EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: mrrrwhat on February 08, 2017, 02:14:58 pm
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Gossen metrahit ultra
Fluke 289
Hioki dt4282
Keysign 1282a
Which one have the highest precision?
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DT4282
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DT4282
Errr.. no it's not..
Gossen Ultra has both best basic accuracy (0.02%) and resolution (310000 mode)
But it is not important..
All those are very good handheld multimeters, but, if you want best accuracy you want benchtop multimeter, not a handheld.
And for price of Gossen or Fluke you can also buy a good benchtop, even entry level 6.5 digit meter, that will be better than any of them..
If you need portable, any of them is more than good enough...
It's all about what you need it for.
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Which one have the highest precision?
Remember, he's asking about precision - not accuracy.
Fluke - Accuracy, resolution, range, counts, digits and precision (http://en-us.fluke.com/training/training-library/test-tools/digital-multimeters/accuracy-resolution-range-counts-digits-and-precision.html)
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Precision is not a spec manufacturers take into consideration.
Resolution and accuracy are.
In Fluke's case, accuracy specifications provide a 99.7% certainty that any sample will fall within the 2.6 mean deviation of the distribution, for one year after calibration. A meter warm up time should also be respected for components to stabilize.
Precision is probably difficult to characterized, as it may vary from one meter to the other and has too many error variables.
I would argue that a meter with high accuracy is inherently precise, as any offset is taken care of in calibration.
http://support.fluke.com/calibration-sales/Download/Asset/2547797_6200_ENG_A_W.PDF (http://support.fluke.com/calibration-sales/Download/Asset/2547797_6200_ENG_A_W.PDF)
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0ahUKEwj2w_6prYLSAhUELsAKHV84C5IQFggfMAE&url=http%3A%2F%2Fdownload.flukecal.com%2Fpub%2Fliterature%2Fdack_ncsl01.pdf&usg=AFQjCNGYUI1eLJa7i5h3nl5ZJsXCipSykA&sig2=g6ZQiZBbd9PFyTX01CfHJA&bvm=bv.146496531,d.d2s&cad=rjt (https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&ved=0ahUKEwj2w_6prYLSAhUELsAKHV84C5IQFggfMAE&url=http%3A%2F%2Fdownload.flukecal.com%2Fpub%2Fliterature%2Fdack_ncsl01.pdf&usg=AFQjCNGYUI1eLJa7i5h3nl5ZJsXCipSykA&sig2=g6ZQiZBbd9PFyTX01CfHJA&bvm=bv.146496531,d.d2s&cad=rjt)
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More info from a Tektronix document that seems to back up what I said :
Repeatability is often more important than absolute accuracy when making a series of measurements. You want the DMM to read the same value each time a measurement is made of exactly the same value. Repeatability is not usually specified directly but a limit is implied by the accuracy specification since it must always be within the specified accuracy. It may or may not be considerably better than the specified accuracy and can vary considerably from one DMM to another, even of the same manufacturer and model. Component aging, battery condition, temperature, and warm-up time may all effect repeatability to some degree. The only way to get a feel for a particular DMM's repeatability is to make a large number of measurements of a precision source under a variety of conditions. The source should have better than four times the rated accuracy of the DMM to be able to sort out repeatability and accuracy limitations.