Metrology Meeting 2024 in Stuttgart/Germany - The finale - Page 1
Forum section: electronics / general

author: branadic
author_rank: Super Contributor
timestamp: March 05, 2019, 10:11:00 pm
content: Hi to everyone,since we have world metrology day in May 2019 and a few new LTZ reference boards are around, I just want to check if there is an interest in a bigger Volt Nut meeting (up to 50 people) and if so what would be the best time?We could use a room at my work location for free, but need to arrange some catering. The idea is that everyone can arrive on friday and set up his equipment to stabilize to ambient temperature. We could use the evening to have some beer. in the local pubs.The meeting itself is on the following saturday, starting at about 9:00am. Hopefully we can manage to get some talks, a small flea market, measurement and comparison sessions and good discussions.What do you think?-branadic-

author: e61_phil
author_rank: Frequent Contributor
timestamp: March 05, 2019, 10:20:54 pm
content: Great idea!

author: TiN
author_rank: Super Contributor
timestamp: March 06, 2019, 04:10:47 am
content: I wish I'd be closer

author: branadic
author_rank: Super Contributor
timestamp: March 06, 2019, 06:54:50 am
content: Well, for those of you with a long way I can offer at least one guest bed.-branadic-

author: try
author_rank: Regular Contributor
timestamp: March 06, 2019, 12:10:34 pm
content: Hi branadic,good idea!I already scheduled a week for holiday in May and would need to know the exact date to see if it fits.Best regardstry

author: Sprock
author_rank: Contributor
timestamp: March 06, 2019, 12:13:14 pm
content: Hello Branadictry to be one of the 50.Thanks for the offerregardsSprock

author: Andreas
author_rank: Super Contributor
timestamp: March 06, 2019, 08:22:23 pm
content: Hello branadic,count me in for the saturdaywith best regardsAndreas

author: DC1MC
author_rank: Super Contributor
timestamp: March 06, 2019, 08:27:43 pm
content: +1 if you allow some uncalibrated Datron.Cheers,DC1MC

author: e61_phil
author_rank: Frequent Contributor
timestamp: March 06, 2019, 08:38:50 pm
content: Quote from: DC1MC on March 06, 2019, 08:27:43 pmAfter that meeting it is no longer uncalibratedI build the calibration fixtures for my Datron 1071 a couple of years ago..

author: DC1MC
author_rank: Super Contributor
timestamp: March 06, 2019, 08:45:39 pm
content: Quote from: e61_phil on March 06, 2019, 08:38:50 pmBring them on!!!

author: Zucca
author_rank: Unknown
timestamp: March 07, 2019, 09:00:17 am
content: Tentatively yes, SWMBO needs to approve.I still consider myself a baby in this metrology planet, so during the discussions I will be the one with a lot of questions and with this faceafter you replied me.I will join the party with my K. 7510 and 34461a, can I bring also my LCR 4263B puppy?If everything (no rushTiN) goes well I will also have one of those:Also if I manage to put the LTZ into the 3245, I will also bring it...PS: I will also bring my zombi K2001 from under the bench (forgotten project). There I want to investigate the swap of the VR801 Zener with a 2DW23x...Can you guys bring me some Ultra Low Noise Reference 2DW232, 2DW233, 2DW23x? I need to buy 1-3 of those.We need also to contact Adrian:https://www.ab-precision.de/akaap:https://www.eevblog.com/forum/profile/?u=120589Kleinstein?

author: branadic
author_rank: Super Contributor
timestamp: March 07, 2019, 09:23:50 pm
content: I was thinking of a date after world metrology day, so enough time to plan and organize everything. I was also hoping to have Henrik from PTB on board with a keynote speech, but everyone else is welcome to talk to the community with an interesting topic.I would like to have Adrian and Frank on board, so hopefully they see this thread.So please feel free to suggest a date and announce what you can contribute. The more we know what we have, the better we can plan and make it a value event.-branadic-

author: Dr. Frank
author_rank: Super Contributor
timestamp: March 07, 2019, 10:03:12 pm
content: Hello branadic,that's really a very good initiative, and a MUST to join.If that's the 25th of May, I may have a problem if I have to play Tennis that Saturday, but June 1st would be safe.Anyhow, count me in, I will come.Frank

author: e61_phil
author_rank: Frequent Contributor
timestamp: March 08, 2019, 07:58:50 am
content: I really appreciate the idea of talks. I think that is much more useful than any experiments in the very limited time.

author: DC1MC
author_rank: Super Contributor
timestamp: March 08, 2019, 11:35:35 am
content: Quote from: e61_phil on March 08, 2019, 07:58:50 amCan't we do both?

author: ap
author_rank: Frequent Contributor
timestamp: March 08, 2019, 02:46:55 pm
content: Would try to join. Maybe not just voltnuts stuff but also stuff around resistors and capacitors and others; you name it?

author: HighVoltage
author_rank: Super Contributor
timestamp: March 08, 2019, 03:00:37 pm
content: I will try to be there as well.Sounds like a really great idea!

author: branadic
author_rank: Super Contributor
timestamp: March 08, 2019, 03:28:05 pm
content: Okay, I changed the title into Metrology Meeting 2019 so everything around metrology is covered.I can offer a talk about precision inclination measurement and hopefully show one or two metrology grade sensors.Nice that the interest is growing-branadic-

author: hwj-d
author_rank: Frequent Contributor
timestamp: March 08, 2019, 04:51:57 pm
content: Quote from: TiN on March 06, 2019, 04:10:47 amSell half of your equipment, then you can charter a private jet, to bring in the other half.

author: chris_11
author_rank: Contributor
timestamp: March 11, 2019, 09:01:01 pm
content: Hello,If it is the weekend 24th 25th May I like to come. Will bring an uncalibrated 3458A and a few LTZ1000 given that I have stuffed the boards by then.BRChristian

author: ober
author_rank: Contributor
timestamp: March 11, 2019, 09:08:48 pm
content: 2019-05-24/-25 would work for me, too (2019-05-31/-06-01 won't).(Might bring an HP3458A and an R6581D, but would need some transport from Northern Germany for the heavy stuff.)

author: ap
author_rank: Frequent Contributor
timestamp: March 12, 2019, 08:56:53 am
content: 24/25 will not work for me unfortunatelly, only 31/1 would. Thought I would bring some standards with me for attendees to use for calibration, if thats of interest. Maybe some selected meters (precision C-meter or so). Guess there wil be enough 3458As anyway.

author: Calvin
author_rank: Regular Contributor
timestamp: March 13, 2019, 05:15:24 pm
content: Hi,I´m generally also interested to come, but can´t make it fixed yet.regardsCalvin

author: cat87
author_rank: Regular Contributor
timestamp: March 19, 2019, 11:18:38 am
content: I've been lurking around the metrology subforum for some time, so I guess this might be a "coming out of the closet" post for me. I would like to attent. Both options are ok for me, 24/25 May or 31/1.I'd bring a Keithley 2000 and a Fluke 8505A. And probably lots of cash in case there will be some impromptuu fleamarket thing.Nothing like some TEA therapy, eh?

author: branadic
author_rank: Super Contributor
timestamp: April 16, 2019, 12:42:28 pm
content: SAVE THE DATE01.06.2019, 9:00 - 17:00UhrFurther details coming soon.If you can deliver a speech, please contact me.-branadic-

author: meandeev
author_rank: Regular Contributor
timestamp: April 16, 2019, 10:03:08 pm
content: Hi branadic,I would also attend.But I have only a 34401A, that was calibrated by the company of ap (Adrian). And 3 of your LTZ1000´s and a 100Ohm/1k/10k/100k self-build "resistor standard" that scream for calibration.best regards

author: branadic
author_rank: Super Contributor
timestamp: April 23, 2019, 07:40:13 am
content: Since it is impossible for the PTB to send someone out for our Metrology Meeting I want to ask you guys for support of our event with a speech. As the event is casual and without tie every contribution is welcome. It's about sharing experience on voltage references, measurement equipment, be it bought or self-made and so on. So beside myself I presumably have one more member willing to talk. There is room for at least two more speeches.I'm looking for your feedback to make it a valuable event. Thank you very much for your support.-branadic-

author: MarkKruetzmann
author_rank: Contributor
timestamp: April 24, 2019, 07:12:55 pm
content: Is this open if I just happen to have a HP3456A as my most precise instrument? I'd love to join you all there.

author: branadic
author_rank: Super Contributor
timestamp: April 24, 2019, 07:28:30 pm
content: Sure it's open. I will spread a registration mail address within the next days.-branadic-

author: BU508A
author_rank: Super Contributor
timestamp: April 29, 2019, 06:12:12 am
content: Hello,please count me in. Thank you for organizing it and the opportunity to take part of this event.I do not know, if I'll have something ready for this event which is worth showing it, but I'll try.And for the catering I'll bring two cakes, made by myself (Bratapfelkuchen and Käsekuchen).Thanks again for the invitation,Andreas

author: HighVoltage
author_rank: Super Contributor
timestamp: May 01, 2019, 05:18:35 pm
content: Most likely I will be there and combine visiting some friends over the weekend in the south.Not 100% but pretty sure.

author: Harfner
author_rank: Contributor
timestamp: May 05, 2019, 08:38:44 pm
content: Even as a complete beginner, I would like to come. I could bring a Prema 5000 (calibrated!) and would like calibrate a Philips 2534 which is far out of calibration.

author: e61_phil
author_rank: Frequent Contributor
timestamp: May 06, 2019, 08:19:07 am
content: Will anybody bring a calibrator to the meeting? That could by helpful to calibrate some meters. 10V only isn't enough

author: DC1MC
author_rank: Super Contributor
timestamp: May 06, 2019, 10:29:46 am
content: This will male me carry both the 1082 and 1071 Datrons. And yes, I'm coming.Cheers,DC1MC

author: Hermann W
author_rank: Contributor
timestamp: May 06, 2019, 10:32:25 am
content: I also want to participate as an absolute beginner. I would like to calibrate my new LTZ1000.My simple 6.5-digit Solartron 7150 shows a relatively strong noise, so accurate readings are difficult. To better assess the measurements, I have built an AVR application that constantly displays the mean, standard deviation, and temperature with linear regression through a ring buffer. In addition, the measured values can be stored on the SD card, e.g. for graphical evaluations. This helps a lot with normal laboratory measurements, e.g. in TC measurements of resistors. I will bring the device.

author: jeremy
author_rank: Super Contributor
timestamp: May 06, 2019, 12:31:52 pm
content: Don’t forget to post a summary for those of us on the other side of the planet

author: BU508A
author_rank: Super Contributor
timestamp: May 06, 2019, 12:39:05 pm
content: Quote from: e61_phil on May 06, 2019, 08:19:07 amI can bring a Fluke 3330B but it is uncalibrated. Perhaps we can calibrate it, I have the manual for it.

author: branadic
author_rank: Super Contributor
timestamp: May 06, 2019, 01:28:56 pm
content: I will bring my Datron 4000A, of course not calibrated yet. Received the new display PCBs today, so I need to assemble them within the next days.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: May 09, 2019, 05:15:43 pm
content: Update: Attached is the official program. The event is free of charge, so hopefully this helps to motivate a few more people the join us. Please register by sending an email to metrology@hahn-schickard.de and let us know who is coming and what you are planing to bring with, so that we can estimate the required space for tables as well as lunch.Hope to see you on 1st of june 2019 in Stuttgart/Germany.-branadic-

author: ap
author_rank: Frequent Contributor
timestamp: May 10, 2019, 08:35:30 am
content: Great, thanks! One comment: Once you get some feedback maybe it is possible to list what people bring, this way gaps can be identified and also those who wish to calibrate gear can see what is present.

author: hwj-d
author_rank: Frequent Contributor
timestamp: May 10, 2019, 05:52:46 pm
content: Hi,now I can say, that I'm coming too! And I'm looking forward getting to know everyone.I will bring my z1000 ref's and my self-made resistance standard to calibrate.Is somebody driving through the Ruhr area and can pick me up somewhere? PLZ 44651. Otherwise, I'll take the train.Thanks to all,H.-W.

author: The Soulman
author_rank: Super Contributor
timestamp: May 12, 2019, 05:21:04 pm
content: Sadly I'm not able to come, but I still have (all diy) a dual 10V voltage reference and two resistor boxes that needs calibration.Anyone willing to take them to the meeting and make some measurements?

author: dietert1
author_rank: Super Contributor
timestamp: May 13, 2019, 08:14:55 am
content: Regrettable, that nobody from PTB will join the event. Distribution of physical standards is their basic task and they get tax money exactly for that. But well, government doesn't work on saturdays.Will anybody actually join with a calibrated 3458A or similar? I am near Karlsruhe and interested to get (for some fee) a 1 ppm or better measurement of our 10V standard (AD587 based). I think it is roughly at +8 or +9 ppm and would like to confirm that. Simple enough. Will this be possible in the afternoon?Grüße, Dieter

author: Echo88
author_rank: Frequent Contributor
timestamp: May 13, 2019, 09:27:26 am
content: So it should be mandatory that a government agency should attend a hobby party for your convenience Dieter?

author: branadic
author_rank: Super Contributor
timestamp: May 13, 2019, 09:54:01 am
content: It's not a hobby party, but an official event.I don't complain about Henrik not joining the event. I do understand that he has a lot to do and family asks for priority on weekend. Henrik seems to do voltage references more for the hobby, as he is in another group at the PTB?But I'm sad that none of his colleagues at PTB can/want to join the meeting, again it's an official event. I can't imagine that traveling costs are a problem.Quotehttps://www.mikrocontroller.net/topic/398160#newHowever, I tried my best to get them for a speech, but had no success.-branadic-

author: dietert1
author_rank: Super Contributor
timestamp: May 13, 2019, 10:06:18 am
content: It's long ago, but i used to work at the PTB and i respect them.No it's neither about hobby nor about convenience. It's about the safety of everybody's standards. I prefer to not send a standard by mail to somebody who i never met before. I think such meetings are a perfect place for checking a standard.Regards, Dieter

author: ap
author_rank: Frequent Contributor
timestamp: May 13, 2019, 12:29:19 pm
content: I plan to have a 732A with me newly calibrated with traceable MU better 1ppm. Same with 10k.

author: branadic
author_rank: Super Contributor
timestamp: May 13, 2019, 01:17:58 pm
content: QuoteHere is what I have listed by now.-branadic-

author: dietert1
author_rank: Super Contributor
timestamp: May 13, 2019, 02:46:08 pm
content: Great, i think i will join and also put our two HP 3456A into the car that appear to be very stable and may be useful as microvoltmeters for the direct comparison of standards.Regards, Dieter

author: try
author_rank: Regular Contributor
timestamp: May 14, 2019, 03:55:37 pm
content: Hello Soulman,Quote from: The Soulman on May 12, 2019, 05:21:04 pmhave you seen that posting from cat87 who is coming from your country?Did you contact him already?Otherwise, what dimensions does your stuff have?I just want to make sure it will fit into the car of a fellow voltnut I'll go with.Being located in Hannover you would have to get your gear to me.There is an option to drop it off behind the border not too far away from Venlo if that fits.Regardstry

author: hwj-d
author_rank: Frequent Contributor
timestamp: May 14, 2019, 04:20:05 pm
content: Hello branadic,is it possible to set this topic on the schedule/agenda?https://www.eevblog.com/forum/metrology/eu-calclub/msg2410806/#msg2410806Except a verbal note, a explicit speech is certainly not necessary, but it would be good to have a list in which interested members can register.Thanks,H.-W.

author: The Soulman
author_rank: Super Contributor
timestamp: May 14, 2019, 08:53:25 pm
content: Quote from: try on May 14, 2019, 03:55:37 pmI have not contacted cat87 but mailing the stuff to Hannover shouldn't be prohibitive as it are three tiny unitsas seen on the a4 sheet of paper:More info to come here:https://www.eevblog.com/forum/metrology/wanted-someone-(preferably-in-nl)-that-can-measure-2-5-v-dc-within-100ppm/25/

author: try
author_rank: Regular Contributor
timestamp: May 15, 2019, 07:44:03 pm
content: Hello soulman,I'll send you a private message with all necessary information.Regardstry

author: YetAnotherTechie
author_rank: Regular Contributor
timestamp: May 17, 2019, 04:49:03 pm
content: Hello,Is there any group wisdom about the influence of airport x-ray on your equipment? Say having your keithley 2001 x-rayd 6 times in one trip?Would that kind of exposure make having your instrument checked at the meeting pointless if you have to get there by plane?Thank you.

author: branadic
author_rank: Super Contributor
timestamp: May 18, 2019, 08:58:22 am
content: One week left to register for the event.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: May 19, 2019, 03:34:37 pm
content: Beside the equipment you all bring along, please don't forget to put some test leads in your pocket. Would also be great if someone could bring some golden copper spade lugs to the meeting. I wasn't lucky to find some good ones by now.None of you registered things for the flea market by now, does this mean none of you has something to sell or exchange?I can bring some of those 2DW232 for sharing but also some of the multi contact LS4 red and black. If someone has good quality cable for sale don't hesitate to bring it with you.-branadic-

author: HighVoltage
author_rank: Super Contributor
timestamp: May 19, 2019, 03:57:56 pm
content: Quote from: branadic on May 19, 2019, 03:34:37 pmMay be I will bring some resistors and may be I can find other things. I will have a look before I leave.

author: hwj-d
author_rank: Frequent Contributor
timestamp: May 19, 2019, 07:30:00 pm
content: Quote from: branadic on May 19, 2019, 03:34:37 pmThese things are rare, but AP sells them in his online shop. Maybe he can bring some of these items?

author: Andreas
author_rank: Super Contributor
timestamp: May 20, 2019, 08:32:12 pm
content: Quote from: HighVoltage on May 19, 2019, 03:57:56 pmHello,perhaps some of the Geller-Labs black edition PCBs could be of interest for some volt-nuts.https://www.eevblog.com/forum/metrology/geller-labs-svr-lars-walenius-black-edition-with-587lq/msg2219955/#msg2219955with best regardsAndreas

author: BU508A
author_rank: Super Contributor
timestamp: May 21, 2019, 12:02:28 pm
content: Quote from: branadic on May 19, 2019, 03:34:37 pmI have some things which I can bring, e.g. two PCB for a modern chopper amp for the Fluke 3330B,some LM387, some resistors which I do not have much information about them but they seem to be selected for matching tempcos.AD588BD, AD587LN ....Will pack some things this evening so I can grab them when I'm off to Stuttgart.

author: branadic
author_rank: Super Contributor
timestamp: May 21, 2019, 12:34:47 pm
content: Here is an updated list of the equipment from registered attendees.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: May 21, 2019, 02:39:00 pm
content: Today I got confirmation of another guest present on the event. Let yourself be surprised.-branadic-

author: The Soulman
author_rank: Super Contributor
timestamp: May 21, 2019, 02:53:35 pm
content: Anyone willing to receive a small package by mail from me and take it to the meeting?Thank you all for your responses, dieter1 is the "lucky" one.

author: ScoobyDoo
author_rank: Regular Contributor
timestamp: May 22, 2019, 06:46:46 pm
content: Hello Branadic - do you have an idea about uncertainty range and absolute value of these DC Voltage Reference Standards and Resistor Standards ... - It would be nice that there is an overview so that attendees can select the appropriate source according to their needs ... ?Thanks !Best regardsScoobyDoo

author: branadic
author_rank: Super Contributor
timestamp: May 23, 2019, 06:56:34 am
content: No I don't and I don't want to open this rabbit hole as it only produces work for me. But I'm sure there is something for everyone willing to join the meeting.-branadic-

author: e61_phil
author_rank: Frequent Contributor
timestamp: May 23, 2019, 08:38:16 am
content: Quote from: ScoobyDoo on May 22, 2019, 06:46:46 pmFor most of the private stuff it should be hard to determine a real uncertainty. And one shouldn't expect to much, I think. A standard calibrated 3458A gives roughly:sqrt( 8.05ppm^2 + 3ppm^2 ) = 8.6ppm for 10V everything else is worse.The 3ppm are already one of the lower uncertainties I saw on KS calibration certificates.If you are dreaming of 1ppm traceable accuracy for 10V, there are very few things which can reach that level of uncertainty.

author: dietert1
author_rank: Super Contributor
timestamp: May 23, 2019, 03:59:28 pm
content: I remember ap wrote he can bring a 1ppm voltage standard. He is running a business making voltage standards. So there will probably be a mixture of private and professional.When you read Wikipedia about Josephson voltage standards, they mention a traveling Josephson standard with typical variations of 1 ppb in comparisons at national metric institutes. And they mention zeners as transfer standards that reach about 10 ppb. As i don't know any better, i understand those should be LTZ1000 based standards - which will be present at the meeting. Technology does not appear to be the limit.By the way, i found a website of "supracon" in Jena who appear to be advertising their Josephson voltage standard. Maybe they should get an invitation as well.Regards, Dieter

author: e61_phil
author_rank: Frequent Contributor
timestamp: May 23, 2019, 04:59:36 pm
content: Quote from: dietert1 on May 23, 2019, 03:59:28 pmPlease have a look at the noise of a typical LTZ1000, yearly drift and transfer specs of the high end meters. After that think again about 0.01ppm transfers .

