Hobbyist-Budget Calibration Services - Page 1
Forum section: electronics / general

author: JP16A60
author_rank: Unknown
timestamp: August 13, 2016, 05:51:16 pm
content: Disclaimer: I am not offering ANY services--I am simply gauging interest for another individual. I do not have any professional or financial relationship with the individual described below, nor any financial interest in any "side business" services that he might provide in the future.Through a bit of luck, I was introduced to a young man in my hometown who works full-time for a metrology service, and who spends most of his days calibrating your typical, industrial-grade electronic measurement instruments, (rotating on-site) for several local manufacturing and aerospace companies. Through a mutual acquaintance, he agreed to calibrate five instruments for me (some Fluke handheld DMMs, an HP 3456A, and a Fluke 313A DC voltage reference) for a VERY affordable fee. He did this "off hours" (using his employer's equipment), and by all indications, did a fine, professional job for me (four devices were still within factory spec, and one device required adjustment). As far as I know, I'm the only person he's done this for.Although he was not able to offer such luxuries as NIST-traceable certificates or official calibration stickers (his employer's policies prohibit this for side work), the overall value of what he provided me was worth several times what I paid. (I did receive an emailed Excel spreadsheet for each device, which provided automated measurement/test data, as well as a generic (Brother PTouch-style) label on each device with the calibration date).So--some questions for electronics hobbyists:Would you be inclined to take advantage of similar, hobbyist-budget calibration services if they were available in your local area?What types or models of devices would you likely want to have calibrated?What would be a "no-brainer/hell-yes" fee per device calibration?What would be a top reasonable fee that you would likely pay per device calibration? andWhat would be a reasonable turn-around time to have your devices calibrated (local drop-off and pick-up only)?This individual has no idea that I'm gauging interest on this forum, or that I'm even posting on the topic.As far as he knows, I'm just a recent, one-time, satisfied customer who may or may not call on him again some day.I'm trying to gauge interest in this forum because it could potentially be a big win/win for hobbyists in my local metro area (Cincinnati/Northern Kentucky and potentially, Dayton, Ohio), as well as potentially help him out financially. He's a younger guy with a new, growing family, and he loves doing what he does for a living.Thoughts?JP

author: Kilrah
author_rank: Unknown
timestamp: August 13, 2016, 08:58:39 pm
content: +1 for checking with the employer... Pretty sure they're OK for one-offs but I doubt they'd be happy if a whole business was made out of it.

author: edpalmer42
author_rank: Super Contributor
timestamp: August 13, 2016, 09:42:38 pm
content: You should get in touch with Joe Geller. He sold NIST-traceable voltage references to hobbyists for over 10 years. I'm sure he'd have some valuable info. He's a member here under the name 'Joe Geller', but hasn't been active for almost a year.http://www.gellerlabs.comEd

author: TiN
author_rank: Super Contributor
timestamp: August 14, 2016, 06:22:37 am
content: +1 on feedback, that employer would be not happy with such practice. Explicit prohibit on official calibration stickers already reveals this point of view, as facility does not want to be responsible on these side jobs if anything goes sour. Also in my book it's not cool to expose stuff like this, without having parties even knowing about such publicity being given.Having all this said, I'm perfectly understand what you trying to do. Perhaps thinking "How hard job could it be to connect my meter to that fancy Fluke 5720A, and hit button "calibrate"?". But it not exactly works like that, and it's a job which require care, accuracy and clear understanding what is happening. Also there is equipment amortization and related risks. (what if UUT is faulty, and cause failure of that 30K$ 5720 employer has?).So it's very shady dark waters you entering. I'd be reluctant to touch any equipment which is not my personal property, as often cal labs have inversted lots of money and time (ofter even much more than gear cost itself) to keep everything traced and in order. It does not take much to mess up there sensitive instruments.

author: Theboel
author_rank: Frequent Contributor
timestamp: August 15, 2016, 09:56:52 am
content: I am only accept a practice like that with a written permission.In Indonesia I can calibrated my voltage reference against Indonesia metrology institute standard with 120USD but they will not adjust Your equipment but they will issue the certificate from whatever they measure.for Voltage reference they will compare to their fluke 732 that already calibrated against their JVS and for frequency they will compare against passive hydrogen maser.I do not think the cost is to much.

