8.5 digit DMMs - Page 1
Forum section: electronics / testgear

author: quarks
author_rank: Frequent Contributor
timestamp: July 08, 2013, 06:37:59 am
content: opened because it was OT in another threadhttps://www.eevblog.com/forum/testgear/new-agilent-34461a-6-5-digit-bench-multimeter/msg258268/#msg258268Here is a collection with more details about the kings of the DMMs:Advantest R6581 / ADCMT 6581http://translate.google.de/translate?hl=de&sl=ja&tl=en&u=http%3A%2F%2Fwww.adcmt.com%2Ftechinfo%2Fproduct%2Fend_of_sale%2FR6581D%2Fco_R6581D.html&sandbox=1Datron/Wavetek 1271 and 1281http://www.fluke.com/fluke/uses/Multimetros-Digitales/Fluke-1281.htm?PID=56003http://datronconnection.com/749/Datron_1281.phpFluke 8508A (Option 01 for rear input Ratio meassurement)http://us.flukecal.com/products/standard-laboratory-meters/8508a-reference-multimeterHP/Agilent 3458A (Option 02 or HFL for best DC accurracy)http://www.home.agilent.com/en/pd-1000001297%3Aepsg%3Apro-pn-3458A/digital-multimeter-8-digit?cc=US&lc=enghttp://www.fluke.com/fluke/r0en/digital-multimeters/HP-3458-HFL.htm?PID=56270Keithley 2002http://www.keithley.com/products/dcac/dmm/highperPREMA 6048http://translate.google.de/translate?hl=de&sl=auto&tl=en&u=http%3A%2F%2Fohh.de%2F6048.htm&sandbox=1Solartron 7081http://www.perdrix.co.uk/Solartron7081/index.htmOur member Mickle T. had some great posts on modifying a 7081 on bbs.38hot.net but they seem to be deletedbut here is his great work savedhttp://www.ko4bb.com/manuals/index.php?dir=09)_Misc_Test_Equipment/Solartron/Solartron_7081)Transmille 8080, 8081 and 8881http://www.transmille.co.uk/8080.htmhttp://www.transmille.co.uk/8081.htmhttp://www.transmille.co.uk/8881.htmZIP Nauchpribor KM300http://translate.google.de/translate?hl=de&sl=ru&tl=en&u=http%3A%2F%2Fwww.znp.ru%2Fprod%2Fkm300.htm&sandbox=1edit: cleanup links and added ZIP Nauchpribor KM300 (listed in Mickle T. DMMs8.5.doc)edit: revised DCV Chart (with input from Dr.Frank about 3458A 1kV range)

author: casper.bang
author_rank: Frequent Contributor
timestamp: July 08, 2013, 06:57:37 am
content: Heh, so while Agilent uses Fluke equipment for calibrating, Fluke uses Datron? I wonder what Datron is measured up against then?!

author: eevblogfan
author_rank: Frequent Contributor
timestamp: July 08, 2013, 07:05:41 am
content: Umm have A look at JJ (Josephson junction ) google it up

author: Shas-O
author_rank: Contributor
timestamp: July 08, 2013, 07:29:11 am
content: Just bought a 3458 and sent it back, see new post.The current posts are loose because they are fused !!affects readings when leads are movedDerek

author: saturation
author_rank: Super Contributor
timestamp: July 16, 2013, 01:24:18 pm
content: This was posted on the forum some years ago but I can't find the original thread, so here's a relink:http://translate.googleusercontent.com/translate_c?depth=1&hl=en&rurl=translate.google.com&sl=zh-CN&tl=en&twu=1&u=http://tm.eefocus.com/stupid/blog/08-06/150647_4b553.html&usg=ALkJrhg-IqXNS7q9DW7EUk8ncQywK4IDbQ

