#### SamR

Joined Mar 19, 2019
2,419
When you get to that level, you expect both precision and accuracy. Which entails calibration by an outside metrology lab at regular intervals... Which ain't cheap either...

#### nsaspook

Joined Aug 27, 2009
7,486
When you get to that level, you expect both precision and accuracy. Which entails calibration by an outside metrology lab at regular intervals... Which ain't cheap either...
For hobby usages regular intervals are over-kill with high quality stable instruments. I ran the EE calibration dept. for 10 years. In that 10 years I had almost no cases of Fluke precision DMM drift out of calibration specifications. During DNV audits we would review trend data for critical instruments to see if replacement was warranted. That almost never happened in a ISO/QS qualified production line.

For these lower cost bench DMM's the long term trend data is likely not as good but more than adequate for hobby use.

#### DarthVolta

Joined Jan 27, 2015
501
Buy a used one on eBay. I got an HP3438A, Fluke 8010A, and Simpson 467 for under $50 each. I did that already, and that's the Keithley 177 I have setup now. I like it except for the manual buttons. It needs modding, for continuity/diode/cap/etc. I want a new modern DMM tho, with adjustable update speed if possible. And even a mode to decrease the digit-count, /round it off, without having to manually change range. I'd love the sdm3055, but it would be nice to turn off the last digit sometimes. #### tautech Joined Oct 8, 2019 123 SDM3045X vs SDM3055 comments SDM3045X 4 1/2 digit (60,000 count) SDM3055 5 1/2 digit (240,000 count) Very very similar but there are some distinct little differences. SDM3045X is fanless so completely quiet however check the datasheets for each as the minimum V range is 600mV vs 200mV for SDM3055. Likewise for amps and resistance, SDM3055 has better low ranges. Each have a user set count speed that impacts on settling time for steady readings. I sell roughly one for one here in NZ however as the SDM3055 has been released a little longer they might have a slight edge on numbers. For the average bench doing repairs the SDM3054X would be adequate. They have proven to be reliable but in early days they had some SW issues but these are all past. At one time I had on my bench the top model, SDM3065X with the factory installed 16ch scanner card but had to let it go to a customer that wouldn't wait for a factory new one. #### rsjsouza Joined Apr 21, 2014 253 At that price range and resolution of 4-1/2 digits I would take a deep look at the handheld Keysight U1282A, which features 60k counts with possibility to reduce the number of counts for faster operation and it is quite featured, with excellent specifications throughout: 600MΩ, 100mF capacitance, fast continuity, 1 μV and 10 nA resolution, 1GΩ input impedance in the 2 V range, temperature, bargraph, dual display, auto power off can be disabled (and battery consumption is ridiculously low), it comes with the datalogging cable (and the software is free), etc. The major advantage is that it seems Keysight charges a reasonable cost for calibration services. The major disadvantage is that it lacks four wire low ohm measurements. In the bench arena, it is hard to fault the models you mentioned. Depending on where you live, you can also check Rigol's clearance bin - there is a DM3058 there for near your budget. If you are looking for the lowest cost possible, an experienced user on another forum loves the 80000 count VC8145. Good luck in your quest! Thread Starter #### DarthVolta Joined Jan 27, 2015 501 No I want a bench meter for sure. I have a stack of Oscope/AWG/bench DMM/PSU (on shelves) I'll probably get the SDM3055, or another 5 1/2 DMM, otherwise I'll immediately want a more sensitive model, that I would then have to put somewhere anyways. I don't need/want to go over ~$500, but if I remember right the bigger names w/ 5 1/2dig are more like +$800 #### rsjsouza Joined Apr 21, 2014 253 I don't need/want to go over ~$500, but if I remember right the bigger names w/ 5 1/2dig are more like +\$800
You remember correctly. The closest ones I saw were the sweet OLED Keysight 34450A and the relatively unknown (to me) Rohde & Schwarz HMC8012. The cheaper Keithley 2110 is frowned upon by some folks due to the fact it is not an original Keithley design but an off brand rebadge (not sure if this is really that terrible, but I don't have one). Funny is that both these two have a poorer 1yr accuracy than my ancient Keithley 191.