author: acbern
author_rank: Frequent Contributor
timestamp: August 15, 2016, 01:42:15 pm
content: I would think the original question is a bit broader. Say a person/entity has calibrated gear (traceable to national standards) and is willing to do low cost calibration for customers without the overhead to be iso/dakks (german standards inst.) certified and do that at a competitive price (because of lack of overhead needed...). So full service, from a company, with report, but no iso (or so) stamp. there are some companies arround doing that, but they do not do much advertsing about it. and not everybody needs a JVS accuracy, a good old 732 for voltage calibration and say 1-2ppm is good for most (actually few cal labs go much below that, Keysight 3458A cal e.g. has 2ppm voltage uncertainty according to the manual).I would think this is attractive to some. Comments?

author: Dbldutch
author_rank: Regular Contributor
timestamp: September 13, 2016, 08:22:40 pm
content: I would be interested. For a hobbyist like me, a real cal lab is out of the question because of cost.

author: guenthert
author_rank: Frequent Contributor
timestamp: September 15, 2016, 03:42:03 pm
content: Quote from: Dbldutch on September 13, 2016, 08:22:40 pmI don't doubt that there is interest in a modestly priced calibration service (even if not by ISO something standards or NIST traceable), although a show of hands might help someone on the fence offering just such a service. The question is, whether it's ok to use someone's else gear to do so.I too would like one or two of my multimeters to get calibrated, but since my livelihood doesn't depend on it, I'm too stingy to send them off to a professional lab (it's not helping that it's apparently common practice in that industry to not post prices, but require the interested party to request a quote).It's not quite so easy though. Beside the cost of the gear (there are quite a few people around who already have fancy voltage references and standard resistors, but who has the complete set of gear needed for calibration of even a medium-precision DMM like a HP34401?) and some form of compensation for the time and effort spent, there's the significant cost of keeping that calibration gear itself in calibration (that seems to have been the reason for the Gellerlab to stop) and - perhaps more importantly - insurance costs (you've seen pictures of some test gear purchased on e-bay after it arrived at the buyer's place).I haven't given up hope, but I won't expect a service announcement any time soon.

author: e61_phil
author_rank: Frequent Contributor
timestamp: September 15, 2016, 07:30:42 pm
content: @DiligentMinds: How do you transfer the accuracy from the SR-104 (10k) Resistor to the very low value resistors? I would like to measure some 0.1R resistors as accurate as I can do it. My reference are some VHP101 10k resistors.A few words to multiple DMM's: A few month ago I took a Fluke 731B an went around our company and measure the 731Bs 10V with every 34401A I can find. Nearly all of them showed a value too high. None of them was out of spec, but a few showed up to 12ppm too high. What I want to say is, I can give you very easy three of these meters and the three will stay within 1-3ppm of each other. Nevertheless, they are about 10ppm out. And it seems to mee, that all of the meters showed a value too high. So it is very unlikely that the average of a few meters will result in the true value.Ok, DiligentMinds said use three diffrent ones, but most of the 6,5 DMMs use the LM399 as reference. Therefore, you don't have much choice.

