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Couple of questions regarding Mission Planner.

Posted by Doug on April 24, 2016 at 2:44pm

 These are accuracy questions really.

First -  Voltage readout. Am using a 3DR pixhawk (genuine) with the 3DR power module.
Testing a 4000mAh 11.1V battery I'm reading 12.61V with a digital multi-meter, and Mission Planner is showing me 12.49V 99% charged.

A difference of 0.12V. My question is - is this within acceptable tolerance? Should I be concerned about that small of a difference and try to adjust the compensation to have it match the multi-meter reading?

Second -  when the quad is sat stationary  I will get readings on things like ground speed ( I don't have an airspeed sensor installed), vertical speed etc. in the 0.X range and they flicker and fluctuate slightly. Again is this something I need to be concerned about or is it just slight variances in the GPS and compass readings?

Advice would be great, thanks.

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Tags: 3dr, module, voltage, power, readout
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Replies

  • iskess April 24, 2016 at 7:16pm
    The accuracy of the voltage sensor is terrible. The problem is that the software assumes linearity but the voltage is more of a curve. Match up the voltage and current at hover or cruise throttle, and the end result will be fairly accurate. At max and min throttle it will always be way off.
  • Moderator
    Dwgsparky April 24, 2016 at 3:25pm
    It is always possible your multimeter is slightly out, a 2% error is normal.
    • Doug > Dwgsparky April 24, 2016 at 3:45pm

       A 2% error on the multimeter or MP?

      And, ya, it's definitely possible the MM could be off whack too.

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