Multimeter With Accurate Temperature Measurement - Page 1
Forum section: electronics / testgear

author: Locator
author_rank: Contributor
timestamp: June 08, 2014, 05:26:45 am
content: Hello. I'm looking for a new multimeter that has accurate temperature measurement with a thermocouple. Can anyone give me some suggestions? I would like to keep it under $200, if possible. I would spend more if I really liked the multimeter. (For example, I saw a Fluke 87-V listed on Ebay by a seller as "New, Open Box" for $240, plus $10 shipping. I started to buy that one, but am curious as to why he has a number of these open box, "new" 87-Vs.)I'm in the USA and would be using this at home - hobbies, electronics, computer.I would also like these features:- Fast continuity testing. No delay or extremely short delay.- Defaults to DC (not a deal-breaker)- Defaults to Fahrenheit when measuring temps- Good display, good backlight- Separate AC and DC switch positions- Measures microamps- Good battery life- Bar graph on the display- Would like to have a 3V capacity to test LEDs, but it's not a deal-breaker- True RMSIs there such an animal in this price range? Some models I've considered are:UEIDM391, DM393AnAmprobeof some sortFluke87-V (maybe)KleinMM6000 (Can't find anyone that's used this model)KleinMM2300 (Can't find anyone that's used this model, either)Brymen(except, I haven't deciphered the model number differences. I'm also in the USA, so would have to buy from an international seller on Ebay.) Is there a chart somewhere with a comparison of the different Brymen models?Greenlee(A Brymen OEM model. These appear to be overpriced for what they are.)Don't Want an Ideal, nor an Extech.Thanks for any suggestions.Best

author: Lightages
author_rank: Unknown
timestamp: June 08, 2014, 06:08:31 am
content: I would not pick a UEi. I got a bad one, and UEi replaced with another out of spec. I adjusted them but I don't have confidence in them. An official at UEI said he was going to look into the problems and get back to me but nothing has ever come from it.The Greenlees are just rebranded Brymens with a higher price tag added and a green color scheme.I think this would hit all your requirements and some. The Brymens remember the last sub-function selected so it will default to your liking. This seller on ebay is a trusted member of the forum and you can have confidence in him.http://www.ebay.com/itm/Brymen-BM829-Digital-Multimeter-Dual-Display-AC-DC-TRMS-Dual-Temp-10-000-Count-/201070664254FYI, I have three Brymens, and for a reason.

author: Locator
author_rank: Contributor
timestamp: June 08, 2014, 06:21:14 am
content: Thanks for the info. There is an older $100 shootout that has the Uei 391 and Dave commented favorably on his model. Was that an anomaly, or are they usually problematic? What kind of trouble did you have?Are there any other companies that are using the BM829 and re-branding? I'm just trying to get my mind around the specs and comparison between the 829 and other multimeters. Also, do you know if the BM820 meets its' safety claims? (I saw another Brymen or two on that list of MMs that don't measure up to their safety claims and wanted to check.) Does the 829 have a good backlight?Is this MM comparable to, say, a UEI 393?Thanks again.

author: dp
author_rank: Contributor
timestamp: June 08, 2014, 10:08:04 am
content: You may also want to have a look at Brymen 869 (there is a short review by Dave on EEVBlog). No idea about the prices in the USA, but it can't exceed by much your price limit.

author: chickenHeadKnob
author_rank: Super Contributor
timestamp: June 08, 2014, 10:45:09 am
content: The brymen 869 has dual temp capability for HVAC people who need to measure delta-T of an inlet and outlet say. I have only used a single probe on mine as that is all I have at the moment. I also have a cheap (but good value I think) type K thermocouple thermometer from Franky Tong, FT2000, 99cent hobbies store on ebay. It agrees with the brymen to about 0.2 degree Celsius. It is marked model TM902C. I haven't performed any real Calibration yet with ice/boiling water as the numbers they both give are reasonable enough for what I am doing now. With a separate thermometer you can pick a simpler cheaper multimeter.You haven't defined what you require as to absolute accuracy or acquisition speed.

author: Lightages
author_rank: Unknown
timestamp: June 08, 2014, 04:28:52 pm
content: Quote from: Locator on June 08, 2014, 06:21:14 amQuote from: Locator on June 08, 2014, 06:21:14 amHave a look at the multimeter spreadsheet that Wytnucls has generously provided in this thread:https://www.eevblog.com/forum/testgear/multimeter-spreadsheet/The BM829 is rated as CATIV/1000V. The problem is that it doesn't have 1000V fuses on the current range, only 600V. This makes it not meet its CAT rating by rule. In effect the meter really should be rated as CATIV/600V which is basically the highest anyone else rates their meters. In short, it is safe. And yes, the back light is very nice.I do not own a BM829. I own a BM869, BM525, and a BM257. The BM829 is a varation of the BM525 basically, and I can confidently make the statements I am making on the BM829 based on my experiences with the models I have.Quote from: Locator on June 08, 2014, 06:21:14 amThe UEis all have the same basic type of construction inside. So Dave got a good 391, and a coupe of other people got a good 397. What you might get is not a sure thing as there isn't much data on them yet. The DM397 is a really great deal if you get one without problems but seeing as accuracy was a problem with both of mine you won't know if you have a problem unless you have something as good or better to check against. The BM829 is what I would buy with my experience with both brands.