author: quantumvolt
author_rank: Frequent Contributor
timestamp: August 01, 2013, 08:22:09 am
content: No, I don't think you want too much. I would like to have it too.But I wonder - what do you people who have 8 1/2 digit meters do with set-up, cables and measurement calculation (adding a loop to zero potential or ratio scaling or ...).I have (after a discussion elsewhere in the forum) checked that the 6 1/2 digit Agilent 34401A quite clearly indirectly measures a 10 Ohm series resistor between a voltage source and the meter (5 Ohm is also detected, but 1 Ohm disappears in noise). With 10 MOhm input impedance 10 Ohm is 1ppm. So this effectively renders the DMM as a 7 1/2 digit (19.999 999) resolution (not accuracy) instrument in RS232 mode for 10 V DC.Today I got a board from Geller that came in at 10.00009 Volt (very happy - means my meter is well within 10 V DC spec - last calib 2003). The reference is stable to 5 decimal points (1ppm for 10 Volt) when averaging the last 10 readings. It suddenly hit me I wanted to check with shorter and better cables. Result: 10.00012 Volt. We are talking about 30 microVolt or 3ppm change as a result of lower cable resistance and better contact/connection (fleabay banana to crocodile). I would have guessed around 1 microVolt [10V in 10 MOhm is 1 microAmpere in max 1 Ohm cable resistance is some 1 or less microVolt]. But I have checked and rechecked, so it might be bad connection, thermocouple effect and .... (I don't know). On another pair of cables the effect was less than 10 microVolt.So I guess measuring at 1ppm and below level is not just like start the meter and read ...? I would like to hear a tale of measuring and verifying with a control calculation on sub ppm level ...

author: Unknown
author_rank: Unknown
timestamp: August 01, 2013, 08:33:48 am
content: Quote from: quantumvolt on August 01, 2013, 08:22:09 amMy guess is indeed offset voltages due to thermal EMF. It would be quite terrible for cable resistance. And why would you measure voltage references with a 10 Mohm input impedance? Set it to > 10 Gohm and cable resistance should be irrelevant.

author: quantumvolt
author_rank: Frequent Contributor
timestamp: August 01, 2013, 09:59:00 am
content: Why I would use 10 MOhm to measure a voltage reference? Because it is the default setting for the meter. Changing it o 10 GOhm+ stores the setting in volatile memory only, so next time you power the box the 10 MOhm is back. And I am too lazy to set it. And if I set it, I have to turn it off again because of too much noise in general hands-on sloppy everyday measurements ... Hard life.My lesson from the experiment is that when I am checking my "references" for drift, the total cable/connector set up can be as important or more than the input impedance effect. I knew that just my body's influence on noise/field/whatever changes the readings and so do powered units surrounding the set-up, but now I understand why you might have to leave your meter, reference and cables untouched for a week in order not to introduce shifts in stability measurements. And if you are interested in accuracy (I expect nothing more than "realistically" +-0.01% - the 34401A is only +-0.0035% per year DC 10V), I now understand why you look for gold-plated or other fine plugs/posts/connectors ...

author: Mickle T.
author_rank: Frequent Contributor
timestamp: August 01, 2013, 11:10:16 am
content: 8,5-digit DMMs summary table and RMS noise chart.

author: PedroDaGr8
author_rank: Super Contributor
timestamp: August 28, 2013, 03:09:02 am
content: robrenz has mentioned previously the tellurium is not important for Thermal EMF properties. It is added to make the copper easier to machine (he's a machinist with years of experience).

author: BravoV
author_rank: Super Contributor
timestamp: August 28, 2013, 03:15:38 am
content: Quote from: PedroDaGr8 on August 28, 2013, 03:09:02 am+1, this, is well written in my personal note, he posted this somewhere in this forum.Btw, just fyi he is a pro machinist and also avolt... I mean microvolt nut, and I guess just few trivial thermal emf difference will not make him sleep well at night.

