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Products => Test Equipment => Topic started by: RoboTechEd on April 21, 2015, 03:22:02 am

Title: Lab Calibration Results
Post by: RoboTechEd on April 21, 2015, 03:22:02 am
Hi All,

In another thread I mentioned getting in a DMMCheck Plus to calibrate all of my test gear (link (https://www.eevblog.com/forum/testgear/best-equipment-calibration-practices/msg656464/#msg656464l)). I got it in today, and measured all of my test equipment to see what was within spec and what wasn't. I have compiled the data below in a google doc spreadsheet. I figured I'd share it here because everyone loves more data   :-/O

Interesting Findings:
-My $10 pocket multimeter is one of my most accurate
-The old Fluke-8012A is still well within spec (incredible considering the age)
-All meters seemed to struggle most with the lowest resistance/AC Voltage/Current

Next step: Calibration!

Feel free to chime in with suggestions/critiques.

https://docs.google.com/spreadsheets/d/1iuMLSG44whJUPThB31mjJ63v_EDOB1AnHA3-22toGvg (https://docs.google.com/spreadsheets/d/1iuMLSG44whJUPThB31mjJ63v_EDOB1AnHA3-22toGvg)
Title: Re: Lab Calibration Results
Post by: ElectroNub on April 21, 2015, 04:04:26 am
pictures or it didn't happen!
Title: Re: Lab Calibration Results
Post by: Dave on April 21, 2015, 04:08:16 am
Variance and error are two entirely different things. ::)

Measuring a square wave with a non-RMS meter will not yield the correct result. If you want to see the actual measurement error, you need a sine wave.
Title: Re: Lab Calibration Results
Post by: RoboTechEd on April 21, 2015, 04:43:13 am
Quote from: Dave on April 21, 2015, 04:08:16 am
Variance and error are two entirely different things. ::)

Measuring a square wave with a non-RMS meter will not yield the correct result. If you want to see the actual measurement error, you need a sine wave.

You are correct. I updated the spreadsheet. oops! Also, All of the meters were RMS meters luckily, besides the Knight DMM. I highlighted those results red to imply to look at the notes. I do think 5.55v is an accurate reading though for a 5vpeak square wave. I just checked on the DMMCheck site, and they confirmed that. Also, it was surprising that so many of my cheap meters were RMS!

Quote from: ElectroNub on April 21, 2015, 04:04:26 am
pictures or it didn't happen!

Whatya want pics of? The results? I guess I could have made the data up without photographing the equipment's screens....Guess we'll never know :P