Author Topic: ESI Resistance Standard SR1010 and Standard Resistor SR104  (Read 22408 times)

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Offline quarks

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ESI Resistance Standard SR1010 and Standard Resistor SR104
« on: December 13, 2012, 08:18:22 pm »
Hello all,

because I am kind of crazy about stuff/gear related to metrology/calibration, I always try to get better accuracy than I already can achieve. I know this is stupid, because it will never be possible to have absolute accuracy. It always will be about the level of uncertainty and only confidence is what counts. But nevertheless I have fun with this kind of stuff and that keeps me going forward.

Right now I am after resistance measurement accuracy and already asked for suggestions around that topic. My dream gear would still be Fluke 8508A but this seems to be hopeless. Therefore I decided to look for good resistor references. And the SR1010 and SR104 were the once I picked. I hope and I feel confident that this is a good choice for many, many years of fun with it.
 
In Reply 42 of an old thread (Re: interested in hobbyist voltage reference standards? https://www.eevblog.com/forum/chat/interested-in-hobbyist-voltage-reference-standards/msg14369/#msg14369 ) saturation posted this very interesting link:

http://translate.googleusercontent.com/translate_c?hl=en&sl=zh-CN&tl=en&u=http://www.hellocq.net/forum/showthread.php%3Ft%3D139719%26page%3D1%26pp%3D30&rurl=translate.google.com&usg=ALkJrhiE1Yx0OUNwnWa_mTxlFYkyoh49wQ

 In there I saw a chart named "Drift of 5 SR104 standard resistors at 23°C" that showed graphs with a recorded timeline from 1973 to 2008. The reported annual drift is around 0.07ppm over many years.

Now I wonder if anyone has experience with Tegam/ESI/IET SR1010/1030/1050 and SR104 and likes to share it?
I would like to know if anyone came across a similar drift information for SR1010 and if the drift of (only) this 5 SR104 is representative and this really can be expected. 
Also I have not yet understood how this resistance transfer really works, especially because I do not have the "Model 242D resistance Measuring System" mentioned as required equipment in the "User and Service manual".

I hope someone is able and willing to share some knowledge or can give some hints.

thx
Quarks

edit:
finalized my research on this topic (meassured 14x SR1010s, result of 168 resistors, almost all were well in spec after at least 10 years of age, but drift is mixed, some drift positive some negative and allmost all with different rates (even within one idividual SR1010).
Also meassured 2 SR104, both showed positive drift, like in the Chart mentioned above, but different rates.
« Last Edit: June 13, 2013, 01:36:21 pm by quarks »
 

Online doktor pyta

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #1 on: January 11, 2016, 06:02:41 pm »
Hi,
I use SR104 in my lab. I needed to have quite well calibrated 100ohms standard resistor, so I've bought ESI SR1010 and got also parallel compensating network. The only missing part was SB 103 shorting bars, so I did it myself.
Pomona 3770 terminals were used.
Below You will find a link to my website and a .dwg file for those who want to use it.
I used 2 mm thick copper base material, then 0,1um of silver plated layer and 0,3um of gold plated layer.
The silver layer aim is to stop diffusion of gold into copper (and vice versa).
Maybe there is to little gold on it but I wanted the bars to be quite inexpensive.

More here: http://rfscientific.eu/esi-sb103-shorting-bars
« Last Edit: January 12, 2016, 10:24:38 pm by doktor pyta »
 

Offline alanambrose

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #2 on: January 11, 2016, 10:11:43 pm »
Wow, how did you do the plating?

Regards, Alan
“A foolish consistency is the hobgoblin of little minds"
 

Offline branadic

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #3 on: January 11, 2016, 10:17:49 pm »
Pretty uncommon putting silver as barrier between copper and gold, standard is a nickel - gold system, isn't it?
Fluke 8050A | Prema 5000 | Prema 5017 SC | Advantest R6581D | GenRad 1434-G | Datron 4000A | Tek 2465A | VNWA2.x with TCXO upgrade and access to: Keysight 3458A, Keithley 2002, Prema 5017 SC, 34401A, 34410A, Keithley 2182A, HDO6054, Keysight 53230A and other goodies at work
 