author: zlymex
author_rank: Frequent Contributor
timestamp: September 16, 2016, 09:28:17 am
content: Quote from: e61_phil on September 15, 2016, 07:30:42 pmThere are four other ways that I known of(apart from the way DiligentMinds.com introduced above) to transfer SR104-10k to 0.1R: the Hamon way, the modern DCC way, the old DCC way and the 3458A way.In each way, there may be other resistors and equipment needed other than specified on the name.In most of the ways, intermediate transfers may needed such as to 100R and 1R(R=Ohm).The Hamon wayEquipment needed: 1k-per-step Hamon transfer standard, 10R-per-step Hamon and others(see notes)Steps:1. Connect 1k-per-step Hamon as 10k.2. Compare SR104-10k and 10k Hamon(note 1).3. Connect 1k-per-step Hamon as 100R and connect 10R-per-step Hamon as 100R.4. Compare these two Hamons at 100R(note 2).5. Connect 10R-per-step Hamon as 1R.6. Compare this 1R with your target 0.1R(note 3).Transfer uncertainty of less than 7ppm can be achieved.The modern DCC wayOther equipment needed: 100R and 1R dummy standard resistors(notes 4)Steps:1. Compare SR104-10k with 100R dummy.2. Compare 100R dummy with 1R dummy.3. Compare 1R dummy with your target 0.1R.Transfer uncertainty of less than 1ppm can be achieved.The old DCC wayOld DCCs such as Guildline 9975 can only compare 10:1 resistor ratio in 0.1R to 10k range.Dummy resistors needed: 1k, 100R, 10R and 1R.There will be five steps to transfer 10k to 0.1R by using those dummies in succession.Transfer uncertainty of less than 2ppm can be achieved.The 3458A way1. Calibrate the 3458A by SR104-10k(or make an ACAL, measure and record the difference).2. Measure 0.1R by the 10R range of 3458A.Measurement uncertainty of 100ppm can be achieved.Note 1There are many ways to compare two 10k either direct or substitute.Below are the ways I may use(comparison uncertainty, estimate):- 10k range of 3458A + automatic switch (0.3ppm)- 10V range of 3458A + automatic switch + 20V voltage source mains powered(0.2ppm)- 10V range of 3458A + automatic switch + 1mA current source battery powered (0.1ppm)- 242D resistance bridge (0.2ppm)- Guildline 9975 (0.2ppm)- 10k Warshawsky bridge + automatic switch (0.1ppm)Note 2There are many ways to compare two 100R either direct or substitute.Below are the ways I may use:- 100R range of 3458A + automatic switch (0.5ppm)- 1V range of 3458A + automatic switch + 2V voltage source (0.3ppm)- 1V range of 3458A + automatic switch + 10mA current source (0.2ppm)- 242D resistance bridge (0.2ppm)- Guildline 9975 (0.2ppm)Note 3The comparison of 1R to 0R1 is more difficult, better to use a DCC(with constant voltage), or use constant current of 0.1A(or 1A, I have both) to run thru those resistors and measure the voltages across both resistors(by 3458A say).Note 4Resistors with large thermal mass and good TCR.

author: e61_phil
author_rank: Frequent Contributor
timestamp: September 16, 2016, 01:00:52 pm
content: Thanks,I think I will go the way to compare voltages 1:10. To build low ohm hammon resistors seems quite hard to me. Even a short bridge with 4mm Banana-shorts is in the range of 1mRQuote from: zlymex on September 16, 2016, 09:28:17 amWhy do you expect lower uncertainties with a current source? All of my voltage sources are much more stable than my current sources (Knick JS 3010 and Valhalla 2500). Or do you expect the benefit from driving the whole thing from batteries? This would also be possible with a 20V voltage source. Or is it due to changes in the wiring which would be compensated by a good current source?

author: zlymex
author_rank: Frequent Contributor
timestamp: September 16, 2016, 02:40:29 pm
content: Quote from: e61_phil on September 16, 2016, 01:00:52 pmI tried both ways. 1mA is better because the current is stable enough and it is battery powered. When I use 20V source(which is two 732B in series, mains powered), the noise is much worse probably because the Lo input of 3458A has much larger leakage current which apply to un-symmetric test circuit. I'm sure I can get a better noise once I use battery powered 20V for the test.There is another way to compare two 10k that I'd like to try: automatic substitute method with off resistor still powered.

author: lars
author_rank: Regular Contributor
timestamp: September 16, 2016, 08:41:10 pm
content: The ESI 242 is mentioned now and when. I tried to read the manual for the 242D to see how the accuracy of 0.2ppm is accomplished. Does it need to be calibrated every time you use it to get 0.2ppm? The resistors used in the 242D seems to be only specified for 2-3ppm/C so just part of a degree change will give larger uncertainties? Also the manual said something about 0.1ppm if Standard and DUT were within +-6ppm but only 1ppm within +-60ppm?? Also if you don´t use the substitution method the accuracy seems to be only 10ppm? With the substitution method you seems to need an ESI SR1010/MT and check all 10 resistors that seems really time consuming, not to say if you want to calibrate the 925 decades?A lot of questions but maybe someone can answer if I totally has misunderstood it.Lars

author: zlymex
author_rank: Frequent Contributor
timestamp: September 17, 2016, 01:07:58 am
content: Quote from: lars on September 16, 2016, 08:41:10 pmThe 0.2ppm is for comparison(substitute) only. It would be 10ppm best accuracy for measurement.

