Author Topic: DMM Noise comparison testing project  (Read 215710 times)

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Offline OldNeurons

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Re: DMM Noise comparison testing project
« Reply #125 on: May 03, 2015, 02:56:27 pm »

Where the hell did you mention that? It seems I've been comparing apples and oranges :palm:

Right then, I will try doing some measurements on the 100 mV, and probably 1 V, ranges.

DMM main settings are indicated on the X axis graph.
 

Offline 6thimage

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Re: DMM Noise comparison testing project
« Reply #126 on: May 03, 2015, 03:05:33 pm »
It shouldn't make any difference, but the rear terminals are closer to the fan so their temperature rate of change might be different. If we are trying to do accurate comparisons, we need to have setups that are as close as possible.

On a separate note - I have just added another python script to my dropbox folder above that will read the internal temperature of the meter without putting it into remote mode, so you can use it whilst other remote scripts are running or whilst you are controlling it from the front panel. It turns out that the 3446xA series have two network ports they answer on - 5025 is the standard sockets port, which will put the meter into remote on almost all commands, but there is also 5042 which is the web port - it is what the java interface uses and has exactly the same SCPI interface. The only exception is that you cannot change any of the meter's settings without putting it into remote mode first (via diag:remote).
 

Offline 6thimage

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Re: DMM Noise comparison testing project
« Reply #127 on: May 03, 2015, 03:07:01 pm »

Where the hell did you mention that? It seems I've been comparing apples and oranges :palm:

Right then, I will try doing some measurements on the 100 mV, and probably 1 V, ranges.

DMM main settings are indicated on the X axis graph.

Yeah, in a nice title ... I don't know how I missed that
 

Offline Galaxyrise

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Re: DMM Noise comparison testing project
« Reply #128 on: May 04, 2015, 05:00:27 am »
I finally repeated my Keithley 2000 measurements, this time without losing the data ;)  I also wrote a program to test the entire matrix of {100V, 10V, 1V, 0.1V} x {1 NPLC, 10 NPLC }.  I only attached the histogram from 10V, 10NPLC.  Not surprisingly, it's about 10x as noisy as Tin's 2001 and very similar to the 34461 data.

The data is a tsv.  The first column is reading number, the first row is range and the second row is nplc.
« Last Edit: May 04, 2015, 05:04:50 am by Galaxyrise »
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Offline OldNeurons

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Re: DMM Noise comparison testing project
« Reply #129 on: May 04, 2015, 04:51:28 pm »
Hi all,

Finally, it's there !
No… not the 'Beaujolais Nouveau', but my DMM noise data.  :clap:

I have been battling  :box: with temperature drifts, and finally decided to move the DMM in a guest bedroom, away from any heat source (including humans), stopped the fan, covered right and left sides of the DMM and let it warm up  until I get a stable temperature at 31°C +0 / +0.3 ... and collected data again!

I uploaded the files on TiN’s ftp server.

