USA calibration club - Page 1
Forum section: electronics / general

author: cellularmitosis
author_rank: Unknown
timestamp: May 15, 2017, 02:20:29 pm
content: New to this thread? Here's a post index:https://goo.gl/GHyj67Volt nuts, unite!Inspired by theoverseas DMM calibration club thread, I'd like for us to organize a US-based club.The most valuable aspect of a reference is its history. As Conrad Hoffman has said, "I'd rather have an ancient reference with a lot of history, than a brand new one with zero history!" . I'd love to see a few references which develop a thorough history by being shipped to many forum members over the course of years.I can't claim to bring much to the table myself -- I'm more of an aspiring volt-nut. I have a 4.5, 5.5, ,and 6.5-digit meter (UT61E, HP 3478A, Keithley 196), and a couple of pre-made voltage references (a Geller Labs SVR-T and a PentaRef). Still working on getting all of these devices to datalog to a computerI'd also like to encourage the creation ofsimplehand-madereferences among the group as well. I've got a handful of LM399's on hand, am in the process of building a small peltier oven to measure tempco's, and have a few of the cheap AD587 boards from ebay on order, just for kicks.I don't want this club to be exclusionary in any way. If you'd like one of the roving references to pay you a visit and you can post some measurements to this thread, you're in the club.I'd be happy to maintain a github page or two with all of the csv files of data, etc. I'm a programmer by trade, so I'm happy to help with any sort of python scripting for logging or analyzing data, plotting, etc.Who's interested?To get the ball rolling, my current offer is this: If you'd like to take some measurements of my Geller Labs reference, I'll pay for shipping (both ways).Other members, please feel free to chime in with what you can bring to the club and how you'd like to participate!

author: cellularmitosis
author_rank: Unknown
timestamp: May 15, 2017, 02:22:35 pm
content: (reserved)

author: dr.diesel
author_rank: Super Contributor
timestamp: May 15, 2017, 02:28:38 pm
content: Count me in. I've got (2) 3458As, DMM7510, K2010, (2) 731Bs, 731A, and a variety of other stuff laying around.Only my 7510/2010 have recent cals, both of my 3458As are rebuilds and cal'ed off my unknown 731B. I REALLY need to get about half my stuff to @CalMachine's for cal, this will happen very soon.EDIT:Plus I've got (3) KX boards that have been burning in for the past few months.

author: kj7e
author_rank: Frequent Contributor
timestamp: May 15, 2017, 05:41:12 pm
content: Interested. Just built a standard resistance box of decent quality I could pass around. Planning on building a KX LTZ1000 reference soon and adding a 34465a or maybe even a 34470a to the shop.Edit, new 34465a just delivered.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: May 15, 2017, 05:42:25 pm
content: Haven't done any reference stuff in years, but I keep my three 731s and a Analogic 8200 tuned up. (What's inside a 8200? Ha, an LM399!) They were last calibrated over a decade ago, but still agree within a few ppm. What I need is a customer willing to pay for a cal on one of the 731s, but so far no luck. Peoples interest in extreme accuracy has faded in our digital world.My best meter is an ancient HP 3455 6.5 digit that also has very low drift. For inter-comparisons I've got a Fluke 845. I can also scale, having several KVDs and a Fluke 752 divider. Anyway, count me in for any kind of round robin measurements.BTW, if anybody wants a traveling capacitance reference added in, I've got some very stable high value C0G caps and a GR1615 bridge.

author: CalMachine
author_rank: Frequent Contributor
timestamp: May 15, 2017, 05:57:19 pm
content: I'm in!In my home lab I have got a Datron 1082 7.5 Digit meter, Keithley 237 HV SMU, Lecroy LC584AL Scope, Fluke 81 FGen, and a GR DAS-47AL Voltage Reference. I've got 1 KX board built, and plan on building the other one here in the next few days. I will also have my own designs and projects to contribute in the future.I've also got a fully accredited cal lab available to me.

