Most Accurate Modern Handheld DMM? Just Curious  - Page 1
Forum section: electronics / general

author: Kennylxix
author_rank: Regular Contributor
timestamp: February 11, 2017, 11:03:10 am
content: So I went to Google to answer what I thought would be an easy question but came away without a clear answer. What is the most accurate dmm available? I do know that is kind of a loaded question I guess I'm wondering if there is one that is generally considered "the one to get"This is purely hypothetical. I'm not in the market to get a second mortgage on my house, just curious. I get the feeling some may find this question annoying so I apologize in advance

author: EEVblog
author_rank: Unknown
timestamp: February 11, 2017, 11:11:31 am
content: Easy, Gossen Metrahit 30MWorld's only 6.5 digit handheldhttps://www.gossenmetrawatt.com/english/produkte/metrahit30m.htm

author: Kennylxix
author_rank: Regular Contributor
timestamp: February 11, 2017, 11:36:48 am
content: Fantastic I figured there was something like that out there I just couldn't find it! Thanks Dave:)Not eve that expensive $1200 for a brand new 6.5digit dmm seems almost reasonable.

author: EEVblog
author_rank: Unknown
timestamp: February 11, 2017, 12:16:36 pm
content: Quote from: Kennylxix on February 11, 2017, 11:36:48 amIt is.But the likes of the new-ish Keysight 34461A are more bang-per-buck.

author: Wytnucls
author_rank: Super Contributor
timestamp: February 11, 2017, 01:15:58 pm
content: The 30M has a few aces up its sleeve:More counts (200,000) and more internal memory (20,000 points extra).It can measure resistance down to 0.1mOhm (versus 100mOhm) and also precise temperatures (0.01K), with its 4 wire capability.And of course, it remains a (very light) portable meter.Unfortunately, there have been rumors that the 30M will be discontinued once current stocks are depleted.

author: Kennylxix
author_rank: Regular Contributor
timestamp: February 11, 2017, 02:59:24 pm
content: I personally don't think the two meters would be cross shopped too often. I feel like their form factors and limitations therein make them aimed at pretty different use cases.It's too bad the 30m would go away. Since I couldn't find an single review or YouTube video on one I'm guessing they aren't selling very well.

author: Wytnucls
author_rank: Super Contributor
timestamp: February 11, 2017, 03:11:07 pm
content: They are very specialized tools and not really suited for run of the mill electronics tasks.Mostly targeted at chemistry and bio labs, with specific high accuracy logging requirements.

author: Wytnucls
author_rank: Super Contributor
timestamp: February 11, 2017, 10:20:56 pm
content: Measuring an LM317 constant current output.Powered from my computer's USB port, the meter draws about 74mA (YZX studio monitor, courtesy Franky Tong).3.5mm plug installed in the recess of the original power connector2 AA batteries only last approximately an eye-watering 16 hours.

author: Muttley Snickers
author_rank: Unknown
timestamp: February 11, 2017, 10:27:40 pm
content: If anybody in Australia is interested in the Gossen Metrahit 30M multimeters Power Parameters in Victoria are currently clearing out a few for $600 AUD each and they have them listed on Ebay AU, I've been tempted and drooling over the desk for a while now, new spectacles or another multimeter, a difficult dilemma I must say.

author: tautech
author_rank: Super Contributor
timestamp: February 11, 2017, 10:37:32 pm
content: Quote from: Muttley Snickers on February 11, 2017, 10:27:40 pmTrue.Without the spectacles you could be a blind Muttley but with the Gossen you risk becoming one eyed Muttley.I had a dog that was one eyed, took him a while to get used to the world after losing it but he was a tough little nut and lived a good long live, 14 IIRC.

author: Wytnucls
author_rank: Super Contributor
timestamp: February 11, 2017, 10:39:55 pm
content: Quote from: Muttley Snickers on February 11, 2017, 10:27:40 pmNowhere to be seen. Do you have a link?

author: Muttley Snickers
author_rank: Unknown
timestamp: February 11, 2017, 10:52:38 pm
content: Quote from: Wytnucls on February 11, 2017, 10:39:55 pmAs a matter of fact I do, they are only ten minutes up the road from me hence the temptation to grab one.Ebay AU Listing.http://www.ebay.com.au/itm/Metrahit-30M-Precision-Digital-Multimeter-/332025257524?

author: EEVblog
author_rank: Unknown
timestamp: February 11, 2017, 10:55:19 pm
content: Quote from: Muttley Snickers on February 11, 2017, 10:27:40 pmWow, that's a bargain!

