Attopilot 180A50V

186

01:35:26

I am working on a drone now and we want to implement a DC voltage and current sensing board to log the flight data onto a SD card. We have two attopilot 180A/50V to work with. The datasheet says that it will scale a 50V input down to a 3.3 V signal so ADC can be done to determine the respective levels on the battery and load.

The problem is that at no load conditions the sensing voltage is scaled down with a ratio of 4:1 instead of 15.7:1 as the datasheet says.
I dont know if it us the previous guy's soldering that may have made a short, but it is consistent over both boards we have. Does anyone have any experience on this?

published 8 years ago

BillyT

8 years ago

Tidying up the circuit seems to reveal a couple of anomalies, http://everycircuit.com/circuit/5734982410829824

boooooooom

8 years ago

Sorry yeah I was pasting it straight out of the datasheet! But still the problem in real life.. according to the simulations the voltage sensing is working accurately, but not in practice..

BillyT

8 years ago

The voltage sensing should be the point you have a trace on , with a resistor voltage devider how can you go wrong.

boooooooom

8 years ago

https://www.sparkfun.com/products/10644 it is a pcb circuit that is designed for this. Thats why I am confused by the fact that the voltage divider gives out the wrong value. Maybe it was bad soldering by the guy that used it prior to me? But according to the datasheet both of the circuits looks correct.

boooooooom

8 years ago

I figured the board had a different resistor in the voltage divider so I fixed that and it works 100%

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