When do u need a bench multimeter ? - Page 1
Forum section: electronics / beginners

author: lordvader88
author_rank: Frequent Contributor
timestamp: April 14, 2018, 10:24:40 pm
content: What's the real advantage of them, past and present ?

author: joeqsmith
author_rank: Super Contributor
timestamp: April 14, 2018, 10:56:13 pm
content: I'm sure there are some low end bench meters. Normally, I would expect support for 4-wire measurements, higher accuracy, resolution, repeatable, Ethernet or some means to interface it to a computer for automated testing and data collection.I do not expect them to have a CAT rating and to be as electrically robust as a handheld meter.

author: tpowell1830
author_rank: Frequent Contributor
timestamp: April 15, 2018, 05:55:18 am
content: Quote from: lordvader88 on April 14, 2018, 10:24:40 pmIn my view, a bench meter is a permanent fixture of convenience so you don't have to get out your meter from your toolbox and unwound the cord while working at bench. I have multiple handheld meters, so this is not an issue, although I still have the bench meter available. Also, some have more digits for precision measurements than a handheld.

author: bd139
author_rank: Super Contributor
timestamp: April 15, 2018, 07:33:36 am
content: I use mine when I need to leave it on for a day or so and measure something via computer (cell discharge, very slow PLL control loop). Also it tends to stay where I last left it. Also battery is never flat and the display is bright all the time (VFD)

author: MosherIV
author_rank: Super Contributor
timestamp: April 15, 2018, 09:33:27 am
content: Resolution and accuracy!You can only get 5.5 or more digit meters as bench meters. Makes sense, the kind of detailed work involving such resulotion generally done on benches. Additionally, they often need to be logged over periods of time ie need to be connected to a logging computer.

author: Nusa
author_rank: Super Contributor
timestamp: April 15, 2018, 10:21:36 am
content: But if you don't need extreme precision and have adequate vision to read smaller displays, the short answer is that you don't NEED a bench multimeter. Good hand-held meters will do >99% of the measuring tasks that most of us need to do, for less money.

author: tautech
author_rank: Super Contributor
timestamp: April 15, 2018, 10:32:06 am
content: Quote from: MosherIV on April 15, 2018, 09:33:27 amActually no.New 4 1/2 digit bench DMM'sareavailable.https://www.siglenteu.com/digital-multimeters/sdm3045x-digital-multimeter/Quote from: Nusa on April 15, 2018, 10:21:36 amThen you've never seen a good bench DMM display that can be seen from meters away.Try that with a HH DMM.SDM3055

author: MosherIV
author_rank: Super Contributor
timestamp: April 15, 2018, 10:38:50 am
content: QuoteI know!You can get 4.5 digit meters as hand held OR bench meters.I have 2 hand held 4.5 digit meters.I know you can get them as bench meters as well.As far as I know you can ONLY get 5.5 digit meters as bench meters.The same is true for 6.5, 7.5 and 8.5 meters.So my original statement was correctQuote

author: Nusa
author_rank: Super Contributor
timestamp: April 15, 2018, 10:46:31 am
content: Quote from: tautech on April 15, 2018, 10:32:06 amThat argument is confusing WANT with NEED. Not that there's anything wrong with WANT, so long as you're willing to PAY.Besides, some HH's can send output to a computer, at which point a making a big display becomes trivial.

author: MosherIV
author_rank: Super Contributor
timestamp: April 15, 2018, 10:53:32 am
content: One more reason comes to mind.To be able to leave the meter running 24-7 without itA. Turning offB. Battery running flat

author: Old Printer
author_rank: Frequent Contributor
timestamp: April 15, 2018, 01:55:13 pm
content: I think at one point bench meter size was needed for high end performance and features. I built a Heathkit bench DMM in the late 70's and the case was packed with components. I recently saw a UniT bench meter with the cover off. It was 95% empty space, almost everything was on the display board and a small ps near the rear. Visual marketing was the only justification for it's size, but it is probably 2x the meter my old Heathkit was.

author: Circlotron
author_rank: Super Contributor
timestamp: April 15, 2018, 02:09:04 pm
content: Quote from: MosherIV on April 15, 2018, 10:53:32 amAnd for thermal stability if it is a very high resolution meter in a controlled environment.

author: Bud
author_rank: Super Contributor
timestamp: April 15, 2018, 02:27:05 pm
content: You can put other things on top of it.

author: Brumby
author_rank: Unknown
timestamp: April 15, 2018, 02:28:34 pm
content: Quote from: Bud on April 15, 2018, 02:27:05 pmMaybe ... but that is not good Karma.

