Any bench meters with USB ~$400? - Page 1
Forum section: electronics / general

author: paulpthcom
author_rank: Contributor
timestamp: December 06, 2010, 11:54:26 pm
content: Hi All,I'm looking for the bench equivalent of one of the Agilent 125Xb series. Keys are reasonable accuracy, ~400 price point and USB (or I guess serial) connectivity (plus either free or reasonably priced software). Neither Agilent nor Fluke have anything in that price range, at least nothing new. This means I'm probably looking at either something Chinese or used.Anyone have any suggestions?

author: Unknown
author_rank: Unknown
timestamp: December 07, 2010, 12:21:18 am
content: I'd say forget new bench meters if you only have $400 to spend. The only candidates will either be crap (like the Keithley 2100, which isn't even that cheap) or won't offer anything above high-end handhelds, and be worse in many other aspects (eg. Uni-T bench meters). I believe Agilent has a cheap(ish) line which may be close to $400, no idea if it's any good, though. Saturation recently posted a review of a Rigol bench meter, which wasn't that positive, and I don't think that Rigol meter was anywhere near $400. I wouldn't bet on the even lesser known brands to do any better. I'd go with used (HP, Keithley and Fluke are the main brands). Used tends to be better bang for the buck if you can stand the risks.Calibration is rarely economical, but I've been lucky so far and have rarely received anything significantly out of spec (unless it was broken), so my impression is that good equipment doesn't tend to drift much. Make sure you know what the seller means if you buy a calibrated unit, some may only mean that they hooked it up and pushed some buttons.If you focus on USB, you'll be limited to the new $$$ stuff. An USB-serial converter (for recent-ish models) is $15 or so, USB-GPIB (for stuff from the eighties, which tends to be cheaper) is $150 (Prologix, don't fall for the worthless $30 ones). Accuracy tends to be plenty good on the 4.5+ digit models. For $400, you may be able to get a used HP 34401A or Keithley 2000 (both are still in production), which support RS-232. Older / cheaper stuff tends to be limited to GPIB, which is fine, as long as you have an interface. Plenty of good options from the eighties with 4.5-6.5 digits and GPIB, eg. HP 3478A/3455A/3456A/3457A, Fluke 8840/8842, Keithley 196/199 (and to lesser degree 192/195(A)). Beware that some basic features like AC or resistance may be optional on some units (I think AC and possibly GPIB is optional on the Fluke 884x). Some of them can be picked up for $100 or less if you get a good deal (eg. HP 3478A or Keithley 199).

author: paulpthcom
author_rank: Contributor
timestamp: December 07, 2010, 01:22:22 pm
content: Thanks for the reply. The ~$400 Agilents don't have serial/USB in them so that knocks them out. And thanks for the warning on the Rigol since I was looking at those, though they don't have anything that close to ~$400.I've been looking at the 34401A but not the Keithley so thanks again for pointing that one out.

author: Bored@Work
author_rank: Super Contributor
timestamp: December 07, 2010, 07:17:08 pm
content: $400 will bring you in the range of the meters "no one" knows about or doesn't write about. Like Tonghui stuff or Picotest. Or BK Precision, Instek and the like.

author: Unknown
author_rank: Unknown
timestamp: December 07, 2010, 07:44:10 pm
content: Quote from: BoredAtWork on December 07, 2010, 07:17:08 pmI believe the Picotest stuff is re-branded from the same OEM as the Keithley 2100 (no relation to the Keithley 2000, which is well regarded and a direct competitor to the HP/Agilent 34401A), which has gotten pretty bad reviews (though some of it is for a well-known brand selling such a shoddy product). Not sure if it's the same model, but I wouldn't bet on it being any better. List price is well above $400. Not sure about the other brands. The trouble with equipment no one knows about is that it's always a gamble, and if you only have $400 to spend, you can't afford that. If you have $1k to spend, you can risk $400 and spend the remaining $600 on a brand-name one if it turns out bad, but there would be no need for a cheaper unit in that case.

author: JohnS_AZ
author_rank: Frequent Contributor
timestamp: December 07, 2010, 07:44:10 pm
content: The wiki list might have manufacturers you haven't yet looked at ...http://www.eevblog.com/wiki/index.php?title=Manufacturers#Digital_Multimeters.2C_Hand_Held_.28DMM.29

author: saturation
author_rank: Super Contributor
timestamp: December 08, 2010, 01:41:12 am
content: Bench meters seem well suited as being being part of a networked automated test & measurement suite. However, your price range puts it well within many higher end Agilent handhelds which have USB support:http://www.home.agilent.com/agilent/product.jspx?nid=-34618.0.00&lc=eng&cc=US#16779520From Fluke. the 287 could be in your price range and have USB support, call tequipment.net as they could quote lower than list to meet your budget.<= $400, I can think of 2 B&K Precision models as new traditionally looking bench DMM with USB support.http://www.tequipment.net/BK5491B.html

author: paulpthcom
author_rank: Contributor
timestamp: December 08, 2010, 04:52:24 am
content: The U125X series is basically what I wanted but in a bench format. The Fluke ones I'm not all that crazy about since, at least the last time I looked, they were charging a fair amount of $ just for the software. The BK one seems interesting, that's somewhat what I expected to find one of the major companies producing, a lower cost lower precision bench meter.Earlier today I was able to locally get a used (but in great condition) Keithley 2016 which ends up doing everything I need and more. I did go over the ~$400 budget but was able to fully test it out and go through most of its features.

