Electrical – Accuracy error of ammeter from specification : is it really just a constant offset


On ammeter specifications it is often written accuracy specification
$$ (….\% rdg+ … digits) $$

While the ammeter can have a certain last digit on the screen, which determine the resolution if the instrument

My question is : is the error expressed in the specification really just an offset (i.e. a constant shift on the current) for all the measurements made with the ammeter?

In other words is it just a systematic error?

Or is it actually something more than just an offset?

I mean, if it was just a constant offset, then its value could be provided to correct all measurements and there would not be need of this error at all!

Best Answer

You can not assume anything more about the error than what the datasheet tells you. So no, it is incorrect to assume that all the error is a offset, and that this offset is the same over the whole measurement range. You don't get to make up your own specs.