Metrology Meeting in Stuttgart/Germany

[Hermann W]

That's why I told the fellow voltnuts to add +8 ppm to the 10k figures of their references.

That's okay. but what about the other measuring ranges.

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.

So probably the correction also applies to the 100R range. But what should one do with the other ranges?

[dietert1]

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

[try]

That's why I told the fellow voltnuts to add +8 ppm to the 10k figures of their references.

That's okay. but what about the other measuring ranges.

I should have foreseen that question. Please give me some time to gather additional information.

[e61_phil]

@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

[try]

Mean measurement mess

After 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.

[Dr. Frank]

Well, I have to byte my tongue for a while now

A former PTB fellow has verified that even inofficial specs are met (or better ).

 

Hello 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.

Thanks
Frank

[Henrik_V]

Well, I have to byte my tongue for a while now

A former PTB fellow has verified that even inofficial specs are met (or better ).

 

Hello 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.

Thanks
Frank

Well, I'm only an interested onlooker (Zaungast)   , but next time I met that former fellow, I will squeeze him   he was pretty much involved in the new A3 board.

[guenthert]

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?

[Henrik_V]

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 relevant subset of all produced units?

Well, if you push the borders you won't find equipment that is spec'ed for it    so 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.

[Andreas]

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 regards

Andreas

[Zucca]

"New 3458A" as in successor of the 3458A we already know? We need juicy details. 

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?   
 

I 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. 

[branadic]

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-

[Zucca]

Thank God I planned to get married in the church on the 2nd of May and not in June.
Sign me up!

[alex-sh]

Thank God I planned to get married in the church on the 2nd of May and not in June.
Sign me up!

Speaking like a true volt-nut.
Please do me a favour - do not tell your future wife about it in the same manner 

[branadic]

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-

[branadic]

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

[Dr. Frank]

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 meantime

Frank

[The Soulman]

-Because reasons- My agenda was almost completely cleared up until September, was kinda hoping I could
attend the MM this year but realistically wasn't expecting for it to happen.. 

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 meantime

Frank

It is time to materialize the EU calclub. 

Edit: previously discussed here:
https://www.eevblog.com/forum/metrology/eu-calclub/

[HighVoltage]

Thank you André, for all the work you have already put in to this event.
Hopefully MM2021 will happen when this crazy is over.

[exe]

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.

[notfaded1]

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

[branadic]

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-

[babysitter]

Now please dont die!

[Dr. Frank]

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-

We 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

[Andreas]

Hello,

perhaps someone finds the missing 2 ppm´s in one of the pictures.

with best regards

Andreas