author: robrenz
author_rank: Super Contributor
timestamp: August 28, 2013, 03:23:38 am
content: Must have trend plot with statistics and histogram. like the 8846A and 34461A

author: Fsck
author_rank: Super Contributor
timestamp: August 28, 2013, 03:50:21 am
content: - way more affordable so a hobbyist afford it relatively easily (this is a delusion)- decent memory, some kind of volatile memory as primary which can be backed up to say NVM every x readings, #M's of points or more- 1U or 2U, not really sure on preference. Thinking 2U if touch screen just to make life easier.- all sides of case must end at right angles.- a 4 year, 4 sigma or greater confidence interval (>99.9937%) *effective* measurement error to be +/- 1 least significant digit of the resolution for all measurable values. (this value is the combination of [% error + x of range]) <a geek can dream right?>-

author: Fsck
author_rank: Super Contributor
timestamp: August 28, 2013, 04:08:03 am
content: a weird idea: a log of calibration history and adjustments stored in some NVM, maybe in some form of table

author: Fsck
author_rank: Super Contributor
timestamp: August 28, 2013, 04:23:07 am
content: the ability to take shrouded banana plugs would be nice though hardly a deal breaker.

author: free_electron
author_rank: Super Contributor
timestamp: August 28, 2013, 04:57:53 am
content: Quote from: Fsck on August 28, 2013, 04:23:07 amWE DONT WANT NO EFFING SHROUDED BANANA PLUGS !!!! Whoever invented those should be tarred, feathered, drawn, quartered, shot, drowned and fed to the rats !Them bloody shoruded blugs are compatible with almost nothing.

author: Hypernova
author_rank: Unknown
timestamp: August 28, 2013, 05:05:13 am
content: Quote from: DiligentMinds.com on August 28, 2013, 04:15:32 amMight as well add a GPS beacon if you're going down that route.

author: Fsck
author_rank: Super Contributor
timestamp: August 28, 2013, 05:07:55 am
content: Quote from: free_electron on August 28, 2013, 04:57:53 amit's why I made unshrouded to shrouded "adapters" so I can use my probes (not on an 8.5d dmm)

author: Unknown
author_rank: Unknown
timestamp: August 28, 2013, 08:37:54 am
content: I like the shrouded banana plugs for measuring higher voltages, even in lower energy circuits. My compromise is that I use shrouded cables for most multimeters (I think the 3458a is one of the few currently available multimeters without shrouded jacks) and unshrouded for other stuff like power supplies.I wouldn't be holding my breath for a replacement. This is probably a low volume, high R&D cost item, so it'll take a long time for it to start making profit, especially since militarily spending is down compared to when the 3458a was designed.

author: Bored@Work
author_rank: Super Contributor
timestamp: August 28, 2013, 03:13:41 pm
content: Quote from: DiligentMinds.com on August 28, 2013, 06:41:13 amWhy do you think people don't use bench meters for higher voltages?By the way, you can get binding posts that take shrouded plugs. However, the safety versions of them, well, meh. Multi contact SPK4http://uk.farnell.com/mc-multi-contact/23-0410-21/connector-panel-mount-black/dp/1116219?Ntt=1116219

author: Unknown
author_rank: Unknown
timestamp: August 28, 2013, 03:47:22 pm
content: Quote from: Bored@Work on August 28, 2013, 03:13:41 pmAre these as clumsy and inconvenient to use as they look?

author: Bored@Work
author_rank: Super Contributor
timestamp: August 28, 2013, 06:41:06 pm
content: Quote from: alm on August 28, 2013, 03:47:22 pmYes, they are.

author: Fsck
author_rank: Super Contributor
timestamp: August 29, 2013, 04:50:21 pm
content: I wonder if a screen with an abnormally high refresh rate would be beneficial for live graphing functions (trendplot, etc. etc)

author: Unknown
author_rank: Unknown
timestamp: August 29, 2013, 04:55:34 pm
content: How would this display look after being turned on 24/7 for 10 years? Because that's the kind of usage a typical 8.5 digit meter might see.