author: TiN
author_rank: Super Contributor
timestamp: May 23, 2019, 05:03:35 pm
content: If all goes well, I'll have 0.1ppm absolute transfer on Monday. Wonder how many days will it preserve till going out

author: e61_phil
author_rank: Frequent Contributor
timestamp: May 23, 2019, 06:47:04 pm
content: Quote from: TiN on May 23, 2019, 05:03:35 pmThat sounds very interesting! Could you tell more about the DUT, the setup and the standard which achieves such low uncertainties?

author: dietert1
author_rank: Super Contributor
timestamp: May 23, 2019, 07:03:12 pm
content: Until learning better, i'd rather assume the wikipedia info is more or less correct. Maybe multiple/selected zener diodes can achieve that goal. I found this report of 1991:https://ws680.nist.gov/publication/get_pdf.cfm?pub_id=23726Appearently the zener standard was good for 40 ppb and they achieved 15 ppb uncertainty by repeated comparisons. Interesting: Over a period of roughly one year their zener standard exhibited a constant linear drift that could be subtracted and that did not destroy the transfer, even when travelling a lot.Regards, Dieter

author: Andreas
author_rank: Super Contributor
timestamp: May 24, 2019, 09:45:28 pm
content: Quote from: dietert1 on May 23, 2019, 07:03:12 pmHello,Its not so easy:4 Wavetek/Datron zeners. (each probably costing around the same as a Fluke 732B). And travelling by "hand" or "over night".But usually in metrology you do not use a (one sigma) standard deviation as uncertainity.So perhaps there is also further "beautifying" in the paper.In a standard lab you also have controlled humidity and not only temperature.At home you have "seasonal changes" due to humidity changes.I do not see linear ageing drifts in my measurements.And of course each zener has also some popcorn noise besides 1/f noise.You have to select between some devices to get a really good one.By the way we should all switch off the mobile phones/WIFI/BLUETOOTH near the calibration area.And: last chance to register for the event.with best regardsAndreas

author: dietert1
author_rank: Super Contributor
timestamp: May 25, 2019, 07:46:33 am
content: Yes i know, 1 ppm or lower is difficult to achieve for a 10 V zener standard.Anyway, everybody should think about their "prior knowledge", even if it's not an official certificate and even if they don't know any better than 30 ppm. As far as i understand, when you have enough comparisons, you can apply kind of a "Maxwell's demon" to separate noise from results. That seems to be adopted practice in metrology.Regards, Dieter

author: HighVoltage
author_rank: Super Contributor
timestamp: May 25, 2019, 08:41:17 am
content: I will be arriving on the 1st from Nürnberg area and should be there around 10:00 AM, I guess.Then the 3458A will need a few hours to warmup.My hotel is booked from the 1st to the 2nd of June so we can stay as long as we want in the evening.

author: The Soulman
author_rank: Super Contributor
timestamp: May 25, 2019, 10:47:55 am
content: Here is my stuff that dieter1 will bring:*Dual (lt1021-dmh10) 10V voltage reference.*Resistor box 1, 100R, 1K, 10K, 99k7 (all ESI resistors) cable included for force connection, the 99k7 is a bit unknown my (low-res..) meters are a bit divided over that one although the resistor is very stable (not damaged just a oddball value)*Resistor box 2, 1M, 9M, 90M 0,1%Also included are the three papers to write down your readings, I expect them to be full at the end of the day.Please do not exceed maximum ratings.

author: HighVoltage
author_rank: Super Contributor
timestamp: May 26, 2019, 01:44:36 pm
content: Is anyone interested in low ohm resistance comparison?I could bring my collection of Burster Kalibrierwiderstaende and the fitting cables for the Keithley 2450 SMU and 3458A0.001 Ohm to 10 Ohm

author: BU508A
author_rank: Super Contributor
timestamp: May 26, 2019, 07:02:22 pm
content: Quote from: branadic on May 21, 2019, 02:39:00 pmKleinstein will show up and do a speech?

author: Kleinstein
author_rank: Super Contributor
timestamp: May 26, 2019, 07:17:50 pm
content: I will not be there. So no speech and presentation of DIY high resolution multi-slope ADC.I though about coming, but did not find the time.

author: Andreas
author_rank: Super Contributor
timestamp: May 26, 2019, 07:54:54 pm
content: Hello,from Flinstone I got the following mail:(see also 2nd entry on branadics list)https://www.eevblog.com/forum/metrology/volt-nut-meeting-2019-in-stuttgartgermany/msg2426568/#msg2426568Quotewith best regardsAndreas

author: hwj-d
author_rank: Frequent Contributor
timestamp: May 27, 2019, 07:55:07 am
content: I got a similar pm from a member where i guess, that could be flintstone.

author: branadic
author_rank: Super Contributor
timestamp: May 27, 2019, 12:06:11 pm
content: I'm sorry for all the late decider, but the time slot for registration is over.To all others joining the event, you can bring your equipment on friday til 5:00pm to the event location to install it in the lab.-branadic-

author: guenthert
author_rank: Frequent Contributor
timestamp: May 27, 2019, 04:46:25 pm
content: Quote from: Kleinstein on May 26, 2019, 07:17:50 pmWell, you could present it here, on-line

author: branadic
author_rank: Super Contributor
timestamp: May 27, 2019, 05:47:43 pm
content: Quote from: Kleinstein on May 26, 2019, 07:17:50 pmWhat a shame, hope you will find the time at the next event including a speech, I'm sure there are a lot of people interested in your project. Until then, a lot of time to finish the design-branadic-

author: babysitter
author_rank: Frequent Contributor
timestamp: May 27, 2019, 06:24:21 pm
content: Glad to hear about the intentions to have a "next time" (then without changing the SI definitions, I guess.)

author: e61_phil
author_rank: Frequent Contributor
timestamp: May 28, 2019, 05:12:40 pm
content: Currently we think which Hotel is the most meaningful to book...In which Hotel we will meet the most of the attendees? Could somebody who has already booked give us a hint?ThxPhilipp

author: branadic
author_rank: Super Contributor
timestamp: May 28, 2019, 05:29:33 pm
content: I suggest Campus Guest, which is 10min walk to the event, 5-10min from the next underground station and 3 stations into the center of Stuttgart.-branadic-

author: HighVoltage
author_rank: Super Contributor
timestamp: May 28, 2019, 06:07:56 pm
content: I am booked at Campus Guest by email and they said they had plenty of rooms available.

author: branadic
author_rank: Super Contributor
timestamp: May 28, 2019, 09:35:51 pm
content: I will have my temperature chamber with me, so if someone wants to perform a temperature cycling, you will have the chance at the event. It takes about 2h from room temperature to 15°C, all the way up to 45°C and back to room temperature.-branadic-

author: Andreas
author_rank: Super Contributor
timestamp: May 31, 2019, 09:02:48 am
content: Hello,I think I have asked that before somewhere but the elementary question is:if a device has been calibrated before 20.05.2019:how much do we have to add / subtract to get the "real" value.with best regardsAndreas

author: MiDi
author_rank: Frequent Contributor
timestamp: May 31, 2019, 02:54:54 pm
content: Quote from: Andreas on May 31, 2019, 09:02:48 amAccording tomzzj it is 0.107 ppm. For 10V this is 1.07uV.Edit: Clarification

author: Andreas
author_rank: Super Contributor
timestamp: May 31, 2019, 03:08:35 pm
content: Thanks,from the linked pdf of fluke:QuoteSo as a volt-nut we have to add 1uV on the before 20.05. calibration readings of a 10V reference.with best regardsAndreas

author: guenthert
author_rank: Frequent Contributor
timestamp: May 31, 2019, 04:35:05 pm
content: You're not serious, are you? Comparing two potentials at 10V above ground to less than 1uV is challenging, but within reach of the (very) dedicated hobbyist. Measuring those potentials with an accuracy of less than .1ppm so that historical values can be compared is out of the question.

author: maginnovision
author_rank: Super Contributor
timestamp: May 31, 2019, 04:44:01 pm
content: Quote from: guenthert on May 31, 2019, 04:35:05 pmHe just said add 1uV to the calibration value. That seems to be perfectly fair.

author: branadic
author_rank: Super Contributor
timestamp: May 31, 2019, 05:40:34 pm
content: Metrology Meeting 2019 already started today. A few members already received, their items are installed in the temperature controlled lab, first discussion started and we will have dinner in 20min.#Volt-Nut-branadic-

author: TiN
author_rank: Super Contributor
timestamp: June 01, 2019, 01:31:53 am
content: Somebody should do a livestream

author: The Soulman
author_rank: Super Contributor
timestamp: June 01, 2019, 12:44:49 pm
content: Someone should post some pictures and data.

author: Andreas
author_rank: Super Contributor
timestamp: June 01, 2019, 06:47:01 pm
content: Hello,what do you expect?-lots of people staring at 8.5 digit displays looking wether the last digit will flip (or not)?BTW: look at the calibration date of the lower 3458A: it is within 24 hrs specs!!!with best regardsAndreas

author: The Soulman
author_rank: Super Contributor
timestamp: June 01, 2019, 07:00:49 pm
content: Quote from: Andreas on June 01, 2019, 06:47:01 pmYes! exactly that.Quote from: Andreas on June 01, 2019, 06:47:01 pmIs the source that good?

author: Andreas
author_rank: Super Contributor
timestamp: June 01, 2019, 07:07:57 pm
content: Its the Fluke 7000 from above.So 10.000 041 +/- 2.5 uVHave not looked up the calibration report of the 3458A up to now if the value fits to the calibration offset.with best regardsAndreas

author: Andreas
author_rank: Super Contributor
timestamp: June 01, 2019, 08:16:42 pm
content: From calibration protocol (of yesterday):for +10V the 3458A reading was 3.4 uV too high against calibrator actual value.for -10V the 3458A reading was 4.1 uV (amount too high)Calibration uncertainity is 2.5 ppm (+/-25uV) with 24 hrs we get 2.6 ppm (+/-26uV)so for 10V + 56.8uV we have to correct to 10V + 53.4 uVfor -10V -58.5uV we have to correct to -10V - 54.4uVthe difference to 10V + 41uV from Fluke 7000 is 12.4 or 13.4 uV which is within the +/- 26 uV +/- 2.5 uV uncertainity.But which device is showing the truth? -> we need more references/DMMsEdit: what where the results between the Fluke 7000 and the other Flukes (732)?Edit: And even more evil: I did not find in the calibration protocol if the calibrator has been already set for the new voltwith best regardsAndreas

author: hwj-d
author_rank: Frequent Contributor
timestamp: June 02, 2019, 05:29:48 am
content: Quote from: Andreas on June 01, 2019, 06:47:01 pmNot me

author: hwj-d
author_rank: Frequent Contributor
timestamp: June 02, 2019, 05:44:44 am
content: Yust arrived at home (Herne), sunday 07:30 local time(On weekends, Deutsche Bahn is even worse than building a german airport.)Thanks a lot. Got to know a lot of really competent and nice people. The meeting was a great success inmanyall the ways.

author: dietert1
author_rank: Super Contributor
timestamp: June 02, 2019, 11:08:39 am
content: I am very satisfied, too. Thank you André and to all others involved.I could learn from the talks and participated in the measurement session. Time passed rapidly.Did some check measurements when returning to office. Appears like i brought back a +/- 2 ppm (plus uncertainty of Fluke reference) calibration for voltage standards and lab DMMs.We also measured some resistor boxes and wrote long lists of readings. In a preliminary evaluation resistance uncertainty at 1K and 10K appears to be +/- 4 ppm.Arjens parts helped increasing redundance for bringing the standards back to our office. They will ship tomorrow, together with my evaluation.Regards, Dieter

author: branadic
author_rank: Super Contributor
timestamp: June 02, 2019, 11:44:18 am
content: Thanks to everyone for coming, bringing all the equipment and making it such a successful event. It was you giving life to the event.Special thanks to Andreas and Frank for their talk and thanks to Michel for having a gold standard in the lab.We had a wonderful atmosphere, nothing got broken, everybody helped each other and there was no time for being bored.Thanks also to Mr. Hadlok from Keysight Böblingen for being with us, showing some equipment and giving some details on the new 3458A in his presentation as well as bringing the fresh calibrated 3458A as a special service.And last but not least, thanks for the feedback.It was great to see the faces behind the names and a pleasure to meet you all.-branadic-

author: Echo88
author_rank: Frequent Contributor
timestamp: June 02, 2019, 01:03:12 pm
content: "New 3458A" as in successor of the 3458A we already know? We need juicy details.

author: hwj-d
author_rank: Frequent Contributor
timestamp: June 02, 2019, 03:45:43 pm
content: However, I would have made a small suggestion for improvement next time, but I would have said that things couldn't have gone better on Friday and Saturday.Next time, as far as possible, we should sit down at the end of a short and constructive concluding round, where we have the opportunity to present our subjective impressions and concrete insights within the group and to reflect briefly.

author: Logical
author_rank: Newbie
timestamp: June 02, 2019, 07:29:08 pm
content: Arrived today back home and from my side it was a big succes and a big thanks goes to Branadic for organazing this "Volt Nuts" Metrology meeting in Stuttgart.For the people that are interesting in the accuracy of the 3458a (from branadic's company) that was freshley calibrated by Keysight.Before i left to go to my hotel i did a queck measurement with the fresh calibrated 732a (10.000010) and measured on branadics 3458a 10.000017x and that would be 0.7 ppm difference.So it would be interested if branadic could tell us what the call lab at keysight measured during the 10V calibration last week.Best regards,Logical

author: try
author_rank: Regular Contributor
timestamp: June 02, 2019, 07:41:19 pm
content: Hello folks!Everybody who has given me gear for calibration should have received an email in his mailbox with all my values recorded in an attached excel file.I am happy having met all you guys from Mid-Europe. There is nothing like direct face-to-face communication.It was really worth arriving the day before and having dinner with some of you.My special thanks go tobranadicfor setting everything up, toHahn-Schickardfor providing us with space and food, forab-precisionto bring in freshly calibrated gear, toKeysightfor sending in a representative and products.Furthermore I'd like to underline that without the support of thePTBgang (Henrik, Harald, Dennis and team) who sacrifiy valuable week-end summertime for promoting the PTB and distributing electrical units at the Maker Fair I would not have gotten to the point to more or less accurately measure the references of my fellow voltnuts.Next Maker Fair is on the 17./18.8.2019 in Hannover, Germany - voltnuts should not miss showing up at the PTB booth!Regardstry

author: branadic
author_rank: Super Contributor
timestamp: June 02, 2019, 08:02:22 pm
content: QuoteIt was calibrated the day before the eventDC Volt OffsetRange Input Minimum Measured Maximum Uncert.10V 0V -0.0023mV 0.0003mV 0.0023mV 0.00032mVDC Volt GainRange Input Minimum Measured Maximum Uncert.10V 10V 9.9999340V 9.9999987V 10.0000566V 0.000025V10V -10V -10.0000618V -10.0000046V -9.9999392V 0.000025V-branadic-

author: hwj-d
author_rank: Frequent Contributor
timestamp: June 02, 2019, 08:04:08 pm
content: Someone asked me about Jason's (cellularmitosis) ltz1000 pcb's, of which I still have a few left to give away for nothing (oshpark ones). Please report the one who asked me. But in total there are only 2-3 pcb's.

author: Andreas
author_rank: Super Contributor
timestamp: June 02, 2019, 08:25:12 pm
content: Hello,To calculate the actual deviation you have to calculate the nominal value of the calibrator as:nominal = (minimum + maximum) / 2see above example for the Wavetek 7000 from me.with best regardsAndreas

author: Sprock
author_rank: Contributor
timestamp: June 02, 2019, 09:14:14 pm
content: Hello,that was me. Please PM. Just to keep here the noise low.regards Sprock

author: hwj-d
author_rank: Frequent Contributor
timestamp: June 02, 2019, 09:42:06 pm
content: Quote from: Sprock on June 02, 2019, 09:14:14 pmSo, do it.

author: HighVoltage
author_rank: Super Contributor
timestamp: June 03, 2019, 07:56:45 am
content: Thank you branadic for making this happen so successfully.It was really great to meet you all and finally putting some faces to the names.Here are some gear pictures.

author: Zucca
author_rank: Unknown
timestamp: June 03, 2019, 09:14:17 am
content: Glad to see it happened.Sorry guys I was a lazy assand I decided to go mountain biking in Italy instead.

author: BU508A
author_rank: Super Contributor
timestamp: June 03, 2019, 09:22:18 am
content: Quote from: zucca on June 03, 2019, 09:14:17 amWhich is, imho, a very good idea, too.Thanks to branadic for all the organisation and your company for giving us all the room and lab space.And also a big "Thank You!" to all other participants. I learned a lot and it was really fun to see allthesechildrenengineers playing around with all this nice test gear.I'm really hoping, we can do this again.Thanks,Mounty

author: Henrik_V
author_rank: Regular Contributor
timestamp: June 03, 2019, 09:39:10 am
content: Quote from: Echo88 on June 02, 2019, 01:03:12 pmWell, I have to byte my tongue for a while nowAnd it should be new threadand there are others more qualified to fill that thread.There will be a new rev. of the 3458A. (I think KS will even keep the same order number (the 3458 is qualified in many applications!)They rebuild the 3458A, board by board with new (without unoptanium) parts. You can swap any old to new board, do a calibration and run it.A former PTB fellow has verified that even inofficial specs are met (or better). (better internal EMC, SMD parts, about 5K lower internal temperature , higher input impedance (more space on the board) ). Linearity (don't nail me on that one, maybe selected boards) down to 0.01 ppm?

author: Echo88
author_rank: Frequent Contributor
timestamp: June 03, 2019, 11:09:57 am
content: Sounds nice. Will be interesting to see if/how they solved the U180-unobtanium-problem. Would be nice if the mentioned involved persons could share their wisdom about the new 3458A in a new thread.

author: hwj-d
author_rank: Frequent Contributor
timestamp: June 03, 2019, 03:06:18 pm
content: Quote from: BU508A on June 03, 2019, 09:22:18 amI've heard someonloudlyspeakin' out in the corridor in front of the door to the lab (to himself):"Endlichunter 'normalen' Menschen ..."that means "finally among 'normal' people ..."Do you know whothatwas?H.-W.

author: Echo88
author_rank: Frequent Contributor
timestamp: June 03, 2019, 03:24:53 pm
content: Did you invite Tom Gerhardt?

author: hwj-d
author_rank: Frequent Contributor
timestamp: June 03, 2019, 03:31:51 pm
content: Didn't even know who held the copyright.But that came from the deepest soul.

author: Dr. Frank
author_rank: Super Contributor
timestamp: June 03, 2019, 06:19:00 pm
content: Quote from: Andreas on June 01, 2019, 08:16:42 pmAndreas,I have compared the 732A from Adrian, 732A from Wulf (?), 7000 from Michel, and my LTZ #2Procedure was similar to yours:using a freshly adjusted 3458A (to Adrians 732A), I measured each polarity @ DUT, 16 x NPLC100, with statistics.Average of these two absolute value gives "true reading", to cancel e.m.f.Adrians 732A (10.000 010 Vnom.) was uncertain to 0.5ppm, Michels 7000 (10.000 041 Vnom.) was uncertain to 0.25ppm, so it got double weight for the difference calculus.I calculated corrected values for these references:732A (Adrian) = 10.000 006 5 V (StD ~ 200nV)7000 (Michel) = 10.000 042 7 V (StD ~ 130nV)732A (Wulf?) = 10.000 008 5 V (StD ~ 132nV)LTZ#2(Frank) = 7.118 228 61 V (StD ~ 104nV)The agreement between these 732A and the 7000 'felt' really impressive.I had to correct my baseline (drift of my 3458A) by about +1.8 ppm. I.e. my 3458A was reading too low.. maybe that's the -2ppm Philipp was looking for.But this is also quite impressive, as the last direct transfer was done 7 years ago, and that demonstrates that an ensemble of 4 references (LTZ and SZA) determines drifts in the sub-ppm range, and also is capable of < 1ppm/yr. drift performance (ovens at 50..55°C).Not bad for home-grown references.A big Thank You to André (branadic), who made that event happen.. it was perfectly organized.It also was a great experience and a great pleasure with all participants.. I really felt deeply inside, that I'm not alone being 'nuts'.Frank

author: try
author_rank: Regular Contributor
timestamp: June 03, 2019, 09:47:01 pm
content: Hi Frank,remember you did not want to believe me when I said that I see your LTZ-2 2 ppm higher?Phil and me ended up searching them in his appartment a whole afternoon long till midnight one week after the Maker Fair 2018.Your 10k reference by the way agreed perfectly to the ESI SR1010 from D. and indicated that my 34401A understated the measurements by -7,6 ppm despite being adjusted in September 2018.That's why I told the fellow voltnuts to add +8 ppm to the 10k figures of their references.Don't forget to bring that reference in to the next meeting. Ohms seem to be more challenging for my opion.This time measurements fit pretty well.The picture attached is taken from my calibration log file that I sent to you as well, names are anonymized except for the publicly known ones.My conclusion:Even without a Keysight 3458A (5 devices present) and Fluke 732A (3 devices present) you can squeeze plausible numbers out of low price gear.Regardstry

author: dietert1
author_rank: Super Contributor
timestamp: June 04, 2019, 05:48:50 am
content: I remember another resistance check with Martins 100R resistor box, where we had readings of 34.. 37 ppm with an expected list value of 43 ppm. Another indication of the -8 ppm resistance calibration of that 34401A.Our three old Lab DVMs 1x Fluke 8502A and 2x HP 3456A, that came to us about 19 years ago and that were never adjusted in all those years, exhibit offsets of -13.6 ppm, 12.7 ppm and 3.1 ppm according to the measurements in Stuttgart. (10 V DC measurements) Those DMMs did receive some maintainance like recapping power supplies and the like. The difference between the two HP 3456A was measured as 6.5 ppm in 2008 and increased to 9.6 ppm since then.Good news that confirms Franks statement of "1 ppm/year" being within reach technically. Of course, if someone needs certificates for legal reasons, that's another story.Regards, Dieter

author: BU508A
author_rank: Super Contributor
timestamp: June 04, 2019, 08:10:01 am
content: Quote from: hwj-d on June 03, 2019, 03:06:18 pmI have NO idea.

