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Vehicle Speed resolution problem

PostPosted: Thu Mar 23, 2023 1:28 am
by HMeier
Hello,
i have a problem with the vehicle speed via CAN with MoTeC C187.
When i drive 0 to 10 km/h the MoTeC shows 0,
When i drive over 10 and under 20, it shows 10.
When i drive over 20 and under 30, its shows 20.
Base Resolution is 1.
Is there a resolution Problem? Or maybe i should edit the vehicle speed Channel output lenght? Or other parameters change?
Is there a solution to show the exact and correct speed?
Best regards

Re: Vehicle Speed resolution problem

PostPosted: Thu Mar 23, 2023 8:46 am
by Stephen Dean
Hi,

It sounds like a scaling issue. What is the device that is sending the data transmitting? Can you do a CAN log of the signals and see what the actual CAN data shows?

Re: Vehicle Speed resolution problem

PostPosted: Fri Mar 24, 2023 1:36 am
by HMeier
Hey,
thanks for your answer.
The problem is partially solved. The vehicle speed is displayed not exact correct. I have a littel deviation. When i drive 20 kmh in the cockpit, the MoTeC shows 23 kmh. The deviation gets bigger if i drive higher velocities.
Here is the Channel.
speedABS.png
speedABS.png (30.88 KiB) Viewed 2642 times


I try some other settings with the divisor an multiplier. If i set multiplier an divisor on 1, the MoTeC shows higher deviation velocities (10kmh in the cockpit = 26 on MoTeC)
Is there a easy solution to get the speed like in the cockpit with no deviation?
Best regards

Re: Vehicle Speed resolution problem

PostPosted: Fri Mar 24, 2023 4:57 pm
by NathanB
Assuming your CAN address information and other settings are all correct, and it is just the scaling factor that is incorrect, The easiest way to work out a potential scaling correcting would be to give more than 1 data point with the same settings.

10 km/h (OE) with 26 km/h (MoTeC) with M-1 D-1 A-0 would mean the CAN value was 260
20 km/h (OE) with 23 km/h (MoTeC) with M-5 D-8 A-0 would mean the CAN value was 368

That doesn't correlate in any way I can work out. It appears an adder is required.

Realistically a CAN log is required to determine any information. The MoTeC dash can do this with our CAN Inspector tool.