author: Fsck
author_rank: Super Contributor
timestamp: August 29, 2013, 05:07:32 pm
content: Quote from: alm on August 29, 2013, 04:55:34 pmI think you're a little bit under on your timeframe. the 3458a was introduced in somewhere around 1988.. probably like the 20+ years. they'll probably be in service for a while yetyou'd probably need to plan for a 30-40+ year 24/7 lifetime.but, then again, VFDs tend to dim over that kind of online time and yet many pieces of equipment with vfd screens are still popularly sold on the used market and in some cases, still produced.

author: Unknown
author_rank: Unknown
timestamp: August 29, 2013, 05:20:36 pm
content: LEDs also have a finite life, depending on how hard they're driven. Not usually a problem for indicator LEDs, but might be an issue for a backlight application. LCDs also have a problem with high temperatures. If the military is still a significant market (it was for the 3458a), then this might be an issue.Note that LCDs only got introduced in Agilent's mainstream bench meters this year. Expect a 8.5 digit meter to have an even more conservative design, since their design cycle is much longer. At the current rate, a design would have to last past 2038...

author: Dr. Frank
author_rank: Super Contributor
timestamp: August 29, 2013, 10:04:51 pm
content: Quote from: alm on August 29, 2013, 05:20:36 pmMy business unit of an automotive supplier company designs instrument clusters, HUDs, HVAC control, and secondary displays.Requirements on application and components are comparable to military, -40..+85°C environmental, >= 10yrs. lifetime.LEDs last that long, w/o any problem, because we chose the appropriate LED-technology and have a sophisticated temperature management.If the temperature rises, the LEDs will be dimmed. Their lifetime (50% of initial luminosity) depends on chip temperature only.Also, the current might be increased, if the luminosity decreases later.We also developed automotive LCDs for that temperature range.Thumb of rule: fully operating between -10..+60°C, outside that range the LCD might be heated at low temperatures, or restrictions to the performance may apply, as longer switching time, lesser contrast, etc.Frank

author: Dr. Frank
author_rank: Super Contributor
timestamp: August 29, 2013, 10:13:49 pm
content: Quote from: DiligentMinds.com on August 29, 2013, 06:02:31 pmIf you use the 3458A in a metrological temp range, i.e. at around 23° +/- 3°C, then it is really near to perfect, and will reward you with really metrological performance.The interior will heat up to no more than 40°C,My unit is always at around 35°C, at 22°C R.T. and as I take care on the fan filter.The LTZ1000 drift only applies if the instrument is turned on 24/7, which would also degrade the VFD.But if you run it intermittently (in Germany we cannot afford high consumption of electricity any more), and pimp the LTZ1000 to a lower than 95°C temperature, you really have very small drift.Therefore, the 3458A is already the machine you're looking for..Frank

author: Unknown
author_rank: Unknown
timestamp: August 29, 2013, 10:25:00 pm
content: Otherwise consider the Fluke 8508a. It's only specified up to 40°C, so it probably runs its reference at a lower temperature. Similar to the Fluke/HP 3458a/HFL. Might be slightly more expensive to acquire, though, and I think some specs (transfer accuracy? AC?) might be worse. Doesn't use artifact calibration either, I think.