author: Hermann W
author_rank: Contributor
timestamp: June 04, 2019, 10:38:58 am
content: Quote from: try on June 03, 2019, 09:47:01 pmThat's okay. but what about the other measuring ranges.Quote from: dietert1 on June 04, 2019, 05:48:50 amSo probably the correction also applies to the 100R range. But what should one do with the other ranges?

author: dietert1
author_rank: Super Contributor
timestamp: June 04, 2019, 02:25:34 pm
content: The SR-1010 mentioned above has twelve 1K resistors in a serial chain and expected values for each one of them and for integrated resistance of all partial chains starting at R1. We checked R1 = 1KOhm + 23.5 ppm and the chain R1 .. R10 = 10 KOHm + 17.6 ppm. Readings were 15 ppm and 10 ppm, which seemed to indicate a similar deviation for both ranges.So we checked with 100R, 1K and 2x 10K resistors and got a consistent 8 ppm deviation. When you look into the 34401A schematic, there are four current sources for resistor measurement. Maybe it uses the same 1 mA source for 100R, 1K and 10K resistors and voltage measurements seemed to be well adjusted. For resistors above 10K one should resort to default 34401A specs. In fact, we also measured Martins higher resistor boxes, but i don't have all those numbers.Regards, Dieter

author: try
author_rank: Regular Contributor
timestamp: June 04, 2019, 04:36:27 pm
content: Quote from: Hermann W on June 04, 2019, 10:38:58 amI should have foreseen that question. Please give me some time to gather additional information.

author: e61_phil
author_rank: Frequent Contributor
timestamp: June 04, 2019, 05:13:14 pm
content: @Dietert1: One could also measure 10x 1k resistors of the SR1010 and the sum of the 10 resistors should match the reading of 10 resistors in series on the 10k range. This way you can transfer the 1k range to the 10k range without knowing any of the SR1010 resistors. But it would have been much easier to use one of the 3458As or the calibrated Fluke 5450A

author: try
author_rank: Regular Contributor
timestamp: June 04, 2019, 08:35:36 pm
content: Mean measurement messAfter keying in all measurement data of my resistor boxes I won't hide the dubious measurement outcome.Fellow conference voltnuts, it's up to you to determine adjustment values.Guess the huge uncertainty given the wide range of measurement outcomes!The resistor boxes were made on the last days before Maker Fair 2018. With the still uncorrected failure of Edwin Pettis to deliver 10k+-10ppm in precision wire wound and Vishay to deliver foil resistors in time as promissed I desperately put together what I had available in stock. That kind of last moment assembly allowed for a settling time of 24-48 hours which seems to be too short I assume.Column D shows the resistor values as measured on the Maker Fair on a freshly calibrated 3458A as an average measurement for a total of 1 minute measurement time.Settings were made as recommended to me by Dr. Frank (Thanks!).Column F reflects internal temperature by measuring a built-in KTY81-110 where 1000 Ohm equals 25 degrees Celsius and 8 Ohm change translates into roughly 1 Kelvin difference in temperature.The orange area contains my measurements during the conference.The conference temperature does not differ more than 1 Kelvin from the Maker Fair.I gave the boxes to two fellow voltnuts with their 3458As. One 3458A was freshly calibrated (during the conference)?The fellow voltnuts did not measure the KTY81-110 as well unfortunately.Please juge for yourself.What I do not understand is the big inconsistency between the aforementioned ESI SR1010 and Frank's VHP on one side and the 3458As on the other side.My resistor boxes are equipped with sense connectors for each individual resistor.

author: Dr. Frank
author_rank: Super Contributor
timestamp: June 05, 2019, 06:43:26 am
content: Quote from: Henrik_V on June 03, 2019, 09:39:10 amHello Henrik,please tell us more about these unofficial specifications!The official ones are still from 1988, and never changed, although the 3458A might operate much better, and these specs are also incomplete, e.g. missing Ohm transfer stability.And I assume, that the PTB might have characterised the 3458A in a better manner.ThanksFrank

author: Henrik_V
author_rank: Regular Contributor
timestamp: June 05, 2019, 12:14:35 pm
content: Quote from: Dr. Frank on June 05, 2019, 06:43:26 amWell, I'm only an interested onlooker (Zaungast), but next time I met that former fellow, I will squeeze himhe was pretty much involved in the new A3 board.

author: guenthert
author_rank: Frequent Contributor
timestamp: June 05, 2019, 04:36:45 pm
content: Will those 'unofficial' specs not be 'just' experience values of the PTB with various units they used? We (the voltnut community) found many (well aged) DMM to perform (at times vastly) better than their specifications suggest. This doesn't give the manufacturer the confidence to tighten the published specifications. The PTB is just in a much better position to determine the actual specification of a given unit or a set of units, quite possibly in a better position than the manufacturer. Or did the PTB characterize a statistically significant subset of all produced units?

author: Henrik_V
author_rank: Regular Contributor
timestamp: June 06, 2019, 07:29:50 am
content: Quote from: guenthert on June 05, 2019, 04:36:45 pmWell, if you push the borders you won't find equipment that is spec'ed for itso you use available stuff (or build it yourself) and qualify it by yourself (needs time, skills and a lot of work). For example: By closer controling the boundary conditions like temperature and EMC conditions ..Example imput impedance : the spec say >10 G\$\Omega\$ but often it's important to know that value. For the new 3458 I heard value in the 400 G\$\Omega\$ range ... since the lab do the calibrations for the PTB internal and external workhorses (3458) and usually check every device to be calibrated for this value, they gain some knowledge about typical and very good values. Devices from cal labs are usually treated very well, but experimenters units sometimes have leaking input protections, resulting in a lower input impedance(All it needs to check is a 100M resisitor and a voltage source in the range to be tested, and always check both polarities)Sidenote: You can order the 3458 with different memory options, in the past that really was added memory (amound not worth of diskussion nowadays) ... while KS was inhouse I asked if one still has to order (and pay for) it, assuming that the new 3458 has all of it onboard even if they used the smallest available modern controllers and memory chips. Guess the answer.

author: Andreas
author_rank: Super Contributor
timestamp: June 15, 2019, 07:46:06 pm
content: Hello,who was the one who spoke to me on the meeting that he also wanted to build a LTC2400 based cirquit?please PM me.with best regardsAndreas

author: Zucca
author_rank: Unknown
timestamp: July 11, 2019, 05:56:59 pm
content: Quote from: Henrik_V on June 03, 2019, 09:39:10 amI just came back from the Keysight HF/RF Training here in Munich. I tried to get some information on this new beast.The only thing I got was that the new 3458A will be produced in Japan, where they have the high precision production line.

author: branadic
author_rank: Super Contributor
timestamp: January 29, 2020, 03:50:19 pm
content: Hello everyone,we preliminary fixed the date for the Metrology Meeting 2020. It will take place on 06.06.2020, with the possibility to arrive on 05.06.2020 to put the equipment into the temperature controlled lab.If everything goes wrong we might need to change to the weekend afterwards (12.06.2020 to 14.06.2020), but I will give an update on that by the end of february???Besides some talks we are still trying to fix, we currently plan a session with an elevator pitch, giving everyone the chance to speak 2min with one slide to present current work and challenges, so that it is easier to start into a discussion afterwards.Stay tuned...-branadic-

author: Zucca
author_rank: Unknown
timestamp: January 29, 2020, 09:08:55 pm
content: Thank God I planned to get married in the church on the 2nd of May and not in June.Sign me up!

author: alex-sh
author_rank: Regular Contributor
timestamp: February 04, 2020, 10:53:25 pm
content: Quote from: Zucca on January 29, 2020, 09:08:55 pmSpeaking like a true volt-nut.Please do me a favour - do not tell your future wife about it in the same manner

author: branadic
author_rank: Super Contributor
timestamp: March 06, 2020, 04:18:07 pm
content: Hi everyone,I was confirmed that we will have a talk by:1. Mr. Zirpel (ex. PTB, now at Wekomm)2. Mr. G. Weckwerth (Wekomm)3. Mr. N. Beev (Cern)I still wait for the 4th talk to be confirmed. Otherwise we will have an open question session to fill the gap.We will also have an elevator pitch to present current work and the like in 2min on 1-2 slides, to initiate a valuable discussion.There will be enough time to measure and compare voltage, resistance and current readings though. The lab will be cleared and the middle island will be removed, so that there should be enough space for everyone and all the gear. I was also confirmed, that Keysight Technologies is with us.We are currently working on the official flyer, so that you guys can register soon.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: April 26, 2020, 11:20:48 am
content: Hello everyone,unfortunately we have to announce, that we need to cancel MM2020. Due to the current governmental rules and the uncertainty how long they will last and how they will change in the next weeks or so, it is allmost impossible for us to seriously plan an event.Metrology Meeting was intended to be a meeting between people, live, not one of those online thingies, which I'm honestly tired of. So please understand, that there won't be online talks, livestreams or the like instead.I'm looking forward for this madness to end, to get back to normal life, where people can meet each other without distance rules and masks. Hopefully MM2021 can happen as it did in 2019.Kind regards, André

author: Dr. Frank
author_rank: Super Contributor
timestamp: April 26, 2020, 11:30:47 am
content: Hello André,that's really a pity, but there's obviously no other chance to decide that way.Thank you for your organization effort so far.Hopefully we can have some exchange in a different manner in the meantimeFrank

author: The Soulman
author_rank: Super Contributor
timestamp: April 26, 2020, 12:53:18 pm
content: -Because reasons- My agenda was almost completely cleared up until September, was kinda hoping I couldattend the MM this year but realistically wasn't expecting for it to happen..Quote from: Dr. Frank on April 26, 2020, 11:30:47 amIt is time to materialize the EU calclub.Edit: previously discussed here:https://www.eevblog.com/forum/metrology/eu-calclub/

author: HighVoltage
author_rank: Super Contributor
timestamp: April 26, 2020, 01:18:15 pm
content: Thank you André, for all the work you have already put in to this event.Hopefully MM2021 will happen when this crazy is over.

author: exe
author_rank: Unknown
timestamp: April 26, 2020, 07:59:25 pm
content: I understand the reasons why not doing it online, or recording it. I want to ask you to reconsider the last option. I'm interested in metrology, but I'm not eligible to visit this event. But I'd still enjoy the recorded talks.

author: notfaded1
author_rank: Frequent Contributor
timestamp: April 26, 2020, 10:38:09 pm
content: All our conferences have been getting cancelled. Cisco Live in Las Vegas this year was cancelled too which is my daytime job thing. I too don't like online replacements for these André... it's just NOT the same. FWIW we're starting to get back to more normal now slowly here in Arizona USA. Hopefully things will be getting back to normal by mid summer I'm hoping. We now know the sun kills this virus quickly and we have LOT of sun here in Arizona.Bill

author: branadic
author_rank: Super Contributor
timestamp: June 08, 2020, 10:47:09 am
content: Even though the official MM2020 was canceled, we had a small scale MM2020 last saturday.Beside measuring references (LTZ, AD587) with different meters, such as K3458A, HP3458A, K2002, R6581D and S7081, we also adjusted Datron4000A voltage range, S7061 and S7081 ohms ranges. Valueable discussions and a session until 4am the next morning plus having some beer was a pleasure.-branadic-

author: babysitter
author_rank: Frequent Contributor
timestamp: June 08, 2020, 02:31:29 pm
content: Now please dont die!

author: Dr. Frank
author_rank: Super Contributor
timestamp: June 08, 2020, 06:23:54 pm
content: Quote from: branadic on June 08, 2020, 10:47:09 amWe compared our DCV reference groups to a disagreement down to about 2ppm.branadics ones are mainly based on recent calibrations of his DMMs, and mine are based on two M7000, 0.25ppm comparisons, 1 and 1/2 year ago.Anyhow, I'd still call this a success, as we later on needed several beer to cool down, ourselves as well as the lab-room, which ran hot at 26°C, having about 35 devices plus 3 volt-nuts up and running.Maybe Andreas is willing to post his pictures of this event..Anyhow, we're still searching for the root cause of this difference.Frank

author: Andreas
author_rank: Super Contributor
timestamp: June 08, 2020, 06:53:57 pm
content: Hello,perhaps someone finds the missing 2 ppm´s in one of the pictures.with best regardsAndreas

author: notfaded1
author_rank: Frequent Contributor
timestamp: June 09, 2020, 04:06:01 pm
content: Did anyone find the missing 2ppm? What kind of beer do you have over there btw?Bill

author: BU508A
author_rank: Super Contributor
timestamp: June 09, 2020, 05:45:13 pm
content: Quote from: notfaded1 on June 09, 2020, 04:06:01 pmAbout the 2ppm I cannot say anything.The beer is most likely this one:https://www.stuttgarter-hofbraeu.de/

author: Dr. Frank
author_rank: Super Contributor
timestamp: June 09, 2020, 09:20:35 pm
content: Nope, we had another Stuttgart local, iconic beer, Vollbier Helles

author: branadic
author_rank: Super Contributor
timestamp: June 13, 2020, 06:38:58 am
content: QuoteAt least we think we did, but I have to fully confirm this measuring the other references one after another.Reason was, that K3458A was in parallel to K2002 influencing each other. I did the test yesterday: readings on K3458A can change, if you connect another meter in parallel to it. On the other hand, now that this issue was found I repeated measurements on first reference with K3458A and they now agree with the readings of HP3458A.So this is the lesson learned for me at this summit, be careful paralleling meters and watch for changes in the readings.Edit: Attached is the current result. In the area marked red are the findings with the meters paralleled, in the area marked green the readings with each meter individually connected to reference LTZ1000-1. The left point in the area marked green is the reading on HP3458A, the other points are K3458A, Prema 6048 as is (no adjustment) and both adjusted meters R6581D and S7081. They now agree within about +/-0.5ppm, with Prema 6048 readings somewhat higher.-branadic-

author: guenthert
author_rank: Frequent Contributor
timestamp: June 13, 2020, 04:27:52 pm
content: Quote from: branadic on June 13, 2020, 06:38:58 amUh, I thought it was well known that you're not supposed to do that. The 'pump-out' current of a DMM might average to just a few pA, but spikes well into the nA range. That's bound to influence other meters.EDIT:Well, on 2nd thought, that's obviously a problem when measuring sources with a significant output resistance (iirc standard cells are about 1kOhm). For low impedance sources I wouldn't know where the discrepancy comes from.

author: dietert1
author_rank: Super Contributor
timestamp: June 13, 2020, 05:52:45 pm
content: To be honest, i can't understand those findings. If a nA current makes a 2 ppm shift on a 10 V or 7 V reference, that reference has an output resistance of 20 KOhm (20 uV / 1 nA). What are you doing there?A well built voltage reference should have an output resistance of about 1 Ohm or less. Of course, then you have cables etc. But never in the KOhm range.Regards, Dieter

author: branadic
author_rank: Super Contributor
timestamp: June 13, 2020, 07:23:27 pm
content: @ DieterI don't llike the sound within your wordsQuote. Sounds like you know it all.It is fact that we made this observation. There is an offset noticeable when K3458A and K2002 where connected in parallel to the references, either LTZ circuit by Andreas, LTZ circuit based on Frank's design but also on AD587 references from Andreas.This offset noticeable changed with additional meters such as R6581D and S7081 in parallel.The references are well build, they are buffered by either LTC2057 or LTC1052. The offset vanished, when only one meter was connected to the reference output and all meters read about the same value. If you have a better explanation for it please let us know.-branadic-

author: e61_phil
author_rank: Frequent Contributor
timestamp: June 13, 2020, 07:25:26 pm
content: Please repeat this experiment with a proper source, like a calibrator.

author: dietert1
author_rank: Super Contributor
timestamp: June 13, 2020, 07:52:44 pm
content: A possible explanation could be RF ("Elektrosmog"). Maybe those references are OK and the DVMs are OK but those old DVMs were not made for an environment with WLAN and switching power supplies.I remember that in high end audio people know they have to put 100 ohm to 1 KOhm resistors into all their audio cabling/device outputs/device inputs to avoid building large antenna systems. Maybe we have to do something similar when measuring references.Regards, Dieter

author: Kleinstein
author_rank: Super Contributor
timestamp: June 13, 2020, 08:14:11 pm
content: There is a chance the DIY reference may have a common weakness. A low impedance voltage regulator may have the tendency to show ringing with only a capacitive load.The AZ OP in the DIY reference could also react to load at the output. Some of the AZ OPs show an offset that changes with the input impedance (especially capacitance) - this could cause trouble if not filtered isolated enough.Another point can be spikes at the OP output, that can get back to the feedback bath. Here the load impedance (e.g. > MHz range) can change things quite a bit. Here it may not need a full 2nd meter - just more cable would be enough.The R6581 is known to have quite significant current spikes at the input, not just nA - more like µA possibly even close to mA. The Solartron and Keithley meters use a chopper stabilized amplifier. At least Solartron has quite some with filtering in front of the chopper part - so it should not cause that much interference.

author: dietert1
author_rank: Super Contributor
timestamp: June 14, 2020, 07:03:17 am
content: Already the most basic configuration of an external reference connected to a single DVM has the potential for RF problems. For example if the reference doesn't run from battery but has a mains supply or USB connection.Our HP 3457A has two common mode chokes for its input terminals (front and scanner). For the mains connection there is a filter, i assume that one includes a common mode choke. Or one might use an external mains filter like in high end audio. For the GPIB connection there is nothing.I think a precision reference should have a common mode choke on its output. There are ready made 3-phase common mode chokes, so one can include the guard, e.g. Schaffner RT8132-6-6M0.Regards, Dieter

author: Kleinstein
author_rank: Super Contributor
timestamp: June 14, 2020, 09:03:12 am
content: Quote from: dietert1 on June 14, 2020, 07:03:17 amThe GPIB is usually isolated on the ground based part, not directly connected to the analog side, only via some capacitance (parasitic and maybe intentional to ground ?). One could add at least a clip on ferrite to the GPIB cable.

author: Andreas
author_rank: Super Contributor
timestamp: June 14, 2020, 05:16:23 pm
content: Quote from: dietert1 on June 14, 2020, 07:03:17 amHello,if I look at the data-sheet: the self resonant frequency of these inductors is around 400 kHz.So they are optimized for switchmode power supply noise.At least the meters should have analog supplies.So I think a different common mode choke (51 uH "CAN" choke) should give better results over the whole frequency range.At least my references run all from NiMH batteries during operation.Quote from: dietert1 on June 13, 2020, 07:52:44 pmThis is only one explanation; another could also be the current spikes from auto-zero cirquits (like in the neighbour threadhttps://www.eevblog.com/forum/metrology/prema-8017-(sick-)-vs-tektronix-dm5120-vs-hp-34401a/msg3094592/#msg3094592) or both.But I think we will find the final reason. It simply takes some time.Quote from: dietert1 on June 14, 2020, 07:03:17 amDo you have a specification of those chokes (inductivity, core material ?)with best regardsAndreas

author: dietert1
author_rank: Super Contributor
timestamp: June 15, 2020, 05:32:03 am
content: The choke in the HP 3457A has about 2.4 to 2.7 uH at 10 KHz, similar to a 2 m wire. The higher number is for the scanner input which has 40 cm extra wire length. The ferrite ring has about 24 mm OD, 15 mm ID and a length of 7 mm with 4 turns. One can try this one: KEMET ESD-R-25D-8Now, that inductance is similar to what you can get with a clip-on ferrite (easier to mount). I measured two of those and got 3.4 and 4 uH. Würth has this nice set:http://www.farnell.com/datasheets/1789626.pdfYes there is no perfect wide band common mode filter part. For high end audio i have seen combinations of that with a wound choke like the one from Schaffner. I think 400 KHz means it works well for pulses of about 1 usec, while beads work better at the nsec time scale. A charge injection pulse from a CMOS MUX would be in the nsec time scale, if the resistance is 50 Ohms and it drives a stray capacitance of 50 pF.Regards, Dieter

author: Kleinstein
author_rank: Super Contributor
timestamp: June 15, 2020, 07:41:18 am
content: The auto zero current spikes from the DMMs would be from JFET switching and they have some filtering inside. So this would be relatively slow, more like µs and longer.For the 3458 it's a JFET turned of with some 1 mA maximum gate current and filtering with some 120 pF - 5 K - 82 pF - 5 K . So the really high frequencies would be there only from parasitic effects in the filter.

