Fluke 8520A reading drifts - diyAudio
Go Back   Home > Forums > Design & Build > Equipment & Tools

Equipment & Tools From test equipment to hand tools

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Reply
 
Thread Tools Search this Thread
Old 24th June 2012, 10:25 PM   #1
diyAudio Member
 
Join Date: Mar 2004
Location: Texas
Default Fluke 8520A reading drifts

I bought this 5 1/2 digit meter a few years ago and it is ok except that trying to read microvolts is impossible. For example, this afternoon it is drifting from .2 to .5 mV DC and won't "sit still" no matter what.

Could it be an A/D or D/A converter or ???
__________________
Any technology sufficiently advanced is indistinguishable from magic
  Reply With Quote
Old 24th June 2012, 10:33 PM   #2
DF96 is online now DF96  England
diyAudio Member
 
Join Date: May 2007
Microvolts AC can pick up hum fields. Microvolts DC can get thermoelectric or contact potential effects.
  Reply With Quote
Old 24th June 2012, 10:36 PM   #3
diyAudio Member
 
Join Date: Mar 2004
Location: Texas
Ok, so what method should I use aside from building a Faraday cage to combat the effects of hum from other sources?
__________________
Any technology sufficiently advanced is indistinguishable from magic
  Reply With Quote
Old 24th June 2012, 10:49 PM   #4
DF96 is online now DF96  England
diyAudio Member
 
Join Date: May 2007
For low level AC you need filtering, so the meter only sees the signals you are interested in. As well as hum there is also all the RF around in a typical location. 3 1/2 digits is good enough for most purposes, and don't believe any figures below a few mV.
  Reply With Quote
Old 16th July 2012, 08:41 PM   #5
lepomis is offline lepomis  United States
diyAudio Member
 
Join Date: Mar 2008
I have that same unit. I don't have a drift problem with either AC or DC. However, I have no idea if those last few digits are correct or not Does the unit pass it's 'self test' ?

Quote:
Originally Posted by johngalt47 View Post
I bought this 5 1/2 digit meter a few years ago and it is ok except that trying to read microvolts is impossible. For example, this afternoon it is drifting from .2 to .5 mV DC and won't "sit still" no matter what.

Could it be an A/D or D/A converter or ???
  Reply With Quote
Old 16th July 2012, 09:33 PM   #6
diyAudio Member
 
Join Date: Mar 2004
Location: Texas
I don't know...I've never run the self test. I will say that on lower value resistors it is rock solid.
__________________
Any technology sufficiently advanced is indistinguishable from magic
  Reply With Quote
Old 16th July 2012, 09:52 PM   #7
asmith is offline asmith  United States
diyAudio Member
 
Join Date: Sep 2011
I bet your in a high RF area, and thats what it's reading. Try shorting the inputs, right at the input and see what it reads.
  Reply With Quote

Reply


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
B+ Drifts down after 2 hours Anchan Tubes / Valves 12 5th December 2011 01:48 AM
Fluke 8502A? nania Parts 5 22nd May 2010 03:29 AM
Fluke 1900A jblmar Solid State 3 25th October 2007 06:50 PM
Get a Fluke DMM ThSpeakerDude88 Parts 107 21st August 2007 12:40 AM


New To Site? Need Help?

All times are GMT. The time now is 03:00 PM.


vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2014 DragonByte Technologies Ltd.
Copyright 1999-2014 diyAudio

Content Relevant URLs by vBSEO 3.3.2