author: zlymex
author_rank: Frequent Contributor
timestamp: September 17, 2016, 09:11:52 am
content: Quote from: DiligentMinds.com on September 17, 2016, 03:48:58 amThe meter is using HP 419A circuit.

author: dzseki
author_rank: Frequent Contributor
timestamp: September 17, 2016, 11:14:21 am
content: I am seriously curious what you guys build home, when you care about if your 6 1/2 digit multimeter reads off value in the 5th digit...

author: dzseki
author_rank: Frequent Contributor
timestamp: September 18, 2016, 12:16:21 pm
content: Ha, I wanted to hear thisI mean at work we also use 6 1/2 digit calibrated multimeters, but here at home I'm happy with my 4 1/2 digit bench multimeter without calibration.

author: e61_phil
author_rank: Frequent Contributor
timestamp: September 18, 2016, 12:49:41 pm
content: And many people will ask: "Why do you need 4,5 digits at home?" To measure the voltage of your car battery or something like this even a 4,5 digit meter is extremly oversized

author: Theboel
author_rank: Frequent Contributor
timestamp: September 18, 2016, 01:41:16 pm
content: for many years I believe with my 189 and HP 3478A say but after read this forum I want to have 3458A that calibrated against NMI with their JVS, That I really need that accuracy 99.9999999 % no but why not

author: e61_phil
author_rank: Frequent Contributor
timestamp: September 18, 2016, 01:50:17 pm
content: In my opinion our hobby is quite cheap compared to fast cars, motorbikes or most sport equipment. The price of our equipment is quite stable. If you buy a 3458A now and sell it in 2 years you will not loose much money. If you do the same with a sportscar...And our hobby is also quite safe compared to many sports activities even if you handle with 1000V.And I think one could learn a lot which is helpfull in some jobs. And with better qualification you have the chance to earn more money someday.

author: joseph nicholas
author_rank: Frequent Contributor
timestamp: September 18, 2016, 03:15:37 pm
content: It does seem strange that calibration should cost anything at all. Governments sponsor health care check ups and there is a minimal (relatively) cost to have your car inspected, the list goes on. Standards are important and they should be available to all regardless of who is seeking them.

author: saturation
author_rank: Super Contributor
timestamp: September 18, 2016, 03:24:45 pm
content: Beyond finding someone with a calibrated 6.5 or greater meter to compare your devices against, as well as a stable variable voltage source, in the USA you can rent a 34401 or similar meter for about $150/mo, or less. You can then calibrate your entire lab, or if you have friends, share the cost at least for V AC and DC, ohms, and amps. You can rent other devices for other standards you wish e.g. frequency.http://www.testequip.com/sale/details/HTE0890.htmlTo calibrate a 6.5 digit DMM against a 6.5 DMM as a reference just be aware of the TUR error.

author: TiN
author_rank: Super Contributor
timestamp: September 18, 2016, 03:39:04 pm
content: QuoteReally strange question.Even if you get suitable standards (e.g. Fluke 57x0 (>25K$USD), Fluke 732B (>5K$), Resistors (>10K$), 3458A (10K$)) how could you keep them in spec without calibration?Calibration labs are not just a room full of expensive equipment, it's mostly calibration and accreditation costs that stuff they have is x.xx ppm verified versus national standards.Calibration of reference meter like 3458A is few K$, and than must be done every year, to ensure meter is in spec and useful to calibrate user meters. Add shipping cost back and forth, maintenance (parts, cables, connectors, etc), annual license fees for calibration software, and there you have it, calibration cost. That's also reason why high-end meters and equipment calibration cost goes exponentially, even though procedure seem to be same (connect DUT to reference, compare reading, record a deviation).Surely you can take your meter to a friend who got 3458A from ebay for 2000$, but that would be calibrating unknown meter to unknown references. Result is as expected = unknown.

author: joseph nicholas
author_rank: Frequent Contributor
timestamp: September 18, 2016, 04:29:48 pm
content: It does seem strange that calibration should cost anything at all. Governments sponsor health care check ups and there is a minimal (relatively) cost to have your car inspected, the list goes on. Standards are important and they should be available to all regardless of who is seeking them.