author: Dr. Frank
author_rank: Super Contributor
timestamp: August 30, 2013, 07:28:50 am
content: Quote from: DiligentMinds.com on August 29, 2013, 11:29:37 pmMine is always 12-13K above R.T. only, standing on a desk, fan entry is freely accessible, also the slots outlets on the sideDid you place yours in a rack? Then some Kelvins are to be added.Anyhow, 60°C is the lowest possible stabilization temperature for this LTZ1000A: (25 + 15 + 10 + 10) °C.Cleaning fan filter every day??Do you let yours run 24/7?(30W - that would be a sin here in Germany! Saving energy and CO2 is nearly a religion here.)It's rumored, that elder 3458As improve on their references stability, so they reach the option 02 after a few yers.But I did nowhere find any specifications, (HP3458A and all the other 8,5 digits DMMs), how the stability parameter is defined, on 24/7 operation only, or also intermittently.And does the stabilization process begin every time you switch the instrument on again?Anyhow, I have published my stability figures in the LTZ thread, showing the comparison between an HP3458A and a Fluke 5442A, both operated intermittently.https://www.eevblog.com/forum/projects/ultra-precision-reference-ltz1000/270/Both remained within 1ppm in 3-4 years, but the comparison graph shows relatively big fluctuations of say 0.3ppm from data acquisition point to the next.. which I relate to the intermittent operation.So I assume a 0.3ppm/sqrt(2)/ yr. stability for each instrument from those data.Frank

author: Dr. Frank
author_rank: Super Contributor
timestamp: August 30, 2013, 10:33:10 pm
content: Quote from: DiligentMinds.com on August 30, 2013, 05:39:38 pm75k gives 12.5k or 50°C, that's too low, I think, especially in your nice, hot place.I have chosen 100k (precision wire wound) for 65°C.Quote from: DiligentMinds.com on August 30, 2013, 05:39:38 pmWell, I'm also very skeptical, as I think those meteorologists do not use strictly scientific methods.They capture very small effects, and comparing the big time scale where natural climate changes happen (several 10k years) to the very small time scale where data were collected precisely (<50years), I feel that the statistical basis and the evidence of their arguments are not correct.Meanwhile, it turns out that they did not take every possible other effects into account to prove root cause by mankind, but perhaps only those, which fit in their picture and in their theory.Especially this very determinative, often agressive attitude of this meteorological community, compared to those subtle effects makes me doubt the correctness of their thesis.That's very weird for me, because the scientific community of physicists is much more cautious in this subject.They also speak of "indication" for a climate change by mankind, but not of "a matter of fact".It is also usual and absolutely required in physics to make very critical reviews of theories and methods.And this is what is totally lacking at the meteorologists.. every critical voice has been damned by them.That's totally un-scientific.For two totally different reasons, I think that we really should save CO2, anyhow:- It's a pity to simply burn oil and other fossil material, instead of producing more valuable products out of it, as medicine, plastics, and so on.If the oil is gone, it will be very hard to find a replacement.- If we simply exhaust fossil material to produce "energy", without the need to search for any alternative afterwards, this will for sure create wars for the remainders.Quote from: DiligentMinds.com on August 30, 2013, 05:39:38 pmOK, then it's really true that Americans use about 10 times more energy than even Europeans..Perhaps only those living in hot areas of the US..We pay 1200€ (1500$) per year for electrical energy, 4800kWh/yr, and the price is still rising (>27 EU-Cents / KWh).Quote from: DiligentMinds.com on August 30, 2013, 05:39:38 pmShould be produced before 2001. Did you check date codes on the components inside?Which serial number do you have? I.e. the digits behind the 2823A?Joe Geller collects those numbers to estimate, when a certain serial number has been produced.He thinks, that the 5 digits are in consecutive order, so about 40k instruments have been built between 1989 and today.He will be delighted, if you send him the serial number of your HP3458A and an estimate from the date codes.Frank

author: Fsck
author_rank: Super Contributor
timestamp: August 30, 2013, 10:42:41 pm
content: I'm Canadian, but I live in an apartment I use between 500-1000kWh per month..How do you use ~3.7k per year?! Heating is provided by the building owner, however the stove is electric.

author: JoeyP
author_rank: Frequent Contributor
timestamp: August 30, 2013, 11:18:02 pm
content: Quote from: Dr. Frank on August 30, 2013, 10:33:10 pmThis is my concern also. I think the CO2 thing is a complete hoax by a bunch of self-serving pseudo-"scientists" profiting from grants to study it. In fact, I make a point of flooring the throttle on my vehicle each time I pass a Prius, leaving them in the biggest cloud of CO2 that I can makeHowever, we get so much more than energy from crude oil. Completely excluding its energy content, it is still the basis for much of our industry and economy, and cannot easily be replaced. The good news, is that as a result of fracking techniques, quite a lot of new oil reserves are being found in the US and other areas of the world, so probably have many many years before we run out.