author: Dr. Frank
author_rank: Super Contributor
timestamp: June 15, 2020, 04:07:53 pm
content: The spikes look exactly like this. DCV 10V, zero input, 10µsec APERTURE, AZERO ON.Scope is set to 1MOhm, 1:1 input, therefore 5nA/div. The AZ measurement happens right in the middle of both group of spikes.It's been discussed in the book of Rado Lapuh "Sampling with 3458A", page 111, 112.Frank

author: dietert1
author_rank: Super Contributor
timestamp: June 15, 2020, 06:15:06 pm
content: If the source impedance is 5 or 10 KOhms like Kleinstein wrote, these spikes are very easy to suppress with a blocking capacitor. A well built reference should be able to drive a capacitor without ringing or oscillating.Regards, Dieter

author: TiN
author_rank: Super Contributor
timestamp: June 18, 2020, 12:31:06 am
content: I also did see shifts when F8846A DMM connected in parallel measuring same LTZ1000A-based reference. But 8846 is very far from being serious meter anyway.Said that, I do not see any measurable difference from connecting tandems of 3458A and 2002s together. I do often run big tandems like 3x3458 + 2x2002 + other meters for group logging on DUT DMM stability (not calibration obviously). So 2ppm shift is also unclear to me here.

author: branadic
author_rank: Super Contributor
timestamp: June 20, 2020, 06:23:54 pm
content: Turned out to be a simple issue with one button in the wrong place. Guard button on K3458A was in "low" position and not in "open". Guard of the cable was connected to case of the reference and Guard jack of K3458A, but on GND on K2002. This created a Guard loop, which created the differences.I was able to recreate this problem today. Having multiple meters in parallel can then influence the readings.So it's not the references and no E.M.I by WiFi or anything like this.-branadic-

author: dietert1
author_rank: Super Contributor
timestamp: June 21, 2020, 04:56:24 pm
content: Assume by "GND on K2002" you meant the Lo input terminal. Looked through some manuals, but no mention of "Gnd" nor "Guard". Maybe a K2002 doesn't have a separate guard terminal?I respect your findings, but can you explain a little how you arrived at the conclusion that no EMI was involved? Isn't the guard/shield all about EMI? How can guard connections affect a DVM reading in a lab without EMI?Regards, Dieter

author: branadic
author_rank: Super Contributor
timestamp: June 25, 2020, 11:28:37 am
content: Exactly, K2002 doesn't have separate Guard connection.QuoteI simply recreated the setup and repeated the measurement, switching the Guard button on K3458A from Open to Low, which resulted in changes of the readings on both meter, K3458A and K2002. I can show this measurement tonight for clarification.EDIT: Attached is the corresponding measurement.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: February 27, 2021, 02:45:56 pm
content: Hi folks,we are planing the next Metrology Meeting for september 2021. By then hopefully temperatures as well as vaccination for people at risk allows us to have a live meeting.I will try to get the lecturer that were planed for MM2020. More infos coming soon.-branadic-

author: Dr. Frank
author_rank: Super Contributor
timestamp: February 27, 2021, 03:51:46 pm
content: that's great, branadicI'll bring the 7000 with me, at leastFrank

author: HighVoltage
author_rank: Super Contributor
timestamp: February 27, 2021, 07:37:52 pm
content: Hello branadicThanks for letting us know, lets hope times will improve and the meeting will happen.

author: branadic
author_rank: Super Contributor
timestamp: June 23, 2021, 10:53:09 am
content: Save the date: 11.09.2021We are already working on a program incl. talks.Thankfully Nikolai Beev already agreed to join us live and talk about HPM7177.Wekomm is also in and talks about resistor standards, which was already planned for MM2020.Propably also Mr. Zirpel from the PTB could be with us and talk about calibration, but that has to be confirmed first.John Pickering agreed to join us at least remotely and give a talk too.I'm sure we will also have a nice discussion about LTFLU, LTZ, 2DW23x and similar, but also some very new "lowest drift/noise voltage reference". Teaser attached.-branadic-

author: okti
author_rank: Contributor
timestamp: June 23, 2021, 08:33:19 pm
content: Yay! Can't wait !

author: exe
author_rank: Unknown
timestamp: June 24, 2021, 11:41:56 am
content: How to buy a ticket?

author: Villain
author_rank: Regular Contributor
timestamp: June 24, 2021, 02:44:01 pm
content: exactly, how to buy a ticket?

author: branadic
author_rank: Super Contributor
timestamp: July 20, 2021, 09:43:35 am
content: Small updateWe are still working on the program incl. talks.Thankfully Nikolai Beev already agreed to join us live and talk about HPM7177.Wekomm is also in and talks about resistor standards, which was already planned for MM2020.Propably also Mr. Zirpel from the PTB could be with us and talk about calibration, but that has to be confirmed first.John Pickering agreed to join us at least remotely and give a talk too.A talk will be given by Eric Modica, Analog Devices, California USA, topic is secretI'm waiting for two more confirmations for talks.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: August 18, 2021, 10:30:14 am
content: Hi everyone,we are in the final steps of organizingMM2021. Here is a first hint on the program for that day9:00 Uhr Opening, André Bülau, Hahn-Schickard Stuttgart9:30 – 10:15 Uhr Online-Talk, „HPM7177 - an open hardware metrology-grade digitizer”, Nikolai Beev, Cern10:30 – 11:15 Uhr Online-Talk, „Aktueller Stand der Entwicklung von Präzisionswiderständen”, Guido Weckwerth, wekomm GmbH11:30 – 14:00 Uhr if possible lunch, discussion and comparison of Volt, Ampere, Ohm, …14:00 – 14:45 Uhr Online-Talk, „60 years in precision Circuits….Hobby, HP, Dana, Datron & Metron”, John Pickering, Metron Designs Ltd15:00 – 15:45 Uhr Talk, „Gold standard calibration (complete calibration of one range on 3458A)” and „History + developement of the RoHS compliante version and roadmap of the 3458A”, Ben Riddle, Keysight Technologies, Loveland USA16:00 – 16:45 Uhr Online-Talk, „ADR100x: An improved LTZ1000 Based Voltage Reference”, Eric Modica, Analog Devices, California USA16:45 - 17:00 Uhr Feedback to the eventDetails about registration coming soon, stay tuned.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: August 18, 2021, 03:58:20 pm
content: I was asked:QuoteThe talks will be available via a Webex conference to everyone registered for the event. Depending on where you are located it will take quite some coffee to not fall asleep in the middle of the night.-branadic-

author: e61_phil
author_rank: Frequent Contributor
timestamp: August 18, 2021, 05:16:54 pm
content: Will anybody from northern germany (Bremen) join? Maybe one can share a car.

author: syau
author_rank: Frequent Contributor
timestamp: August 19, 2021, 12:12:37 am
content: Quote from: branadic on August 18, 2021, 03:58:20 pmHow to register for just a Webex conference ?

author: branadic
author_rank: Super Contributor
timestamp: August 19, 2021, 04:24:54 pm
content: QuoteQuote-branadic-

author: ScoobyDoo
author_rank: Regular Contributor
timestamp: August 19, 2021, 08:37:56 pm
content: Hello Branadic, all - can anyone tell me if it is easy to take public transportation between airport of Stuttgart and University of Stuttgart - location of MM2021 event ?I could arrive on Friday and return on Sunday ...Thank you !Best regardsScoobyDoo

author: branadic
author_rank: Super Contributor
timestamp: August 19, 2021, 09:01:04 pm
content: Hi,there is an underground from the airport to university as well as from the main station to the university. Unfortunately, the tracks are currently being replaced and some of the stations in between being renewed, so that underground doesn't drive. However, there is a shuttle service from the airport and the main station to the university replacing the underground. And guess what, three weeks of the renovation are over and the weekend 11.09.2021 is the last weekend of renovation, on monday 13.09.2021 underground is driving again as normalNevertheless, shuttle works perfect and drives every 10min on weekend and every 5 minutes during the week.-branadic-

author: Teti
author_rank: Regular Contributor
timestamp: August 23, 2021, 07:36:26 pm
content: Please don't forget to post a lot of pictures or video

author: branadic
author_rank: Super Contributor
timestamp: August 24, 2021, 03:43:34 pm
content: Hello everyone,we today finished the official flyer, that you please find attached including the program.Online registration for joining the event is possible via: metrology@hahn-schickard.deRegistration requires:1. Name and nickname on eevblog.com if existent2. Registration for remote/online talks or for live event?In case of registration for the live event at Hahn-Schickard Stuttgart:3. Vaccination state (3G rules – geimpft, getestet, genesen – vaccinated, tested, healed)4. What will be brought to the live event?5. 1-2 questions to John PickeringPlease bear in mind, that due to possible Covid restrictions in September the number of people that can join the event live might be limited.Edit 1: The event is free of charge. For visitors that want to join live it is possible to arrive already on friday and to warm-up test equipment in our temperature controlled room.Edit 2: There is a hotel on the campus close to our location:https://commundo-tagungshotel-stuttgart.hotel-mix.de/-branadic-

author: ScoobyDoo
author_rank: Regular Contributor
timestamp: August 24, 2021, 06:53:25 pm
content: Hello Branadic & Folks - just confirmed that I will be present and hope to bring a METRON/FLUKE M7000 (ADR1000) and ADR1000 EVB ... - I will be on campus for 3 days - 2 nights.Best regardsScoobyDoo

author: branadic
author_rank: Super Contributor
timestamp: August 25, 2021, 08:28:56 am
content: Someone reported, that the above mentioned hotel has no rooms, so here are some alternatives:Bus connection to institute:• Pullman Stuttgart Fontana• ibis Styles Stuttgart Vaihingen• Vienna House Easy Mo. StuttgartWithin walking distance:• Römerhof Hotelbetriebs GmbH-branadic-

author: branadic
author_rank: Super Contributor
timestamp: August 25, 2021, 11:36:46 am
content: Prior to the event all registered attendees will get a link to our Webex conference as well as links to the online discussion tables.Webex can either be used as a local app or via your internet browser.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: September 02, 2021, 06:55:35 am
content: Morning,just a quick overview of what visitors will bring to the live event:- ein Keithley DMM 7510- Ich möchte meinen Satz Kalibrierwiderstände (100 Ohm bis 10M) zur Kalibrierung und mein 34401 für Gleichspannung bis 100V / Gleichstom bis 100mA und ggf. Justage mitbringen.- 1x KX-Ref, will attempt S7061 but this might not work out amazingly due to distances and transport (train) involved. And just maybe, if the stars align and me, JLCPCB and Mouser are fast enough- self designed LTZ board and/or self designed- Bringe die F731B und die W 7 sowie die restlichen LTZ´s und eine LTFLU mit. Mit Prema 5017 sowie Agilent 34411A - ergibt wohl eine Messorgie- K2000 mit Scanner, ESI Kelvin-Varney Poti, Selbstbau-Referenz mit MAX6279, läuft seit Mai 2019 mit einer Babyzelle (20000h), war schon beim MM 2019 dabei. Ich werde EMV-Bauteile für Tausch oder Verkauf mitbringen.- 3 LTZ1000-References, Solartron 7081- Möchte mein HP3458A mitbringen und evt. noch einen 4x Satz LTZ1000 Referenzen zum Nachmessen. Bin als mittelmässiger "Voltnut" an vielen Fragen zur Messtechnik interessiert und arbeite in der Branche als analoger Applikationsingenieur. Kenn im übrigen als ehemaliger LTC Mitarbeiter die LTZ1000 Entwickler Carl Nelson und Bob Dobkin persönlich.- Fluke 7000, LTZ #5 - battery powered 7,138V reference (Andreas design), several 10kOhm secondary standards (VHP202Z), a 1kOhm secondary standard (VH102), HP3458A, assortment of PTFE cables- Geräte: 10 MHz Rb, Fluke 902, Knick U/I-Kalibratoren, Keithley 237, 34970A, vllt HP 8922 + 1kW SMU (19“ 3x 4U)- Widerstandsbox, 1G Ohm Widerstand, LTZ1000 (branadic version), ADC (Kleinstein/Rerouter), Laptop- Fluke / Wavetek 7001 DCV standard (powered) and Fluke 1 Ohm, HP 1 kOhm and Guildline 10 MOhm standard resistors. Possibly also Keithley 5155 1 GOhm resistor.- Mitbringen würde ich einen Fluke 732B, der letztmalig vor zwei Jahren durch Vergleich mit einem beim MM2019 und der Maker Faire 2019 kalibriertem Fluke 732A von mir justiert wurde- HP 3458A, Digibridge 1689, verschiedene Widerstände, Kondensatoren, InduktivitätenWe do have our 3458A and at least one 2182A in the lab connected to a RPi, but I will also have my F7000s with me.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: September 02, 2021, 03:00:45 pm
content: For all of you arriving on friday, you can enter the institute and room from 4:00 pm on until 7:00 pm.-branadic-

author: exe
author_rank: Unknown
timestamp: September 03, 2021, 06:23:36 am
content: I'm so jealous! I'm on vacation on that day. Anyway, may be next year. Not sure how I could contribute to the event (apart for my small max6226 array). May be I'll make an oven-stabilized reference based on lm317. If there is a competition "best cheap reference", I'd participate in that.

author: branadic
author_rank: Super Contributor
timestamp: September 03, 2021, 10:32:40 am
content: The time slot for registration is closing tonight.We already hit the maximum limit for contributors for the live event. So if you haven't yet done, quickly register for the online event until tonight.EDIT: In case you have registered for the live event, but can't join for whatever reason, please let us know, as there are more people that are waiting to join the live event, but we are limited to 20 persons maximum.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: September 09, 2021, 11:38:58 am
content: Small update to everyone arriving on Friday, actually tomorrowI've booked a table for 8 pm at Sophie’s Brauhaus, Marienstraße 28, 70178 Stuttgart.-branadic-

author: eplpwr
author_rank: Regular Contributor
timestamp: September 11, 2021, 03:06:45 pm
content: Thank you, branadic / André, for an excellent MM2021!All the presentations were very good on interesting topics.Regarding Keysights behaviour, I'm out of words. Please note that this in no way reflects on the splendid arrangement of MM2021.Best regards,eplpwr

author: TiN
author_rank: Super Contributor
timestamp: September 11, 2021, 04:51:37 pm
content: Event was a blast, hugefor metrology professionals that did manage find time to show up and prepare excellent presentations. Special Thank you for organizers as well, you showing examples what can be done with a simple idea to get team together for good times.Not just performance of actual product, but also events and stuff like this motivates today hobbyists and tomorrow business decision makers to choose these products and not the others.My wish for Santa would be ADI sales team hearing and going forward with the desire from our small but friendly community to be allowed to buy ADR1000 parts (for full price, no need to do freebies). Maybe 5 years from now we will see someone here start a company and design first 9.5-digit DVM

author: Kleinstein
author_rank: Super Contributor
timestamp: September 11, 2021, 05:18:53 pm
content: I don't think there is a real need for a 9 digit DMM, unless you deal with superconductiing parts. There are still not many references that low. The noise is usually not the problem at the high end DMM. The problem is more like the linearity and the thermal effects. Because of the thermal effects, the very high resolution measurements usually can't be fast. I see at least a chance to see a new 8 digit meter.I found the persepective for the ADR1399 interesting as an easy update for an LM399 based design (if the voltage is about the same). Let's see if it will be actually available.

author: rigrunner
author_rank: Frequent Contributor
timestamp: September 11, 2021, 05:53:02 pm
content: A very enjoyable eventBig thank you to everyone involvedShame Keysight bottled it.Quote from: TiN on September 11, 2021, 04:51:37 pm+1 for This ^^^

author: macaba
author_rank: Regular Contributor
timestamp: September 11, 2021, 05:56:49 pm
content: Throughly enjoyable, my thanks to the organizing team and the presenters. Eric - thanks for the level of detail you went into, it was extremely educational!

author: maat
author_rank: Regular Contributor
timestamp: September 11, 2021, 05:58:20 pm
content: Thank you very much André. This was a great selection of speakers. I am truly excited to see the ADR1001. This could easily pave the way for a huge upgrade of the references used in university projects, where typically the designer is not an EE. Exciting futureAnd that Keysight stunt...wow, I can't believe they pulled that...

author: MiDi
author_rank: Frequent Contributor
timestamp: September 11, 2021, 06:12:41 pm
content: Absence of Keysight gave John Pickering at least enough time to answer all questionsEdit: he gave probably a hint why 3458A has only one precision resistor

author: The Soulman
author_rank: Super Contributor
timestamp: September 11, 2021, 06:15:34 pm
content: What did Keysight (not) do??

author: rigrunner
author_rank: Frequent Contributor
timestamp: September 11, 2021, 06:19:57 pm
content: Quote from: The Soulman on September 11, 2021, 06:15:34 pmMinutes before their talk was about to start their lawyers pulled consent.

author: MiDi
author_rank: Frequent Contributor
timestamp: September 11, 2021, 07:13:00 pm
content: Quote from: rigrunner on September 11, 2021, 06:19:57 pmActually it was on friday, branadic overlooked Keysights Mail.

author: branadic
author_rank: Super Contributor
timestamp: September 11, 2021, 07:14:44 pm
content: A hugh shoutout to todays speakers, namely Nikolai Beev (Cern), Guido Weckwerth (wekomm GmbH), John Pickering (Metron Designs Ltd.) and Eric Modica (ADI). This event would have been nothing without your contribution and talks. Thanks for all the details that otherwise noone else would have heard. It was a pleasure and an honor to listen to you. The applause belongs to you.Hopefully everyone jumping into the remote session had a little bit of fun and I hopefully covered most of the questions. Give me a break and let me recover on sunday. I'm on a business trip on monday, so I will get back to all the mails and feedback after that. Enjoy the rest of the weekend.André Bülau aka-branadic-

author: HighVoltage
author_rank: Super Contributor
timestamp: September 11, 2021, 07:19:27 pm
content: I have enjoyed the event very much.Thank you so much for organizing this.The remote access worked very well.

author: chris_11
author_rank: Contributor
timestamp: September 11, 2021, 10:05:01 pm
content: Was a great event. Still wonder why Keysight could not get their hands around an instrument which details filled a complete HP Journal in April 1989.http://hparchive.com/Journals/HPJ-1989-04.pdfIf a company can't even talk about over 30 year old test gear...

author: ScoobyDoo
author_rank: Regular Contributor
timestamp: September 12, 2021, 05:30:56 am
content: Hello folks - this was a great team event and many thanks to André & Claudia for all (hidden) efforts to make this event happen.Special thanks to all speakers Nikolai - Guido - John - EricI also wanted to thank the ADR1000 team in general- it is (was) a pleasure to work with them - ADI is still a great company and pleasure to work with ...We hope that CoVid is over next time so that we can join and enjoy the aftermath with friends(in local Brauhaus :-) ... LoL).Best regardsScoobyDoo

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: September 12, 2021, 06:02:41 am
content: Did ADI give a reason why for not releasing ADR1000 to general market?

author: syau
author_rank: Frequent Contributor
timestamp: September 12, 2021, 06:18:20 am
content: Anyone have a record of the presentations ?

author: ScoobyDoo
author_rank: Regular Contributor
timestamp: September 12, 2021, 06:22:55 am
content: Hello syau -Quote from: syau on September 12, 2021, 06:18:20 amThose will come for sure - but it can take a few days - some people need a breakBest regardsScoobyDoo

author: Dr. Frank
author_rank: Super Contributor
timestamp: September 12, 2021, 10:31:08 am
content: Many thanks to André and Claudia for the organization of this great event.The lectures all have been extremely rich in content, so a big Thank You also to all speakers.I returned my equipment safely and quickly home (only a 2h ride to Frankfurt, this time), and the comparison to my other standards this morning showed no shifts at all, within the usual 0.2ppm transfer variations.Therefore the nominal values I have provided yesterday for my 3458A, the resistors and the voltage references are valid.It was really a great joy to meet all you guys live on these two days, and hope that we'll see each other again in less than two yearsFrank

author: e61_phil
author_rank: Frequent Contributor
timestamp: September 12, 2021, 11:01:42 am
content: Quote from: Dr. Frank on September 12, 2021, 10:31:08 amThanks a lot to everybody who helped making this a great event!@Frank, Andre: I'm also very interested what the result of the 7000 reunion was?Best regardsPhilipp

author: BU508A
author_rank: Super Contributor
timestamp: September 12, 2021, 12:08:45 pm
content: I've promised to some TEA people to do a little report about the MM2021.It can be found in the TEA threadhere.Also from my side many thanks to the organizers, Branadic and Claudia, to all those contributors and, of course,to all participants which brought their devices so a lot of measuring could be done.At least, it was good for me to break out of this bloody Covid-bubble.Looking forward to (hopefully) the next MM in Stuttgart.

author: syau
author_rank: Frequent Contributor
timestamp: September 12, 2021, 12:15:29 pm
content: Many thanks to André and Claudia for the organisation of this great event. Due to time zone diff (UTC+8), the session on ADR1000 happened during my dinner time and my wife think I am having a remote lecture on electronicsThe session with John on Datron is fascinating as seldom have a founder of an equipment company talk about the company history

author: Zucca
author_rank: Unknown
timestamp: September 13, 2021, 12:06:43 am
content: Congrats from the far USA!!!!

