cheapest effective DMM 6+1/2 digit metrology with VXI/LAN ? - Page 1
Forum section: electronics / general

author: Hella_Wini22
author_rank: Contributor
timestamp: September 07, 2024, 04:41:17 pm
content: I'd like to fundametnally update my miserable chinesium $20 DMM to with some desktop model that could be used for serious measuerements.Unfortunately, I'm constantly on a shoestring bugdet, so I have to aggressively search for various shortcuts, which often include some DIY work.I'd like to automate my measurements and do it over several/many points, which means using VXI protocol, LAN and some kind of switch matrix.Even cheapest DMM sources ( SIglent, Rigol) that I could find charge substantially for extensions that are little more than cheap PCB with a couple of relays, which I can do myself for peanuts.So far, I have narrowed it down to 2 choices that seem to satisfy my minimums:* Rigol DM3068 for €699* Siglent SDM3065X for €672Have I overlooked something ? IS there a third, cheaper option, worth looking at ? 🙄

author: janoc
author_rank: Super Contributor
timestamp: September 07, 2024, 05:31:50 pm
content: Get a used HP/Agilent HP34401A.These can be had even for 200€ on eBay if you get lucky, in a good shape, often even with still valid calibration. Maybe the display will be needing replacement (the VFDs tend to be faded after years of service in various measurement racks) but there are aftermarket ones on eBay too. I did swap mine for one of those, works just fine. Big bonus is that these are pretty well documented, service manuals are available - and the meters are designed to be serviced and repaired, even though they are normally extremely reliable and well built.It doesn't have LAN but has GPIB and RS232, so you can easily build your own network solution by adding a small dongle and automate the measurements.

author: Hella_Wini22
author_rank: Contributor
timestamp: September 07, 2024, 05:34:18 pm
content: I need LAN for galvanic insulation.Also I might not always have USB at hand at the measurement place or the ability to run the SW.Also used gear is another category with its own risks and rewards, which I would rather not pursue at this point, if there is another option.Less than €700 for a new instrument with warranty, support etc ain't that bad.

author: voltsandjolts
author_rank: Unknown
timestamp: September 07, 2024, 05:38:10 pm
content: The inguard/outguard gives you galvanic iso. No need for ethernet for that.

author: janoc
author_rank: Super Contributor
timestamp: September 07, 2024, 05:46:56 pm
content: Quote from: Hella_Wini22 on September 07, 2024, 05:34:18 pmThere are USB isolators available, as are there RS232 or GPIB to ethernet dongles.Quote from: Hella_Wini22 on September 07, 2024, 05:34:18 pmWell, you have said you are on a shoestring budgetIn that case warranty and support are not something one would care about as long the meter can be fixed and calibration still obtained.If you have the 700€ for a new instrument then go with those you have picked, you aren't going to get a good new instrument in this category for less, IMO.

author: voltsandjolts
author_rank: Unknown
timestamp: September 07, 2024, 05:48:18 pm
content: Quote from: Hella_Wini22 on September 07, 2024, 04:41:17 pm34970A or 34972AKeep an eye on ebay and you'll pick one up for $300ish with a scan card.Not pleasant to use as a bench dmm but perfect for automated scanning and small production tests systems.

author: J-R
author_rank: Super Contributor
timestamp: September 07, 2024, 08:01:44 pm
content: Can you post more information about what you are going to be using this for?Going from $20 to €700 (are you in the US or not???) is a big jump all at once. It seems suspicious that you're on a "shoestring budget" after all?Both the Rigol and Siglent are probably going to drift a bit after purchase, so you are going to need to have them calibrated regularly, which is going to increase the TCO significantly. Without regular calibrations, the last two to three digits may not be reliable, which defeats the purpose of all those digits.The Siglent SDM3065X-SC is the clear choice of Rigol/Siglent if you want new AND want to do scanning. The other models can't support a scanner card as there are components missing.The Rigol DMMs are outdated IMHO due to their tiny displays and Rigol's products are not so great anyway.A used 34401A with a fresh calibration is a VERY solid option. The serial interface is easy to work around. No internal card option though.There was also an eBay listing that you missed just recently with a bunch of used 34410A units for about $400. It's worth being patient on eBay for a few weeks or so to see what you can find.As mentioned, there are a few DAQ options from HPAK and also Fluke that might be worth looking into. Software support might be an issue, especially with the Flukes. They offer limited functions, so typically no current, etc.

author: Roehrenonkel
author_rank: Frequent Contributor
timestamp: September 08, 2024, 08:26:35 am
content: Hi Hella_Wini22,Quote from: Hella_Wini22 on September 07, 2024, 04:41:17 pmI guess you mean VXI-11 (protocol) and not VXI. ;-)But it may be the solution. If you got the space for 19"-gear look for a HP E1300 or 1301 mainframe.Most of them have a E1326 Multimeter fitted and can be upgraded with Multiplexer-cards.Communication is over GPIB (one address, each modules via subaddress) or RS232.Good luck

author: krish2487
author_rank: Frequent Contributor
timestamp: September 09, 2024, 12:05:31 pm
content: I dont have anything on the lower end.. but if you have the budget for 700 euro.. then with a bit of patience you might come across a 34461a in that budget..Thats is a solid bit of kit and pretty much the most modern offering.. You can also find a 34460a for a bit cheaper and buy the lan upgrade later from keysight ( which is what I did.. ).. you dont save anything... but you dont spend the 700 euro immediately either..(the 34460a does not come with the lan option enabled by default )The license for the lan upgrade costs about 130 euro if memory serves..

author: rhb
author_rank: Super Contributor
timestamp: September 10, 2024, 02:37:38 pm
content: A 34401A or 3457A with a multiplexer card should do nicely. Use an AR-488 for the GPIB to USB. There’s a long thread on the AR-488. A 3478A is also an excellent choice at 1/3 to 1/2 the cost if 5.5 digits will do.Have Fun!Reg

author: esmIII
author_rank: Newbie
timestamp: September 10, 2024, 03:03:53 pm
content: L4411A is a 34401A without front panel controls and an Ethernet interface. You can find them used for 500ish on ebay. Maybe cheaper if you can wait.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: September 11, 2024, 10:27:55 pm
content: I was also in for a better DMM and I was on the edge of buying a Siglent, but the case was so horribly deep (over 300mm). I thought about sawing the case in half ( the back half only has a power supply PCB), but it's madness to buy a DMM for EUR500 and saw it's case in half.So I sat back, scratched behind my ears really hard and had some thoughts about what I really needed.Then I bought a Brymen BM869s for less then EUR200. It's got plenty of digits (half a million) and it's got a data output (plenty of projects to convert that to some other format). So if you want to DIY a scanner card, then you may as well DIY your DMM interface too.BM869s is a significant upgrade compared to most other handheld DMM's and if you later decide you really want to spend the money on a benchtop meter, it's still a nice second meter.Something else you may have missed is that those scanner cards do not have the simplest 13 in a dozen relays. But depending on what things you want to measure, maybe you can even start with a CD4051.