author: saturation
author_rank: Super Contributor
timestamp: December 08, 2010, 12:34:14 pm
content: Wow, that's a great buy. I've never seen those but heard of them; more expensive than many high end bench 6.5 digit DMM from Agilent, and they go for $1000+ used; it was near $3-5K new. Part of the added costs are they are also used for audio fidelity measurements.They've been around for over 10 years, can you tell us where it was made? US, Taiwan or China, etc.,?If its anywhere in the $400 ball park its a far better deal than a new B&K in measurement performance.Quote from: paulpthcom on December 08, 2010, 04:52:24 am

author: paulpthcom
author_rank: Contributor
timestamp: December 08, 2010, 02:09:12 pm
content: I'm pretty sure all the Keithley stuff is made in the US, maybe not the 2100 series, but at least all the higher end stuff.Honestly the 2016 is a 2000 with audio bits tacked on. I very much doubt I'll ever use any of the audio bits, though it does have a built in (slow) signal generator that will probably come in handy.It's a really nice piece of equipment very nice hooking up a 5V reference and seeing it output 4.999999x.

author: saturation
author_rank: Super Contributor
timestamp: December 08, 2010, 04:41:01 pm
content: They used to be, but not recently.A lot are made in China in the past 10+ years; if your unit is a 2000 variant it could be US or Taiwan; its easy to find, check the label. I think those 2015/6 are from 1998.Do you really mean your 6.5 digit DMM outputs 8.5 digits?You actually have a 5V source stable to 100nV?Nice, then.Quote from: paulpthcom on December 08, 2010, 02:09:12 pm

author: paulpthcom
author_rank: Contributor
timestamp: December 08, 2010, 04:53:26 pm
content: I didn't count the 9s on my reply.It's 4.9999xThis one is made in the U.S.A. says so on the back.

author: Unknown
author_rank: Unknown
timestamp: December 08, 2010, 05:15:06 pm
content: Nice deal. Being able to buy locally and test before you buy is also worth something.I think the lack of proper low-end bench meters is mainly because handhelds have gotten pretty good. Bench meters were more popular when handheld DMM's didn't exist, or only offered 3.5 digits of resolution with mediocre accuracy. Now they're mainly for exotic measurements like high accuracy / resolution, high speed or automated test setups. A bench meter with similar specs as a HP 34401A with just 4.5 digits of resolution probably wouldn't be that much cheaper, you still need an ADC that can do 1kS/s instead of the 2S/s or so that a handheld does, and more expensive case, front panel and power supply. If you drop the speed, you lose all customers doing automated tests (eg. testing all states of a DAC). I know companies that upgraded from an Agilent 34401A on every engineer's bench to a 34410A for the 10x increase in reading speed (1kS/s -> 10kS/s), which means they can measure a DAC in minutes instead of tens of minutes.I like bench meters even when I don't need the high accuracy/resolution, because of their form factor (handhelds don't stack well), bright display and infinite power source. Something like a Fluke 289 would probably need to have its batteries replaced fairly regularly in the same setup, same with the Agilent OLED one. LCD without continuous backlight (power issue again) is also much worse than LED or VFD, if power draw is not an object. Even backlit LCD usually has a much worse viewing angle than LED/VFD, at least the ones in most DMM's. VFD is not suited for pretty graphics, but excellent for just displaying text in my opinion.I would be a potential customer for good, relatively cheap 4.5-5.5 digit bench meters if I couldn't get them for <$100 or so used.

author: saturation
author_rank: Super Contributor
timestamp: December 08, 2010, 06:38:59 pm
content: A sweet deal, its meets everything you initiall specified plus a really good quality older Keithley. Happy for you.I concur with alm's post, I look for high accuracy in bench meters: 4 wire ohm, 6.5 digit types at the minimum. I would love to have speed too, as is possible. So I've been happy looking for viable HP 3456a, which can range between $50-120, uncalibrated.I wonder what those companies upgrading their 34401a to the 34410A do with them? They maybe slower, but they're faster than the HP3456a and near the same general specifications ... their eBay prices are high, they start typically $300-500 working and not recently calibrated; the 3456a is a poor mans 34401a.Quote from: paulpthcom on December 08, 2010, 04:53:26 pm