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: June 08, 2014, 07:56:17 pm
content: I don't like the thermocouple that came with my 87-V, it does not seem to be too rugged. I do have a Fluke 80T-150U that is great to use and can be used with any dmm (handheld or bench).You did not mention if an add-on was not an option, but I thought you should consider it if you could get more value from a meter that did not offer a temperature range.

author: dp
author_rank: Contributor
timestamp: June 08, 2014, 09:11:12 pm
content: Quote from: Locator on June 08, 2014, 05:26:45 amNot a chart, but you can download pdfs for their various series fromhttp://brymen.com/product-html/index.html#Digital-MultimeterQuoteExtech EX470 can do both contact (K-type thermocouple) and non-contact (IR) temperature measurements and it's within your price range. Depending on your actual needs, it might be worth considering, even if it doesn't match your full requirement list and you don't like the brand.

author: nanofrog
author_rank: Super Contributor
timestamp: June 08, 2014, 10:34:30 pm
content: Another vote for Brymen.BTW, you can get theBM869 for ~$250(figure ~$20 for shipping). They're located in Poland, but they accept PayPal and shipping is quick (other members have bought from there).FWIW, you won't get that much meter anywhere else for the same money (new). Even used, a 50k count DMM for $270 in the US is tough to find.

author: Lightages
author_rank: Unknown
timestamp: June 08, 2014, 10:44:53 pm
content: nanofrog's link is broken. The place in Poland is:http://www.tme.eu/en/details/bm869/portable-digital-multimeters/brymen/bm869s/#or you can buy from our friend Franky (iloveelectronics):http://www.ebay.com/itm/Brymen-BM869-Digital-Multimeter-500-000-count-Dual-Temp-AC-DC-TRMS-PC-Logging-/171272486755although he can't seem to match the price on the BM869 that TME has. The BM829, he beats it.

author: nanofrog
author_rank: Super Contributor
timestamp: June 08, 2014, 11:20:33 pm
content: Quote from: Lightages on June 08, 2014, 10:44:53 pmSorry about that.Not needed, but I did fix it.Quote from: Lightages on June 08, 2014, 10:44:53 pmOnly reason I tried to link that one instead of franky's.Surprised that he's able to beat them on the 829, but I'm glad he can.I've always assumed TME had an advantage with volume discounts Franky can't qualify for.

author: Locator
author_rank: Contributor
timestamp: June 09, 2014, 02:29:25 am
content: Thanks for the info. I'll take a closer look at the BM829. If you were to choose a MM other than a Brymen, what would be the next pick? the Fluke 87-V?As for accuracy, I don't need it laboratory accurate, but if it's boiling water, I want it to read 212 degrees (dependent on elevation) and not 210 or 209.As an aside, I recently had a chance to take apart a Klein MM2000. It's not a model I'm looking for, but wanted to see its' build quality. The board looked very, very much like the UEI DM391 that Dave reviewed. It looked a little bit updated from the other MM2000 teardown on the forum and didn't have the "Finest" stamp on the PCB. I have a feeling it's made by UEI. We tested boiling water with it and it was accurate, for what it's worth. I wasn't crazy about the leads that came with it.I haven't been able to see a MM6000 and am going to order one of those to examine, as well.What about the "open box" Fluke 87-Vs I mentioned? Does anyone know anything about these?Thanks.

author: Lightages
author_rank: Unknown
timestamp: June 09, 2014, 02:58:22 am
content: A link to the ebay auction would be helpful. The Fluke 87V is a great meter, the industry benchmark for quality, and a very useful and accurate meter. If you can get one new for $240, but open box, with full warranty and from a trusted seller, then go for it. That is, if it does what you want.Other meters have more features and/or better value, especially if you pay full price.The BM829 has a non-contact electrical field detector function, auto test function, dual temperature, dBm with impedance selection, dual display, and remembers your last function selection so it defaults to your liking.The Fluke has the Fluke lifetime warranty vs 1 year for the Brymen.

