RaceCapture app Timer Speed relationship to clock divider?

GTIspirit · Post by **GTIspirit** » Sun May 31, 2015 8:40 pm

I finally upgraded to the RaceCapture app so I've got to go through the whole configuration setup.

Timer Speed is now Slow / Medium / Fast

What is the relationship to the previous "Clock Divider" setting? Is Slow == Clock / 128?

Mash · Post by **Mash** » Sun Jan 31, 2016 11:55 am

Same question - I don't understand a math behind Timer Speed...

Post by **brentp** » Fri Feb 05, 2016 5:08 pm

Hi - That parameter isn't well documented, sorry. It basically describes the resolution of the timer. Since it measures the pulse by counting the amount of time between pulses, then transforming that into RPM / uSec / etc, we have different settings for different types of signals.

A faster timer will be able to handle faster pulses / frequency ranges
Medium is best for RPM signals where pulses arrive within about 10ms
Slow is for slower signals.

And yes, it was the same as the divider setting in MK1; we renamed it to be a little more friendly.

What I would do is start with Medium (the default) and see if you get stable readings with the signal you're working with.

We'll work to get this documented, preferably within the app via help. Thanks!

Mash · Post by **Mash** » Fri Feb 05, 2016 5:46 pm

Thank you, Brent.

I'm dealing here with Borg Warner turbine wheel speed sensor. It makes nice square 50% 0-5v pulses (osc verified) at frequencies up to 4500Hz. So I'm using fast mode while turbo is at idle and numbers it shows make no sense. At this time osc shows 100hz and rpm shows nothing like that...

Maybe just change names to the frequency limits? Like Fast (>1000hz). I am still not sure which one should be used at what exactly condition.

Post by **brentp** » Fri Feb 05, 2016 5:47 pm

Hi Mash,

Thanks. So up to 4500Hz - I will simulate that here with a signal generator to see what it looks like. I'll follow up with some results.

Mash · Post by **Mash** » Fri Feb 05, 2016 6:02 pm

Thank you.

This is how it looks for me as well:

My particular compressor would choke above 4083Hz.

GTIspirit · Post by **GTIspirit** » Wed Feb 17, 2016 5:10 pm

Mash wrote:
Maybe just change names to the frequency limits? Like Fast (>1000hz). I am still not sure which one should be used at what exactly condition.

:thumbup:

Mash · Post by **Mash** » Wed Feb 17, 2016 7:07 pm

brentp wrote:Hi Mash,

Thanks. So up to 4500Hz - I will simulate that here with a signal generator to see what it looks like. I'll follow up with some results.

Any news?

Post by **brentp** » Thu Feb 18, 2016 2:08 am

Yes. Re-created the setup using a 5v square wave and a sweep of frequencies.

Observed accurate results using the settings: Medium / frequency / 1 pulse per revolution. Video demo:

https://www.youtube.com/watch?v=tX9ALqI26WU

If you can, please try re-creating what you see here in the video. Stick with the medium speed: Fast was yielding a measured frequency that's 1/2 of actual; slow is yielding a measured value that's off by a factor of 10. Will log a bug to fix targeting 2.8.8.

Thanks,