author: TheSteve
author_rank: Unknown
timestamp: February 11, 2017, 10:55:52 pm
content: Quote from: EEVblog on February 11, 2017, 10:55:19 pmBuy one for the lab - you can show it off.

author: Wytnucls
author_rank: Super Contributor
timestamp: February 11, 2017, 11:03:17 pm
content: New old stock. 2011 calibration. They don't drift very much if looked after, so well worth consideration at that price, especially that so few of them are ever listed.

author: Muttley Snickers
author_rank: Unknown
timestamp: February 11, 2017, 11:18:07 pm
content: I've been desperately trying to justify the purchase of another multimeter and I find it rather difficult to pass up a good deal particularly one of this calibre, since first seeing the listing for these meters quite a while back I have been religiously studying the manual and specifications which makes it even more of a task to leave them be.Edit: Added the data sheet and manual below.

author: EEVblog
author_rank: Unknown
timestamp: February 11, 2017, 11:22:08 pm
content: Quote from: TheSteve on February 11, 2017, 10:55:52 pmDo I need another 6.5 digit meter?I already have 3!Maybe $100-$150 ad revenue from a video if I'm lucky means it still costs me $500 out of pocket.

author: Muttley Snickers
author_rank: Unknown
timestamp: February 11, 2017, 11:28:44 pm
content: They are a good company and I've dealt with them before, they are also open to offers so if you decided you wanted one then perhaps we could organise a bulk buy of say two or more and with your approval maybe drop their name about the place once or twice.

author: Wytnucls
author_rank: Super Contributor
timestamp: February 11, 2017, 11:31:21 pm
content: These meters don't sell so easily. They may accept a very low offer, just to get rid of them.

author: TheSteve
author_rank: Unknown
timestamp: February 11, 2017, 11:47:35 pm
content: Quote from: EEVblog on February 11, 2017, 11:22:08 pmBut you don't have a handheld 6.5 digit meter do you.

author: Wytnucls
author_rank: Super Contributor
timestamp: February 12, 2017, 12:55:58 am
content: One sold in the last hour. 8 left.Listed since Nov16. Dave should get a commission.

author: Muttley Snickers
author_rank: Unknown
timestamp: February 12, 2017, 01:07:49 am
content: You just beat me to it, I also forgot to mention Wytnucls that Power Parameters is a Gossen distributor and calibration laboratory as well so it should be a pretty safe purchase.Power Parameters Victoria.http://www.parameters.com.au/

author: hwj-d
author_rank: Frequent Contributor
timestamp: February 12, 2017, 01:29:45 am
content: That's the way, Dave comes in, with his new

author: enut11
author_rank: Super Contributor
timestamp: February 12, 2017, 01:39:10 am
content: Quote from: Wytnucls on February 11, 2017, 01:15:58 pmI am interested in getting one. Group buy?How long does it take to stabilise from cold start to get reliable long digit DCv readings?enut11Specifications (attached) are impressive.

author: Muttley Snickers
author_rank: Unknown
timestamp: February 12, 2017, 02:19:50 am
content: @enut11PM on its way in relation to the multimeters and also the calibration club.

author: Wytnucls
author_rank: Super Contributor
timestamp: February 12, 2017, 02:54:45 am
content: According to the manual, the accuracy specs are good after a 5 minute warm-up.In DCV mode, the meter takes a new measurement every second. There is a fluctuation in the last digit, which gets a little less with time. In my experience (I can't guarantee the test is free of outside interference), the fluctuation stabilizes at about 3 to 4 counts on either side of the mean.The meter has a filter which can be set to 1, 2, 4, 8 or 16 samples running average.The test was done in the 10V range, with a resolution of 10uV, measuring a AAA battery voltage.

author: enut11
author_rank: Super Contributor
timestamp: February 12, 2017, 03:00:29 am
content: Thanks Wytnucls. That is quick settling time.Does the meter normally come with accessories such as temperature probe and PC software/interface?enut11

author: Wytnucls
author_rank: Super Contributor
timestamp: February 12, 2017, 03:04:18 am
content: No accessories whatsoever and if you need any, be prepared for a shock.I made my own USB power connector, from bits and pieces. The mod is easily reversed.USB-Hit $224USB-Hit+cable+software $337Mains power transformer $150Hit-Bag $60

author: TheSteve
author_rank: Unknown
timestamp: February 12, 2017, 03:10:30 am
content: If these were listed on US ebay at the same price they would be sold very quickly.I might even have to have one.

author: Wytnucls
author_rank: Super Contributor
timestamp: February 12, 2017, 03:33:43 am
content: 10 offers pending...