author: xans
author_rank: Newbie
timestamp: September 13, 2021, 07:20:15 am
content: Maybe a little late to the party here, but a huge thank you to Branadic (and Claudia) for organizing and hosting the event.And of course a thank you to all the speakers involved (except for Keysight, though I appreciate the attempt).Last but not least, I want to thank the participants, it was very nice to meet you all and to compare all the volts, ohms, amperes and see all the t&m goodness.

author: okti
author_rank: Contributor
timestamp: September 13, 2021, 08:05:18 pm
content: Wow! Huge thanks and kudos to organisers and exceptional speakers. That was my first MM, won't be my last. Thank you!

author: ScoobyDoo
author_rank: Regular Contributor
timestamp: September 13, 2021, 08:31:57 pm
content: Hello everyone - I have an update for all potential ADR1000AHZ buyers:They can buy through ADI’s distribution arm. It is called ADXAnalog Devices Express (ADX) | Design Center | Analog Deviceshttps://www.analog.com/en/design-center/device-programming.htmlAlso any customer can reach out to Rui Zhou or Carlos Sanchez to inquire about product availability and sales of the ADR1000AHZ.ADI will provide them with a datasheet but no extensive technical support.This is why it is not on the web.Carlos.Sanchez@analog.comRui.Zhou@analog.comBest regardsScoobyDoo

author: MiDi
author_rank: Frequent Contributor
timestamp: September 13, 2021, 10:08:38 pm
content: If someone organizes group buy of ADR1000 for Europe, count me in

author: engiadina
author_rank: Contributor
timestamp: September 14, 2021, 08:55:11 am
content: We try to get a bunch of devices for wekomm. If ADI / ADX ever answers my mail I can tell you about the conditions and the numbers to get.But up to now, all my mails have been unanswered yet ... looks like many inquiries are coming in.Many regardsGuido

author: The Soulman
author_rank: Super Contributor
timestamp: September 14, 2021, 09:21:07 am
content: Somehow I don't think they (Rui and Carlos) appreciate every hobbyist emailing them to obtain a few (payed) samples of adr1000and asking them all sorts questions about the different versions that are in the pipeline, shipping estimates, delivery times etc..I'm sure they try their best to help everyone but imagine the amount of emails being sent, this is just a utter inefficient way of doing things for anything more than just a handful of people or businesses.I'd say they need to list it on the website like all the other parts and for customers to be able to purchase samples, perhaps with the agreement that AD can not and will not supply any engineering support for those purchased samples.Alternatively a group buy will work or even better, if a "normal" distributor would carry the parts in a web shop.

author: quarks
author_rank: Frequent Contributor
timestamp: September 14, 2021, 02:41:14 pm
content: I have contacted AD and asked if and how a private individual can order.If and when I will get an answer, I do not know.But my guess is they might feel bothered, when to many hobbyists contact them.

author: rigrunner
author_rank: Frequent Contributor
timestamp: September 14, 2021, 02:51:31 pm
content: Quote from: quarks on September 14, 2021, 02:41:14 pmI'm interested to see what their reply to this will be.If anyone in the UK is planning to buy via their company I'd like to add 5 to their order.

author: ScoobyDoo
author_rank: Regular Contributor
timestamp: September 14, 2021, 07:01:42 pm
content: Hello Folksgood news is coming - Carlos, Rui and ADI team are adding theADR1000AHZin the ADI webshop online - part will be visible within a day or so.You will be able to pay with credit card - no credit letter is needed and MOQ = 5.To be updated soon !Best regardsScoobyDoo

author: quarks
author_rank: Frequent Contributor
timestamp: September 14, 2021, 07:19:55 pm
content: Today I already received an answer from AD.My information is, it will be possible to buy with minimum order quantity of 5 units.I will check how exactly this works and will let you know.

author: rigrunner
author_rank: Frequent Contributor
timestamp: September 14, 2021, 07:59:17 pm
content: Quote from: ScoobyDoo on September 14, 2021, 07:01:42 pmSplendid news!Hats off to the ADI folks. They're making things happen pretty quickly for us

author: Dr. Frank
author_rank: Super Contributor
timestamp: September 14, 2021, 09:37:56 pm
content: Here are the comparison values for the five 7000 and the 732B.We had a calibration by Illya last year, and could confirm his values apart from F7000-1 within a few tenths of ppm.Now, after 9 months we brought together again all four 7000, and made some quick measurements on 10th September evening using my HP3458A, which was not yet fully stabilized, and one more precise one next day. (Has anybody made a comparison with the KS 3458A on 11th? Please send me your results!)Latter was done by Wolfgang and me, with my HP3458A, compensating each +/- polarity measurement by comparing and correcting to my LTZ #5, which is temperature compensated.This accounted for the vastly varying room temperature, as my HP3458A features a T.C. of its LTZ reference of about + 0.25ppm/K.Andrés measurements were corrected for the calibration protocol (+2.4ppm deviation).His measurements then were all +2ppm high, compared to mine, but otherwise consistent in difference.Wulf made another direct difference measurement between all 6 references, which were also consistent to my absolute measurements to less or equal than 0.2ppm.I observed, or estimate, that my F7000-3 drifted about -0.8ppm compared to my reference group during the last 9 months, so the absolute values from my HP3458A should be closest to the actual values.Unfortunately, we did not have any better baselining reference this year, so I also do not want to give any uncertainty estimation.I also provide the environmental parameters for my whole trip from Frankfurt area to Stuttgart/Vaihingen.You can see, that the room temperature on the MM 2021 Day had been between 23 and 27°C, not the best conditions for precision measurements, but I think we all did quite well despite that.Then in the pressure data you can nicely see, that I had to move my car from 130m level to about 400 ..500m, when quickly ascending / descending the precursors of the 'Schwäbische Alb'.As we've heard in one talk, atmospheric pressure variations might also influence such precision measurements.. but I doubt that we really are able to detect such an effect for this set up.I can recommend these data sticks from UNI-T, UT 330C and UT 330A. They are quite cheap, consume very few energy (battery lasts ~ 1.5 years if you sample once per minute).The user interface is simply horrible, so I provide the Excel sheet for convenient import and display of the .cvs - data.Please also take notice of my cool basement lab.Frank

author: ramon
author_rank: Regular Contributor
timestamp: September 14, 2021, 09:54:56 pm
content: Quote from: Kleinstein on September 11, 2021, 05:18:53 pmPlease, can anyone provide details about this. I did not join the online meeting so don't know what they said.I find very nteresting an improved LM399 version.

author: MiDi
author_rank: Frequent Contributor
timestamp: September 15, 2021, 05:25:28 am
content: Quote from: ramon on September 14, 2021, 09:54:56 pmADR1399 has half the noise of LM399 and will be released soon.

author: ramon
author_rank: Regular Contributor
timestamp: September 15, 2021, 07:12:57 am
content: That's great news, thanks!I am far more interested in testing the new ADR1399 than the ADR1000. Is it possible to get some devices for testing, or they are not yet in that phase?

author: Kleinstein
author_rank: Super Contributor
timestamp: September 15, 2021, 07:24:03 am
content: It think there is not really much testing needed with the LM1399. It is supposed to be rather similar to the LM399, just needs more curent to the zener part and is a bit more picky about the capacitance at the output. So the main change to a LM399 based circuit would be a smaller resistor to provide the current and maybe (details should be in the data sheet) a slight change (e.g. suitable capacitance, maybe series R) to capacitors that may be in parallel to the zener.The LM1399 was supposed to be offered later this year. Chances are a few prime customers (e.g. KS) already have samples.Time will tell how good the long term stability is. So it may need a little more time before we will really see it in 6 digit DMMs.

author: quarks
author_rank: Frequent Contributor
timestamp: September 15, 2021, 02:55:22 pm
content: Quote from: quarks on September 14, 2021, 07:19:55 pmI will post my updates here:https://www.eevblog.com/forum/metrology/adr1000-availability/

author: MiDi
author_rank: Frequent Contributor
timestamp: September 15, 2021, 10:32:20 pm
content: My results, more in the attachments.

author: Okertime
author_rank: Contributor
timestamp: September 16, 2021, 09:00:54 am
content: I would like to show the differential voltages measured between the Fluke 732B and two Fluke 732A before and after the meeting. Unhappily the 732B decided to drift away some days before the meeting and might continue to drift - we will see. I am monitoring the three standards for the last two years and know the 732B is the least longtime stable of them. But it is by far the easiest to transport. The measuring points are calculated from the average of 16 NPLC100 measurement in the 100mV range of a 3458A, followed by 16 NPLC100 measurements with reversed polarity (Dr. Frank´s recipe). All points are independent from each other. The plots show the real spread of data, you will get, when comparing traditional Zener voltage standards over longer time. No Volt-nut should believe a Zener voltage standard outputs a DC voltage - there is always noise on top of it.The red points are measured before the meeting, the blue data-points after the meeting. There are at least 80 points per day. A Dataproof 160A scanner is used to select the voltage source and to reverse the polarity.

author: dietert1
author_rank: Super Contributor
timestamp: September 16, 2021, 10:00:41 am
content: I would be interested in a log of the "round-robin" difference. It should be zero in theory but it isn't due to measurement imperfections, like time sharing of the meter or thermal EMF. I am wondering about a similar "drift event" between days 59390 and 59405 that appears only in the Fluke 732A#2-732A#1 diagram but isn't reflected in the other diagrams. The check sum can help to clarify this. Also this is meant to find out the significance of your conclusion about drift of your Fluke 732B.Regards, Dieter

author: Okertime
author_rank: Contributor
timestamp: September 16, 2021, 03:42:21 pm
content: You are right, I only measure differences and can see a drift. Everybody is free to believe the 732B is stable and the two others drift away at the same time with the same speed into the same direction. I made a plot showing the sum of the difference during the measurement loops and can not find any abnormalities.This plot includes the noise of the 732B and 732A#1 and 732A#2 and 3458A and scanner and cables and and...... The plot is auto-scaled - no point is outside the plot-range.I measured the noise-level of my Zener standards as well as the noise of HP3458A in the 100mV range at zero volt. Conclusion: more than 90% of the noise is coming from the Zener standards.

author: dietert1
author_rank: Super Contributor
timestamp: September 16, 2021, 05:58:13 pm
content: Thanks, your cross-check looks perfectly clean to a level of about 100 nV and the suspected -1.5 uV drift of the 732B is significant. Maybe your reference needs some care. I think 1.5 uV from an ovenized LTFLU is already suspicious.Regards, Dieter

author: ScoobyDoo
author_rank: Regular Contributor
timestamp: September 16, 2021, 09:09:28 pm
content: Hello folksThe ADR1000AHZ is now available from the ADI online webshop.The MOQ has been set as low as 5 (one) to reach all Voltnuts - (MOQ = 5).The part will be monitored for a period of at least six months to understand if this is a viable (sustainable) path for ADI -so pls. order as much as you can ...Best regardsScoobyDoo

author: miro123
author_rank: Frequent Contributor
timestamp: October 02, 2021, 01:54:11 pm
content: Can I find the MM video record from Stuttgard? I'm more interested on AD presentation Q&A.Many metrology threads refers to MM ADi presentation.

author: branadic
author_rank: Super Contributor
timestamp: October 02, 2021, 02:47:02 pm
content: No you can't. I didn't had the time to clarify on that and would have cut the video anyways. However, I'm now a few weeks off and can't address that.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: October 08, 2021, 11:30:36 am
content: Eric Modica already announced it at MM2021, now there is some very first datasheet available,ADR1399-branadic

author: miro123
author_rank: Frequent Contributor
timestamp: October 09, 2021, 06:45:06 am
content: I really wonder what will be the rumored ADR1001. There is not much free space for new product between ADR1399 and LTZ1000I'm newbie in this forum. Do we need to start separate ADR1399 thread?

author: Kleinstein
author_rank: Super Contributor
timestamp: October 09, 2021, 07:18:57 am
content: The data-sheet for the ADR1399 looks promissing, even a bit lower noise than I had expected. It looks like their ouput impedance curve was made with a slightly small capacitor (e.g. not accounting for the capacitive loss with a 1 µF X7R when used at 7 V). The need for the extra RC is not so bad as the resistor for the zener current is now less important.The MM2021 had a few more infos on the ADR1001: Like the ADR1399 it has the complete support circuit and temperature controller included, and the noise performance of the ADR1001, which is still quite a bit better than the ADR1399. There is also some scaling to 5 V or maybe 10 V. So it would be more like made to work with high performance DAC or ADC chips.

author: MiDi
author_rank: Frequent Contributor
timestamp: October 09, 2021, 07:56:29 am
content: Quote from: miro123 on October 09, 2021, 06:45:06 amWhy not? Simply start a thread.

author: branadic
author_rank: Super Contributor
timestamp: March 20, 2022, 09:48:12 pm
content: What about a Metrology Meeting 2022 in August?Are there any suggestions on possible talks for this years event? Would be nice to have some people talking about their privat projects related to metrology, as I fear it is hard to beat last years session. Any comments on that?-branadic-

author: cat87
author_rank: Regular Contributor
timestamp: March 21, 2022, 08:13:50 pm
content: Hey, I already asked you last year if there was gonna be a MM2022, so yeah, I'd be all for it

author: branadic
author_rank: Super Contributor
timestamp: March 23, 2022, 04:01:26 pm
content: Let's be a bit more specific, what about the 27th of August, with the possibility to arrive already on 26th of August?-branadic-

author: kleiner Rainer
author_rank: Regular Contributor
timestamp: March 24, 2022, 09:11:05 am
content: Sounds good - but I have to leave early, because that day is also the European Bat Night, and as a member of the local "Naturschutzbund", I will show our schoolchildren bats in their natural environment. Metrology alert: we use "bat detectors" to make the ultrasonic signals audible and determine which species we observe (mostly Pipistrellus pipistrellus).Greetings,Rainer

author: meandeev
author_rank: Regular Contributor
timestamp: March 28, 2022, 08:14:08 pm
content: Every date will fit+1 vote for this oneQuote from: branadic on March 23, 2022, 04:01:26 pm

author: bastl_r
author_rank: Regular Contributor
timestamp: March 29, 2022, 02:52:32 am
content: HelloIs this event for everyone?Do i need a invitation to participate?I only have a couple of kilometers to Stuttgart.regards

author: branadic
author_rank: Super Contributor
timestamp: March 29, 2022, 07:41:20 am
content: Hi folks,attached is the official announcement.As alway the event is for everyone who registered to it. The registration info will follow prior to the event, not today. It's just that you have enough time to plan everything around that date.I would also like to ask you for a contribution in form of a talk about a very interesting project you have been working on, such as a voltage reference, a resistor standard, a low noise amplifiers and such. That would help us all to make it an interesting and entertaining day. If you have any suggestion whom to ask for a talk, if you can make a contact to a very specific person that we could ask that would be very great too. Every support is welcome.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: May 16, 2022, 03:09:35 pm
content: Hi everyone,we are still looking for talkers and talks. If you like to contribute to the event or you know someone we could ask, please contact me. Thanks.https://www.hahn-schickard.de/veranstaltung-detail/metrology-meeting-2022-branadic-

author: branadic
author_rank: Super Contributor
timestamp: June 28, 2022, 08:41:13 am
content: Hi everyone,in about 2 months from now we have the event happening. Since noone made any suggestion for talks yet and I wasn't successful in aquiring some interesting talks either, my suggestion is that every participant gets some ~10 min time with ~2 slides to talk about his/her most interesting project as a base for a fruitful discussion. What do you think about that?-branadic-

author: Olivia
author_rank: Regular Contributor
timestamp: June 28, 2022, 10:10:35 am
content: Sounds good, I hope I can make it and at least visit.Might be too new in the metrology scene to be holding a presentation...

author: branadic
author_rank: Super Contributor
timestamp: July 29, 2022, 02:39:53 pm
content: The date for the event is coming closer, time to register for "Metrology Meeting 2022".As always, send a mail tometrology@hahn-schickard.dewith name, e-mail address, nickname and what you are about to bring with you.Please notice, this years event will by in person only, so there is no remote access.Everyone joining the meeting should prepare 2-3 power point slides for theopen pitchto present recent projects, results, purchase or whatever as a basis for a fruitful discussion in ourlive session.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: August 02, 2022, 08:43:46 am
content: Note: As always everyone is invited to arrive on friday afternoon/evening to drop off and hook up equipment so it can warm up.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: August 05, 2022, 04:35:13 pm
content: Let me remaind you all.We will have a special guest with us giving a talk. It's noone else than iconic Prof. Dr. Klaus von Klitzing.If you are still hesitating, during lunch you will have the opportunity to ask him questions face to face. Not yet convienced?-branadic-

author: branadic
author_rank: Super Contributor
timestamp: August 13, 2022, 10:32:08 am
content: In two weeks from now MM2022 will take place. Don't forget to register for it.-branadic-

author: alm
author_rank: Super Contributor
timestamp: August 20, 2022, 08:50:51 pm
content: I'm limited in what I can bring because I'll be traveling by train. So 35kg calibrators are out. Is anyone interested in measuringlow resistance standards(L&N 10 mOhm and 100 mOhm), orhigh resistance standards(Keithley 5155 1 GOhm and Penn Airborne 100 GOhm), space permitting? Obviously both need specialized equipment to measure with any accuracy, which I won't be able to bring. I'd have a measure of their value, but probably nothing particularly tight, never mind traceable.

author: MiDi
author_rank: Frequent Contributor
timestamp: August 21, 2022, 07:19:17 am
content: @branadic: Thanks for organizing this event, highly appreciated!Unfortunately I cannot be there this year, but I would like to participate remotely.

author: HighVoltage
author_rank: Super Contributor
timestamp: August 21, 2022, 11:56:42 am
content: Quote from: branadic on August 13, 2022, 10:32:08 amSorry to say, but unfortunately I can not come this year and would participate remotely.

author: maat
author_rank: Regular Contributor
timestamp: August 27, 2022, 06:01:58 pm
content: Thank you all so much for the lovely presentations and especially branadic and C. for organizing the event.I am so sorry I could not attend in person, because my whole family turned sick on Friday nightI hope to see you next year.Anyway I uploaded my presentation on Github here:https://github.com/PatrickBaus/mm2022

author: branadic
author_rank: Super Contributor
timestamp: September 03, 2022, 02:37:43 pm
content: It was again a very successful event, with interesting talks thanks to the open pitch session and the talk by Mr. von Klitzing, who took some time during lunch to answer questions, good discussions but also some intercomparisons of several references.To be honest, I had expected a bit more feedback here, but also results presented from that day. At least the results from the EU CalClub test run have been posted:https://www.eevblog.com/forum/metrology/eu-calclub/msg4385281/#msg4385281-branadic-

author: Sprock
author_rank: Contributor
timestamp: September 06, 2022, 09:36:29 am
content: Hello Voltnutsthis review is a bit late after MM2022 Stuttgart. Nobody got time anymore, even so pensionersAndré gave his intro to around 35 people and showed all his amasing previos projects.Dont´d know when he sleeps!He also managed to have a live session.Among us older also lot of young international people showed up.There were quite some colored and very interesting lectures.Noise on high stability Oscillators - Dr. W. GriebelAutomated Measurements - A. van der MeulenMy Ring comparison results - W. VongehrThree corner hat measurements - W. OelschlegelHorizon EDA - Lukas K.Visit Taiwan Cal Lab - TINHome made Calibrator - J. KrummsdorfSuper PulsCaps - R. SchmitzMeasuring smal pulses M. von RosenbergSelecting LM 399 P. BausMeasurement Technology for the extreme Demands E. SchreiberHighlight was Prof. Dr. Klaus von Klitzing talking about Quantum Hall Effect.At the end every body could hold his Novel Prize medal with one exception -nobody has to left the room before he got the medal backDuring lunch( finger food and drinks ) he gave a nice discussion before he left.After then there were busy measurements with all sort of Instruments, References and Resistors.Sorry for no more pictures. Only few space on the table were left empty.André provided a 3458 witch was calibrated (+- 5.5ppm ) a few days before the event.So everybody could compare his own Instrument or Reference to this value.Wulf has done the 3 corner hat measurements to find the lowest noise performeramong F7000, W7000, F732A/B.Now hopefully every body knows his " Volt - Ohm" respectively Referencwith correction factor seen on the cal paper of 3458 Instrument.André also showed the Ring comparison results done from may to august.For me the values varied in an small acceptable range, except one.This was also a big success and now a good starting point for the next round.A great THANK YOU André and to all the contributors.Hope to see you all healthy on the 4. MM Stuttgart also the this year missing people too.Sorry, no pictures from all contributor taken.Sprock

author: branadic
author_rank: Super Contributor
timestamp: September 10, 2022, 07:40:17 pm
content: At MM2022 Rainer Schmitz presented his idea of "SuperPulseCap as voltage reference" and brought some EVE SPC1550 with him. Fortunately, he gave me two of them for good reason, I wanted to test them in series for noise with the 0.1 - 10Hz LNA from user pipelie attached to my R9211 and did so today.So the caps and the LNA input were charged to 7.4 V and everything connected inside a cookie box. Attached is the result. The noise we are looking at is essentially the noise of the LNA itself (100 nVpp).So the caps can serve as a low noise reference to measure ADR/LTZ1000 zener voltage with nanovoltmeters like 34420A in difference mode.-branadic-

author: e61_phil
author_rank: Frequent Contributor
timestamp: September 10, 2022, 07:51:14 pm
content: Would be really interesting to measure the difference DC coupled. Even better against a proper reference. A slow drift downwards wouldn't be shown with the AC coupling of the LNA.

