Inexpensive Accurate DMM - Page 1
Forum section: electronics / general

author: darrenb
author_rank: Contributor
timestamp: April 13, 2012, 04:55:55 am
content: Hi,Just wondering if there's such a thing as an inexpensive 0.05% accuracy DMM available?I'd love to get a Fluke 87V but the only thing it would give me is increased accuracy over my current meter. Is there something less expensive available that would guarantee me this accuracy?

author: retiredcaps
author_rank: Super Contributor
timestamp: April 13, 2012, 05:28:00 am
content: Quote from: darrenb on April 13, 2012, 04:55:55 amWhat is your definition of inexpensive? Are you willing to buy used?

author: T4P
author_rank: Super Contributor
timestamp: April 13, 2012, 05:39:29 am
content: Extech EX530 $219 .Or do you want the UT61E that does 0.1% ?Instek GDM-451 $71

author: Nermash
author_rank: Frequent Contributor
timestamp: April 13, 2012, 06:32:51 am
content: Quote from: darrenb on April 13, 2012, 04:55:55 amAs an airline pilot, I presume that you can afford something like Agilent U1272A / Fluke 87V / Fluke 289. If you need accuracy, long term stability and you can afford it, why settle for less?But, for guarantee of accuracy, every meter must be calibrated at least every 12 months. It is the only way you can have near absolute certainty that reading is within accuracy specs.

author: Lightages
author_rank: Unknown
timestamp: April 13, 2012, 06:35:05 am
content: An even better price for the Extech 530 at 0.06% basic accuracy is here:http://www.use-enco.com/CGI/INSRIT?PMAKA=317-6341&PMPXNO=19499740&PARTPG=INLMK3The problem with this meter is it looks like it is constructed very much the same way as the 505 reviewed by Dave Jones. If it has the same performance quirks and quality control problems I am not sure I would buy one.I have purchased many things from them and they are a very helpful full service friendly company.Another meter I have been looking at for big bang for the buck, if it performs as advertised is this one:http://www.tequipment.net/Protek608.aspAt $129 it is a steal IF it works to specs. I have seen a couple of favorable reviews, but not very thorough ones.I am 100% sure, to state this again on this forum, that I would not buy anything Unitrend again except maybe the UT61E. It is a gamble whether the model you want from them was designed by monkeys or not.

author: jnd
author_rank: Regular Contributor
timestamp: April 13, 2012, 09:15:48 am
content: I don't know where you can get it outside of Europe but I can recommend Brymen BM867:http://www.tme.eu/en/details/bm867/portable-digital-multimeters/brymen/It has 0.03% basic accuracy, 500 000 count mode for DC Voltages. Here it costs €129 and IMO it's one of the best meters I can get for this price range.

author: saturation
author_rank: Super Contributor
timestamp: April 13, 2012, 02:52:14 pm
content: In mission critical field applications, like doing aerosopace electronics in hangars, naval while at sea, medical or military under fire or camp conditions, reliability is as important as the accuracy. Meaning, if you paid for 0.5% it better be 24/7 throughout the year, and in environment expected of the field. Since you can never know when the meter will drift or get subtly damaged between use, its important to get one that is rugged.Unfortunately, rugged and high accuracy aren't usually found together because rugged conditions also tend to be electrically noisy and become moot. I'm not sure there are tough DMM at 0.05% basic DC accuracy that are cheap [ e.g. the Fluke 28II.]So the Fluke 87V or lesser are a good meld of rugged, accurate and reliable, proven over 20 years. Low cost options would be used 80 series than can still be CAT certified that sell between $80-200, or older series 70 or military surplus or civilian version of Fluke 27 usually sells for under $30-100.Most are still in cal over 20 years old and still working is a testament to its reliability, and is as close as you can get for guarantee of accuracy.Note, if you intend to use the DMM in flight or ASL, you'd have to insure your DMM work in lower atmospheric conditions which many Fluke are rated for and have been proven to work.

author: free_electron
author_rank: Super Contributor
timestamp: April 13, 2012, 04:24:25 pm
content: Get on ebay and find yourself a used Agilent 34401 or a keithley 2002.If you are lucky you may find a used 34401 for about 400$ ( i got one at 350 and the others two were about 450 )You can get them cal'd for about 50$.There is nothing better than those two ( apart from the outrageously expensive 3458A .. or the new fluke reference meter , and those two need to sit in climatized rooms)

author: rbola35618
author_rank: Frequent Contributor
timestamp: April 13, 2012, 06:53:34 pm
content: NO NO NO, don't get the Protek 608. I have had two of them and they both are not working. On one of the protek, the ohms at high resisttance stopped working. The second, the voltage reading were not correct. I eventully got a Amp Porbe AM-140. So far I have been happy with them.