author: RandallMcRee
author_rank: Frequent Contributor
timestamp: May 15, 2017, 09:52:53 pm
content: Would like to participate!I have a host of five volt references that I have been playing with: MAX6530, LTC6655B-5LS8 (4), LT6654, MAX6126, ADR4550, ADR450. Current favorite is the 6655B which seems best for long term drift. Would like to calibrate some of these. I'm interested in averaging one or more to create a more stable reference. Possibly an ovenized reference.Have a calibratory D105-5 supposedly = 4.9999971 volts at 19.4 degrees! Hmmm, bought this before knowing about thread at eevblog.Keithley 2015 6.5 digit meter, on 24x7. Seems quite stable, would like to know how stable.Also, a HaoQiXin LRC cal box. Some miscellaneous reference capacitors and a 0.1% UT822C LCR meter.Thanks, Randy

author: Muxr
author_rank: Super Contributor
timestamp: May 16, 2017, 12:21:26 am
content: Count me in as well. I have a 8842A Fluke 5 1/2 digit meter, Keithley 2015 6 1/2 and the Fluke 8845A 6 1/2. I also have the DMMcheck plus (It's out of cal now) reference as well as one of those cheap chinese AD584-M (2).I am only really just now getting into high resolution measurements, up until this point I was just happy making sure my collection of handhelds (bunch of vintage and modern Flukes) were in spec. Recently I was doing some zener effect characterization and I find I really need to explore this field more. It seems like a lot of fun.I am on a lookout for a 7 1/2 or an 8 1/2 meter as well as building Tin's KX reference, or whatever other reference we decide to share.

author: CatalinaWOW
author_rank: Super Contributor
timestamp: May 16, 2017, 03:04:20 am
content: I think I'm in. Don't really have the volt-nut disease but some of the symptoms are coming to the fore. I have several 3468, a couple of 3478, 3456 and others and would like to be able to evaluate their accuracy.

author: technogeeky
author_rank: Frequent Contributor
timestamp: May 16, 2017, 03:12:15 am
content: I'm in, but like some others I can't contribute measurements that are comparable with yours. The best equipment I have are ~ 5.5 digit Keithley 197s.I humbly suggest you alter your goals to carve out a well-detailed place for people who can benefit from but not strongly contribute to the roving calibration devices. Perhaps those who can benefit from but not contribute to, can pay for shipping to and from someone who can contribute.For example, the mail path might look like:A 7.5 digit measurer reports results, contributing and thus not paying for shipping.A 5.5 digit calibrator reports results (for posterity only), pays for shipping from and to the next person.A 8.5 digit measurer reports results, contributing and thus not paying...A 6.5 digit calibrator calibrates, and pays for two ways of shipping...In this way, those of us without the ability to contribute to a high reliability history of the unitcancontribute to the history: by using and forwarding the device.Or maybe this is a horrible idea, what do I know.

author: cellularmitosis
author_rank: Unknown
timestamp: May 16, 2017, 02:41:18 pm
content: Wonderful! Thanks everyone for replying.CalMachine: I've just been made aware of your generous calibration service offer -- needless to say, you'll soon be receiving some business from metechnogeeky: That's a very considerate proposal, but I'm more interested in general participation and enthusiasm than the value of each member's contribution. After all, why would anyone with an 8.5 digit meter "waste their time" with me? If they are willing to extend a hand to the 6.5-digit guys, I'm happy to extend a hand to the 5.5-digit fellows. I've learned so much from this community over the past few years, I have no qualms with sponsoring some shipping in order to give back to it.Speaking of shipping... I need to figure out a solution there (USPS flat rate? Parcel post? Perhaps I can keep it under 13 ounces and use First Class?). PM me if you have any experience or tips on that front.I'll start sending out some PM's to coordinate things this evening. Thanks again everyone for responding!

author: VintageNut
author_rank: Frequent Contributor
timestamp: May 16, 2017, 02:44:59 pm
content: I am in, and will help where possible. The list of my equipment is in my signature.My short list of in-cal instrumentsQty 2 Fluke 731BDMM7510Fluke 5450AHome-made 100M, 10G, 100G knock-offs of KE5155I did a calibration of my 236 a year or so ago. I calibrated and adjusted it against a much better calibrated current source.I would be willing to ship the high value resistors around but not any of the other calibrated gear. The resistors were calibrated at 10V and that is how they should be used. Its convenient for using them with the 731Bs.

author: CalMachine
author_rank: Frequent Contributor
timestamp: May 16, 2017, 09:23:55 pm
content: Quote from: cellularmitosis on May 16, 2017, 02:41:18 pmDefinitely! Feel free to send me a PM if you have any questions.Quote from: cellularmitosis on May 16, 2017, 02:41:18 pmWhat are you trying to ship at 13 ounces or less? Most test gear is going to be decently heavy to the point where you either need to know how to pack it properly, to avoid damage in shipping... or strap the units in their boxes to a pallet and ship it freight (more expensive by exponentially more safe for the equipment)

author: CatalinaWOW
author_rank: Super Contributor
timestamp: May 16, 2017, 11:26:08 pm
content: I am not interested in being responsible someone else's actual test gear. A travelling reference is what I was thinking of. I think at least some others are of that inclination. I know some of those can be large and heavy, but some of those under discussion are very light and portable.

author: vindoline
author_rank: Unknown
timestamp: May 17, 2017, 12:22:18 am
content: I'll play! I'd love to check the accuracy of my Keithley 196 6.5 digit meter!