author: dzseki
author_rank: Frequent Contributor
timestamp: September 18, 2016, 04:54:56 pm
content: Quote from: e61_phil on September 18, 2016, 12:49:41 pmI know, that's why I'm happy with itI think I'd be OK even with my MTM Vielfachmesser III (old analog multimeter) as well, but to be honest I'm not a Volt/Amper guy, but a frequency guy...

author: Simon
author_rank: Unknown
timestamp: September 18, 2016, 08:17:46 pm
content: Quote from: joseph nicholas on September 18, 2016, 04:29:48 pmWhy do you think anything at all should be free? Everything is paid for one way or another. You want your instrument calibrated, you pay for the service.

author: bitseeker
author_rank: Super Contributor
timestamp: September 18, 2016, 10:45:42 pm
content: Quote from: DiligentMinds.com on September 17, 2016, 08:15:53 pmIt really depends what you're trying to measure. Even an uncalibrated 6.5-digit meter is useful for seeing small changes over time (i.e., the delta is useful regardless of the accuracy of the absolute value). For example, a battery that is discharging might take many minutes or hours to drop far enough to see the change if your meter can only display values down to 1 mV (e.g., 3.5 or 4.5 digits). With a 6.5- or 7.5-digit DMM set to the same range, you can see 1 uV changes. Watching values that small often requires averaging in order to stabilize the display, but is still very useful.

author: zlymex
author_rank: Frequent Contributor
timestamp: September 19, 2016, 05:32:47 am
content: Sometime it is a circle/spiral. When I bought the 6.5 digit DMM, there were need for resistance/voltage standards, then I got some precision resistors and LM399. In the building and testing those standards, often the 6.5 DMM is not very efficient or limited, so I bought a 8.5 digit DMM, and then I need more accurate standard, and the process is going on.......

author: bitseeker
author_rank: Super Contributor
timestamp: September 19, 2016, 06:03:54 am
content: Quote from: DiligentMinds.com on September 19, 2016, 05:14:45 amUnfortunately, I had to use it several times recently while diagnosing a problem with the charger in my handheld DMM. Earlier I was using it to track down a short in an old bench DMM. So, I'd say I benefit from it periodically. Some people maybe more, but most much less.

author: e61_phil
author_rank: Frequent Contributor
timestamp: September 19, 2016, 06:13:58 am
content: High resolution ohms is also very usefull to track down shorts on PCBs. This was the main task for my 5.5 digit multimeter before the volt-nutting starts.

author: Simon
author_rank: Unknown
timestamp: September 19, 2016, 06:15:31 am
content: I got work to calibrate Mike Flook 179, I'm glad I did as now it means I can use it as a measurement device for high currents when put across a 1 million ohm shunt resistor. This is because at 500 mV it measured 499.9 millivolts which beats having to buy the display that goes with the shunt resistor and bothered to power it as I get measurements in many volts for amps.

author: zlymex
author_rank: Frequent Contributor
timestamp: September 19, 2016, 07:17:44 am
content: Quote from: DiligentMinds.com on September 19, 2016, 05:38:51 amThat's right. I remember like you(?) said, procedure is more important than the goal, so I am a kind of slow, worrying just in case to have reached the final destination before I still have time to spend.

author: Assafl
author_rank: Frequent Contributor
timestamp: September 19, 2016, 08:48:19 am
content: Quote from: zlymex on September 19, 2016, 07:17:44 amI am way over my head being an electronics engineer (and not a metrologist) but *to me* the fun of a 6.5 digit or higher multi-meter is that (given operator care) it can destroy the care-free convenience of the "lumped element" model we all love from the Arduinos, the Forrest Mims Notebooks and our breadboards and drive you squarely into the realm of the physical phenomena behind electronics (and for metrologists - into the even higher fun plane of statistics).At 3.5 digits dynamic range is so constrained that components tend to operate idealized, SPICE models work, there may be little to no offset, no losses and may even be noise free. What is the fun in that?(NB - having worked on sensors for the first 10 years of my engineering life - and semiconductor IR detectors during university - having a noise free reading means something is wrong, or that I am wasting valuable dynamic range - never a confidence inspiring measurement).

