Add-On and voltmeter

markok

I tried use Shelly Add-On voltmeter option, but it doesn't work correctly. I tried measure 4 VDC supply and wires was connected to Add-On analog input and GND connections. Shelly app shows voltage changing between 3,1 - 4.6V althought supply voltage doesn't change. What could be wrong? I have connected to same Add-On five ds18b20 temperature sensors.

thgoebel

Please turn off ECO mode! And yes - the linearity of the on-board V-f converter isn’t very good! You should not expect 14 bit precision like an ADC chip would deliver…

markok

Thank you for the quick reply. I try tomorrow turn eco mode off. Now it is turned on. Would Shelly UNI be better product to measuring voltage? I think that Shelly UNI has this ADC chip, but I am not sure?

thgoebel

Yes, the ADC of Shelly UNI and UNI plus is much better! It uses the internal ADC of the ESP processors

markok

Zitat von thgoebel

Please turn off ECO mode!

This was a good hint, thank you. I turned Eco mode off and now voltage measuring works well.