author: Muttley Snickers
author_rank: Unknown
timestamp: February 12, 2017, 03:39:31 am
content: I probably should have keep my mouth shut until after an acquisition.I just hope people who buy these meters remember where they heard about them and offer up a proper thanks, a biscuit, some flea powder or something.

author: Wytnucls
author_rank: Super Contributor
timestamp: February 12, 2017, 03:57:33 am
content: Bite the bullet and get one. You can always sell it to Dave for a profit, when he figures later he should have bought one too!

author: tautech
author_rank: Super Contributor
timestamp: February 12, 2017, 04:06:53 am
content: Quote from: Muttley Snickers on February 12, 2017, 03:39:31 amNew specsSnickers barsRawhide boneDog shampooFlea collarAnd so you keep quiet about these cool finds next time: a choker chain collar.

author: Muttley Snickers
author_rank: Unknown
timestamp: February 12, 2017, 04:21:59 am
content: Quote from: Wytnucls on February 12, 2017, 03:57:33 amDon't worry I considered buying a couple of these in addition to some other specialty meters they have available only a few weeks ago and even rang the company to discuss both the meters along with verification and documentation of certain reference modules, they were very helpful indeed.I would probably be banned or demoted to regular member status if I even thought about making a profit on he who seems to know when someone is taxing, being shrewd when it come to purchasing test equipment can be either an art form or a curse from my experience, all things are gone for those who wait and all that.

author: Muttley Snickers
author_rank: Unknown
timestamp: February 12, 2017, 04:32:18 am
content: Quote from: tautech on February 12, 2017, 04:06:53 amI have a phone call to make first thing in the morning and if we miss out and not just for my benefit then it could easily end up a noose tied to a tree, I probably wouldn't hear the end of it if they all went beforehand, risky business indeed

author: enut11
author_rank: Super Contributor
timestamp: February 12, 2017, 04:56:28 am
content: All gone..

author: Muttley Snickers
author_rank: Unknown
timestamp: February 12, 2017, 05:09:14 am
content: Quote from: enut11 on February 12, 2017, 04:56:28 amOh well look on the bright side, at least it removes the dilemma of whether or not to buy one. Somebody bought eight in one hit with an offer they couldn't refuse, funny thing is they have been sitting there for ages with no bites whatsoever and then one or two mentions here and they go like hot cakes.

author: TheSteve
author_rank: Unknown
timestamp: February 12, 2017, 05:17:26 am
content: I am sure we'll see them for sale again, albeit at a higher price.

author: Wytnucls
author_rank: Super Contributor
timestamp: February 12, 2017, 05:27:10 am
content: To show that these meters don't drift much, here is an accuracy test I hadn't done for a while:Full 10V range test. (Fluctuations of a couple of counts on either side)Last calibration was the original one, in Oct 2012.

author: Wytnucls
author_rank: Super Contributor
timestamp: February 12, 2017, 05:37:17 am
content: Wouldn't surprise me if Dave bought them all. Wait for the garage sale!

author: Vgkid
author_rank: Super Contributor
timestamp: February 12, 2017, 05:46:50 am
content: Has anyone torn one apart yet? Which V-ref are they using?

author: Wytnucls
author_rank: Super Contributor
timestamp: February 12, 2017, 06:02:24 am
content: Quote from: Vgkid on February 12, 2017, 05:46:50 amLT1236 ACN 8-10http://www.linear.com/product/LT1236http://cds.linear.com/docs/en/datasheet/lt1236.pdf

author: Pipelie
author_rank: Regular Contributor
timestamp: February 12, 2017, 06:23:25 am
content: check herehttps://sigrok.org/wiki/Gossen_Metrawatthttps://www.eevblog.com/forum/testgear/gossen-metrahit-15s-calibration/I got one for parts from local, cost around $xxx, and yes, I fixed it. now it's in working condition.did anybody happen to known how to calibrate this unit?

author: Pipelie
author_rank: Regular Contributor
timestamp: February 12, 2017, 06:44:55 am
content: attached some photos, don't have time to finish the test yet.

author: Pipelie
author_rank: Regular Contributor
timestamp: February 12, 2017, 06:46:16 am
content: Continue ....test result

author: Pipelie
author_rank: Regular Contributor
timestamp: February 12, 2017, 06:47:40 am
content: USB TO IR I used for data-log.....

author: Vgkid
author_rank: Super Contributor
timestamp: February 12, 2017, 06:50:53 am
content: Quote from: Wytnucls on February 12, 2017, 06:02:24 amThanks. Interesting that they are running a 10V reference in there. I'm wondering if those 2 beefy diodes in the pics are for a boost converter. Similar to one that is implemented in the datasheet(except that is for 5v reference running off a 5v supply).