author: Unknown
author_rank: Unknown
timestamp: April 13, 2012, 07:02:40 pm
content: Quote from: Dave.S on April 13, 2012, 05:39:29 amDoes or claims?Quote from: free_electron on April 13, 2012, 04:24:25 pmI can think of several bench meters with better accuracy than the 34401, but that's not very relevant since almost any decent 5.5+ digit bench meter, and even some 4.5 digit bench meters, will have better than 0.5 % basic DCV accuracy. I have bought several models used for < $100 or even << $100. None of them will probably qualify for whatever definition of inexpensive darrenb has in mind when buying new, however.

author: free_electron
author_rank: Super Contributor
timestamp: April 13, 2012, 09:01:10 pm
content: Quote from: alm on April 13, 2012, 07:02:40 pmplease do elaborate ... i've been looking for one for a while now. I know of the solartrons but those are obsolete. It's got to be something that is still being made.The only machine i can think of is either the 3458 or the fluke reference meter ( sold with their calibrators )

author: Unknown
author_rank: Unknown
timestamp: April 13, 2012, 09:56:17 pm
content: The main ones I had in mind are discontinued like the HP 3456A or various Datron meters (eg. 1081), since we were talking about used prices and some definition of inexpensive. Other discontinued ones would be meters from Solartron or Prema (I believe they also made an 8.5 digit meter at some point).New, the Fluke 8846A has better accuracy. I believe the Agilent 34410A is slightly better, though barely enough to matter. Fluke and Agilent are the only sources for high-end meters these days. Keithley hasn't designed a new meter in years, and probably won't design any new meters.

author: free_electron
author_rank: Super Contributor
timestamp: April 13, 2012, 10:30:24 pm
content: Yep , that's what i thought. There were the datron / solatrons but they are a bitch to find and even more difficult to get them calibrated ...Keithley is dead ... Since Tek and Keitlhey goat absorbed by danaher those guys have been shooting in the available products ... not good... Oh how deep the giants have fallen....A 3456 can be had at a reasonable price on fleabay but those too are bitch to repair if they die (they rarely do , but if they do ... good luck finding parts ... everything (the front-end) on those machines is buitl on teflon or ceramic standoffs using hand selected parts.I'd go for a used 34401 on ebay. Those things are the workhorses in any lab. Built like a tank , first introduced 30 years ago, and still in production ,and still not beat in their price segment ( apart from the 34410 and 34411. the 34405 is 5 1/2 digit ). They are virtually indestructible. I got some in racks at work that haven't been powered of in almost 20 years ...

author: PedroDaGr8
author_rank: Super Contributor
timestamp: April 14, 2012, 01:02:50 am
content: Quote from: alm on April 13, 2012, 07:02:40 pmWhile I can't speak to the 0.1% voltage accuracy I did test a variety of caps and resistors and it met its rated specs for those measurements. Albeit those are more loose at 0.5% for resistance and 3% for capacitance. It often exceeded its rating by a decent margin (especially for capacitance).

author: Kilroy
author_rank: Regular Contributor
timestamp: April 14, 2012, 02:55:35 am
content: Quote from: darrenb on April 13, 2012, 04:55:55 amUEI DM397?50,000 count, high accuracy, expanded feature set big brother to the UEI 393 Dave reviewed favorably. No idea what you want in a DMM, but the DM397 I have certainly measures *well* within its rated specifications and costs less than a Fluke 87V.

author: robrenz
author_rank: Super Contributor
timestamp: April 14, 2012, 03:24:10 am
content: Quote from: alm on April 13, 2012, 09:56:17 pmI love my 8846A, I studied the manuals for the 8846A, 34401 and 34410 before purchase with an open mind. Hands down the fluke is the most bang for the buck. You definitely won't beat Fluke tech support on the 8846A.

author: Lightages
author_rank: Unknown
timestamp: April 14, 2012, 04:10:23 am
content: Quote from: rbola35618 on April 13, 2012, 06:53:34 pmThanks for that information. Nice to know one way or the other.