Online doktor pyta

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #4 on: January 12, 2016, 06:48:43 pm »
@alanambrose: Nope, I found a company which does electroplating since 1958. Gold plating requires a lot of experience and harmful chemicals.
@branadic: as we all know, a typical buffer layer consists of nickel which is cheap however I was worried about thermal emf (as the gold layer is very thin in my case -may not be very reliable if the gold layer is scratched). The guys from electroplating company told me that they sometimes use high purity silver as a buffer layer with good results. The time will tell if this solution is suitable for protecting electric stuff :)

PS. The users of SR1010 transfer standards should notice that when using it with SB103 and SPC102 (or PC101) the ratio transfer accuracy is independent from ageing of the internal resistors.

PS2. Could someone measure the thickness of the original SB103 bar?
PS3. SR1010 utilizes Hamon transfer scheme
« Last Edit: January 12, 2016, 09:18:11 pm by doktor pyta »
 

Offline ManateeMafia

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #5 on: January 13, 2016, 02:54:42 am »
@doktor pyta

I measure 1.70mm (from several locations) on the SB103 bar.
 

Offline quarks

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #6 on: January 13, 2016, 05:19:08 pm »
good to see this old topic is still of interest

about the plating, Fluke uses gold plating over silver plating (contains no nickel) in the "Low Thermal Test Leads" 5730A-7003

BTW very nice job, original looks like this (see att. pic)
« Last Edit: January 13, 2016, 05:41:35 pm by quarks »
 

Offline ManateeMafia

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #7 on: January 14, 2016, 01:18:46 am »
@Quarks

This is OT but ESI used lots of gold plating inside the SR-1050 too. They certainly are impressive to look at. Let me know, and I will post a few photos of mine in need of repair.
 

Offline Vgkid

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #8 on: January 14, 2016, 02:23:38 am »
Nice job doktor pyta. The closest thing to a SR1010 i have is a SR1 resistor, plus 2 decade resistors.
If you own any North Hills Electronics gear, message me. L&N Fan
 

Offline quarks

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #9 on: January 14, 2016, 09:40:46 am »
@Quarks

This is OT but ESI used lots of gold plating inside the SR-1050 too. They certainly are impressive to look at. Let me know, and I will post a few photos of mine in need of repair.

yes, please share it with us
 

Offline acbern

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #10 on: January 14, 2016, 04:05:23 pm »
Moving all this into the new metrology folder has the nice effect that it is kind of reviving. :)

Anyway, a few comments:

SR104: I bought one around 2 years ago, it was built in the 70ties, to replace my home-brew 10k reference resistor (VPG hermetic, which has a track record so far to drift about 0,2ppm/a). At the time, I did not have a meter with a guaranteed ohms transfer accuracy (the 3458A does not have that). So I decided that I would apply a stable voltage to the SR104 in series with my 10k ref and compare the voltages (the 3458A is pretty good at that). That resulted in a deviation of less than 1ppm between the two, so by coincidence, they were more or less equal (at the 23C I measured them). I then, about 1+ year later, got other meters (a 7071, 1ppm resistance transfer accuracy, and a 1281, well below 1ppm transfer acc.), so I decided to redo the measurement, and in comparison also with a 3458A in ohms mode. To my surprise, I measured about 7ppm delta. I also redid the voltage drop method described above, essentially same result. That eliminated the dielectric absorption issue (known from the 3458A, using OCOMP, but I did use a delay anyway, and switching OCOMP off did not make considerable changes, and so I had not expect this to be the issue anyhow; see also Dr Franks story about this here). Conclusion was, something has drifted, rather than the current measurement being wrong, too many equal results with different meters. A SR104 does not drift 7ppm in about a year (actually, if the last measurement was right, it would have drifted less than 5ppm in 40 years). I had the suspicion that my SR104 maybe had lost its sealing, so I decided (yes, I know the comments that I will be getting) to look inside (I just lifted the lid a bit, so not much stress applied). It had no history, other than its original value, and it needs to be call'ed now anyway, so this was not a loss for me. And at the moment I cannot use it. No leak recognized though. So next third party cal. , due soon, needs to tell what drifted (it could of course as well be that my initial measurement was wrong for unclear reasons, we will see).
What surprised me was the wiring. This is supposed to be a 4-wire resistor, so each lead at the resistor terminals being connected by two wires to two binding posts. That way the wire resistance is eliminated. What they had done though was to connect the two binding posts of each side directly, and then connect two wires to that pair. That does not make any sense. I changed this, the change in resistance was marginal (0.6ppm less, one would expect a slightly lower resistance as the copper cable resistance is eliminated; ma hope was a bad solder joint too, explaining the 7ppm above when I saw the strange wiring, but that was not the case).