author: branadic
author_rank: Super Contributor
timestamp: September 10, 2022, 08:05:44 pm
content: I agree, that would be interesting.Wolfgang presented some measurements here:https://electronicprojectsforfun.wordpress.com/can-a-supercap-be-used-as-a-filter/with worse result. I guess that is due to the 34470A itself, Echo suggested that this could be due to charges being transported during Azero.I guess some low noise buffer behind the SuperPulseCaps could help.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: September 11, 2022, 08:54:47 am
content: During MM2022 the F700x system was running on battery, used on multiple instruments. During that time the low power LED on F7000-2 went red, so we directly reconnected the system to its power supply and everything seemed to be fine. It wasn't low enough to force a conditioning, puh.After the event, when all gear was back in our temperature controlled lab for a while I measured F7000-1 and F7000-2 on our 3458A and went home afterwards. Back home, F700x was reconnected to my ADR1000 setup. During the next days of measurements I noticed a ~0.2 ppm jump between prior and post MM2022.I ordered two new battery packs right the next day.https://www.ebay.de/itm/192544097733They meanwhile arrived and I hot swapped the packs yesterday - reference connected with its wall adapter to mains power, while battery pack was removed. Indeed, the battery pack of the suspicious reference already started leaking. Now that both references are back in the rack it seems like I got my ~0.2 pmm's back. More confidence to come within the next days. So please include that ~0.2 ppm's to your difference measurements.For all W/F7000 owners, better replace your battery packs earlier than later.-branadic-

author: ScoobyDoo
author_rank: Regular Contributor
timestamp: September 11, 2022, 02:02:54 pm
content: Hello Branadic - my Wavetek 7000 has undergone service and the original battery pack (10 cells of 850mAh NiMH) were replaced by 1700mAh cells (Ansmann) - I remember vaguely that we tried first NiMH cells with higher capacity - but those did not get fully charged with the FSM in place - hence we had to select a lower capacity - the autonomy should be around 18-20 hours after battery upgrade (850mAh => 1700mAh).I am little bit worried that the cells of 2200mAh might not become fully charged - pls. verifyHerzliche Grüße/Meilleures salutations/Best regardsBest regardsScoobyDoo

author: bsdphk
author_rank: Regular Contributor
timestamp: September 11, 2022, 06:26:58 pm
content: Can you try to measure the effect of changing temperature on the "supercap" ?When I played with one (diff. type) I found it was very sensitive to temperature, to the point of being usable as a high-resolution thermometer.

author: Okertime
author_rank: Contributor
timestamp: September 12, 2022, 10:54:48 am
content: During the meeting, I measured the voltage difference of some voltage standards to my F732Bwith a K2182 and logged the data with a sample rate of 62 ms.Here are the mean values of the measured voltage differences:F7000-1 - F732B = -42.97 uVF7000-2 - F732B = -13.36 uVW7000 - F732B = -12.58 uVF7000 Alm - F732B = -64.64 uVF732A Söh - F732B = 23.14 uV not sure about the signF732A Ron - F732B = -11.93 uV not sure about the signBecause I did not connect the measurement cables by myself to the last two instruments, I am not sure aboutthe sign of those two measurements.When attached to my F732B, the calibrated K3458A multi-meter measured 10.000054 V for both polarities - averaged by eye. According to the calibration protocol, the measured voltage of my F732B is 10.000000 V +- 5.5ppm.Than I used the program `Timelab`from John Miles to calculate the noise in form of overlapping Allan Deviation forthe measured voltage differences. The first attached plot shows the ADEV curves with estimated error limits.The second plot shows the same measurements in time domain.Immediately after coming home from the meeting, I tested the performance of my F732B by measuring and logging the voltage difference to my F732A#2 for 37 hours. Nothing has changed.The Allan Deviation of this measurement is shown in the black line in attachment three.All ADEV curves in attachment three show the RMS values of the noise of a device under test together with the noise of the reference - the F732B. The absolute noise level of my F732B is know by using previous measurements and 3-cornered hat method. After removing the reference noise from the RMS values, the absolute noise level of the devices under test is received. Plot four shows Allan Deviation curves after removing the noise of the reference.Allan Deviation curves are noisy as well but their noise can be reduced by measuring over long time. The measuring time during the meeting was limited and different for the DUTs. I estimate the AVEV curve to be trustworthy for F7000-Als up to 30 s, for F7000-1 and F7000-2 to 20 s and for W7000 to 10s.I also attach a PDF with 3-cornered hat measurements on Voltage Standards. I am not proud about this document - it was made with a hot needle. But the measurements are OK.My attachments disappeared - next try

author: alm
author_rank: Super Contributor
timestamp: September 12, 2022, 02:37:28 pm
content: Thanks for the results! Does the knowledge of ADEV allow you to make a more accurate estimate of the uncertainty of the voltage difference you measured than basic sample standard error of the mean?I calculated an uncertainty of 3.4 ppm for my 10 VDC measurements with branadic's 3458A based on GUM (k=2). The procedure was calculate standard error of the mean for my samples, convert the uncertainty of the calibration to standard error (95% confidence interval, so divide by 1.96), convert 90 day voltage specifications for 3458A option 2 to standard error by assuming it's a rectangular distribution, and add them all up as sum of squares, and multiply this by k. I'll publish the results when I'm done analyzing them all.

author: Kleinstein
author_rank: Super Contributor
timestamp: September 12, 2022, 03:21:01 pm
content: The ADEV is a more detailed desctiption of the noise. It is a bit comparable to a noise spectrum. The normal standard deviation is just the first point of the ADEV curve. In how fast the curve flattens out or even goes up to longer times is an indication of the extra low frequency noise. This part can be impartant if averaging over longer time is used to reduce the noise.For the measurements with the 10 V references the noise is usually only a small part of the uncertainty and other errors (e.g. cable thermal EMF, temperature drift, long term drift, linearity) dominate the uncertainty.

author: e61_phil
author_rank: Frequent Contributor
timestamp: September 13, 2022, 12:11:51 pm
content: Quote from: alm on September 12, 2022, 02:37:28 pmIf I understood it correctly the calibration of the 3458A already had an uncertainty of 5.5ppm?

author: alm
author_rank: Super Contributor
timestamp: September 13, 2022, 12:26:43 pm
content: The calibration uncertainty was 1.5 ppm (95% confidence interval). See attachment. The 90 day accuracy of the 3458a option 2 at 10 VDC is 2.65 ppm relative to the calibration (see datasheet), which I treated as a rectangular distribution.

author: e61_phil
author_rank: Frequent Contributor
timestamp: September 13, 2022, 12:43:21 pm
content: Ahh, thanks. I misinterpreted that post:Quote from: Sprock on September 06, 2022, 09:36:29 am

author: alm
author_rank: Super Contributor
timestamp: September 13, 2022, 12:48:39 pm
content: There's an offset of I believe 5.4 ppm in the 10 VDC calibration, but that's not uncertainty, that's a known value you can calculate from the calibration certificate: the expected value is (min limit + max limit) / 2, and the 3458a reading is also in the certificate, so you can calculate the offset from that (keeping the 1.5 ppm uncertainty), and correct the readings from that. Just pay attention to the sign.I don't have the numbers in front of me, so I can't tell you the offset that I used.

author: e61_phil
author_rank: Frequent Contributor
timestamp: September 13, 2022, 12:59:58 pm
content: I would calculate a correction gain not an offset. But for comparison of just 10V it doesn't matter. For measuring of 7V it is important.

author: alm
author_rank: Super Contributor
timestamp: September 13, 2022, 01:17:55 pm
content: That's fair, but the only data I have was for references that measured 10 V +/- 10 ppm, so there offset or ratio does not matter. If you're analyzing data from ~7V references, then ratios is absolutely is the way to go.

author: alm
author_rank: Super Contributor
timestamp: September 20, 2022, 09:26:01 pm
content: I finally got done with analyzing all data I collected, so here are the results. For all data from banadic's 3458A my procedure was that I calculated the expected value from the calibration certificate by the formula the certificate gives: (lower limit + upper limit) / 2, and divide this by the reading to get the correction factor to convert the observed reading to what at the time of calibration would have matched the value of the cal lab. I did not have access to a calibration certificate for the Keithley 2182A, so I have not corrected these values. For all 3458A measurements the unit was set to defaults, NDIG 9, NPLC 100.For the uncertainty, in the case of the 3458A, per GUM, I calculated it from these three terms:1. The standard error of the mean from the observed measurements2. The uncertainty from the calibration certificate (a 95% confidence interval) divided by 1.96 (the coverage factor of a 95% confidence interval as recommended per GUM)3. The 90 day uncertainty (for absolute measurements) or 10 minute transfer stability (for voltage comparisons) as a rectangular interval converted to a standard uncertainty by \$\frac{a^2}{3}\$ where a is the specified uncertainty.I calculated the sum of squares of these terms, and multiplied by the coverage factor k = 2.For the Keithley 2182A I did not have a calibration uncertainty, and the uncertainty fo the 2182A was small compared to the observed standard error of the mean, so I took the most conservative 2 year specifications with analog filter on, converted this to standard uncertainty the same way, calculated the sum of squares of this and the observed, standard error of the mean, and multiplied this by the coverage factor.DC voltage referencesFirst the results of comparing the various Fluke/Wavetek 7000 DC voltage standards. I did both absolute measurements with branandic's 3458A that had been calibrated about two weeks before the event, and also did relative measurements between my F7001, which was running on battery all the time and not running inside the mainframe, by connecting the negative terminals using a low-EMF spade lug lead, and then connecting the Keithley 2182A as measuring between the positive terminals.With both methods I measured a roughly equal number of samples using both polarities of the meter, took the average of either sign, and then inverted the sign of the negative polarity readings, and report the average of the two groups with the standard error of the mean propagated all the way through. There was some confusing with the guard switch on the 3458A, which appears to becomea tradition at the Metrology Meet events: Both branadic and I had verified the guard switch was set to open in the morning. But somehow at the end of the day the switch had changed to connect guard to lo. And even without any other meters connected in parallel, connecting the guard to the same W7000 terminal as the lo lead resulted in a -2 ppm shift in reading compared to without guard connected (or with guard connected and the switch set to open). I don't understand this, and want to try to reproduce this on my own 3458As. So I ended up ignoring all data with guard connected and the guard set to lo.I measured the ambient temperature using a Uni-T UT330C environmental logger and combined this with the other data based on time stamps.Absolute measurements using 3458Adevice under testguardcountambient temperature (°C)mean value (V)expanded uncertainty (V, k=2)Fluke 7001 on battery (alm)with guard to open5022.609.9999350.000034Fluke 7000 on battery (#4)with guard to open322.509.9999860.000034Fluke 7000 on battery (#1)no guard, to lo522.509.9999590.000034Fluke 7000 on mains power (#2)no guard, to lo1022.459.9999870.000034Fluke 7000 on mains power (#4)no guard, to lo1022.509.9999870.000034Fluke 7001 on battery (alm)no guard, to lo1022.409.9999370.000034Fluke 7001 on battery (alm)with guard to open522.409.9999360.000034The first set of readings of my F7001 was done right after ACAL DC with a larger number of readings and proper guard connection, so is probably the best absolute DCV measurement of the bunch. The rest roughly an hour later, some on battery and some on mains power due to a low battery condition.Relative comparisons using Keithley 2182AAs a secondary check we measured the difference between my F7001 and the other F7000 units using a Keithley 2182A nanovoltmeter. We used my F7001 as reference because it was fully independent, running from battery and not connected to the mainframe. This reduced the risk of ground loops, although in theory the F7000's isolated power supply should prevent those ground loops even when all are plugged into the same mainframe and running from mains power. I converted the mV values to ppm of the F7001 (alm) reference, and the expanded uncertainty to ppm of F7001 (alm).device under testcountambient temperature (°C)mean difference to F7001 (alm) (ppm)expanded uncertainty (ppm)Fluke 7000 on battery (#1)2722.5000002.1271290.008974Fluke 7000 on battery (#2)2622.5000004.9863890.012099Fluke 7000 on battery (#4)2522.5409095.1075280.011392Comparing 3458A measurements and Keithley 2182A measurementsTo compare the 3458A values to this, we can also consider the 3458A readings taken within 14 minutes as a series of relative comparisons between the references. This reduces the uncertainty to the 10 minute transfer stability. For this, I converted the values to the difference to my F7001 (in ppm), since the 2182A measurements were also relative to my F7001. I also converted the expanded uncertainty to ppms of the F7001 (alm) value based on the transfer stability. For this I only considered readings with the guard disconnected (and set to lo).device under testcountambient temperature (°C)mean difference to F7001 (alm) (ppm)expanded uncertainty (ppm)Fluke 7000 on battery (#1)522.502.2630020.11695064Fluke 7000 on mains power (#2)1022.455.0960050.11834481Fluke 7000 on mains power (#4)1022.505.0980050.12231724Fluke 7001 on battery (alm)1022.400.0000000.11564350These sets of measurements can be compared, with the K2182A clearly having the better resolution and noise under these conditions (error bars are expanded uncertainty at k=2):The data as table:labelmean difference (ppm)expanded uncertainty (ppm)1 - 3458A2.2630020.116950641 - K2182A2.1271290.0089742 - 3458A5.0960050.118344812 - K2182A4.9863890.0120994 - 3458A5.0980050.122317244 - K2182A5.1075280.011392alm - 3458A0.0000000.11564350To me the agreement confirms the validity of both setups, and that there were no ground loops or other things going on here.AC voltage referenceI brought a Fluke 510A 2400 Hz AC voltage standard that I had no history on. I'll report the value here in case someone else measured this unit. I measured it using the 3458A and calculated expanded uncertainty the same was as DCV (obviously using different values for calibration data and specifications).device under testcountambient temperature (°C)corrected mean (Vrms)expanded uncertainty (V, k=2)Fluke 510A1622.510.0007040.001895ResistanceI brought an almost full decade set of standard resistors from 10 Ohm to 10 MOhm. I measured them using branadic's 3458A, relying on its absolute accuracy, with the following settings. For <= 1 kOhm range, I used 4-wire Ohms, NPLC 100, OCOMP ON, DELAY 0, NDIG 9 and otherwise defaults. For the 10 kOhm range, I used the same settings, but DELAY 1. For the 100 kOhm range, I used the same settings, but DELAY 5. For ranges >= 1 MOhm, I used 2-wire Ohms, OCOMP OFF, DELAY 0.I had three temperature sources for this: The UT-330C measuring ambient temperature, an industrial PT100 sensor measured by a Fluke 189 that I put in the temperature well for the resistors that had one (including the SR104), and in the case of the SR104 the internal thermistor measured by branadic's HPAK 34401A.device under testcountambient temperature (°C)temperature PT100 (°C)SR104 thermistor (°C)mean resistance (Ohm)expanded uncertainty (Ohm, k=2)difference from calibration value in ppm (year)SR104-alm2022.65000024.67997822.435659999.9303000.099929-5.57 (1993)SR104-S122.40000025.00000022.9640010000.0719990.099854+2.90 (2002)SR104-alm522.50000025.00000022.682009999.9816000.099856-0.44 (1993)Guildline 9330-100k522.66000024.993153100004.4599991.034870HP 11103A1222.55000024.6056621000.0124080.010093Fluke 742A-10922.53333325.94474410.0003910.000237Fluke 742A-1M1022.60000025.2741341.000020e+0618.132762Guildline 952065122.49215725.2796439.999867e+06728.569857I'm slightly confused by the SR104 measurements: The initial series of measurements, shortly after ACAL DC+OHMS on the 3458A, had a lot of drift during the measurement, producing a standard deviation of 0.9 ppm over 20 measurements, while it was much more stable during the later series of 5 measurements, about 3 hours after ACAL. There is a 5 ppm difference between the two readings, which is more than I would expect either the SR104 or 3458A to change over the span of 3 hours. So I'm unsure which value to trust. The second value is closer to its 1993 calibration value, for whatever that's worth.I attached all raw data as a zip file. Note that the UT330C clock was set to UTC+1. All other times are in UTC. I corrected for this in my results.2023-11-20 Edit:I made a mistake calculating uncertainty for the 3458A DCV transfer measurements. I mistakenly included the calibration uncertainty, which is not relevant for ratio measurements like this, in the uncertainty calculation. I updated the two tables showing relative measurements based on 3458A data, and the figure comparing HPAK 3458A measurements to Keithley 2182A measurements.

author: Dr. Frank
author_rank: Super Contributor
timestamp: September 20, 2022, 10:19:43 pm
content: Thanks alm for for your very interesting analysis!!Concerning manual resistance measurements, I strictly recommend these settings:'OHMF 1000;APER 1;OCOMP ON;TRIG HOLD;DELAY 0.1;'; // up to and for 1kOhm'OHMF 10000;APER 1;OCOMP ON;TRIG HOLD;DELAY 1;'; // OCOMP requires settling time, 1s for 10k due to polarization'OHMF 100000;APER 1;OCOMP ON;TRIG HOLD;DELAY 5;'; // OCOMP requires settling time, 5s for 100kand then NRDGS 16; STAT ON; TRIG; reading statistical data afterwards.You have to check, though, if 1sec delay time is sufficient for the SR104. Think of the mass of oil and these many stacked resistors inside. The polarization relaxation effect might take longer than with a 5450A or a VHP resistor. The StD should always be around 0.2ppm, using PTFE cables with its shield connected to Guard and to case of the reference resistor.APER 1 (equiv. to NPLC 50) makes only a 1sec long uninterrupted A/D conversion and 1 sec OCOMP phase, 4sec in total for 10k, therefore DELAY time applies 2 times only, whereas with NPLC100, which are 10 times NPLC10 measurement cycles, 20 times DELAY time apply, i.e. for 100k that takes forever, 100sec plus x.I have no clue, why the 3458A behaved that different a few hours later.By chance, didn't you compare Andrés travelling LM399, which many of the absent volt-nuts measured in the ring-comparison, with evidently or hopefully < 1ppm uncertainty?Frank

author: alm
author_rank: Super Contributor
timestamp: September 20, 2022, 11:15:28 pm
content: Thanks for your response and insights, Frank! Those settings are close to what I used. I'll use DELAY 0.1 instead of DELAY 0 for 1k and under in the future. I was using ~1m PTFE cables with shield attached to guard (with guard set to open) on the 3458A and to the resistor guard / shield when available. I'll run some tests with the SR104 using different values of DELAY. TiN also suggested that measuring the 10 kOhm on the 100kOhm range of the 3458A is more stable because the 100kOhm range uses the most stable VHP 40 kOhm resistor. I've always used NPLC 100 and lived with samples taking forever at 100 kOhm, but APER 1 makes more sense with large delay values indeed.I'm used to recording values via GPIB, so I recorded the individual values on paper. This has the advantage that it allows a more in depth analysis. For example I found for some of the measurements I did in the past that using certain procedures the first or last sample in a series might be off, and by recording individual values it's easy to check if leaving them out substantially improves the standard deviation. For example, re the unstable SR104 readings, I can easily plot the values and learn that it's not a monotonic drift, and that the range of the values is a little under 3 ppm. Something not easily learned from descriptive statistics.What's your opinion of using 2-wire vs 4-wire for resistances up to 10 MOhm? I've always used 2-wire for 1 MOhm and up, since the Fluke 742A-1M only has two terminals, and I figured they know what they're doing in balancing contact resistance and leakage. But on the 3458A cal certificate they test the 1 MOhm resistance only in 4-wire mode, and 10 MOhm in both, so maybe I should use 4-wire resistance for 1 MOhm?I wasn't aware of the traveling LM399 until late in the day, otherwise I'd have certainly liked to measure it. I hope my data on the F7000s at least helps anyone who measured relative to one of the references to relate the values to the other references and to the 3458A's calibration. That's one of the motivations for publishing this data: if someone measured for example one of my resistors using their multimeter, then this gives my best estimate of their absolute value with uncertainty.

author: Kleinstein
author_rank: Super Contributor
timestamp: September 21, 2022, 06:50:51 am
content: The APER1 uses a 1 second integration at a time (=50 PLC), but noise wise this is not equivalent to 5 x 10 PLC conversions because of 1/f noise. Chances are this would be more comparable to 2-3 x 10 PLC. There is little return in extending the integration time very much. Using the 10 or 100 PLC setting has the advanatge that most of the calibrations and CAL also use this mode. So there is no additional step between different integration times (though likely not a big difference).For the delay needed the relevant factor is not the physical size of the resistor, but the parasitic capacitance and the quality (especially dielectric absorbtion) of the dielectric there. If in doubt one should do a measurements with 2 different delay settings (e.g. dealy 5 and delay 10 for the 100 K resistor) to see if there is a difference.The needed delay should depend on the resistor to test and not the range. So for testing the 10 K resistor in the 100 K range the shorter 1 second delay should be sufficient.The 100 K resistor range does not directly use the the VHP40K resistor, but the 50 µA current source is directly measured to this resistor in the ACAL procedure.The source for the 10 K range uses the 100 µA current source and this could also be (and likely is) directly measured relative to the 40 K resistor.A difference is that the 10 K range would use amplification of the voltage, while the 100 K range uses directly the 10 V range.