author: IanB
author_rank: Super Contributor
timestamp: April 14, 2012, 05:09:12 am
content: I have a Protek 6500. It seems to be a different design from the 608 and I have had no problems with it other than a small zero offset on the DC volts range of about -0.0005 V. I can rel this out, however.

author: The Electrician
author_rank: Frequent Contributor
timestamp: April 14, 2012, 05:11:09 am
content: Here's a large list of links to DMMs:http://www.tequipment.net/TMTDigitalMultimeters.html

author: saturation
author_rank: Super Contributor
timestamp: April 14, 2012, 01:19:58 pm
content: FYI the 3456a are fairly easy to repairexceptthe front panel switch assembly. While the panel is unobtanium this meter was made in fairly large quantities, its a very good low cost alternative for accuracy, but slow read speeds compared to modern alternatives. Its certainly a good option for small or home labs. Its can be eBay bid for between $60-200, s&h included, and no formal calibration. Its also easier to self calibrate, if you have references.This palette of 3456a is going for no reserve, if you want parts, you got them!The 34401a is a great meter, and its easy to repair because its supported by Agilent. Alas, because of that you find used onesstartingat $300 in unknown condition, and it has less user serviceability for parts, which means pricey factory repairs. So, owning one really is justified it its used professionally, so those costs can be depreciated.Quote from: free_electron on April 13, 2012, 10:30:24 pm

author: jnd
author_rank: Regular Contributor
timestamp: April 15, 2012, 02:04:26 am
content: Nice stack of meters, saturation. I'd buy one like this but the problem is the end price for me would be more than double. I just asked the seller about shipping to Europe and it's $132. Then add 20% tax for the whole value including shipping, customs and other fees if it goes through the Czech post. Now it's over $400 and that's just too much for me. I know ebay is full of US sellers with good equipment and it would be great to live there and buy all kinds of such instruments; in the Czech Republic it's rare to get anything like this with reasonable price.

author: saturation
author_rank: Super Contributor
timestamp: April 15, 2012, 01:34:52 pm
content: Yes, its important to consider the country you are in when buying electronics. In the USA, these are all 'home grown' local equipment, elsewhere its 'imported' and could be taxed, not to mention the cost of your shipping.Quote from: jnd on April 15, 2012, 02:04:26 am

author: free_electron
author_rank: Super Contributor
timestamp: April 15, 2012, 05:33:02 pm
content: that palette of meters .. they want 200$ for 1 machine !. waaaay too much money for such an old clunker.50$ is what it is really worth. A lot of ebay sellers think they are sitting on 'gold'. Go to a real auction and it goes for 1/4 of what you see on ebay ( or less ). Of course you have to go in person. Living in the valley as its perks as there's one every few monthsrepairing the front panels on those things is easy. the funny keys fail after years of use because the spring blade pops out. a pair of weezers is all you need. and a temperature controlled iron to melt the plastic...calibration is a bitch too on those things. there's like 100 trimmers you have to tweak.. the 34401 on the other hand .. hook it up to the fluke calibrator run the agilent supplied cal program thru GPIB and 2 minutes later the machine is calibrated.then again i guess i' spoiled since i have easy access to all these goodies...

author: saturation
author_rank: Super Contributor
timestamp: April 15, 2012, 07:23:25 pm
content: Well, it is OBOBut you are right, median price I've seen it go for is ~ $50, but since its heavy and big the shipping adds another $30.A recent low end sale:http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&_trksid=p4340.l2557&item=370586900115&nma=true&rt=nc&si=4mM6StkG1oZ9VxnikhqijQ8rsQM%253D&sspagename=STRK%3AMESINDXX%3AIT&orig_cvip=true&rt=ncIt would be very laborious to calibrate the meter from scratch, but in practicality one only need tweak what few ranges are off. You're right about repairing the switch panel, it can be salvaged with some work compared to units with membrane or dome switches.While fully automated cal is the best, it will depend on the up front costs to use that equipment. Old manual meters like this one can be self maintained probably indefinitely as you will be independent of any software, specific type of automatic calibrators or even the existence of Agilent. All one needs is a reference and a screwdriver.Quote from: free_electron on April 15, 2012, 05:33:02 pm

author: Lightages
author_rank: Unknown
timestamp: April 15, 2012, 08:28:10 pm
content: Well seeing now that the Protek is not desirable, perhaps this BK meter could be the best deal for an accurate meter. Its basic accuracy is 0.1% in the middle DC ranges. The price is not hard to take either at $115USD. f it is built the same way as the BK meter that was reviewed by Dave in his $100 shoot out then it would also be a bargain.http://www.tequipment.net/BK2712.html

author: darrenb
author_rank: Contributor
timestamp: April 15, 2012, 09:35:42 pm
content: Quote from: Nermash on April 13, 2012, 06:32:51 amFlying a SAAB 340 all over New South Wales. The base salary is 55k.