author: EEVblog
author_rank: Unknown
timestamp: February 12, 2017, 06:55:53 am
content: Quote from: Muttley Snickers on February 12, 2017, 05:09:14 amI didn't notice there was 8 of them!Yep, someone is going to resell for a profit. They will be back on sale in a few days.

author: EEVblog
author_rank: Unknown
timestamp: February 12, 2017, 06:58:26 am
content: $580 each

author: Pipelie
author_rank: Regular Contributor
timestamp: February 12, 2017, 07:05:33 am
content: Quote from: Vgkid on February 12, 2017, 06:50:53 amThe boost converter is max863, and you are right, the boost converter provide +5V for digital section, +8V for analog, and there is a -8V come from +8V, don't known how to explain it in English.attached a photo, that is what I learned when I repaired my 30M meter.

author: Vgkid
author_rank: Super Contributor
timestamp: February 12, 2017, 07:47:58 am
content: Quote from: Pipelie on February 12, 2017, 07:05:33 amYour English explanation is good, there are no issues with it.I guess they are using the +/-8v to create a floating 16v for the reference. That is a bit different, but oh well.

author: Wytnucls
author_rank: Super Contributor
timestamp: February 12, 2017, 08:14:04 am
content: Here is a 2003 model for sale in Germany. Has reached a fairly high price already, considering how old it is.http://www.ebay.de/itm/Metra-Hit30M-Precision-AC-DC-/252754967403?hash=item3ad95ebb6b:g:Hw4AAOSwjDZYlc1M

author: TheAmmoniacal
author_rank: Unknown
timestamp: February 12, 2017, 01:37:34 pm
content: Too bad neither of the listings offer international shipping! I would probably sacrifice both my U1272A and U1282A to get one of these!

author: quarks
author_rank: Frequent Contributor
timestamp: February 12, 2017, 03:23:41 pm
content: Quote from: Pipelie on February 12, 2017, 06:47:40 amVery interesting, so far I was not able to datalog my 30M.Can you share some more details?As others already stated the 30M is kind of unique and therefore is a great DMM, but there are some drawbacks I do not like.- Battery runtime is only 15h to 16h!- AFAIK there are no schematics available and also Gossen was not helpfull, when I contacted them and asked for calibration details. Even a cal lab I later contacted, said they do not get calibration details from Gossen.It would be great if anyone could share how to calibrate a 30M.

author: Assafl
author_rank: Frequent Contributor
timestamp: February 12, 2017, 03:50:27 pm
content: I can sort of rationalize why Gossen Metrawatt avoids giving out service and calibration guides for their low end products (planned obsolescence) .But what is the use of making a 6 digit multimeter that cannot even be verified (unless you build your own test procedures)? I would highly expect T&M departments to discourage the acquisition of these (perhaps except for very specific niche mobile uses).Bummer - The Gossen/Metrawatt/Camille Bauer 29s is my favorite handheld DMM (300,000 count, energy).

author: Delta
author_rank: Super Contributor
timestamp: February 12, 2017, 05:16:02 pm
content: Do you mean most precise, or most accurate?

author: Pipelie
author_rank: Regular Contributor
timestamp: February 12, 2017, 05:24:18 pm
content: Quote from: quarks on February 12, 2017, 03:23:41 pmcheck out the link I posted(thanks to 0xdeadbeef who share the link with me),https://sigrok.org/wiki/Gossen_Metrawattlook into the photos of Metrawatt BD232, you will find out it is just a simple, RAW RS232 ot IR adapter.something like the "Fluke 189/187 USB-IR Cable adapter" will work on 30M for sure.the adapter I use is a USB to UART, part number of the chip is Pl2303, the circuit is quiet simple, you can tell by the photo.or you can build a RS-232 to IR adapter, schematic attached below , it will work properly. designed by Jambalaya.

