A2 analog voltage sensor limit

[rcyoda]

I connected 12S battery pack to the A2 sensor of X4R receiver, of course via some resistor voltage divider, to get max 3.3V corresponding to 50.4V of the pack. Easy so far.

But seems there is a limit in the OpenTX, so it can only read voltage up to 19.9V on A2 sensor.

Am I right? If so, how to overcome this limitation?

[Kilrah]

We don't know what radio, what OpenTX version... but you should be able to adjust the Ratio setting appropriately.

[rcyoda]

Sorry. Horus X12S, OpenTX 2.2.2

Whatever I setup as a ratio, over 19.9V (after the ratio) it seems it switches to 1:1 mode, not doing proportional calculations.

[rcyoda]

I also checked with standard FBVS-01 with 5S voltage. I calibrated it so it shows proper voltage, but still you cannot get over 19.9V.

[rcyoda]

Similar effect is even visible in the Companion sim, for X9D:




Above is OK. But look what happens if I increase the source voltage, even by 0.1V:




The voltage of the sensor is not going above 19.0V (sorry, I may mismatched the limit - seems it is 19.0V, not 19.9V).

It goes down though:

[rcyoda]

Is this possible that limit is set for 19.0V in the software?

(sorry for multiple posting, had issues with images)

[Kilrah]

Works fine for me.

[rcyoda]

Thanks Kilrah for checking it out.

I cannot replicate it any more as well. Must have been some brain black-out or it was simply too late... Next time will go to sleep instead of trying to debug the problem in the middle of the night.