Question: wrong read value

Question

Question: wrong read value

Closed this issue a year ago · 9 comments

lukasa1993 commented a year ago

hello, i was using this lib to read 24v battery voltage started using it 6 month ago and it was working perfectly 1:1 with my multimeter but not after sitting turned off in drawer it measures wrong value there is about 0.4 volt difference between adc reading and multimeter reading on same pin on adc ground any way it could have been ruined ?

Answer 1 · 2023-03-30T16:23:04.000Z

Hi, can't imagine it's broken. In such a case I would expect no response, arbitrary value or always the same. Difficult to say what's wrong when I don't have it on my desk. The first thing I would is checking all connections. Is there maybe a resistance on a line where shouldn't be any (due to a bad contact or so)?

Answer 2 · 2023-03-30T16:24:46.000Z

same difference for this particular value battery is stable right now so it doesn't fluctuate much only by 0.0001.

i checked connections and resistances all seems good + when i test same pin with multimeter value is exactly right but adc returns wrong

Answer 3 · 2023-03-30T17:00:53.000Z

No spontaneous idea at the moment to be honest. Can you try different input channels? Or: if you directly connect let's say AIN0 and AIN1 (or any other input channels) and you measure the differential voltage with the ADS1115, do you always get this difference?

Answer 4 · 2023-03-30T17:24:42.000Z

No spontaneous idea at the moment to be honest. Can you try different input channels? Or: if you directly connect let's say AIN0 and AIN1 (or any other input channels) and you measure the differential voltage with the ADS1115, do you always get this difference?

i need to do bunch of soldering to try other channels can there be single channel failure or something ? i was planning to do that but wanted to make sure there is nothing less destructive

Answer 5 · 2023-03-30T17:40:54.000Z

Connecting two channels directly is something you could do reversibly I think. Whatever the result is, it will of course not solved the issue, it might just give an idea what the issue could be.

Answer 6 · 2023-03-30T17:54:32.000Z

thank you and sorry for weird case :)

Answer 7 · 2023-03-30T17:57:43.000Z

No problem, I am happy to at least try to help. If you should find the problem I would still be interested to know what it was. Good luck!

Answer 8 · 2023-03-31T12:26:23.000Z

apparently ADC fails very weird way i replaced ads1115 board and all is good again

Answer 9 · 2023-03-31T12:31:17.000Z

Thanks for letting me know. Strange, indeed. I thought it would not be related with the ADS1115. Interesting learning.