author: quarks
author_rank: Frequent Contributor
timestamp: May 08, 2014, 04:50:01 pm
content: For those who are intersted, I updated some Content (see first page).i.e. added the russian ZIP Nauchpribor KM300, which Mickle T. had in his comparison document

author: Mickle T.
author_rank: Frequent Contributor
timestamp: October 10, 2014, 08:09:14 am
content: 8.5-digit DMMs summary update:

author: saturation
author_rank: Super Contributor
timestamp: October 10, 2014, 02:43:23 pm
content: Here's an updated link to a Chinese forum with a detailed evaluation of 8.5 digit DMMs:http://www.eefocus.com/article/09-04/70848s.html

author: quarks
author_rank: Frequent Contributor
timestamp: February 17, 2016, 06:43:29 pm
content: Does anybody know how to move this to "Metrology"?

author: nidlaX
author_rank: Frequent Contributor
timestamp: February 17, 2016, 07:04:51 pm
content: Are there any reviews / teardowns of the ZIP Nauchpribor KM300 or any of those other Russian designs?

author: Macbeth
author_rank: Super Contributor
timestamp: February 17, 2016, 10:24:32 pm
content: Quote from: saturation on October 10, 2014, 02:43:23 pmThis old interesting link is dead. Google translatedweb.archive.org link here.

author: quarks
author_rank: Frequent Contributor
timestamp: November 06, 2016, 04:19:32 pm
content: today I had to check some resistance dataAfter that I updated the resistance comparison graph and changed the 1 year spec for the Fluke 8508A to "Uncertainty Relative to Cal Stds".Before I used the 365 day "Absolute Uncertainties", which most other DMMs do not specify.Now the data is better comparable.@Moderator, is it possible to move this to "Metrology"?Edit: new graph because of an error I found

author: fonograph
author_rank: Frequent Contributor
timestamp: December 18, 2016, 06:31:39 pm
content: Did anybody have any experience with the Transmille unit? especialy compared to Fluke 8508a...What is the fastest time they can measure 8.5 digit?How much they cost? Is Fluke still being made & sold or its second hand ebay only?

author: saturnin
author_rank: Regular Contributor
timestamp: December 18, 2016, 09:16:00 pm
content: @fonographFYI:https://www.transmillecalibration.com/8-5-digit-precision-multimeter-comparison/

author: Mickle T.
author_rank: Frequent Contributor
timestamp: August 09, 2017, 08:19:22 pm
content: Well, it's time to update the Hi-DMMs summary with a newest ADCMT 7480T (Japan) and Rhythm V2-45 (Russia).

author: FrankBuss
author_rank: Unknown
timestamp: August 09, 2017, 10:32:51 pm
content: Quote from: Mickle T. on August 09, 2017, 08:19:22 pmAn additional column for the price would be useful.

author: kultakala
author_rank: Regular Contributor
timestamp: August 10, 2017, 01:28:19 pm
content: Quote from: saturnin on December 18, 2016, 09:16:00 pmI found the linked video quite interesting... first time i saw the 8081 in action... Okay, the guy is a little bit lulling me

author: cellularmitosis
author_rank: Unknown
timestamp: August 11, 2017, 06:57:57 am
content: Quote from: Mickle T. on August 09, 2017, 08:19:22 pmThis table is great! Has anyone assembled something similar for 6.5-digit models?

author: alm
author_rank: Super Contributor
timestamp: August 11, 2017, 12:34:26 pm
content: That list would be much longer. 6.5 digit has been the standard for high-end bench meters for decades, so pretty much any serious bench meter manufacturer has made one.