SR1010: This is normally used to transfer resistances, rather than as a reference. So normally, before their use, they are calibrated (important is their deviation). I bought a couple for them (10R, 1k, 100k, 10M; per resistor) with bars recently, for the purpose of transfering 10k to a range of 1 ohm to 100M with better accuracy than I do so far. So what  I want to do in specific is going from the 1k (10 in series is 10k, 10 in parallel 100R) and measure each one with a (non-calibrated, at least not to that accuracy) meter in transfer mode. That gives certain deviations. Then, with 10 in series, I would  compare this value to the precisely known 10k standard and transfer the total deviation measured to each of the single deviations I had determined before (relative, but not absolute). That way, although I do not have a 10k SR1010, I still can do a proper transfer from the 10k standard to the 1k SR1010. Al this with an error propagation calc should give a good transfer within the abilities of the SR1010 as per manual. Any objections to this?
 

Online Dr. Frank

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #11 on: January 14, 2016, 05:47:47 pm »

SR104: .. So I decided that I would apply a stable voltage to the SR104 in series with my 10k ref and compare the voltages (the 3458A is pretty good at that).


What level of voltage did you apply?
I assume, you had <= 20V over both resistors, so that the 3458A measured at about 10V over each individually , not having to change its range, and also that the power dissipation was small enough.. <= 10mW

Did you numerically remove offset voltages, by measuring with and without driving voltage?


To my surprise, I measured about 7ppm delta. I also redid the voltage drop method described above, essentially same result.

Same setup as above?
That's again the Man-With-Only-Two-Clocks problem!
You urgently need a third (..fourth, fifth..) stable 10k resistor standard!   ;D ;D ;D
The VHPxy had not been heated for some reason, I assume, so that these 7ppm difference would origin from hysteresis?

And at the moment I cannot use it. 


Huh? Why? Lost some oil? ("Auslaufmodell"?)  :-DD



SR1010: This is normally used to transfer resistances, rather than as a reference. So normally, before their use, they are calibrated (important is their deviation). I bought a couple for them (10R, 1k, 100k, 10M; per resistor) with bars recently, for the purpose of transfering 10k to a range of 1 ohm to 100M with better accuracy than I do so far. So what  I want to do in specific is going from the 1k (10 in series is 10k, 10 in parallel 100R) and measure each one with a (non-calibrated, at least not to that accuracy) meter in transfer mode. That gives certain deviations. Then, with 10 in series, I would  compare this value to the precisely known 10k standard and transfer the total deviation measured to each of the single deviations I had determined before (relative, but not absolute). That way, although I do not have a 10k SR1010, I still can do a proper transfer from the 10k standard to the 1k SR1010. Al this with an error propagation calc should give a good transfer within the abilities of the SR1010 as per manual. Any objections to this?

The SR1010 allows 100:1 transfers of about 1ppm uncertainty.. what about 10:1 transfers, is that more precise (due to Hammon divider principle?)

As the 3458A allows 10:1 transfers of 0.3ppm at least, I would also verify the SR1010 transfer with that alternative technique.
I was doing a similar thing, see my post inside Daves eevblog thread about the Fluke 5450A. That seemed to work very well.

Finally, a 752A Hammon like 10:1 / 100:1 divider might be an additional, independent verification method.

Or as you have the 1281, you could use this as a third independent instrument.

