Author Topic: 8.5 digit DMMs  (Read 61632 times)

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Offline Mickle T.

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Re: 8.5 digit DMMs
« Reply #50 on: August 13, 2017, 10:16:37 am »
Wow! Another 8.5-d DMM that I missed. A dark horse - Transmille 8091 :o
 
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Offline TiN

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Re: 8.5 digit DMMs
« Reply #51 on: September 04, 2017, 04:27:10 am »
And another one, Transmille 8104/8108, specified to 4ppm base DCV, together with 4010 MFC.





Funny how they used russian resistance standards.

I see they decided to flood 8.5 digit market with amount of models they have instead of showing off the instrument abilities instead.  :blah:
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Offline Mickle T.

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Re: 8.5 digit DMMs
« Reply #52 on: September 05, 2017, 06:58:33 am »
Transmille 8081 teardown:
 
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Offline TiN

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Re: 8.5 digit DMMs
« Reply #53 on: September 05, 2017, 12:06:28 pm »
Not impressed, looks like just bunch of boards hacked together with cables and wires running around.
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Online lukier

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Re: 8.5 digit DMMs
« Reply #54 on: September 05, 2017, 02:27:36 pm »
looks like just bunch of boards hacked together with cables and wires running around.

Well, to be honest this description would fit 3458A as well :D Especially the DC board and boards on boards on boards (especially the latest revision with mini-modules to replace obsolete parts).

Too bad Mickle T's pictures don't show much detail, but from what I can see there is one interesting thing to note. Look how all the TO-220 power elements (inguard/outguard PSU I guess) are bolted to a metal side of the chassis, so the DMM is completely fanless - nice.
 

Online Kleinstein

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Re: 8.5 digit DMMs
« Reply #55 on: September 05, 2017, 04:29:14 pm »
Not having a fan has it's pros and cons. It is good only if the power consumption is so low that there is really no need for a fan. Otherwise it can be a problem in a rack - or would need a fan unit just above or below.

The closes metal shields look good, but no shield on the bottom, and quite some lose cables going to the front / display.
 

Offline Mickle T.

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Re: 8.5 digit DMMs
« Reply #56 on: September 06, 2017, 07:42:01 am »
Transmille don't have a patented ADC design, so it is possible that 80xx series don't use a multislope or PWM ADC. On the other hand, Transmille has a lot of experience in designing of multifunction calibrators (DACs) and 8081 Operation Manual contains a small hint about DAC's linearity. Suchwise, IMHO, 80xx series uses some sort of balancing DAC-based ADC (just like all russian 8.5-d DMMs it does).
« Last Edit: September 06, 2017, 07:44:07 am by Mickle T. »
 
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Offline razberik

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Re: 8.5 digit DMMs
« Reply #57 on: September 06, 2017, 08:24:07 am »
Tell us more about that russian machines please. There arent many information out there.
 

Online TheSteve

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Re: 8.5 digit DMMs
« Reply #58 on: December 31, 2017, 06:09:30 am »
Spotted a ADCMT 7480T on my work bench.

DCV and 2/4 wire ohms. Ohms top range is 10 meg.
LTZ1000CH ref with 1K/13K for temp and what appears to be a LT6011 op.
10V/10K artifact cal.
Can't find any specs, ADCMT says they don't sell them and only produced them for Advantest. Advantest has not answered any of my requests yet.
Found the manual for the 7470T, firmware/operation is 98% the same.
It says 6581T when it powers on.

Powered it up for an hour, performed an ACAL and it is reading within 1 ppm of the last known value for my 732A.

Once I get a camera worthy of proper internal pictures I'll start a new thread.
« Last Edit: December 31, 2017, 06:22:42 am by TheSteve »
VE7FM
 
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Offline Mickle T.

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Re: 8.5 digit DMMs
« Reply #59 on: December 31, 2017, 06:27:51 am »
Wow! I see the same auxiliary voltage references, as in the 6581.

Any hi-res photos?
 

Offline TiN

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Re: 8.5 digit DMMs
« Reply #60 on: December 20, 2018, 04:09:21 am »
Got a chance to test INL of Transmille 8081 DMM versus respected industry standard oldies.



 :o
I kept testing and testing, but no amount of data massaging and settings combinations seem to improve the situation.



 :-//

Some additional ranges reflect the INL as well:





So we might have a reason why 8081 does not have specified INL  :--

Heck, if all 8081 are similar to this one, then even typical 6.5-digit 34401A is much better than this :(
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Offline ManateeMafia

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Re: 8.5 digit DMMs
« Reply #61 on: December 20, 2018, 05:23:03 am »
Don't be shy. Post some R6581T comparisons so we can see who gets the 8.5 digit stinker award.

I have 7081, 1271, and 1281 for testing.
How come you don't have a 1281 yet? :-//
 
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Offline TiN

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Re: 8.5 digit DMMs
« Reply #62 on: December 20, 2018, 10:17:31 am »
Maybe ppm-Santa will stop by with some 1281? I promise I will be good and supply no more than 1000V into it.  :-DMM
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Offline TiN

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Re: 8.5 digit DMMs
« Reply #63 on: December 21, 2018, 04:20:35 am »
Completed test for 1kV range as well. Area between -100V and 100V not tested due to source limitations.

.

Other than questionable HP 3458 "B", 8081 shows same "shape" on this range as expected.
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Offline chickenHeadKnob

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Re: 8.5 digit DMMs
« Reply #64 on: December 23, 2018, 09:54:44 pm »
Am I reading the graph correctly? The 3458a and flukster mirror each other across zero inl line? That is some schpoooky  coincidence or systematic error in setup/methodolgy
 

Offline TiN

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Re: 8.5 digit DMMs
« Reply #65 on: December 23, 2018, 10:48:27 pm »
8508A data used as reference here. I'll plot direct data with calibrator combined error later.
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Offline beanflying

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Re: 8.5 digit DMMs
« Reply #66 on: January 24, 2019, 02:02:44 am »
Looked for a relevant thread this one seemed like a good spot. Via email this morning from the GM of Sales for ADCMT (Japan) while trying to track down a service manual for my 6871E (still looking).

Quote
Thank you for your reply.
We are providing 6581 8・1/2digit digital multimeter to market now.
But we don't have some English documents of 6581.
Therefore we inserted 6581 into our English Website.
The specification of 6581 is same as R6581.
  http://www.adcmt.com/techinfo/product/intro/i_6581.html
But we will discontinue this 6581 at end of March.
If you need 6581 products, please contact and request quotation with our distributor in US.

No further information if they intend a replacement for it?
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Offline carl_lab

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Re: 8.5 digit DMMs
« Reply #67 on: February 26, 2019, 08:23:12 am »
Anybody heard about Fluke 8558A or 8588A?
 

Offline HighVoltage

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Re: 8.5 digit DMMs
« Reply #68 on: February 26, 2019, 08:38:00 am »
Only that I was invited to a presentation of the new instruments on March 20th in Garmany.
No datasheets have been openly published.
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