author: Dr. Frank
author_rank: Super Contributor
timestamp: September 21, 2022, 08:23:56 am
content: Quote from: alm on September 20, 2022, 11:15:28 pmThat's all not correct. The 40k VHP101 resistor is used only during ACAL, but not used during measurement. See CLIP.10k measured in 100k range is at least 10 times less "stable", because you have 10 times less resolution, and because the reference current is10 times smalleronly half as big as in 10k range, leading to increased noise. You should see that in the StD.TiN might have confused this with the HFL specification, where Fluke obviously specified a betteruncertaintyTransfer Accuracy for the 100k range compared to 10k. This I can not confirm, as I regularily achieve transfer accuracies of about 0.2ppm for the 10k range.10k resistors measured on the 10k range, and 100k on 100k range both yield a StD of around 0.2ppm as well.That's also valid for a 1k resistor in 1k range, of course. Concerning absolute uncertainty, that might be different, depending on how or where the 40k VHP101 resistor is implemented in the ACAL chain, i.e. which of the Ohm ranges is transferred first. Each consecutive 10:1 range transfer then always increases the uncertainty by about 0.33ppm, or so. But the uncertainty specifications are quite wide, anyhow.One should study the description in the hp Journal 4/89, once more.Quote from: alm on September 20, 2022, 11:15:28 pmThat's mainly a question of measurement time. In the end, using APER 1 is about 6 times faster compared to NPLC100. The lesser averaging is also sufficient, if you simply judge that from the achievable StD value of 0.2ppm, i.e. NPLC100 won't give you an advantage here.Quote from: alm on September 20, 2022, 11:15:28 pmYes, I also make these measurements via GPIB and calculate the statistical data inside my program, using the Welford algorithm. As well for DCV measurements.Mostly, there is no need to skip any extreme values (outliers), but the first sample of an armed and triggered data set might be off, sometimes.There's even a small footnote in the specification, I think for each DC mode of the 3458A, that the first reading might be off by several ppm.I append an example from my old TP program.I always measure the resistors temperature and correct for its T.C. to R(25°C), 4th column.The measured resistance values directly from the 3458A are in the 3rd column, and you see how stable these are, giving 0.12ppm StD in the end.I read the data with 8 or 9 digits, using DREAL format, as normally the resolution of Ohm would be limited to 7 digits only.But this was an exceptionally good measurement.Quote from: alm on September 20, 2022, 11:15:28 pmWell, calibrating and measuring are two different stories, concerning 2W or 4W.For regular measurements, I also use 2W for 10M and above, because it's really less noisy, due to less cables involved.If you want to measure 1M with < 1ppm "accuracy", you must use 4W, that should be evident due to around 0.2 Ohm cable resistances.Quote from: alm on September 20, 2022, 11:15:28 pmYes, much appreciated!Maybe you have a look to Andrés publication of our ring comparisonhttps://www.eevblog.com/forum/metrology/eu-calclub/msg4385281/#msg4385281which indicates that his calibrated 3458A (#18) reads a bit higher compared to the two calibrated references with low uncertainty (#2, #13), which we had in our group.In the end, the readings of his 3458A seem to be within 1ppm, If I estimated that correctly.Frank

author: branadic
author_rank: Super Contributor
timestamp: September 21, 2022, 09:44:58 am
content: Hello,at the "Metrologietage" 2020 in Kassel I heard a talk "Neue Messmöglichkeiten im Hochohmbereich" given by B. Schumacher and C. Rohrig, both from PTB. They presented the results of a K2 comparison:- participation in CCEM K2 1999 and 2012- in 1999 unknown systematic error detected- apparently, a solution had been found- Re measurement in 2012 showed:the error is back againwhere PTB was off measuring a 10meg and a 1G resistor.They came to the conclusion:- Looking at the result, the possible discrepancy in the CCEM K2 can be attributed to excess dielectric absorption in the wiring used.- A change of the wiring reduces the necessary waiting time for the measurement.Beforehand they were using PTFE insulated cables (known for piezo electric effects) as most of us do, but changed to some low noise cable with additional carbon film? to avoid effects coming from the cables.Just in case someone is interested in this info.-branadic-EDIT:https://www.koax24.de/produktinfos/triaxialkabel/uebersicht/001101.htmlhttps://www.koax24.de/produktinfos/triaxialkabel/uebersicht/g-02330-ht.html

author: alm
author_rank: Super Contributor
timestamp: September 21, 2022, 07:49:50 pm
content: Quote from: Kleinstein on September 21, 2022, 06:50:51 amI'm going to run some tests here with different resistors and cables, but collecting the data will take a while given I'm testing up to delay 10.Quote from: Kleinstein on September 21, 2022, 06:50:51 amQuote from: Dr. Frank on September 21, 2022, 08:23:56 amYou're both right, the standard deviation when measuring 10 kOhm is substantially higher on the 100 kOhm range. I picked some equal length sequences of samples, so there will be some difference in environmental conditions etc, explaining the variance of the variance:dutdut_settingrangemeanstdcountsemSR10410 kOhm1000010000.0581870.001831440.000276Fluke 5450A10 kOhm1000010000.4472710.001022440.000154Fluke 5450A10 kOhm1000010000.4681340.001130440.000170SR10410 kOhm1000010000.0694910.001294440.000195SR10410 kOhm10000010000.0709290.002691440.000406Fluke 5450A10 kOhm10000010000.4754530.003017440.000455Quote from: Dr. Frank on September 21, 2022, 08:23:56 amThe program I commonly use to collect data will sample continuously and automatically change a change in DUT by a change in value over an absolute and relative threshold. But sometimes when changing connections late during a sample the change is too small to be detected, but just enough to affect the standard deviation. For those measurements I'll discard the last sample in each series.Quote from: Dr. Frank on September 21, 2022, 08:23:56 amThe normal ASCII result gives me 10 digits for the 10 kOhm range using NDIG 9. Looks like a nice program. I separate acquisition and analysis, so my acquisition programs just write raw data to CSV files, and the main thing is to record all important parameters, for example last ACAL time or TEMP? value. I just added a column "delay" for resistance measurements with the 3458A, since I'm going to be changing that. I do the analysis separately in Jupyter notebooks, where I then write functions to analyze a set of voltage reference comparisons, for example. There I will combine data from multiple sources like environmental sensors in addition to the meter readings. In the case of the MM2022 data I manually entered it in CSV files but otherwise used pretty much the same analysis I use for the data I generate in my own lab.Quote from: Dr. Frank on September 21, 2022, 08:23:56 amWell, I don't expect <1 ppm accuracy (or "accuracy") from a 3458A measuring a 1 MOhm resistor, but I guess I should start using 4w measurements for 1 MOhm in the future either way.Quote from: Dr. Frank on September 21, 2022, 08:23:56 amBased on my analysis of the last calibration certificate (nominal and as found), the 3458A read 5.4 ppm high measuring 10 V, on the 10 V range at the time of calibration, with a calibration uncertainty of 1.5 ppm (95 confidence interval), and 2.6 ppm of value + 0.05 ppm of range 90 day accuracy (I assumed this to be a uniform distribution). The points where reported as passing but within one expanded uncertainty of the limit (P‡). I corrected the results and uncertainties I gave for this. Based on this, I'd think it would have been more than 1 ppm high, although this is of course a measurement at a single point of time on August, 17. If you'd compare it to previous calibration certificates, which I don't have a copy of but I'm sure branadic could share, you might be able to establish a better estimate of what the value was X months ago.Quote from: branadic on September 21, 2022, 09:44:58 amInteresting! Was it really dielectric absorption? Or tribo / piezoelectric effects? I'd expect measuring MOhm resistors to be a DC only process that would not use offset compensation or AC excitation. Would dieletric absorption really be so slow that it added substantial waiting times? According to Keithley's low level measurements handbook, PTFE is quite good for dieletric absorption, but not so great for piezo/triboelectric effects. Something like polyethlyne, which is I believe what the low noise Keithley cables use, with additional lubrication between layers to to reduce the effects even further, might perform better, then. I do have such cables that I use with electrometers, but adapting them to binding posts might be a pain.

author: Kleinstein
author_rank: Super Contributor
timestamp: September 21, 2022, 08:44:19 pm
content: Dielectric absorbtion does extend to very low time scales, it just gets a bit more tricky to measure when very long. The US MIL standard uses some 15 minutes waiting time.With longer time the effect on the resistance measurement gets naturally smaller: due to the DA a small fraction of the capacitance effects the reading longer than normal. The required waiting time is not so much dectated by the time constant of the DA but more by the size / amplitude and the capacitance. The dielectric absorbtion kind of extends the RC time constant by a factor of the materials DA (some 1E-5 for PTFE to 1E-2 for PVC) divided by the required accuracy (e.g. 0.1 ppm).There is not just dielectric absorbtion of the isolation material (that part should be relatively small with good isulators), but there are also more macroscopic partially isolated islands that can act like dielectric absorbtion. An especially bad example to avoid would be a floating shield / guard. Part of the absorbtion can also be inside the meter (e.g. from the PCB, terminals,protection circuit).The lower ohms ranges may have some thermal effect in the ohms current source. Here it can help to use the same 10 or 100 PLC and delay as during ACAL. So for the 10 and 100 Ohm ranges extra delay may be more of a problem than good.For the stability of the 3458 resistance ranges one contribution is the OP-amp to regulate the current source. This is a low bias JFET OP-amp that does have 1/f noise. More waiting time can lead to additional noise as the overall time gets longer. Ideally the offset compensation part would also correct drift and some 1/f noise of the OP-amp, but with the current hardware it does not look like this is done.A good warm up and the time from ACAL may be important to get the best accurcy for the resistance measurements.For the metrological measurements the noise would however usually only be a small factor to the uncertainty. The more tricky part is drift and similar errors.

author: alm
author_rank: Super Contributor
timestamp: September 21, 2022, 09:25:00 pm
content: Quote from: Kleinstein on September 21, 2022, 08:44:19 pmBut apparently the presentation claimed that switching away from the standard PTFE cables improved the situation. I'm not sure if you can do much better than PTFE for DA, so maybe some very low capacitance cable? Or reducing the capacitance with a driven guard?

author: alm
author_rank: Super Contributor
timestamp: September 22, 2022, 12:00:22 am
content: We again had the issue of a 3458A guard switch mysteriously getting set to LO while the guard was connected to the low lead at the voltage reference side and this affecting our voltage reference measurements. On branadic's 3458A, the effect was about -2ppm for both positive and negative values relative to the guard switch set to OPEN. Disconnecting guard has no measurable effect compared to connecting it while it's set to "OPEN". I find it truly odd that setting the switch to LO while the guard is connected to the LO lead has any different effect than not connected the guard, so I tried to replicate it on my 3458As at home. I am using a different shielded 2-wire PTFE cable with low EMF spade lugs than at MM2022, and was measuring the Fluke 7001 while powered from battery and not connected to anything else to prevent ground loops.On both my 3458As, #1 and #2, there was a clear effect. See these two plots. I plotted the absolute values of both positive and negative measurements, and marked measurements with and without guard. The first conclusion was that the guard switches on my 3458As are very intermittent. A clear sign of how often I do unguarded measurements. I actually had to hold down the guard button for a reliable connection when setting it to LO.For #1, the effect of connecting guard to low appears to be about -6 ppm to -8 ppm for both positive and negative (note that the negative values are shown as absolute values). Error bars indicate standard deviation, but are barely visible because the standard deviation is < 0.1 ppm. I measured the resistance between the guard and lo terminal, and with the switch set to LO it measured ~1 Ohm, and with the switch set to open it measured roughly 390 Ohm. On my #2 unit I measured > 40 MOhm when the switch was set to open.For #2, the effect is about -2 ppm. I don't know if this is related to the higher open resistance.Here is the same data as table:3458A #1dutdut_settingguard_settingag3458a_1_dcvlastlastlastmeanstdcountgroup13F7001bat10 Vopen9.9999443.452683e-071914F7001bat10 Vlo9.9998812.727258e-071915F7001bat10 Vopen9.9999454.649933e-071816F7001bat10 Vlo9.9998823.685633e-071617F7001bat10 Vopen9.9999444.956515e-073318F7001bat-10 Vopen-9.9999452.952243e-072419F7001bat-10 Vlo-10.0000154.131728e-071720F7001bat-10 Vopen-9.9999453.375280e-071821F7001bat-10 Vlo-10.0000153.458366e-071822F7001bat-10 Vopen-9.9999453.184028e-07403458A #2dutdut_settingguard_settingag3458a_2_dcvlastlastlastmeanstdcountgroup1F7001bat-10 Vopen-9.9999811.874827e-07212F7001bat-10 Vlo-10.0000021.782087e-07163F7001bat-10 Vopen-9.9999811.541816e-07194F7001bat-10 Vlo-10.0000041.949000e-07175F7001bat-10 Vopen-9.9999811.374771e-07206F7001bat10 Vopen9.9999693.444780e-07327F7001bat10 Vlo9.9999492.418221e-07188F7001bat10 Vopen9.9999701.736869e-07179F7001bat10 Vlo9.9999491.559997e-071610F7001bat10 Vopen9.9999702.599496e-0757So clearly this effect is not isolated to branadic's 3458A or the setup at the MM. I don't understand it, but it's not generally a problem for me since I always have the guard switch set to open and guard connected on the DUT side.

author: dietert1
author_rank: Super Contributor
timestamp: September 22, 2022, 10:55:00 am
content: I would check whether both guard binding posts of reference and meter are of low thermal EMF quality.

author: alm
author_rank: Super Contributor
timestamp: September 22, 2022, 12:36:57 pm
content: One side is the 3458A (with original binding posts) the other a Fluke 7001 voltage reference with also original binding posts. The connections stay the same during the measurement, except when switching polarity. The shield is on the 3458A side connected to the guard terminal, and on the F7001 side the same terminal that the low input lead is connected to. The only thing that changes is the guard switch on the 3458A.We saw the same effect (with different equipment) at MM2022 and I believe at the mini MM2020.I guess it would be interesting to connect another meter in parallel and see if that reading is also affect, and try with different voltage references.

author: MiDi
author_rank: Frequent Contributor
timestamp: September 22, 2022, 01:02:31 pm
content: Did you take the measurements with GPIB connected?@MM21 there was a difference between readings w/ and w/o GPIB connected.Quote from: dietert1 on September 22, 2022, 10:55:00 amWhy would that make any difference if there is some t-emf for guard?

author: dietert1
author_rank: Super Contributor
timestamp: September 22, 2022, 01:11:46 pm
content: Thermal EMF is a possible explanation for the observed deviations by some uV, when guard terminals/connections were mixed into the measurements.Guard terminals are not made for that, and it isn't guaranteed they are of similar quality as the measurement terminals although they may look similar.Regards, Dieter

author: alm
author_rank: Super Contributor
timestamp: September 22, 2022, 01:27:56 pm
content: Quote from: MiDi on September 22, 2022, 01:02:31 pmI remember. These results I posted were with GPIB connected, but the voltage reference was fully floating. At MM2022 where we observed the same effect with branadic's 3458A, a different PTFE 2w cable, and several F7000 references, both running from battery and mains, nothing was connected to the GPIB connector.Quote from: dietert1 on September 22, 2022, 01:11:46 pmThe low input remains directly connected throughout the measurement, so in my mind guard is merely a higher impedance parallel path. I guess it's worth investigating, though.

author: Dr. Frank
author_rank: Super Contributor
timestamp: September 22, 2022, 05:18:02 pm
content: Quote from: alm on September 22, 2022, 12:36:57 pmI also use the GUARD connection at the 3458A side, always OPEN, but never connect GUARD at the DUT side to its negative jack.So I let it flapping in the breeze for the F7000, but connect it to GUARD jack on the FLUKE 5442A, and on my DIY LTZ1000 references.Latter GUARD and GND connections are illustrated here:https://www.eevblog.com/forum/metrology/ultra-precision-reference-ltz1000/msg3886166/#msg3886166I think that the 3458A GUARD is connected to its internal shielding box, and will create a parasitic ground loop if the GUARD switch is set to LO, and may influence the 3458A itself, and maybe the DUT as well.I struggled in a similar manner when I used the 752A with either the 3458A, or the FLUKE 845AR as Null meters.https://www.eevblog.com/forum/metrology/influence-of-switch-resistance-in-hamon-dividers/msg4207093/#msg4207093I used my F7000 as a 10V reference to calibrate my 5442A. In the addendum to the 752A manual, there are corrected GND and GUARD connections shown, which are different for battery and mains operated 845A. You need to precisely follow this scheme, otherwise you get shifts of zero and unstable null readings.I assume, that's a related problem, though I have to admit, that I still have not understood this issue.Frank

author: alm
author_rank: Super Contributor
timestamp: September 22, 2022, 07:58:28 pm
content: Quote from: Dr. Frank on September 22, 2022, 05:18:02 pmLet me be clear is that I don't think the guard switch to lo and guard connected at the DUT side is a valid configuration. But I don't yet understand why it's causing such a big difference either. I believe in 2020 you reported also seeing a 2 ppm offset in other meters connected in parallel. I have not yet checked if I measure the same effect. If that's the case, then I'd think it's some sort of offset voltage, current or capacitance affecting the F7000 output.My approach to guarding is based onHP AN 123: Floating Measurements and Guarding, which is the most complete and clearest treatment of guarding I've found. However, I'm the student who read the textbook and mostly understands it, but certainly not an expert.Two rules of thumb (from page 7 are):QuoteAt the bottom of page 8 it says:QuoteWhen connecting to a voltage reference like F7000 without a guard terminal, I follow figure 7A from the app note and connect it to low at the DUT side, aka the F7000 lo terminal for the 10V output:For references with a guard terminal, like Fluke 732A or Datron 4910, I connect the guard to that guard terminal and assume the Fluke / Datron engineers knew what they're doing, but I didn't do any thorough analysis from that. It could be that connecting the guard also to lo at the reference would improve CMR even further.The Fluke 752A example is a lot more complicated, and it looks like they're worried about ground loops when the null detector is line operated. With the Fluke 7000 battery powered an on its rubber feet, I think the risk of ground loops is low, though of course there will be plenty of capacitance to ground.My empirical evidence at MM2022 where I did a quick comparison of 5 measurements with various guard configurations (it was well past 17.00 by the time we noticed this):guardmeanstdcountsemno guard connection, switch to lo9.9999896e+008.3666003e-0853.7416574e-08with guard connection, switch to lo9.9999707e+001.5811388e-0757.0710678e-08with guard connection, switch to open9.9999900e+001.1401754e-0755.0990195e-08Obviously no reliable estimate of standard deviation can be derived from this, but the fact that the means of guard switch to lo and guard unconnected at reference, and guard switch open and guard connected to F7000, are within 400 nV (0.04 ppm) suggests to me that both methods are pretty valid, although I'd expect the guarded method to have a lower noise. Based on this I concluded there was no need to redo the measurements without guard connected and the switch set to lo.I did not test guard switch open and guard unconnected at the F7000, since in my mind based on reading AN 123 this is not a valid configuration either. If you don't want to connect the guard at the DUT, then at least connect it at the meter.

author: alm
author_rank: Super Contributor
timestamp: September 26, 2022, 12:02:20 am
content: Quote from: alm on September 21, 2022, 07:49:50 pmI did this test and posted the results in anew topic.

author: alm
author_rank: Super Contributor
timestamp: September 27, 2022, 01:11:12 am
content: I had time to run one more test to continue the 3458A guard switch saga, which was to check if the same problem also occurs if I use a different voltage reference than the Fluke 7001. So now I used the same 3458A #1 DMM and cable, but I used a Fluke 732A running off mains power (it does not have batteries yet) instead of the Fluke 7001 running of battery I used for the previous experiments. I tried both with connecting the guard lead to the F732A guard terminal, which is isolated from the 10 V HI/LO terminals. Unsurprisingly the guard switch did not make a difference there, and the difference are way down in the noise (0.05 ppm). Note that the vertical scale spans 0.2 ppm here:Then I connected the guard to the same terminal as the low input lead to the DMM (so 10 V LO when measuring positive polarity and 10 V HI when measuring negative polarity). Here I observed a very similar effect to what I saw on the F7001, -6 to -8 ppm for this meter. So clearly the effect isn't just that the setting upsets the F7001 output stage:Error bars again indicate standard deviation, n >= 20.

author: alm
author_rank: Super Contributor
timestamp: November 13, 2023, 08:40:54 pm
content: branadic and I on short notice came up with the idea of a mini (or micro) metrology meet at branadic's place in Stuttgart. The goal was to compare and transfer our best representation of 10 V and 10 kOhm between our labs over the span of a bit over 24h with a few hours of sleep. branadic was also so kind to add a thermistor to my 10 kOhm reference that was sorely missing an internal thermistor (see picture). All raw data isavailable on xDevs.comand the preliminary analysis (without nice plots / summary tables and without proper uncertainty calculations) arehere on Github in a Jupyter Notebook.A full article on xDevs.com should follow soon.