author: ModemHead
author_rank: Frequent Contributor
timestamp: April 15, 2012, 10:05:47 pm
content: Quote from: Lightages on April 15, 2012, 08:28:10 pmIt's interesting to note that model does not have the usual 10Mohm input impedance:Input Impedance: 400 mV: > 3 M?; 4V to 1000 V: 2.3 M?

author: Lightages
author_rank: Unknown
timestamp: April 16, 2012, 12:17:52 am
content: Wow, I missed that. It seems that every time I find something that looks great for the price has something wrong with it. Not that this nput impedance is a real deal breaker but it is weird.

author: Bored@Work
author_rank: Super Contributor
timestamp: April 16, 2012, 09:37:44 am
content: Quote from: darrenb on April 15, 2012, 09:35:42 pmYou have my sympathy. Did you HEAR THAT? YOU HAVE MY SYMPATHYMy ears hurt from just reading that. I had to spend a lot of time on Saab 340s during business travels. First time I ever saw a stewardess plugging in ear protection before the engines were started. First time I ever thought we had strange rough weather, just to find out that we were still on the ground, hadn't even moved, and all the rattling and shaking came from the engines.Here are some hints for the young players. If you ever have to travel on board a Saab 340 bring your own ear protection. Don't forget to use the toilet at the airport before departure. Forget about normal size hand luggage. If you show up with these, the stewardess will take it away from you, walk around the aircraft, lift the boot and try to squeeze it in with the regular luggage. Which hardly works. And don't make jokes about small aircrafts. The stewardess might forget to hand you a sandwich for "lunch".

author: cybergibbons
author_rank: Frequent Contributor
timestamp: April 16, 2012, 10:42:20 am
content: I've flown on them twice. First time was OK. Second time, the thing felt and sounded like a WW2 era prop plane. I think there were quite a lot of improvements made in the later models.

author: SeanB
author_rank: Super Contributor
timestamp: April 16, 2012, 08:17:47 pm
content: You are spoilt! try flying in C130's, where you have a symphony of 4 turbines, an echoing interior and a standby hydraulic pump all combined. My trick was to bring a can along and drink it in turbulence, keeping the can normal while the plane did it's usual gyrations. I generally could get somebody to toss their cookies if I did this right.Must admit the best landing ever was on a Dakota - RH undercart would not show locked, even with the FE and me leaning out the door, looking down at the gear and agreeing it looked like it went into lock position. Was disconcerting to land with a 45 odd ton Pathfinder keeping pace next to us on the dirt next to the runway, with a foam cannon aimed at us. Landed, did a little percussive maintenance on the switch ( bashed the cr*p out of it with a big spanner until it worked) and got back in to get to my destination. Landed a little late - 3PM instead of 11AM, walked in and out from work, on asking said we had a little undercarriage problem and had to wait around till we ran out of fuel.

author: darrenb
author_rank: Contributor
timestamp: July 23, 2012, 01:56:13 pm
content: Thanks for all the replies to this thread. I ended up buying a new Fluke 87V off eBay and it is a thing of absolute pleasure to use.The previous best meter I had was a Fluke 17B and I thought it was superb until the 87V arrived and now it is slow, clunky and inaccurate in comparison.It is such a nice thing to be able to measure with 0.05% accuracy. I'm not certain yet how accurate the 0.05% accuracy is so I'll probably include a precision voltage reference in my next shopping list just to be sure.Still flying the SAAB. Yes it can be bloody noisy and the flight attendants do get issued with custom made and heavy duty ear plugs. But the best seat on the plane is up the front with a set of noise cancelling headsets and spectacular views every day. There is nothing creative about flying a SAAB, or a 737 which is the same thing except for engine type. I'd rather spend three hours creating something in Eagle than fly to Ballina and back.