DMM Volts/Ohm Calibration Club - anyone interested?

[enut11]

Thanks for the update @VK5RC. It all goes to show that when you venture beyond 6 digits all manner of influences can affect the readings. So it is important to talk about it so that we can learn and improve our measurement skills.

Even with a 6.5 digit dmm I am not certain of the true origins of the fluctuations that I see in my home made Lm399 voltage refs. Consequently I am hoping that the next step, an LTZ1000 REF, will clarify the situation.

Now that the Aussie Cal Club is up and running, we will soon be in a position to exchange cal data which I believe is an important step in estabishing confidence in our DMMs.
Enut11

[VK5RC]

Hi enut11, 
The more you look the more you see (or don't want to see). It does get very confusing. I am now pretty sure just switching on my laptop about 50cm away from the reference and the 3458 alters the reading by around 3-4uV. Connecting it (with Prologix) and connecting its power supply also add a lesser but not trivial voltage 'errors' .
Arrrrggggghhhh.
Robert

[VK5RC]

Just an update, the "Aussie Cal Club" has completed its first round - below is an action shot of testing one of the last references in Round1.
My desk is usually that messy!
Next photo is the references boxed up heading back to New South Wales from my state of South Australia.

I am not sure what to fully conclude from the first round.
One member has an 'in calibration Fluke 7 1/2" - this is very likely to give the best results but the methodology of warming up. what power supply, what is switched on in the room, what cables are used, and what temperature it is inside the reference are some of the issues that will be being looked at in Round2.

My 3458 definitely reads high on DC V (prob about 3ppm) but is pretty consistent, my ability to get repeatable ohms readings out of it definitely need improvement.
A 34461 has done quite well, esp for the price.
Robert

[TiN]

Maybe you want to wait till LTZ get back to you?
High chances you'd get it by end of the may...

[VK5RC]

Hi TiN,
No rush re getting the reference back,  I have another three LTZ based references (and a Fluke 731b), one LTZ  is on an HP board the other two are your KXs design, one of the KXs has gone for round 2 around Australia - its the same as the one you have with Edwin's resistors but I can't seem to get its temp sensor to work!!!
Regards Rob
PS When the reference you have does comes back , I will have play with it for a short while then I might get it to go around and get the fellow with the new Fluke to liaise with you.
Rob

[bitseeker]

Just an update, the "Aussie Cal Club" has completed its first round - below is an action shot of testing one of the last references in Round1.
My desk is usually that messy!
Next photo is the references boxed up heading back to New South Wales from my state of South Australia.

Congrats, Aussie Cal Club. Rob, I just had to mention that I like your alligator/croc clip storage method. I'll have to give that a try. Otherwise, they tend to wander off.

[enut11]

Hi VK5RC. Love the pic of your lab. I am currently set up in a shared computer room and under strict orders to keep it tidy! In a way its good because it forces me to clean up after every session.

I am currently analysing the data from Round #1. 5 members took part, mostly junior voltnuts. We shared voltage, resistance and current standards. Although we did not adhere to strict metrology methodology there was still a lot of useful data gathered. Already I have a lot more confidence in my old uncalibrated HP3456A.

Round #2 will be better with a number of LTZ1000 and LM399 refs as well as better resistance refs. We are also looking to standardise our measurement techniques.
Enut11

[TiN]

Hopefully all the data will be published, so we all can learn and enjoy the ride 

[VK5RC]

enut11 is  the driving force behind the group, Thanks Lou,  TiNs work continues to inspire 

The funniest part of my setup is the old sheet on the chair - it has a hole in the middle (for your head)  so if I feel the need to do a bit of soldering or spray painting and I can't be bothered to get out of work clothes.........
Rob

[bitseeker]

Rob's lab trivia.

[cellularmitosis]

Just wanted to say I'd love to be in on the next round!  I can send out a Gellar Labs reference, as well as a Pentaref, if that's considered stable enough to be useful.  On my end I have an HP 3478A (5.5-digit) and Keithley 196 (6.5-digit), both of which are uncalibrated.  I'm also working on a LM399 design but haven't aged my 399's yet.

[enut11]

Hi cellularmitosis. I presume you are talking about a USA Cal Club. I suggest you PM other Forum members from USA/Canada who have posted on this thread and see what you can arrange between yourselves. This way you can get things moving quickly without the complexities of international shipping.
enut11

[julianhigginson]

I'd love to get in on the Australian club... How does someone new apply?

[enut11]

I'd love to get in on the Australian club... How does someone new apply?

PM me. Tell me where you live and what equipment you have, both meters and standards (if any).
enut11

[bitseeker]

Just wanted to say I'd love to be in on the next round!  I can send out a Gellar Labs reference, as well as a Pentaref, if that's considered stable enough to be useful.

Hi cellularmitosis. Which model is the Geller Labs reference and to what resolution is the calibration data? I wasn't sure from the info on their retired product page to what extent it can be used as a transfer standard.

The Pentaref data is to four decimal places, so I surmise it'd be OK to check a 3.5- or 4.5-digit DMM against. I'm sure others here can provide more experienced guidance.

I'd be interested in participating with the various meters I have (up to 6.5 digits), but I don't have the expertise to run a cal program for this region like there now is for Aus/NZ.

