Autosport Labs

I'm trying to connect an AnalogX to measure the load on each corner using shock load donuts. On the workbench I connected the AnalogX to a RaceCapture Pro2 and connected a load cell amp to the AnalogX analog input 1 (blue wire). I have a voltmeter on the load cell amp output and it reads a steady 0.09V with no load and goes up when I lean on the load cell. However, when I watch the CAN channel in RaceCapture it varies a lot and does not track the input voltage.
Here is my setup in RaceCapture:
Can Bus: On
Can ID: 935444, offset 0, length 2, unsigned, mask 0, little endian, non-bitmode, 10 Hz
Formula: *1.0 / 1.0 -0.09
I set the precision to 2 with a min/max of 0/5 V.
I'm seeing values of 40 to 200, and no correlation to what is happening at the input. This is above the max value of 5V also.

Any ideas on what I should look at next?

Thanks!

Doug

I decided I was making this too complicated to start out, so I removed the load cell and load cell amp and replaced them with a potentiometer connected between the 5V and ground on the analog input side of the AnalogX, with the wiper going to the channel 1 input. I put a voltmeter on the pot and was able to watch the voltage go from 0.00 to 5.05 volts as I adjusted it. I set it at 4.12 volts on my voltmeter and left it there.

I changed the formula in RaceCapture to be x 1.0 / 1000 + 0.0 because I realized the units the AnalogX was sending were millivolts.

With the voltage at the input a steady 4.12 volts I could watch the RaceCapture channel vary from 3.07 volts up to 4.34 and back down, somewhat randomly, but it would not hold steady. Suspecting noise I put an oscilloscope on the input signal - it was clean.

Still struggling with this... anyone have any ideas?

Doug

Hi Doug, is this related to the other topic where you suspect the data offset was wrong? Is this still an issue?

Brent,

I think this issue is related to the other one I posted about the input order being reversed. When I changed the input offset (or when I changed which analog wire I connected my input to) the data displayed in RaceCapture tracked that on my voltmeter much more closely. That said, there is another issue I opened under the bug report section of RaceCapture - I cannot select offsets greater than 5 from the CAN channel mapping menu - they are off the bottom of the dialog , not visible, and cannot be made selectable. So, this particular issue about shock load should probably be replaced with the other ones.

Doug

Thanks, it's what I figured. I see you also resolved the CAN mapping issue in the other thread, too.