author: TiN
author_rank: Super Contributor
timestamp: August 11, 2017, 01:21:07 pm
content: Never heard of Transmille used in any of the standards lab.Also their specifications are mmm.... very scarce. Probably good meters, but not for metrology applications.

author: tooki
author_rank: Super Contributor
timestamp: August 12, 2017, 03:47:11 pm
content: Quote from: kultakala on August 10, 2017, 01:28:19 pmThe design of that meter is vaguely reminiscent of the Datron models - given that it's also English, I wonder if maybe former Datron engineers formed a new company after the Fluke acquisition?

author: Vgkid
author_rank: Super Contributor
timestamp: August 12, 2017, 05:17:28 pm
content: Those Transmille multimeters remind me of updated Solartron multimeters.

author: Mickle T.
author_rank: Frequent Contributor
timestamp: August 13, 2017, 10:16:37 am
content: Wow! Another 8.5-d DMM that I missed. A dark horse - Transmille 8091

author: TiN
author_rank: Super Contributor
timestamp: September 04, 2017, 04:27:10 am
content: 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.

author: Mickle T.
author_rank: Frequent Contributor
timestamp: September 05, 2017, 06:58:33 am
content: Transmille 8081 teardown:

author: TiN
author_rank: Super Contributor
timestamp: September 05, 2017, 12:06:28 pm
content: Not impressed, looks like just bunch of boards hacked together with cables and wires running around.

author: lukier
author_rank: Unknown
timestamp: September 05, 2017, 02:27:36 pm
content: Quote from: TiN on September 05, 2017, 12:06:28 pmWell, to be honest this description would fit 3458A as wellEspecially 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.

author: Kleinstein
author_rank: Super Contributor
timestamp: September 05, 2017, 04:29:14 pm
content: 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.

author: Mickle T.
author_rank: Frequent Contributor
timestamp: September 06, 2017, 07:42:01 am
content: 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).

author: razberik
author_rank: Frequent Contributor
timestamp: September 06, 2017, 08:24:07 am
content: Tell us more about that russian machines please. There arent many information out there.

author: TheSteve
author_rank: Unknown
timestamp: December 31, 2017, 06:09:30 am
content: 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.

author: Mickle T.
author_rank: Frequent Contributor
timestamp: December 31, 2017, 06:27:51 am
content: Wow! I see the same auxiliary voltage references, as in the 6581.Any hi-res photos?

author: TiN
author_rank: Super Contributor
timestamp: December 20, 2018, 04:09:21 am
content: Got a chance to test INL of Transmille 8081 DMM versus respected industry standard oldies.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 INLHeck, if all 8081 are similar to this one, then even typical 6.5-digit 34401A is much better than this

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: December 20, 2018, 05:23:03 am
content: 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?

author: TiN
author_rank: Super Contributor
timestamp: December 20, 2018, 10:17:31 am
content: Maybe ppm-Santa will stop by with some 1281? I promise I will be good and supply no more than 1000V into it.

author: TiN
author_rank: Super Contributor
timestamp: December 21, 2018, 04:20:35 am
content: 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.

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: December 23, 2018, 09:54:44 pm
content: 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

author: TiN
author_rank: Super Contributor
timestamp: December 23, 2018, 10:48:27 pm
content: 8508A data used as reference here. I'll plot direct data with calibrator combined error later.

author: beanflying
author_rank: Super Contributor
timestamp: January 24, 2019, 02:02:44 am
content: 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).QuoteNo further information if they intend a replacement for it?

author: carl_lab
author_rank: Frequent Contributor
timestamp: February 26, 2019, 08:23:12 am
content: Anybody heard about Fluke 8558A or 8588A?

author: HighVoltage
author_rank: Super Contributor
timestamp: February 26, 2019, 08:38:00 am
content: Only that I was invited to a presentation of the new instruments on March 20th in Garmany.No datasheets have been openly published.