[julianhigginson]

PM me. Tell me where you live and what equipment you have, both meters and standards (if any).
enut11

done!

[BradC]

I'd be interested in participating with the various meters I have (up to 6.5 digits), but I don't have the expertise to run a cal program for this region like there now is for Aus/NZ.

Now, now. Don't go mistaking our enthusiasm for expertise!

[enut11]

PM me. Tell me where you live and what equipment you have, both meters and standards (if any).
enut11

done!

Hi julianhigginson.

Welcome to the Aussie Cal Club. An enthusiastic group of (6 now) junior voltnuts. We are in the throws of starting another roving standards session where we each commit one or more voltage/resistance/current standards to travel around the country. This is a good time to join.

I will PM you with more info.
enut11

[bitseeker]

I'd be interested in participating with the various meters I have (up to 6.5 digits), but I don't have the expertise to run a cal program for this region like there now is for Aus/NZ.

Now, now. Don't go mistaking our enthusiasm for expertise!

LOL! Well, I figured I'd err on the side of compliments.

[Ash]

I've just noticed that there is an Aussie Cal club. (I've only really been active on the forum for the last month I guess). 

I'd love to get involved as well. @enut11, Do I just PM you my details?

I've got a Keithley 2015, and will have 2 Keithley 196s soon (all 6.5 digit). Nothing in cal, but all should have good well aged references to compare against.

I do also have an EDC 521 voltage calibrator that I fixed, but I don't trust that it is anywhere near in cal, but it would be a good baseline to compare against I guess. I was planning on constantly tracking it against all the Keithleys to get some relative drift confidence.

I also have a matrix switch coming and I was planning to design and build some "simple" zener references (a little ways off yet) and use this gear the track them all against each other. I use Prologix Ethernet GPIB interface and can write code to drive it all.

If there is anyone in the Brisbane area with access to a calibrated 6.5+ meter, I'd like to adjust my EDC voltage standard if that would be possible??

Thanks,
Ash.

[IconicPCB]

Hello Ash,

I am in Brisbane  too but unfortunately all I can offer is a well calibrated wit.
Glad to see You are a local lad, may be some day we can exchange salty tales and cross reference the reference.

PS I too am expecting some of the chinese zeners to land on my door step any day now. I would like to try them out in a slightly different configuration to what’s been done so far.

[Ash]

I am in Brisbane  too but unfortunately all I can offer is a well calibrated wit.

  Perhaps that will be useful 

Glad to see You are a local lad, may be some day we can exchange salty tales and cross reference the reference.

PS I too am expecting some of the chinese zeners to land on my door step any day now. I would like to try them out in a slightly different configuration to what’s been done so far.

Sounds good. I've not got involved in the Chinese Zeners yet (tempted) but I was going to first of all try to do something with some 1N829A like in my calibrator. I was also going to play around with some others as well. But first I have to get my K196s and switch matrix up and running with some software support so I can monitor them against my calibrator to see how things behave.

PM me if you want to have a chat one day.
Ash.

[technix]

PS I too am expecting some of the chinese zeners to land on my door step any day now. I would like to try them out in a slightly different configuration to what’s been done so far.

I have placed the order to the factory. There will be some leading time as their own stock is running low (someone placed a GINORMOUS order in the aggregation.)

Are those diodes really that good a reference? I am still deciding between that 2DW23x and LM399 for my own calibrated voltage transfer standard. There are government-operated cal labs in Shanghai that is two or three steps away in tracing from the global standard.

[VK5RC]

Hi Guys, re Aussie Cal Club, there is a group of 5 or so (I am one) who have done one round - each contributing a voltage reference and or resistor reference - measuring then forwarding results and the references to the next person. Round two has just begun. One of the guys has an 'in Cal' 7 1/2 digit meter but if I can summarise a very complex situation - when you get below 10s of uV (out of a 7-10V reference) almost EVERYTHING counts. I think our first round has showed that. Temperature, humidity, warm up, on time, EMF interference from anything etc - the list goes on.
enut11 is probably the main contact and if he doesn't see this shortly I would PM him. 

[Ash]

Hi Guys, re Aussie Cal Club, there is a group of 5 or so (I am one) who have done one round - each contributing a voltage reference and or resistor reference - measuring then forwarding results and the references to the next person. Round two has just begun. One of the guys has an 'in Cal' 7 1/2 digit meter but if I can summarise a very complex situation - when you get below 10s of uV (out of a 7-10V reference) almost EVERYTHING counts. I think our first round has showed that. Temperature, humidity, warm up, on time, EMF interference from anything etc - the list goes on.
enut11 is probably the main contact and if he doesn't see this shortly I would PM him. 

Hi VK5RC, I'm keen to get involved so I can get a chance to develop my knowledge and skills in this area more. It wouldn't be fun if it was easy

I may not be ready for the next round as I still have to get my equipment and set it all up and get some confidence in it before I would feel like I can be of use. Might take me a month or two to get at least a little organised. So I'm not sure how that fits in with the next round.

I will be trying to build some sort of references and I was also putting together a resistance box as well for myself. Again, the initial cal is the trick