question

dunnp avatar image
dunnp asked

Tank sensor calibration

There have been several questions over many months about setting up non-standard tank sensor resistance values in Venus devices on these pages - but no real answers!!

Like quite a few others, I have a couple of tank senders that don't conform to the 0-180 or 240-33 ohm settings available in Venus. Mine are roughly 8-110 ohms.

It would be nice if the OS/GUI gave the ability to 'calibrate' the readings like it does with temperature sensors - eg adjustable scale and offset on the remote console.

But failing that, could someone within Victron tell me (and this community) where/how these resistance values can be tweaked in code? They are obviously defined somewhere but endless searching hasn't located them. One post mentioned a couple of lines of code defining the max/min resistance and the 680ohm series resistor - but I'm unable to locate it in my device. Maybe that was in compiled code somewhere??

I know I could fiddle resistor values on the ADC input to fudge approximate readings but that is nor practical with a real GX device (I'm using a RPi but still rather not be soldering resistors). It would be so much nicer to make the adjustments in code.

If this can be solved - ie get reasonably accurate tank readings from different senders - it opens up some neat possibilities for me. Example - automating a transfer pump in my caravan. And maybe other cool stuff.

Any guidance appreciated.

Phil

Venus OS
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1 Answer
mvader (Victron Energy) avatar image
mvader (Victron Energy) answered ·

Hey @dunnp, good news, I think your request came in right at the good time and its being made now. If all goes well, you should see it in a v2.60 beta version soon enough.

Then next, we'll also be adding an option to calibrate for non linear tanks: https://github.com/victronenergy/venus/issues/604 .




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dunnp avatar image dunnp commented ·

Great news - look forward to testing it.

Phil

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Mark avatar image Mark dunnp commented ·

Hi Phil

Have you tested yet?

I just installed the test V2.60~9 and noticed the custom setting for tank resistance. I appreciate its a test version so as feed back, although the custom is in the menu it wont let you select it? I also noticed that in the I/O menu Analog inputs sub menu is not populated?

I've added the Dbus-ADC files and the relay files in the delegates folder to active the 4 relays and the temp / tank inputs.


Thanks

Mark

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jeroen avatar image jeroen ♦ Mark commented ·

Which device are you testing? You should get this:



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1583610904683.png (23.8 KiB)
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dunnp avatar image dunnp Mark commented ·

I’ll give this a try tomorrow. Thanks for the heads up on the test build. I didn’t think to check there.

Phil

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