[HOWTO] Debugging OBD Communication

[froggy47]

I set my accelerometer update rate to 100Hz. It shows up as 91Hz on the accelerometer display. At 20Hz, the filter time constant is too low for autocross, in my opinion. YMMV. If I get time, I'll put up some graphs to show the effect. I've got to prep the car for the Dixie National Tour event this weekend.

I would really like to see those, thanks you if you can post.

[froggy47]

Is there any downside to going higher than 30 Hz?

[Harry]

Yes, processing load / battery drain. 30 Hz is good for GPS update rates of 10 Hz and below. Some prefer higher resolution to get less smoothing, but for most, 30 Hz is fine.

- Harry

[froggy47]

Yes, processing load / battery drain. 30 Hz is good for GPS update rates of 10 Hz and below. Some prefer higher resolution to get less smoothing, but for most, 30 Hz is fine.

- Harry

Thanks Harry!

I just realized there are (in expert settings):

Accelerator tweaks update rate (mine is now 30)

AND

Sensor Delays (also in expert settings):

GPS 1.5
OBD 1.0
Accelerator 0.5

Those I believe are the default sensor delays, are they OK?

[Harry]

Yes, these are the default. Please don't change them. Video Synchronization / Video should be 1.0.

- Harry

P.S. None of these are related to OBD communication.

[froggy47]

Yes, these are the default. Please don't change them. Video Synchronization / Video should be 1.0.

- Harry

P.S. None of these are related to OBD communication.

Overlay Synchronization

Video 0.0-9.0s
This preference's current value: "0.5"

I HAVE NEVER TOUCHED THIS.

[Harry]

Yes, sure

[gplracerx]

30Hz is fine for track use. In autocross, the time constants for direction changes are much shorter than on a race track and need a correspondingly smaller time constant filter. The filter time constant is proportional to the sampling time constant. A higher sampling rate gives a smaller time constant.

[froggy47]

30Hz is fine for track use. In autocross, the time constants for direction changes are much shorter than on a race track and need a correspondingly smaller time constant filter. The filter time constant is proportional to the sampling time constant. A higher sampling rate gives a smaller time constant.

Trying 100.

[froggy47]

Yes, sure

Haha, really I never touched it, should it be 1.0? I don't even know what it does.