ftp://datashort@xdevs.com/OldNeurons/Noise_Data_04_05_2015/OldNeurons_RAW_01_344641A_10V_%200.02PLC.csv
ftp://datashort@xdevs.com/OldNeurons/Noise_Data_04_05_2015/OldNeurons_RAW_02_344641A_10V_%200.2PLC.csv
ftp://datashort@xdevs.com/OldNeurons/Noise_Data_04_05_2015/OldNeurons_RAW_03_344641A_10V_1PLC.csv
ftp://datashort@xdevs.com/OldNeurons/Noise_Data_04_05_2015/OldNeurons_RAW_04_344641A_10V_%2010PLC.csv
ftp://datashort@xdevs.com/OldNeurons/Noise_Data_04_05_2015/OldNeurons_RAW_05_344641A_10V_100PLC.csv
ftp://datashort@xdevs.com/OldNeurons/Noise_Data_04_05_2015/OldNeurons_RAW_06_344641A_1V_%200.02PLC.csv
ftp://datashort@xdevs.com/OldNeurons/Noise_Data_04_05_2015/OldNeurons_RAW_07_344641A_1V_%200.2PLC.csv
ftp://datashort@xdevs.com/OldNeurons/Noise_Data_04_05_2015/OldNeurons_RAW_08_344641A_1V_1PLC.csv
ftp://datashort@xdevs.com/OldNeurons/Noise_Data_04_05_2015/OldNeurons_RAW_09_344641A_1V_%2010PLC.csv
ftp://datashort@xdevs.com/OldNeurons/Noise_Data_04_05_2015/OldNeurons_RAW_10_344641A_1V_%20100PLC.csv
ftp://datashort@xdevs.com/OldNeurons/Noise_Data_04_05_2015/OldNeurons_RAW_11_344641A_0.1V_%200.02PLC.csv
ftp://datashort@xdevs.com/OldNeurons/Noise_Data_04_05_2015/OldNeurons_RAW_12_344641A_0.1V_%200.2PLC.csv
ftp://datashort@xdevs.com/OldNeurons/Noise_Data_04_05_2015/OldNeurons_RAW_13_344641A_0.1V_%201PLC.csv
ftp://datashort@xdevs.com/OldNeurons/Noise_Data_04_05_2015/OldNeurons_RAW_14_344641A_0.1V_%2010PLC.csv
ftp://datashort@xdevs.com/OldNeurons/Noise_Data_04_05_2015/OldNeurons_RAW_15_344641A_0.1V_%20100PLC.csv


All are RAW data, with a pretty  large DC offset due to DMM temperature.

I also added an Excel file containing the raw and normalized data,  a summary with the RMS values for each combination, DMM infos and settings.

ftp://datashort@xdevs.com/OldNeurons/Noise_Data_04_05_2015/OldNeurons_34461A_Noise_Data.xlsx

I also like the chart proposed by Frank some days ago. A very nice way to summarize all that stuff.
https://www.eevblog.com/forum/testgear/dmm-adc-noise-comparison-testing-project/msg658530/#msg658530

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« Last Edit: May 04, 2015, 04:56:02 pm by OldNeurons »
 

Offline OldNeurons

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Re: DMM Noise comparison testing project
« Reply #130 on: May 06, 2015, 09:36:24 am »
I updated the Excel file on TiN's FTP (Added graph).
 

Offline Dr. Frank

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Re: DMM Noise comparison testing project
« Reply #131 on: May 06, 2015, 11:14:32 am »
OldNeurons,

these measurements, and especially the overview diagram are well done!

I think we'll open une bouteille de Moussy Maurice, ce soir..  :popcorn:

One question: the NPLC 0.02 and NPLC 0.2, are these measurements done in real time, i.e.  each 40µs / 400µs?

Frank
 

Offline ManateeMafia

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Re: DMM Noise comparison testing project
« Reply #132 on: May 06, 2015, 04:37:56 pm »
TiN,

Did you get time to run your 2001 and 2400 last week? I would like to know if you were able to get it to work as expected?
 

Offline OldNeurons

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Re: DMM Noise comparison testing project
« Reply #133 on: May 06, 2015, 07:40:54 pm »
these measurements, and especially the overview diagram are well done!

Thank you Frank, but for the diagram, you showed me the way, which is, to my opinion, the most concise one.
I return the compliment to you.

I think we'll open une bouteille de Moussy Maurice, ce soir..  :popcorn:

Seems to be be a good choice! Birthday?
Santé !

One question: the NPLC 0.02 and NPLC 0.2, are these measurements done in real time, i.e.  each 40µs / 400µs?

At 0.02 and 0.2 NPLC the 34461A, running either at 50Hz or 60 Hz have the same aperture times: 3ms at 0.2 NPLC and 0.3ms at 0.02 NPLC. The Auto Zero fonction doubles the time between 2 samples. Some time ago I measured 6.444 ms at 0.2 NPLC, AutoZero ON (from the front panel).