author: Bud
author_rank: Super Contributor
timestamp: April 15, 2018, 02:40:14 pm
content: Ok how about you can stack them.

author: george4657
author_rank: Contributor
timestamp: April 15, 2018, 02:59:27 pm
content: In my case I could find it and not have to remember where i left it last.

author: bd139
author_rank: Super Contributor
timestamp: April 15, 2018, 04:19:04 pm
content: Quote from: Bud on April 15, 2018, 02:40:14 pmThis is a good point.My "pile" a couple of months back. There's a frequency counter you can just about see on the top.

author: BillB
author_rank: Unknown
timestamp: April 15, 2018, 05:01:59 pm
content: Quote from: blueskull on April 15, 2018, 10:26:39 amThis! Besides all the practical reasons already given, how else will you be able to confirm that your calibrator is calibrating and all your other meters are in agreement unless you can have one or more 8.5 digit bench meters to tell you.

author: capt bullshot
author_rank: Super Contributor
timestamp: April 15, 2018, 05:12:21 pm
content: Quote from: lordvader88 on April 14, 2018, 10:24:40 pmThey are not battery operated.

author: EEVblog
author_rank: Unknown
timestamp: April 15, 2018, 09:46:47 pm
content: Seeing small changes like this:

author: Terry01
author_rank: Frequent Contributor
timestamp: April 15, 2018, 10:21:50 pm
content: Quote from: blueskull on April 15, 2018, 10:26:39 amAnd.......So you can stack um!The only 2 answers you should pay any attention to because sooner or later they will be the only 2 things you will consider when you see/""need"" new instruments or equipment......YOU'LL SEE!!

author: bson
author_rank: Unknown
timestamp: April 16, 2018, 01:22:40 am
content: Quote from: lordvader88 on April 14, 2018, 10:24:40 pmNever run out of batteries.Higher precision acquisition, or faster acquisition at lower precision.Remote SCPI control (including high speed acquisition) - in modern instruments using VXI-11 over ethernet.In many cases multiplexed inputs that lets you scan many measurement points from a single instrument.In modern instruments, a larger display for things like tabulated probe hold readings and statistics.4W measurements.Stackable.

author: Cerebus
author_rank: Super Contributor
timestamp: April 16, 2018, 01:48:04 am
content: Two things that haven't been mentioned:1) Reading speed. Most handheld DMMs run at a few readings a second, the fastest bench DMMs can run at 100,000 4.5 digit readings a second. If you need to measure fast events more accurately than an oscilloscope can then you need this. It's also a question of throughput. It's no accident that a lot of these high speed DMMs end up in racks on the test equipment for electronics and semiconductor production lines.2) Accurately triggered readings. Most higher end bench DMMs have a trigger input that you can use to get readings at well defined times related to what your DUT is doing.

author: Mr. Scram
author_rank: Super Contributor
timestamp: April 16, 2018, 02:00:43 am
content: Quote from: MosherIV on April 15, 2018, 10:38:50 amYour statement was a bit ambivalent as it can be interpreted as "bench meters with less than 5,5 digits don't exist" or "5,5 digits or more are only available in a bench meter".The BM869S does 5,5 digits in a handheld meter, but only on DC.

author: BrianHG
author_rank: Super Contributor
timestamp: April 16, 2018, 03:47:46 am
content: Quote from: tautech on April 15, 2018, 10:32:06 amDid you read the sampling speed speck for that bench multimeter?

author: CatalinaWOW
author_rank: Super Contributor
timestamp: April 16, 2018, 04:07:30 am
content: For me some of the most important reasons have been mentioned often: rare battery replacement, display size, and harder to misplace. And one reason that hasn't been mentioned - they are harder to pull off of the bench when you reach for a test point that is just a bit farther than the lead length. Not that any of the rest of you ever do that, but it matters to me.

author: nanofrog
author_rank: Super Contributor
timestamp: April 16, 2018, 04:41:42 am
content: Quote from: CatalinaWOW on April 16, 2018, 04:07:30 amOr fall over like a handheld can (especially if the stand isn't that wonderful).Rather common IME if the meter isn't repositioned so you're not pulling on the leads.Still, I like handhelds for multiple measurements on the bench as they don't take up as much real estate as bench meters (reposition as needed). For disclosure, I've both a bench and handheld DMM's. For the record, I love the VFD on my bench meter, even when compared to an excellent backlit LCD.