#### DarthVolta

Joined Jan 27, 2015
501
Yeah the Keysight would be great, I've spent that much on videocards before, but it's so hard to save the money that long and not spend it. What about the Rigol's ? Or Uni-T models around 500 ? I think the Rigols were more expensive than the Siglent's.

IDK tho, maybe for my birthday I'll get the Keysight, with it's 4 wire capability too. I was thinking about a new gaming computer, but I don't even play games anymore, I'm just doing EE/CS in ALL my spear? time

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#### rsjsouza

Joined Apr 21, 2014
253
@DarthVolta, given that you do not seem to be pressed to get a DMM, I would probably take my time in evaluating the options and see if there is a possibility of getting a demo unit (a very unusual option for home/hobby use) or perhaps a free return item (in case you dislike it).

Unfortunately I haven't used the RigSig meters, but their reputation is alright. Their product pages also show service and calibration information - something that shows the manufacturers believe their lab grade equipment is capable of being used in a professional environment. And that is my problem with the bench offers from Uni-T and Owon: I couldn't find any calibration information publicly available.

If you nitpick their specifications you can go completely crazy - the Uni-T has more logging memory than the others and samples at a much faster speed, but has a worse capacitance meter and the faster speed can translate to higher noise as well. The Owon and the Siglent seem to have the nicest interfaces, while the Rigol seems to be sturdier (it talks about a MIL spec for vibration) and it has double the memory of the other two.

A thread with several photos, opinions and video reviews is shown at:
https://www.eevblog.com/forum/testgear/which-desk-digital-multimeter-to-pick/

#### DarthVolta

Joined Jan 27, 2015
501
Maybe I should just fit my backup DMM in a box, and tape it to my bench for now, my bench DMM has no continuity/caps/diode

Well another thing tho, if i get a 5-1/2d DMM, I'll probably never afford a worth-while 7-1/2d DMM , so the next step would be down the road get a 6-1/2d DMM. But that's pretty redundant, so from that POV a nice 4-1/2d would be fine for now, and then get a 6-1/2d DMM later.

I can afford either the 3045x or 3055, the latter is barely more expensive, it's almost a crime not to get the 3055 tho....or I could wait and get the 3065x in the fall..but I don't want that as a day to day DMM, or to wait that long. So I'm back to saying just get the 4-1/2d DMM for day to day.....mind loops

What's a cheaper 4-1/2 digit DMM than the 3045x, that's also not a toy ?

#### DarthVolta

Joined Jan 27, 2015
501
Well no matter now, I just found out about the Keithley 197, and for under 1/3 the price of the sdm3055 I got a used 1 off ebay, they all look a bit ugly, but I could paint it
http://web.mit.edu/8.13/8.13d/manuals/keithly-197a-microvoltmeter.pdf

So the K197 is 5-1/2d 220,000 count, it looks fairly quick in the little video I saw. I think I saw this DMM before and forgot all about it. The LCD screen is small, but down the road I seriously plan to mod in a fully programmable screen w/ a MCU.

Then later this summer, I can get a SDM3065x if I still want to.

#### rsjsouza

Joined Apr 21, 2014
253
Keithley 197s are seriously good meters. Sure, the interface is older, but the performance is quite alright.

#### DarthVolta

Joined Jan 27, 2015
501
yeah I like the big red LED display on my keithley177, and apparrentl the K197 non A model doesn't have the backlight, but othre than that it should be great.

But a if a 5-1/2d meter will be my preferred range, I would rather have the newer DMM with 5-1/2d, and get an old weathered in 6-1/2d meter, for occasional us. I forgot that part when I decided to buy it.

No matter, at least the keithley will be light, I'll keep it either way, I can't wait till it gets here in a month

#### rsjsouza

Joined Apr 21, 2014
253
My Keithley 191 (with LED displays) is quite accurate but its Achilles' heel is the gang of switches. They seem to require some continuous action if the meter stays off for quite some time.

Anyways, one can't have too many multimeters...