You have probably looked carefully to the Excel file and noticed that NPLC 0.02 and 0.2 data are not the 14 decimal places as for the other measurements, and this is probably why you are asking.

This is my mistake.

As previously mentionned, I moved my device in a bedroom with no LAN connection. So, all measurements have been performed the same way, from the front panel, data saved on a USB stick.
My mistake occured during the moves from the USB stick to Excel, and saving from Excel to CSV format. You probably know that within Excel, when saving to the csv format, you save what is visible in your cells. In my case, I had data in scientific notation, with 2 decimal places and saved to csv format like this.
When I discovered my mistake, all original files on my USB stick where deleted ...
So, I performed again all measurements except the 0.2 and 0.02 NPLC measurements because in fact that does not affect really the final results.
A long story ...

Jean
 

Offline timofonic

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Re: DMM Noise comparison testing project
« Reply #134 on: May 07, 2015, 12:25:23 am »
Are there going to be a explained summary about the less noise ones in different price ranges and such? That would be amazing!
 

Offline TiNTopic starter

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Re: DMM Noise comparison testing project
« Reply #135 on: May 07, 2015, 04:24:23 am »
ManateeMafia,

I did some runs on 2001, but had some issues (unrelated to script) and still need little more time.
Hope to post summary and details this weekend.
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Offline Fsck

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Re: DMM Noise comparison testing project
« Reply #136 on: May 07, 2015, 04:26:06 am »
Are there going to be a explained summary about the less noise ones in different price ranges and such? That would be amazing!

that kind of summary would be hell with the used markets.
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Offline timofonic

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Re: DMM Noise comparison testing project
« Reply #137 on: May 07, 2015, 05:22:05 am »
Are there going to be a explained summary about the less noise ones in different price ranges and such? That would be amazing!

that kind of summary would be hell with the used markets.
What do you mean? Sorry, maybe my English skills need improvements.
 

Offline PedroDaGr8

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Re: DMM Noise comparison testing project
« Reply #138 on: May 07, 2015, 05:26:22 am »
Are there going to be a explained summary about the less noise ones in different price ranges and such? That would be amazing!

that kind of summary would be hell with the used markets.
What do you mean? Sorry, maybe my English skills need improvements.
Since these are mostly models of DMMs which are no longer produced, all purchases would be used items. Prices vary so widely on the used market, it would be very difficult to provide the breakdown you requested.
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Offline Fsck

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Re: DMM Noise comparison testing project
« Reply #139 on: May 07, 2015, 05:29:32 am »
Are there going to be a explained summary about the less noise ones in different price ranges and such? That would be amazing!

that kind of summary would be hell with the used markets.
What do you mean? Sorry, maybe my English skills need improvements.

the fluctuating prices. like the keithley 2000 and 2001, you probably wouldn't buy new with the great used market and age of the design. the 2002 is sort of uninteresting in comparison to the agilent 3458 or the fluke 8508. the agilent 34401 hasn't been discontinued, but it's not a great buy with the 34461/65/70, etc.
"This is a one line proof...if we start sufficiently far to the left."
 

Offline timofonic

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Re: DMM Noise comparison testing project
« Reply #140 on: May 07, 2015, 06:16:33 pm »
Are there going to be a explained summary about the less noise ones in different price ranges and such? That would be amazing!

that kind of summary would be hell with the used markets.
What do you mean? Sorry, maybe my English skills need improvements.

the fluctuating prices. like the keithley 2000 and 2001, you probably wouldn't buy new with the great used market and age of the design. the 2002 is sort of uninteresting in comparison to the agilent 3458 or the fluke 8508. the agilent 34401 hasn't been discontinued, but it's not a great buy with the 34461/65/70, etc.
Those can be marked as special cases, right?