Frank

« Last Edit: January 14, 2016, 06:15:11 pm by Dr. Frank »
 

Offline ltz2000

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #12 on: January 14, 2016, 06:02:23 pm »
What surprised me was the wiring. This is supposed to be a 4-wire resistor, so each lead at the resistor terminals being connected by two wires to two binding posts. That way the wire resistance is eliminated. What they had done though was to connect the two binding posts of each side directly, and then connect two wires to that pair. That does not make any sense. I changed this, the change in resistance was marginal (0.6ppm less, one would expect a slightly lower resistance as the copper cable resistance is eliminated; ma hope was a bad solder joint too, explaining the 7ppm above when I saw the strange wiring, but that was not the case).

There is four wire cabling inside connected in two wire style. The reason was getting better 2-wire compatibility. At the time the SR104 was introduced, still a number of two wire bridges were in use. The hermetic feed through is also two wire...

SR104: I bought one around 2 years ago, it was built in the 70ties ... To my surprise, I measured about 7ppm delta ... A SR104 does not drift 7ppm in about a year (actually, if the last measurement was right, it would have drifted less than 5ppm in 40 years). I had the suspicion that my SR104 maybe had lost its sealing, so I decided (yes, I know the comments that I will be getting) to look inside (I just lifted the lid a bit, so not much stress applied). It had no history, other than its original value, and it needs to be call'ed now anyway, so this was not a loss for me. And at the moment I cannot use it. No leak recognized though. So next third party cal. , due soon, needs to tell what drifted (it could of course as well be that my initial measurement was wrong for unclear reasons, we will see).

Did you forget to let it dry the top lid open after shipping? Or did you possibly cleaned it with a damp cloth?

If any humidity gets under/inside the binding posts, it stays there a long time and you will get readings several ppm low.

That is why I always measured the leak resistance before any SR104 calibrations.
 

Offline acbern

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #13 on: January 14, 2016, 06:12:34 pm »
Interesting, the drying may really have been an issue. I do not remember exactly, but I think it may have been maybe 2 to 4 weeks between when I received it (it came through air freight, so condensation possible) and I did the test. I opened the lid for a couple hours only in that time, but certainly not days, essentially when I did the test. No cleaning with wet cloth. No removal of the aluminium plate. I did not measure leakage.
So are you saying this was not enough and may have caused it?

Dr Frank, re. your questions:
voltage below 20V to limit load, did reversal measurement and zero-comp, so offset should not have been an issue. I took special care to not overlaod the standard, to keep the load below 10mW, unless for any mistake I unknowingly made, should not be an issue. Thought about that too. Need to have the thing calibrated. The reason why I cannot use it is because it just has no valid calibration, and I cannot even calibrate it against my standard, because this may be the problem (dont know which clock is wrong). But this will be resolved soon once I have it calibrated.

Re. the SR1010, I will probably use the 1281, it is the fastest way to get there. In fact so far I did my 10:1 transfers with a 3458A in voltage divider mode (as described above), but error propagation calc shows that the SR1010 should lead to better results.
« Last Edit: January 14, 2016, 06:27:24 pm by acbern »
 

Offline ltz2000

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #14 on: January 14, 2016, 06:26:21 pm »
So are you saying this was not enough and may have caused it?

Please post your relative measurements (and also the absolute ones made with the 3458A). Makes it easier to see the whole picture.

Did you measure the tempco? If there is a problem inside the hermetic container, it usually affects the resistor matching.

 

Online doktor pyta

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #15 on: January 14, 2016, 10:03:49 pm »
The SR1010 allows 100:1 transfers of about 1ppm uncertainty.. what about 10:1 transfers, is that more precise (due to Hammon divider principle?)

@ Dr. Frank
http://www.ietlabs.com/pdf/Manuals/SR-1010_im.pdf
Pages 11, 25, 31.

From the IET website "Transfer Accuracy:
±(1 ppm + 0.1u ohm) at parallel value for 100:1 transfer
±(1 ppm + 1u ohm) at series-parallel value for 10:1 transfer".

This is slightly different from data shown on the manual, page 11 (see attachment), but I could omit something.

« Last Edit: January 14, 2016, 10:05:29 pm by doktor pyta »
 

Offline acbern

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #16 on: January 15, 2016, 09:05:59 am »

Please post your relative measurements (and also the absolute ones made with the 3458A). Makes it easier to see the whole picture.

Did you measure the tempco? If there is a problem inside the hermetic container, it usually affects the resistor matching.


