Hi,
I’ve been trying to make sense of my diesel tank level.
I have a US tank probe 240 - 30 ohm, the cerbo shows that this is reading 127.6 ohms and makes that out to be 53%
I would have expected that to be nearer 40%
Thoughts please
Empty 240 Ohm
Full 30 Ohm
Total range 240 - 30 = 210 Ohm
current level range = 240 - 127.6 = 112.4 Ohm
Reading = 112.4 / 210 = 53.5%. QED.
A simple thought experiment, 127.6 Ohm is closer to 30 Ohm (full) than 240 Ohm (empty) so it should be above 50%.
Hi,
Yep, your maths is spot on.
I was working from a spreadsheet of real values that I measured from an identical probe.
The probe has 12 resistance steps, but the values for the first 2 steps from the bottom decrease by 50 ohms each, then the rest of the steps are around 12 ohms.
I think this is what is throwing out the reading, when I dip the tank it’s around 35 to 40% full.
If I had a high resistance joint then I would expect it to show less.
More investigation required, or bin it and get a more linear probe
Cheers