author: janoc
author_rank: Super Contributor
timestamp: October 16, 2016, 07:12:59 pm
content: Quote from: DiligentMinds.com on September 18, 2016, 08:16:07 pmSorry, that's bull. Put away that anti-communist torch and pitchfork.All he is saying is that measurement standards are important and important goods like that are often funded by the taxpayers for the society's benefit, so why not also pay for this. NIST is paid from the taxes already, isn't it? It is a matter of what the society considers important enough that it should be paid for from the taxpayers' money, that's all (nothing is "free", not even in the communism - even the commies were paying taxes in one way or another, you know?).So I can see the point of his argument. On the other hand, whether or not a calibration service is of such importance to the society that it warrants having it funded from everyone's taxes is another question. I personally don't think so - unlike e.g. health care, pensions or police, for example. However, the question is completely valid.

author: rob77
author_rank: Super Contributor
timestamp: October 16, 2016, 09:04:55 pm
content: Quote from: Theboel on September 18, 2016, 01:41:16 pmif you define your own volt, then you'll have 100.00% accuracy without paying an arm and a leg for calibration

author: Samogon
author_rank: Frequent Contributor
timestamp: November 29, 2016, 06:11:23 pm
content: Quote from: janoc on October 16, 2016, 07:12:59 pmTell that to me, poor scientist from USSR.

author: janoc
author_rank: Super Contributor
timestamp: December 01, 2016, 09:49:19 pm
content: Quote from: Samogon on November 29, 2016, 06:11:23 pmNot quite sure what your point is.

author: CalMachine
author_rank: Frequent Contributor
timestamp: December 01, 2016, 11:02:09 pm
content: See my posts in this thread.https://www.eevblog.com/forum/metrology/dmm-voltsohm-calibration-club-anyone-interested/Quote from: janoc on October 16, 2016, 07:12:59 pmDo you know what the turn around time would be, given their current turn around time, if NIST gave out free calibrations? It would be like 10+ years.

author: janoc
author_rank: Super Contributor
timestamp: December 02, 2016, 09:15:39 pm
content: Quote from: CalMachine on December 01, 2016, 11:02:09 pmMost likely. Unfortunately, you have missed my point completely. I amnotadvocating that this is a good idea or something that should be done. Re-read my post again and to the end this time.I was merely commenting on that rather offensive communism/mass murder/ideology laced rant from DiligentMinds which was completely unwarranted.

author: CalMachine
author_rank: Frequent Contributor
timestamp: December 02, 2016, 10:27:29 pm
content: Quote from: janoc on December 02, 2016, 09:15:39 pmI read your comment multiple times, yes to the end, before I made my comment. Why are you lashing out for stating a simple observation?? no matter who's question is valid... which is quite subjective.

author: janoc
author_rank: Super Contributor
timestamp: December 03, 2016, 01:12:19 am
content: Quote from: CalMachine on December 02, 2016, 10:27:29 pmI am not lashing out, but that Diligent's comment was simply BS. Perhaps I am a bit too sensitive to people throwing terms like "communism" around whenever they don't like some idea, me being from a former Eastern Bloc country.And now you seem to be assuming that I am somehow advocating the free cal for everyone idea - otherwise why to bring the overload of NIST into it?Once again - the only thing I have said is that to ask whether or not there should be such free service is a valid question to pose. If a question isn't asked (or is shot down right away by someone berating it as a "communist" idea), it cannot be debated. And shutting down free debate is something typical for totalitarian societies, not democracies. Paradoxical, isn't it.Of course, thatdoes notmean that the answer to the question is "yes", only that it is a valid point to discuss and there is no need to go all medieval on its author for daring to raise it. I hope you understand the difference between those two things.

author: CalMachine
author_rank: Frequent Contributor
timestamp: December 03, 2016, 02:29:57 am
content: Quote from: janoc on December 03, 2016, 01:12:19 amI apologize for thinking you were lashing out and I can empathize for your sensitiveness to communism.I am in full agreement with you on the need for all ideas to be heard and debated, but it needs to be kept civil. I wasn't trying to shut anyone or ideas down with my comment... just asking a question that maybe not everyone has thought of if cals were paid for by the government, followed with my best guestimate.