VSS resetting to 0

[tobmag]

And just continuing here with the same thing at 1300hz, here its even worse and here there is no difference when I put the probe at the VR1 pin at the 25pin header.

[tobmag]

and here is the .msq

[Bernard Fife]

tobmag,

Do you get a clean speedo if you use the default values with your function generator?

What speeds do 500 Hz and 1300 Hz represent with your VSS settings (tire diam., axle ratio, number of VSS teeth)?

What happens if you move smoothly from one frequency to another, rather than using fixed frequencies with big jumps?

Do you have logs, rather than screen shots of log? Actual logs are always preferable, as screen shots general don't give key information.

Lance.

[Bernard Fife]

Whoops, I just found the link for the datalog in the previous post. Sorry for missing that!

It definitely looks like something is either rolling over or resetting in the speedo.

Lance.

[Bernard Fife]

tobmag,

When the speedo resets, the Error value jumps from 67 to 91. These are:

67 = 64 + 2 + 1, which is the bit pattern for low voltage, no CAN comms, and serial comms okay

91 = 64 + 16 + 8 + 2 + 1, which is the bit pattern for low voltage, other VSS error, VSS reset, no CAN comms, and serial comms okay.

Ignoring the other errors, the differences are other VSS error and VSS reset. The VSS will go to an error state if the number of 'false' teeth exceeds the user specified value (Max. Errors to Reset; http://www.msgpio.com/manuals/mshift/V41tune.html#gv )

So the speedo pattern you are seeing is a symptom of another problem (teeth being skipped, or teeth being added between legitimate teeth), not the cause. Either the filtering is not right for the signal, or the signal is unusable, or the combination of settings is outside the calculation range at some point in the code. I will check the last item here when I get chance. You should check the speedo using the default VSS settings - these worked fine last time I checked, and should be a good starting point for checking your bench setup.

Lance.

[tobmag]

Lance.

What do you mean with standard settings on the function generator?
I did set the ppv to about 5V since thats the reading I got in the car in D and engine at idle....

Well with the filter settings Im using the speedo is quite sluggish,
The function generator will only give me 50hz increments, the funny thing is that if I do like a run 0 to 100km/h in 15 sec its really sluggish....I can increase/decrease the hz but I need to do like stop for 2-3 sec to make it realise its a change in speed going on....I can do some runs tomorrow and log for you to see

Br//Tobmag

[tobmag]

Lance,

Which default settings?

Did you look at my .msq?

Br//Tobmag

[Bernard Fife]

tobmag,

The way the filtering works is that it only lets the speedo go up or down smoothly. Sudden jumps in the VSS signal will always cause tooth errors/resets/sluggish responses, and all sorts of other issues. Of course, in the car, the speed jumps are always smooth (even if the tires break loose, this would still be 'smooth' to the code). So what you are seeing may be an artifact of your test setup. My function generator lets me adjust the VSS in a continuous manner (over a 15x range), and I don't see the issues you are seeing. So you issues may go away once you start testing on the vehicle.

By defaults, I mean the code defaults. That is, load new code, don't change any settings, and see how the speedo responds to the VSS input on your bench.

I have looked at your log, but not your MSQ yet.

Lance.

[tobmag]

By defaults, I mean the code defaults. That is, load new code, don't change any settings, and see how the speedo responds to the VSS input on your bench.

That is loading the code, using the aproriate .ini and also the default .msq, not my own?

Reason behind the testing is that I had a lot of noice in the car below 500hz, did try with resistor in the vss line but no change.
So I will now change the bias since I have about 6V peak to peak at 150 Hz so the default rigger level of 0,7V seems very low.

Dont know if I was clear with the 500hz issue, The thing is that I have a terrible noice locking at the TS log but as soon as I put the scope probe on the VR1 pin at the 25pin header it stops and I get a clear signal in TS, so what you see in the log is > noice > clear signal > noice.....that is me putting/removing the probe.....

BR//Tobmag

[gui67]

Hello Tobmag,

It seems you have the problem at the same OS as me: approx 1900RPM (with 40 teeth, 1300Hz = 1950 RPM OS speed)

Do you have the same problem with the IS or only the OS?
for me the IS is clean when I look at the logs. but I always have that VSS ressetting to 0 at 65km/h.