Anyway, a summary of the less noisy ones would be great. Data is cool, but it's better if it's in a didactical and easier to read form for us newbies.

I understand this data is targeted for hardcore geeks , the task is difficult to do and very probably too much time consuming. Take it as an ingenious suggestion! ;)
 

Offline ManateeMafia

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Re: DMM Noise comparison testing project
« Reply #141 on: May 08, 2015, 02:30:46 pm »
TiN,

I have uploaded a dataset from the 2002. It looks small but it may be the meter itself. The script is nearly identical to the 2001 except there is no analog filter option.

I also uploaded the 2002 and 2001 scripts. I made a small change to the 2001, it appeared that I could set the trigger count after calling the INIT function, but I should have set the count before it. I had to make the change for the 8846A and 2400.

The 8846A is being retested but it should be uploaded tonight. The 2400 script is being worked on now and should be finished in the next day.
 

Offline OldNeurons

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Re: DMM Noise comparison testing project
« Reply #142 on: May 09, 2015, 08:20:19 pm »
Added 100 V data from my 34461A and updated Excel file.
ftp://datashort@xdevs.com/OldNeurons/Noise_Data_09_05_2015
X axis now shows integration time as defined in user manual.
 

Offline OldNeurons

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Re: DMM Noise comparison testing project
« Reply #143 on: May 10, 2015, 03:17:36 pm »
Finally added 1000 V range data ... No more to come now.
Excel file updated and uploaded, as well as new files.
As you can see below, the 10 and 1000 V curves overlap.
 

Offline ManateeMafia

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Re: DMM Noise comparison testing project
« Reply #144 on: May 11, 2015, 11:48:03 am »
I uploaded several scripts to the xDevs ftp server. They are for the Keithley 2400, HP 34420A, and Fluke 8846A (finally). The 8846A was challenging and several of the changes were added to all the scripts to deal with the random timeouts from the 8846A. The 2001 and 2002 scripts were also modified and replaced. The 34420A is configurable to either input channel.

I am finally getting around to collecting data. I just uploaded a dataset for one 8846A. I will be adding more through the week.





 

Offline OldNeurons

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Re: DMM Noise comparison testing project
« Reply #145 on: May 11, 2015, 01:47:48 pm »
I uploaded several scripts to the xDevs ftp server. They are for the Keithley 2400, HP 34420A, and Fluke 8846A (finally). The 8846A was challenging and several of the changes were added to all the scripts to deal with the random timeouts from the 8846A. The 2001 and 2002 scripts were also modified and replaced. The 34420A is configurable to either input channel.

I am finally getting around to collecting data. I just uploaded a dataset for one 8846A. I will be adding more through the week.

Can't find your scripts or dataset ... Where are they?
 

Offline ManateeMafia

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Re: DMM Noise comparison testing project
« Reply #146 on: May 11, 2015, 02:28:33 pm »
I was using a different login/pwd.   I followed the link in the first post and created a directory called EZGPIB_Scripts.

They should be downloadable now.



 

Offline ManateeMafia

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Re: DMM Noise comparison testing project
« Reply #147 on: May 11, 2015, 02:55:01 pm »
The Keithley 2400 is running slower than the other Keithley scripts. I changed the Timeout value from 15 to 5 and it is running a little faster now.
 

Offline OldNeurons

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Re: DMM Noise comparison testing project
« Reply #148 on: May 11, 2015, 03:22:05 pm »
I was using a different login/pwd.   I followed the link in the first post and created a directory called EZGPIB_Scripts.

They should be downloadable now.
They are visible now. Thank you.
 

Offline ManateeMafia

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Re: DMM Noise comparison testing project
« Reply #149 on: May 11, 2015, 04:15:53 pm »
@OldNeurons

I made one (hopefully) last change. I added a version line to the files so I can track which file gets changed. I recommend only downloading the 2400 file again since one other change was overlooked late last night.
 


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