rFactor2 FFB output - technical analysis

Discussion in 'General Discussion' started by Pax, Oct 31, 2012.

  1. DrR1pper

    DrR1pper Registered

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    Good theory
     
  2. TechAde

    TechAde Registered

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    Well, it's a theory, not sure I'd call it a good one though! :D
     
  3. TechAde

    TechAde Registered

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    Here's a few more plots, this time of a longer data set (3 minutes or so @ Brianza in the BT20) with the default smoothing level of 9.

    Interestingly this shows something in the timing that the earlier plots didn't - the consistent spiking in the timing. The bottom plot is zoomed in to one of the spiky areas of the middle timing plot.

    Edit: Yes, I spun off into the grass at the end!
     
  4. Pax

    Pax Registered

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    Nice one Ade!

    If you like this, have you seen the other technical analysis I did on rF2 which I posted here just a few days ago? It should be right up you wheel house!

    http://isiforums.net/f/showthread.php/14482-rFactor2-FFB-Technical-Analysis

    Also, I'm too slow; I was about to ask you if the plugin is called at full 400 Hz rate, but apparently it is.

    On the FFB command timing variation, I can confirm that is seen also in the FFB controller, check the linked thread. On the observed integer ms, USB full speed operates at integer ms intervals for I/O data units, so with a full speed FFB controller you either have 2 or 3 ms for 400 Hz, which averages to exactly 2.5 ms over time (see the linked thread).

    If the Win USB driver stack for your wheel operates in a synchronous manner, you will see the same in the Win application code - in this case your plug in. What wheel are you testing with?

    BR,
     
  5. TechAde

    TechAde Registered

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    Ha, I actually thought I was posting in that other thread and got very confused when I couldn't see all your plots when I scrolled back up after posting. Now it all makes sense, there were two threads! :)

    That's very interesting about the synchronous operation, thanks. I'll go take another read of your other thread when I get a chance. :)

    I was testing with a G27.
     
  6. DrR1pper

    DrR1pper Registered

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    Told ya it was a good theory ;)
     
  7. Pax

    Pax Registered

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    Heh, no I should probably not have created a new thread for the latest analysis, but I did not think as far when reposting it here... :S

    I am pretty sure the G27 USB driver stack is asynchronous in operation, so the reason you see integer ms intervals I think is due to ISI. Somewhere they seem to use a a low resolution timer (i.e. integer ms only), which affects plug in timing.

    BR,
     

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