author: branadic
author_rank: Super Contributor
timestamp: November 14, 2023, 06:36:17 am
content: Fun it was, attached an image of the DUTs that we focused on.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: February 08, 2024, 08:46:12 pm
content: Since I'm currently in the process of comparing the volt with Frank facing some trouble with measurements performed on our 3458A, I remembered again similar trouble we had at MM2023, that were fixed once we applied the guarding scheme as described inHP AN-123.So I thought it is worth mentioning here and drawing it in color, as it might be helpful to others, too.-branadic-

author: Dr. Frank
author_rank: Super Contributor
timestamp: February 08, 2024, 08:55:15 pm
content: Dr. branadic, did you already find the culprit?

author: branadic
author_rank: Super Contributor
timestamp: February 10, 2024, 08:02:19 am
content: Not yet, but I hope to spot it this weekend. All my measurements at home look good so far.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: February 18, 2024, 07:34:45 am
content: I finally managed to find the culprit and leave it here as an additional reminder to the above image.I used a wall socket in the lab for powering your reference that was nearby. Obviously this wall socket is connected to a different phase, so meter and wall adapter of the reference were running on different phases, which led to large shifts during polartity reversal, that vanished when I ran the reference from batteries.I also cleaned all posts and cable connectors again before I repeated the measurements and tada the result now make sense.-branadic-

author: Dr. Frank
author_rank: Super Contributor
timestamp: February 18, 2024, 10:05:18 am
content: Hello Dr. branadic,that's a great finding!I have never seen that polarity change effect in my lab, as all instruments and all the references are supplied from the identical phase.We should ask the colleagues from CERN, PTB tomorrow, how they analyse and manage the mains and power supply (CMMR), illumination (EMC) and temperature (T.C.) characteristics in their labs.This is another very important aspect, to achieve lower uncertainty and higher stability.In our EE company, all mains plugs are marked individually, I.e. the red ones are connected to the USV system, and the black ones are marked for the 3 different phases, if I remember right. Have not been in the company recently.I guess that our engineers don't care, because they are not doing such high precision stuff, usuallyFrank

author: Kleinstein
author_rank: Super Contributor
timestamp: February 18, 2024, 10:30:28 am
content: Just the normal mains phase alone should not have much effect. The meters should have enough shields and mains hum suppression to cope with this. Especially if the guard terminals are connected there should not be much mains effect left.The problem is likely more some higher frequencies that also live on the mains and also different ground paths. It may be worth testing if an EMI mains filter make a difference.

author: The Soulman
author_rank: Super Contributor
timestamp: February 18, 2024, 11:59:31 am
content: Interesting, if polarity reversal has a effect I'd assume there is a dc component to it.Leakage from the power supply?

author: alm
author_rank: Super Contributor
timestamp: February 18, 2024, 05:26:09 pm
content: I think there are two questions here: Why does connecting to a different AC circuit (different phase or frequency?) matter, and why does this affect polarity reversal. To me phase cannot matter unless the meter is sampling an odd number of power line cycles, like NPLC 1. It also seems unlikely that the frequency is very different (probably coming from the same three phase feed). So I agree with Kleinstein that this is something else than just the phase difference. Like indeed ground currents or EMI. And then the question that The Soulman raies is why does this increase the polarity reversal deviation, and my best guess is there that the noise is getting rectified at the bridge rectifier of the reference's power supply and is leaking through the regulator.I wonder if the same problem would happen if you connected the 3458A and reference both to the other phase. If it's EMI on that phase, it should show the same result. And then it would be interesting to see what the ref's output looks like on a scope (AC coupled and ideally differentially) when connected to either phase. Maybe the noise is so high that you don't even need a low noise amplifier

author: babysitter
author_rank: Frequent Contributor
timestamp: February 22, 2024, 06:37:39 pm
content: Would offer a handful of split ferrites to@branadicfor CM and DM supression games, if its possible to do the right thing (tm) with them.

author: Wollvieh
author_rank: Contributor
timestamp: March 04, 2024, 06:57:11 pm
content: Will there be a meeting in 2024?Asking for a friend(ly Keithley 2000 and a Prema 5000.)

author: branadic
author_rank: Super Contributor
timestamp: March 06, 2024, 10:05:01 am
content: Hello,we can have MM2024. Possible dates are:06.07.202413.07.202420.07.202427.07.202403.08.202410.08.202417.08.202424.08.2024I would like to ask you to give me a feedback. Depending on that and some additional feedback from a person I'm asking for a talk we will fix the date.-branadic-

author: Wollvieh
author_rank: Contributor
timestamp: March 06, 2024, 05:11:00 pm
content: Personally I would prefer July over August.Local school holidays start end of July, so generally more people might be on vacation from then on.

author: Olivia
author_rank: Regular Contributor
timestamp: March 09, 2024, 11:14:07 am
content: HihoI would second Wollvieh‘s preference for a date in July over Augustcheers, Ole

author: branadic
author_rank: Super Contributor
timestamp: March 09, 2024, 07:08:34 pm
content: From July 8, 2024 – July 12, 2024 there is the CPEM while IMEKO World Congress is from August, 26 – August 29, 2024.On the other hand, if I would schedule the meeting on August 17, 2024 we could have a talk by PTB.-branadic-

author: Dr. Frank
author_rank: Super Contributor
timestamp: March 10, 2024, 09:21:11 am
content: August 17th is perfectly fine for me, as well July 8th to August 29th, which are the Summer holidays. André, thank you!Frank

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: March 10, 2024, 10:38:33 am
content: Hi,i'd like to come too. I don't mind the date.Does someone from southern-bavaria go there and could give me and my Prema-5017 a lift?(DB / german railservice sucks big time)Would bring some "cheap" voltage-references as well.Best regards

author: bastl_r
author_rank: Regular Contributor
timestamp: March 10, 2024, 03:43:25 pm
content: I think I'll be there this year too. Last time it didn't work out for me due to the coronavirus.I would bring my "new" 1Ohm standard resistor and my Prema5017.Greetings until then

author: branadic
author_rank: Super Contributor
timestamp: March 11, 2024, 09:46:26 am
content: Save the Date for MM2024: August 17, 2024-branadic-

author: ap
author_rank: Frequent Contributor
timestamp: March 11, 2024, 02:49:42 pm
content: That fits well, saved!

author: branadic
author_rank: Super Contributor
timestamp: July 17, 2024, 12:14:01 pm
content: Here is the official announcement for MM2024. The possibility to register for the event will follow soon.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: July 17, 2024, 04:14:07 pm
content: Here is the portal to register for MM2024:https://klima-neutral-digital.de/veranstaltungen/metrology-meeting/To have a fruitful discussion, we repeat what was done at MM2022, that is, everyone joining the meeting is asked to contribute to the event with a short pitch of what he/she has been working on in the last years, results found from own experiments and the like. Everything is welcome.Hopefully, the offer is still valid and we will have an additional talk from someone external. I'm in the process of verifying that. If you know someone else that you are in contact with and that we can ask to give a talk, feel free to contact me via PN. Thanks for contributing to the event.Edit: Please register, even if you want to join remotely. I will arrange a Webex session.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: July 20, 2024, 03:53:05 pm
content: As always, you can arrive the day before, Friday 16.08.2024. I've booked a table for Friday evening at Bären (Paulinenstraße, Stuttgart) at 7pm, where we can have some drinks and "schwäbische Tapas".I will contact everyone registered so far soon to find out who will join in person and who remotely. I will also ask you again to prepare a short/long presentation and to send me your slides (PDF, PowerPoint, LibreOffice) for the pitch session. We will have at least one talk given by Luis Palafox (PTB,https://www.researchgate.net/profile/Luis-Palafox-3).I hope for your contribution to make is an interesting event for everyone.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: July 25, 2024, 05:15:53 pm
content: Quick reminder:Don't forget to register for the event, we need to plan the day and organize everything.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: July 29, 2024, 01:45:11 pm
content: In case your registration was successful, you should have received an email today. In case you haven't received an email, I assume your registration was not successful for whatever reason. In this case, please register by sending an email to Metrology@Hahn-Schickard.de and let me know who you are and if you will join in person or want to access the event remotely. Thanks.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: July 31, 2024, 09:02:18 am
content: Update:As always you can bring your test equipment on Friday until 6:00 pm and let it warmup overnight. We have to leave latest at 6:15 pm to be in time at the restaurant.On Saturday you will have access to the room from 9:00 am on, we will go online at 9:15 am and officially start at 9:30 am.-branadic-

author: branadic
author_rank: Super Contributor
timestamp: August 09, 2024, 11:25:44 am
content: Here is an update with the current agenda for Saturday in one week from now:9:15 – 9:30 Start of remote session9:30 – 9:45 What happened since MM2022? (A. Bülau)9:45 – 10:15 Voltage references, voltage standards and Josephson voltage standards (L. Palafox, PTB)10:15 – 10:45 Performance evaluation results with Analog Devices ADR1000 Ics (I. Tsemenko, xDevs.com)10:45 – 11:15 The World's Second Best Voltage Standard. (C. Beuning, Beuning Labs)11:15 – 12:00 Open Pitch SessionADR1399 – Lessons learned (A. Jahn)Simple DC coupled 0.1-10 Hz amplifier (V. Baranov)Keithley 7700 extender board (J. Krummsdorf)Day to day stability of some Fluke 732 Voltage Standards (W. Oelschlägel)Linearity Measurement of Resistors in the 10 MOhm to TOhm value range (E. Schreiber)Metrology After Hours - few commercialized Ideas from RF Scientific (B. Radzik)wrytech: Relaunching the PDVS 2 Mini and Where to Go From There (J. Vorderobermeier)12:00 – 13:00 Lunch13:00 – 17:00 Live SessionIf you like, take the final chance to register for the event now.https://klima-neutral-digital.de/veranstaltungen/metrology-meeting/-branadic-

author: laichh
author_rank: Regular Contributor
timestamp: August 09, 2024, 01:09:57 pm
content: I think there's a typo error by TiN onhttps://xdevs.com/article/mm2024/.Quote

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: August 14, 2024, 05:05:24 pm
content: Hello,is there by any chance someone staying in Stuttgart the night 16 to 17and passes by the Hauptbahnhof/Main-station on their way to the meeting?I would highly appreciate a lift from the Hauptbahnhof to Vaihingen (MM24).Best regards

author: bastl_r
author_rank: Regular Contributor
timestamp: August 17, 2024, 06:12:07 pm
content: Wonderful day at the meeting!Had a lot of grear contacts.Thankyou, brandiac, for organising the meeting.

author: Dr. Frank
author_rank: Super Contributor
timestamp: August 17, 2024, 06:39:03 pm
content: Back in the LabIt was a wonderful event, and a great pleasure, to see all of you, exchanging stories and references!Thanks especially to Dr. André, for the organisation and for the hospitality.The instruments are safely back in the cool basement lab (23.4°C, 80%rH), everything set up for consistency check later in the night.Happy measuring and low uncertainty to everybodyFrank

author: Echo88
author_rank: Frequent Contributor
timestamp: August 17, 2024, 06:44:38 pm
content: Thanks for the MM2024 branadic!Now i can speculate all night long how this magic box works:https://www.beuninglabs.com/info_Z10_2024.pdf

author: rigrunner
author_rank: Frequent Contributor
timestamp: August 18, 2024, 12:27:04 am
content: Quote from: bastl_r on August 17, 2024, 06:12:07 pm+1And thank you to the contributors, most enjoyable.

author: Sprock
author_rank: Contributor
timestamp: August 18, 2024, 04:05:28 am
content: Review MM Stuttgart 2024 from my sight.Like to say a big Thank You to Dr. André and Claudia.Thank you to all people who contributed live or via Internet.Thank you also to the wonderful helper to find the values( µV, µOhm ) for our toys.Thank you for the possibility meeting new Volt Nuts anddiscussing there experiences or ideas.Hope all visitors arrived well back home and equipmentstill workingLooking forward to meet you again some day.Stay well.Sprockexcuse grammar and spelling.

author: branadic
author_rank: Super Contributor
timestamp: August 18, 2024, 05:25:41 am
content: 1. I hope everyone and everything made it safely back home.2. A power cord marked Fluke 731B is looking for its owner.3. A selfmade 4-terminal copper short from copper nails? and a sheet of copper soldered together is looking for its owner.Thanks also from my side, thanks for the presentations yesterday and the years before, thanks to all contributors and attendees. It was a pleasure.Finally, I wonder if anyone spotted the easter-egg hidden on one of my slides?-branadic-

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: August 18, 2024, 09:00:05 am
content: Hi,what a great day, i meat just nice people the whole day.Hope to meet you all again someday someplace.Big thanks to Andre, Armin and Johannes.My Prema arrived back home in better condition than me. ;-))Best regards

author: guenthert
author_rank: Frequent Contributor
timestamp: August 18, 2024, 09:30:04 am
content: Quote from: Echo88 on August 17, 2024, 06:44:38 pmCan't wait for a tear-down. Although we should give@chuckbtime to file his patent...

author: ScoobyDoo
author_rank: Regular Contributor
timestamp: August 18, 2024, 09:53:56 am
content: Hello - Thanks to BRANADIC and his Hahn-Schickard crew for organising this ...The effort spent is always underestimatedWe have enjoyed the agenda and overall impression was that MM2024 was very succesful.Best regardsScoobyDoo

author: Andreas
author_rank: Super Contributor
timestamp: August 18, 2024, 02:13:46 pm
content: Hello,also from my side a big "thumbs up" for the successful event.And big thanks for André and Claudia for oranizing this.And of course thanks to all who contributed to the talks.Andreas

author: mendip_discovery
author_rank: Super Contributor
timestamp: August 18, 2024, 02:35:25 pm
content: Apologies for not joining in. I missed the event as I got dragged into stuff outside of the house and by the time I was back it was a little too late to log in.On a side note, I see@Dr. Frankhas started to get serious about traceability...a Toblerone reference standard.

author: Dr. Frank
author_rank: Super Contributor
timestamp: August 18, 2024, 09:51:28 pm
content: Quote from: mendip_discovery on August 18, 2024, 02:35:25 pmGreat discovery, mendip .. that's a present from a very nice co-participant, so we did not only exchange reference standards ..A pity that you did not only miss the meeting, but also all these kind people ..

author: HighVoltage
author_rank: Super Contributor
timestamp: August 19, 2024, 10:33:34 am
content: Sorry to say, that I could not participate in this year's MM, because I had a log planned event on my own.From what I have heard, you had a great gathering, great people and great instrumentation.Thanks to Dr. André for organizing this again.

author: RolandK
author_rank: Regular Contributor
timestamp: August 19, 2024, 01:45:02 pm
content: Thanks to Dr. André and all lecturers and participants for this highlight.Just found something from the PTB:https://www.ptb.de/cms/presseaktuelles/veranstaltungen/quantum-2025.htmlcitation of the last paragraph:Theopen day, which is popular far beyond the region, will take place onSeptember 13, 2025on thePTB site in Braunschweig. Here, scientists will open the doors to their laboratories and offer insights into cutting-edge quantum technology research - from ion traps for atomic clocks and quantum computers to quantum sensors for medicine.

author: meandeev
author_rank: Regular Contributor
timestamp: August 19, 2024, 06:01:55 pm
content: also big thanks from me to André for organizing these great meetings!A great day with great people and great discussions - I really enjoyed it.

author: ITArchitect
author_rank: Contributor
timestamp: August 19, 2024, 07:10:21 pm
content: I was able to attend virtually for a portion of it. Here, it was 1:00 am so I was a bit groggy, but just wanted to thank all those incredibly intelligent people that put it together! Super smart people and all ultra-kind!

author: Sprock
author_rank: Contributor
timestamp: August 20, 2024, 01:16:54 pm
content: some pictures at MM2024

author: Sprock
author_rank: Contributor
timestamp: August 20, 2024, 01:17:49 pm
content: MM2024 -2

author: Sprock
author_rank: Contributor
timestamp: August 20, 2024, 01:18:25 pm
content: Pictures MM2024-3

author: Sprock
author_rank: Contributor
timestamp: August 20, 2024, 01:19:49 pm
content: Pic MM2024 all Ziped.Sprock

author: Dr. Frank
author_rank: Super Contributor
timestamp: August 20, 2024, 02:08:26 pm
content: Hello Sprock,Zip_3 attachment is missing!Maybe too big?Anyhow, many thanks for the picturesFrank

author: Sprock
author_rank: Contributor
timestamp: August 20, 2024, 04:17:53 pm
content: Thanks for Info

author: branadic
author_rank: Super Contributor
timestamp: August 20, 2024, 08:56:18 pm
content: Thanks for sharing the photos. To also share some numbers, I've taken some measurements on Sunday after MM2024:F7000-1 drifted from 9.9999807 V (measured on 26. Nov. 2020 at xDevs.com) to 9.9999271 V (18. Aug. 2024) --> delta: -53.6 µV in 1361 daysF7000-2 drifted from 9.9999918 V (measured on 26. Nov. 2020 at xDevs.com) to 9.9999739 V (18. Aug. 2024) --> delta: -17.86 µV in 1361 daysThat's -14.37 µV/year for F7000-1 and -4.79 µV/year for F7000-2, which agrees with the diagrams I presented at MM2024 showing a larger drift for F7000-1. The huge drift for F7000-1 might explain why it was sold back in 2020. I remember Frank reporting excess drift on his F7000-3 too, but I currently don't know the drift of W7000, that came with F7004T.-branadic-

author: Okertime
author_rank: Contributor
timestamp: August 21, 2024, 07:54:27 am
content: Here are some measured differential voltages to my Fluke 732B over time:MM2021 MM2022 MM2024F732B 0 0 0F7000-1 -30.4 uV -43.0 uV -63.4 uVF7000-2 -7.0 uV -13.4 uV -17.2 uVW7000 -11.1 uV -12.6 uV -25.6 uVF732A ron -?11.9 uV +27.0 uV

author: Sprock
author_rank: Contributor
timestamp: August 22, 2024, 03:26:52 am
content: Here we go.W7000 from Nov 2020 --> 9,999991 VW7000 at MM 2024 --> 9,9999619 Vas temperature was around 28°C this is for me a bit questionable.should doing this again under better condition.anyway lot´s of fun

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: August 22, 2024, 07:41:10 am
content: Hi,the photos i took are basicaly the same as from Sprock.If anyone is interested in the whole set i can send a "wetransfer.com"-link to your e-mail.Best regards

author: iMo
author_rank: Super Contributor
timestamp: August 28, 2024, 12:25:58 pm
content: Is there any info how the Z10 is made?An ovenized Jfet Vref(s) with a Chuck's "opamp noise thread" winner as the buffer?

author: BU508A
author_rank: Super Contributor
timestamp: August 28, 2024, 12:32:06 pm
content: Quote from: iMo on August 28, 2024, 12:25:58 pmNo technical details have been revealed. It is still a magic box with lots of coloured charts.

author: MiDi
author_rank: Frequent Contributor
timestamp: August 31, 2024, 08:21:23 pm
content: Big thanks for the wonderful meeting, sad that this was the last meeting in this formA bit late to the party, but here are my results:LTZ#3 as brought: 7.1006285V ±0.30ppmas measured by Dr. Frank: 7.1006253V ±0.42ppm (-0.40ppm)as measured by 732B from Okertime: 7.1006324V ±0.5ppm (+0.55ppm)as measured by F7000-1 from branadic: 7.1006282V ±2ppm (-0.05ppm)as measured by F7000-2 from branadic: 7.1006286V ±2ppm (+0.01ppm)as measured by 3458A from branadic: 7.1006344V ±2ppm (+0.82ppm)

author: Andreas
author_rank: Super Contributor
timestamp: September 14, 2025, 03:44:52 pm
content: Hello,some impressions of the small MM2025 in Neckarsulm:Happy to import the volt and seeing that the drift since 2024 is well below 1 ppm on my most stable references.with best regardsAndreas

author: Andreas
author_rank: Super Contributor
timestamp: September 14, 2025, 03:46:24 pm
content: part 2

author: Andreas
author_rank: Super Contributor
timestamp: September 14, 2025, 03:48:02 pm
content: part 3

author: branadic
author_rank: Super Contributor
timestamp: September 14, 2025, 07:02:04 pm
content: It was a wonderful day with good discussions, good catering and first time with a quantum device around.My references also turned out to have a 1 year drift well below 1 ppm with respect to Frank's 3458A. They have drifted:LTZ1000#1: 0.57 ppmLTZ1000#2: -0.6 ppmLTZ1000#3: -0.67 ppmin 596 days.-branadic-

author: Andreas
author_rank: Super Contributor
timestamp: September 14, 2025, 07:41:56 pm
content: Hello,my results after lookup of old calibration from 17.08.2024LTZ#4: -0.16 ppm/yearLTZ#9: -0.09 ppm/yearADR#2: -0.01 ppm/yearwith best regardsAndreas

author: Dr. Frank
author_rank: Super Contributor
timestamp: September 14, 2025, 09:05:54 pm
content: It was a wonderful meeting today, and thanks to Philipp as well, that he made 10kΩ and 10V available with 0.3ppm uncertaintyThanks to Andreas for his hospitality, and to his wife for Spaghetti BolognaiseFrank