of anything up to a second before I see a change in my 'UIPCHello.exe' window.

... Is this normal, or would it be something in the code of the UIPCHello.exe that causes this?

Jon

It is pretty well instantaneous herehave you used FSUIPC's extensive logging features to log the reads and writes (Monitor the offsets involved to the log as well) so you can see the timing relationships.

I really don't know how you've programmed you EXE -- if you scan the values you are reading every 2 seconds then you'd expect an average delay of 1 second. If you scan every millisecond then, apart from bringing FS to its knees you'd see it change faster, but put much more load on the system.

It also depends on FS frame rates. If FS is running at 30 fps, say, then most requests should be easily met in 33 mSecs (1/30th second), assuming your program is matching the frame rate and doing so without impinging upon performance.

Programs like Project Magenta's MCP perform many interactions with FS every second -- that part of the PM suite is an advanced autopilot and would not be able to control the aircraft properly unless the response was good. And it does control it, and very well, even over a WideFS network link in some folks' systems.

As you see, there are too many imponderables for me to judge timing from what you say. You'd need to research both what your program is doing and what FSUIPC is seeing -- the logging helps with the latter.

Regards,

Pete

[VFRJON]

Thanks Pete, I shall look at this a little more closely.

Id just like to say thanks for the great support you give for FSUIPC. While most of us only have 1 project on the go that we are trying to work out, you have to put up with our problems and then try and understand what we are trying to do so you can help us.

Good on ya!

Jon

[rickalty]

The Hello example app uses a timer event to trigger the process calls. What do you have the value for the timer set to? If that's too high, there will be a visible delay.

I found that if looking at the radio stack on the screen and my hardware stack side by side, a timer interval of more than 200ms is visually noticeable.

Since a MSFS frame rate of 20 fps is a timer delay of 50ms, there's not much point in going below that. I've found that 100ms seems to be a reasonable value.

Richard

[VFRJON]

Thanks Richard, I noticed that last night, and am expermenting with different settings.

Cheers

[VFRJON]

Yeap, Timer was set to 500ms.

Bringing that back to 100ms works great.

Thanks for that.

Jon