author: bck
author_rank: Contributor
timestamp: February 12, 2017, 07:19:46 pm
content: Hi,attached is a lib for reading out the Metrahit 30M in python3sample usage:Code:from lib.Metrahit30M import Metrahit30Mfrom time import sleep, timea = Metrahit30M()a.set_baudrate(9600)a.set_device("/dev/ttyUSB0")a.connect()a.set_range(a.RANGES['VDC']['10V'])while True:sleep(1)tmp = a.get_measurement()csv_data = str(time())+", "+tmp+", "+tmp+", "+tmpwith open("test.txt", "a") as file:file.write(csv_data+"\n")print(csv_data)sample output:Code:1486926880.095561, +04.99996, V VDC, 10V VDC1486926881.1968956, +04.99996, V VDC, 10V VDC1486926882.2983227, +04.99996, V VDC, 10V VDC1486926883.3987503, +04.99997, V VDC, 10V VDC1486926884.5000813, +04.99997, V VDC, 10V VDC1486926885.601423, +04.99997, V VDC, 10V VDC1486926886.7028775, +04.99997, V VDC, 10V VDC1486926887.8032846, +04.99996, V VDC, 10V VDC1486926888.9046874, +04.99996, V VDC, 10V VDC1486926890.0051658, +04.99996, V VDC, 10V VDC1486926891.106339, +04.99996, V VDC, 10V VDC1486926892.2070792, +04.99996, V VDC, 10V VDC

author: bluey
author_rank: Regular Contributor
timestamp: July 19, 2020, 06:40:07 am
content: Presume the Gossen Metrawatt Metrahit 30M has been superceded by something newer. Eg Gossen Metrawatt Metrahit PM Prime +/- BT. Around 800 euros. 310,000 counts:https://www.gossenmetrawatt.com/english/produkte/metrahit-pm-prime.htmMaybe one of the Metrahit S series has higher spec?https://www.gossenmetrawatt.com/english/produkte/metrahitsseries.htm

author: EEVblog
author_rank: Unknown
timestamp: July 19, 2020, 01:23:25 pm
content: Quote from: bluey on July 19, 2020, 06:40:07 amThat's a replacement for the Ultra, not the 30M.

author: rsjsouza
author_rank: Super Contributor
timestamp: July 19, 2020, 02:02:02 pm
content: This got me confused a bit as well. Earlier in this thread it was said the 30M had 200.000 counts, which put it on par with this modem and in the 5,5 digit multimeter range.However, the 30M was indeed a 6,5 with its 1.200.000 counts.

author: notfaded1
author_rank: Frequent Contributor
timestamp: July 20, 2020, 02:16:59 pm
content: WIKI with internal pictures:https://sigrok.org/wiki/Gossen-Metrawatt_METRAHIT_30M

author: joeqsmith
author_rank: Super Contributor
timestamp: July 20, 2020, 04:35:34 pm
content: Quote from: bluey on July 19, 2020, 06:40:07 amSo they obsolete the Ultra and replace it with the Prime. They don't clearly state in their literature what makes the Prime different from the Ultra. Then the best part, they use the exact same M248B part number for both meters.Someone had wrote me a while back that Gossen had told them they had added a shield to the Ultra, actually calling out the Netic material I had used. Maybe the Prime addresses some of my concerns with the Ultra. I will write them.

author: joeqsmith
author_rank: Super Contributor
timestamp: July 23, 2020, 12:48:10 am
content: Sadly but not too surprising, no response. I used the same email address and history chain and wasn't trying to hide the fact that I had looked at the Ultra. Rather than to look at it as an opportunity to show off the Prime, it seems they have little to say about it.Again, if they addressed the problems with the Ultra, I would be willing to have another look at it. I can't see buying the Prime just to find out that their marketing group felt giving it a new name was going to solve the problems.

author: rsjsouza
author_rank: Super Contributor
timestamp: July 23, 2020, 02:14:52 am
content: It is indeed sad. Their silence comes across as very arrogant, especially if the product revision was partially based on your conclusions (this is unconfirmed, right?). Oh well... We can't always win.

author: niner_007
author_rank: Frequent Contributor
timestamp: July 23, 2020, 02:40:43 am
content: Quote from: EEVblog on February 11, 2017, 11:11:31 am6.5 is the resolution not accuracy, if I'm reading their accuracy spec right, basic DCV is 34ppm, and the time range is not specified, I assume per year(I edited my post as a I was wrong) this is actually pretty good, but stability and noise figures are not specifiedyou should look for a bench DMM if you need accuracy and solid specs expected from a 6.5 meter, the Gossen is already in that price range, with worse specs

author: joeqsmith
author_rank: Super Contributor
timestamp: July 23, 2020, 03:00:24 am
content: Quote from: rsjsouza on July 23, 2020, 02:14:52 amI can't personally vouch for them having made any changes outside of the new name.You could also try contacting them. They may be more open to having a dialog with someone besides me. If you do try, I would be interested in hearing what becomes of it.

author: bluey
author_rank: Regular Contributor
timestamp: August 04, 2020, 11:45:55 am
content: Quote from: rsjsouza on July 23, 2020, 02:14:52 amI had no problem getting Gossen to answer my question about TRMS in the cheap models.vertrieb@gossenmetrawatt.com