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: May 17, 2017, 03:34:58 pm
content: There's no reason a decent voltage reference has to be large or heavy. I'd also like to include one or more standard capacitors and resistors that I can supply, which should also be small. Just guessing, everything should fit in less than a cubic foot and ship USPS or FedEx ground for under $25.

author: CalMachine
author_rank: Frequent Contributor
timestamp: May 17, 2017, 04:35:55 pm
content: I guess I was thinking more along the lines of test equipment and not small prototypes. I do apologize!

author: cellularmitosis
author_rank: Unknown
timestamp: May 18, 2017, 03:42:37 am
content: Ok! Here's the route I've planned for my little SVR-T to go on it's journey!Still arranging the shipping details (prepaid shipping labels, etc).

author: bitseeker
author_rank: Super Contributor
timestamp: May 18, 2017, 11:34:33 pm
content: @cellularmitosis: Just saw the thread. Thanks for getting it started. This is a great turnout! More than I was expecting for the kickoff.I have two calibrated meters, but they're handhelds: U1252B @ 50,000 counts and U1282A @ 60,000 counts. Not sure how useful they'll be in adding to the reference's data history as compared to the higher-res equipment others have.For bench DMMs, I have several 6.5-digit ones (Keithley 196, Keithley 2700, Agilent 34401A, Agilent 34410A), but they don't have recent calibrations.Since I don't have experience with voltage standards, calibration, etc., this'll be a new adventure and I look forward to participating, learning, and contributing what I can. Plus, it'll be interesting to see how far off my uncalibrated equipment has gotten.

author: Conrad Hoffman
author_rank: Super Contributor
timestamp: May 19, 2017, 01:28:47 pm
content: That's odd, no voltnuts in the middle of the country.

author: VintageNut
author_rank: Frequent Contributor
timestamp: May 19, 2017, 02:45:05 pm
content: Quote from: Conrad Hoffman on May 19, 2017, 01:28:47 pmThis is the time of year that farmers watch the corn grow.

author: kj7e
author_rank: Frequent Contributor
timestamp: May 19, 2017, 04:27:13 pm
content: Quote from: Conrad Hoffman on May 19, 2017, 01:28:47 pmFringe lunatics.

author: enut11
author_rank: Super Contributor
timestamp: May 21, 2017, 06:50:16 am
content: Quote from: cellularmitosis on May 15, 2017, 02:20:29 pmWay-to-go @cellularmitosis. What a response in such a short time!. I suggest you or someone in your group put together a simple set of measurement instructions so that everyone does it the same way and you end up with more meaningful results. Things such as temperature, humidity, air drafts, equipment warm-up times, types of connectors, etc, etc can and do affect the outcome. Also, the number of power-line-cycles or averaging maths may be beneficial. All this is second nature to voltnuts but may not be obvious to novices.enut11 (Australia).

author: cellularmitosis
author_rank: Unknown
timestamp: May 21, 2017, 03:19:32 pm
content: Thanks enut! Great ideas!Yeah, I actually just got in a couple of BME280 and Si7021 boards for measuring the lab temperature and humidity. My intention was to include those sensors with the voltage standard, so that everyone was using the same environmental sensors when taking measurements. However, I'm not sure I'll have time to get that working before I mail out the SVR-T, at least for this first round!Similarly, I also have a couple of pomona hook-grabbers on order as well, with the idea that I could include the cabling in the setup. I've weighed similar cables and I think I should be able to fit everything in under 13 ounces, which will keep the shipping cheap.

author: Andreas
author_rank: Super Contributor
timestamp: May 21, 2017, 03:55:12 pm
content: Hello,Why not use a simple passive PT1000 or 10K NTC which can be measured in the Ohms range?Or do you want to deliver a unit which can be read out by USB/RS232?With best regardsAndreas