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: June 09, 2014, 03:18:12 am
content: I am pretty sure it is this one ...http://www.ebay.com/itm/Fluke-87-5-Industrial-True-RMS-Multimeter-W-Temperature-/111366334491?pt=LH_DefaultDomain_0&hash=item19edf3681b

author: Nerull
author_rank: Frequent Contributor
timestamp: June 09, 2014, 04:08:23 am
content: Multimeter thermocouple support is more of a convenience feature than something meant for accurate temperature measurement. They lack high-quality cold junction compensation. The 87V is specced at +/- 2.2C or 2%, whichever is greater.

author: Locator
author_rank: Contributor
timestamp: June 09, 2014, 05:19:32 am
content: Manatee beat me to it - thanks. I sent that seller a message, asking how old these are. I want to make sure they are post-GSM fix. That was two days ago and have not received a response. That may be my answer as to whether I should buy it from him. I'm also concerned as to why he has so many of these open box 87Vs. I can understand one, maybe two, but why an inventory of them?If he had plausible answers for those two concerns, I would by one. Without an answer, though, I'll pass for now.Nerull - I didn't know that on the temp accuracy. Maybe I'm expecting too much.

author: mimmus78
author_rank: Unknown
timestamp: June 10, 2014, 09:35:47 am
content: I think you can also get BM257 o BM867 or any other good multimeter and take one of this U1586B unit.I guess this external temperature module has better cold junction compensation than any other general purpose multimeter.

author: ManateeMafia
author_rank: Frequent Contributor
timestamp: June 10, 2014, 09:51:11 am
content: It depends on what range of temperature Locator needs to measure. The K-type thermocouples have a wide range of use, but the specs are +- 2 or more deg F. I think the T-type is better but if accuracy is important , a thermistor or prt style thermometer will be needed. The Fluke I mentioned in my first post is better than the K-type but the accuracy of the meter will still have to be added too.

author: larry42
author_rank: Regular Contributor
timestamp: June 10, 2014, 10:53:41 am
content: Quote from: Locator on June 09, 2014, 02:29:25 amA thermocouple is not the right tool for +-0.5K measurements... (Have to consider thermocouple aging etc as well)Sent from my One S using Tapatalk

author: mimmus78
author_rank: Unknown
timestamp: June 10, 2014, 08:45:08 pm
content: Quote from: larry42 on June 10, 2014, 10:53:41 amAs also error margin introduced by the cold junction temperature measurement.

author: Nerull
author_rank: Frequent Contributor
timestamp: June 10, 2014, 09:00:28 pm
content: Quote from: ManateeMafia on June 10, 2014, 09:51:11 amOmega K-types are +/- 1C and T types are +/- .5C. The meter used will have its own accuracy, added on top of this. A proper thermocouple meter like a Fluke 50-series will be somewhere around 0.05% +/- 0.3C, considerably better than the 87V. These meters will have high thermal mass contacts, thermally bonded to each other and to the thermistor used for compensation. Multimeters will lack any of that.

author: Wytnucls
author_rank: Super Contributor
timestamp: June 10, 2014, 09:43:58 pm
content: The Gossen 30M can do 4-wire temperature measurement and has a quoted accuracy of 0.05%+0.08K+sensor deviation with Pt100/1000 probes.

author: Locator
author_rank: Contributor
timestamp: June 11, 2014, 05:04:55 am
content: I would be using this for various things, but would also be using it to test brew temperatures of coffee machines. The targeted temp range would be between 195-205 degrees F. It would be important to be able to know if it's actually 194 or if it's actually 195, as well as up to 205 and not 206. It sounds like I'll have to settle for less accuracy.Thanks again.

author: kripton2035
author_rank: Super Contributor
timestamp: June 11, 2014, 05:49:41 am
content: I would buy a specialized device for the temperature. you need some great precision and reproductibility.did you try any infrared thermometer ?

author: Locator
author_rank: Contributor
timestamp: June 11, 2014, 06:15:08 am
content: Quote from: kripton2035 on June 11, 2014, 05:49:41 amYes, I have a Raytek gun, but it's a bit sketchy to measure the temps of dripping water accurately with it. The temps move around too much as the water vacillates.A more specialized device may be in order. Thanks.

author: kripton2035
author_rank: Super Contributor
timestamp: June 11, 2014, 09:19:58 am
content: use a "max" feature of the infrared gun if it has one ?

author: kripton2035
author_rank: Super Contributor
timestamp: June 11, 2014, 09:23:24 am
content: you can also make yourself a small device with an NTC or a PT100 as a probeonce calibrated in the temperatures you need a simple NTC can be really precise (and cheap)a µcontroller with a small display and that's all.I made one but with a ds1820 probe so goes only to 125°C but would be easy to adapt to your case.