So I measured (indirect method through voltage measurement with 3458A and a Fluke 5440 as source) 9.999,962 kohms back in 2014.

Recently I measured 10.000,032 kohms (with a Datron 1281). That is + 7.0ppm. I also measured a 6,8ppm increase in voltage measurement mode with a 3458A as part of a control measurement which confirms the Datron result within limits of acc.



 

Offline ManateeMafia

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #17 on: January 15, 2016, 09:14:38 am »
Here are some pics. The unit was received with a bad resistor. The 10M resistance is made using three 3.3M resistors and a small trim mica resistor. On mine, one of the 3.3M resistors is open. It is currently awaiting repair by someone who works with custom wirewound resistors.
 
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Online Dr. Frank

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #18 on: January 15, 2016, 09:27:18 am »

@ Dr. Frank
http://www.ietlabs.com/pdf/Manuals/SR-1010_im.pdf
Pages 11, 25, 31.

From the IET website "Transfer Accuracy:
±(1 ppm + 0.1u ohm) at parallel value for 100:1 transfer
±(1 ppm + 1u ohm) at series-parallel value for 10:1 transfer".

This is slightly different from data shown on the manual, page 11 (see attachment), but I could omit something.

Thanks for that information; I already had that in mind, but always wondered why 10:1 uncertainty is 1ppm only.

For a 40k / 400k / 4M Hamon divider, like the Fluke 752A, you usually get about 0.2ppm of output for 10:1 and also for 100:1 (neglecting self heating effects), which is better than the HP3458A.

Frank
« Last Edit: January 15, 2016, 09:28:50 am by Dr. Frank »
 

Online Dr. Frank

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #19 on: January 15, 2016, 09:36:05 am »
The reason why I cannot use it is because it just has no valid calibration, and I cannot even calibrate it against my standard, because this may be the problem (dont know which clock is wrong). But this will be resolved soon once I have it calibrated.


I'm confused a bit, which one do you regard as your actual standard? Is it the Vishay VHPxxx?

If you want to have one of your standards calibrated, wouldn't it be better to send the SR104 to the cal lab?

Frank
« Last Edit: January 15, 2016, 12:57:50 pm by Dr. Frank »
 

Offline ltz2000

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #20 on: January 15, 2016, 12:27:36 pm »
Here are some pics.

And for comparison a later unit manufactured by IET labs.

It is so sad what has happened to many classic ESI and General Radio products after adopted by IET.
 

Offline ltz2000

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #21 on: January 15, 2016, 12:53:22 pm »
So I measured (indirect method through voltage measurement with 3458A and a Fluke 5440 as source) 9.999,962 kohms back in 2014.

Recently I measured 10.000,032 kohms (with a Datron 1281). That is + 7.0ppm. I also measured a 6,8ppm increase in voltage measurement mode with a 3458A as part of a control measurement which confirms the Datron result within limits of acc.

+3...4 ppm is typical for an SR104 of that era.

Let the unit cool down to +15...18 C and after that warm back to the room temparature while measuring the main resistor and the thermistor. The tempco should be very close match to the original chart. And there shouln't be any hystereresis left after reaching the original temperature.
 

Offline quarks

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #22 on: January 15, 2016, 03:25:03 pm »
Here are some pics. The unit was received with a bad resistor. The 10M resistance is made using three 3.3M resistors and a small trim mica resistor. On mine, one of the 3.3M resistors is open. It is currently awaiting repair by someone who works with custom wirewound resistors.

thanks a lot for sharing
that looks very nice and totally diff. to my SR1010s
 

Offline quarks

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #23 on: January 15, 2016, 03:27:05 pm »
Here are some pics.

And for comparison a later unit manufactured by IET labs.

It is so sad what has happened to many classic ESI and General Radio products after adopted by IET.

Looks by far not as impressive as the ESI design :(
 

Offline ltz2000

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Re: ESI Resistance Standard SR1010 and Standard Resistor SR104
« Reply #24 on: January 15, 2016, 03:56:00 pm »
that looks very nice and totally diff. to my SR1010s

At 10 Mohm level the contact resistances are not the main problem anymore allowing to use switches. The real problems are leakage resistance related instead.
 


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