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I'm writing a driver for a QMC5883L triple-axis magnetometer and in the datasheet it specifies "Full Scale" as a configurable parameter which can either be 2G or 8G. I've seen this on other datasheets as well.

What is the unit "G" and what does full scale actually mean in the context of a magnetometer? This is not covered in the datasheet and google isn't any help.

Thank you for your time.

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  • \$\begingroup\$ G is gauss, and 'full-scale' is the limiting value that can be measured. \$\endgroup\$
    – jayben
    Commented Aug 13, 2022 at 15:59

2 Answers 2

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Since it is a magnetometer, one would expect G to stand for Gauss, a unit of magnetic field strength. The sensor can be configured so that either an external field of 2 Gauss or 8 Gauss corresponds to the maximum output of the sensor. This enables the user to have a tradeoff between the maximum field strength that can measured and resolution of the measurement.

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  • \$\begingroup\$ Ahhh, yes. The convoluted units of magnetics. \$\endgroup\$
    – DKNguyen
    Commented Aug 13, 2022 at 16:03
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Full scale is simply the maximum range the sensor can measure. Its configurable so that you can either get a bigger range of output , or a more sensitive one. If you only want to measure accelerations below 2G , the 2G full scale will give you better resolution, but will clip above 2G.

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  • \$\begingroup\$ The question also asks what the unit G is, so you might want to mention that to fully answer it. \$\endgroup\$
    – Hearth
    Commented Aug 13, 2022 at 15:51
  • \$\begingroup\$ the question was about a magnetometer, so it's likely to measure all accelerations as 0. \$\endgroup\$
    – Neil_UK
    Commented Aug 13, 2022 at 17:41

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