author: FriedMule
author_rank: Frequent Contributor
timestamp: April 16, 2018, 04:50:42 am
content: First if you will avoid wrong information, please ignore my answer:-)I think that one would never need a bench DMM or in other words, a "cheap" Bench DMM is a normal DMM inside a box + some log, statistic function with a price that can give you a fantastic handheld DMM.Unless you sell your kidney, one leg and your mother, then you can get higher precision, faster update and higher accuracy.So you will (as many says) only need one if you need to log your data, measure over extremely long time or find it cool to own one.The rest of the time, you can get handheld DMM that are allmost as good in most cases.

author: tautech
author_rank: Super Contributor
timestamp: April 16, 2018, 05:45:57 am
content: Quote from: BrianHG on April 16, 2018, 03:47:46 amYep and I prefer the Middle or Slow setting.

author: Dave
author_rank: Super Contributor
timestamp: April 21, 2018, 11:28:45 pm
content: Quote from: Mr. Scram on April 16, 2018, 02:00:43 amGossen Metrawatt make a handheld meter that does 6.5 digits. It's called Metrahit 30M, if you're interested.The precision, though, leave some to be desired.

author: MosherIV
author_rank: Super Contributor
timestamp: April 21, 2018, 11:35:35 pm
content: QuoteGood to know, thanks for letting me know and not being rude about itYes, anything with that kind of precision needs stability, thermal stability which will be near impossible to achieve in a hand held.

author: Dave
author_rank: Super Contributor
timestamp: April 21, 2018, 11:46:47 pm
content: Quote from: MosherIV on April 21, 2018, 11:35:35 pmYup, you want a heated zener reference for that kind of stability and you want to leave it on for an hour or two before measuring something. Not the most battery-friendly requirements, if you ask me.

author: AlfBaz
author_rank: Super Contributor
timestamp: April 22, 2018, 12:30:02 am
content: Aside from what has already being mentioned there is also increased functionality built in with respect to data such as statistics, filtering, pass/fail test with indication via an output, external triggering and a host of other mathematical functions.Most modern bench meters have trend plots as well, which can be zoomed in bringing us greater data storage and the capability to extract it for analysis on a PC

author: Cerebus
author_rank: Super Contributor
timestamp: April 22, 2018, 12:31:48 am
content: Quote from: Dave on April 21, 2018, 11:46:47 pmThe LM399 datasheetclaimsthat it can be used in battery powered sources, i.e. it can achieve good accuracy shortly after being turned on. Quite how much salt one should take with that claim is another question, but it might offer a fair compromise if one really wanted that degree of temperature stability in a handheld. Of course the battery pack you'd have to lug around for any decent working time might not be exactly handheld.

author: james_s
author_rank: Super Contributor
timestamp: April 22, 2018, 03:41:21 am
content: It's rare that you *need* a bench meter, although at the very top end you can get more features and better performance in a bench meter, handhelds have caught up with all but the higher end bench meters. 30-40 years ago there was no contest, bench meters then offered much better performance and more features than most handhelds. One significant remaining advantage is they don't run off batteries so you can leave them on for long periods without draining the battery or auto shutoff.Oh and if you need GPIB or network connectivity for taking automated measurements few if any handhelds offer that.

author: lordvader88
author_rank: Frequent Contributor
timestamp: April 22, 2018, 05:34:54 am
content: Soon I'll get a used older 1 , and some day a nice new 1. Right now I only have 1 quality meter, I think a bench meter for be a great idea as my 2nd quality meter

author: AG6QR
author_rank: Frequent Contributor
timestamp: April 22, 2018, 06:09:56 am
content: In addition to the many reasons already mentioned, some school labs use them because bench meters are less likely to escape the lab inside a student's backpack. The large size is a positive attribute, making the meter more likely to remain on the bench. I think that's one reason why some low-end bench meters are made with precision and accuracy that is unremarkable compared to similarly-priced handheld meters. For a home lab, or any reasonably secure workplace lab, this shouldn't be a factor, though.I think for most individuals, the best bang for the buck is in handheld meters, usually. But if you need to leave the meter on for extended periods of time without worrying about battery life, or if you find yourself needing precision and accuracy unavailable in a handheld unit, go for a bench unit.Or if you really will be using it always on the bench, I think a bench unit is a bit more convenient. It's just that it's a lot more convenient to use a handheld meter on the bench than it is to use a bench meter in the field.

author: nanofrog
author_rank: Super Contributor
timestamp: April 22, 2018, 08:31:53 am
content: Precision & accuracy aside, one advantage bench meters can have over handhelds on a bench is readability IME (i.e. VFD, 8 segment LED, and the newer color LCD displays). And with the addition of color on some of the newer models, it's even easier to distinguish information (particularly for dual measurement cases).Other than that however, I still favor handhelds as they don't suck up a lot of bench space. I just have to pay more attention to their position in order to read them. Always compromises...