R&S UDS500/UDS600 vs Keysight & Keithley? - Page 1
Forum section: electronics / testgear

author: gdr771
author_rank: Contributor
timestamp: September 27, 2025, 01:40:45 am
content: I was about to pull the trigger on a Keysight 33465A but then found the new Rohde & Schwarz UDS600. I can't find a user manual (too new?) so does anyone know how these really compare to the Keysight and maybe the Keithley DMM6500? Use case is average embedded microcontroller, switching power supply, and DC motor driver board design. I'm especially interested in the dual measurement which seems to be simultaneous voltage & current from the brochure & datasheet, but I don't know if that's actually dual voltage with a shunt, switching slowly back & forth with the relays, or what.

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 27, 2025, 02:28:55 am
content: The specs look decent on the R&S, but I hate the non-standard jack placement.I have the DAQ6510 (same analog board as DMM6510), and the Keysight 34465A, among others. The Keithley is my favorite. YMMV.Here's the datasheet:https://scdn.rohde-schwarz.com/ur/pws/dl_downloads/pdm/cl_brochures_and_datasheets/data_sheet/3673_1318_32/UDS_dat_en_3673-1318-32_v0100.pdfThanks,Josh

author: pdenisowski
author_rank: Super Contributor
timestamp: September 27, 2025, 08:31:07 am
content: It's basically an update of our HMC8012 multimeter (which is now discontinued). I made a video that goes over all of the HMC8012 functions, including the simultaneous voltage and current measurements.https://www.rohde-schwarz.com/us/products/test-and-measurement/rs-essentials-meters-and-analyzers/rs-hmc8012-digital-multimeter_63493-44315.htmlhttps://scdn.rohde-schwarz.com/ur/pws/dl_downloads/pdm/cl_manuals/user_manual/5800_4505_01/HMC8012_UserManual_de_en_06.pdfI'll ask around next week and see if we have a manual ready yet, but it really is pretty much just an update of the HMC8012 and the user interface, functions, etc. are mostly the same. (And I will do a video on the UDS sometime soon as well)

author: pdenisowski
author_rank: Super Contributor
timestamp: September 27, 2025, 08:36:34 am
content: Quote from: gdr771 on September 27, 2025, 01:40:45 amSince you asked, we do have a comparison sheethttps://scdn.rohde-schwarz.com/ur/pws/dl_downloads/pdm/cl_brochures_and_datasheets/comparison_sheet/3673_2943_32/UDS-versus-Keysight_sh_en_3673-2943-32_v0100.pdf

author: Kean
author_rank: Unknown
timestamp: September 27, 2025, 09:35:25 am
content: I have a couple of HMC8012 DMMs in my lab. I bought them around the time I got my RTB2K scope, along with a HMC8042 PSU. These DMMs and PSU live on my bench where I do EMC measurements or do longer performance analysis or data logging sessions.I quite like the features, connectivity, and the shallow form factor. The display can be a bit busy due to the aspect ratio and dual readout/stats, but that isn't a big deal when you are mostly using them for automation. Not experienced any other issues with them.If the price was about the same, I would definitely prefer to get another Keysight 34465A. Otherwise, I'd be quite happy to own more of the R&S Essentials T&M range. With the current state of the economy, as a small business I am more likely to get Siglent...

author: tautech
author_rank: Super Contributor
timestamp: September 27, 2025, 09:49:12 am
content: Quote from: Kean on September 27, 2025, 09:35:25 amThe new 7.5 digit SDM4075A coming ?

author: Kean
author_rank: Unknown
timestamp: September 27, 2025, 09:58:55 am
content: Quote from: tautech on September 27, 2025, 09:49:12 amHmm, we shall see. It will depend on timing, ppm needs/desires, and cash flow.I'd probably need to get rid of some other T&M gear to justify it, and that ain't something I am good at.

author: tautech
author_rank: Super Contributor
timestamp: September 27, 2025, 10:52:47 am
content: Quote from: Kean on September 27, 2025, 09:58:55 amTell me about it ! The story of my life and business !The 5.5 digits is ~$740 USD, 6.5 digit ~$930 so the 7.5 is gunna be a good bit more, I'm guessing ~$1200 or a little more.I'll get one for shits and giggles as I get great demo model pricing but only the once when new products get released.Had a quick play with SDM4065A when at HQ last year and just recently got our first stock of the 5.5 digit model which I'll forward to Defpom for a review shortly.

author: gdr771
author_rank: Contributor
timestamp: September 27, 2025, 02:17:51 pm
content: I found some of what I was looking for in the HMC8012 video and in the manual. So it can simultaneously measure current and voltage, which is quite cool if it's truly simultaneous and not switching back and forth every second with a relay.I can see those connectors being a pain when stacking instruments, which I'm thankfully not doing.

author: 2N3055
author_rank: Super Contributor
timestamp: September 27, 2025, 03:00:48 pm
content: Quote from: gdr771 on September 27, 2025, 02:17:51 pmIt is switching back and forth. It does not have 2 separate ADCs. None of them do.

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 27, 2025, 03:10:14 pm
content: Quote from: pdenisowski on September 27, 2025, 08:36:34 amJust to clarify: OP was asking about the 34465A, which does have 10A, and a better general DC accuracy of 0.003%.The 34465A can show 2 measurements and statistics at the same time, but the choices are limited.I think the on-screen label is a big bonus for the Keysight.Based on the companies and product updates, I'd prefer R&S vs Keysight, but I still wish R&S would use a standard jack setup. I prefer Keithley over anybody though in that regard.I think it's embarrassing that Keysight hasn't made any new firmware for over 4 years! The meters could absolutely use some improvements.Keithley's last firmware update was in March. IMHO the Keithley is superior to the Keysight. I'd give points to the Keysight for the label thing, but with Keithley's TSP script system, you can make a custom measurement script with a silly full screen display of anything you want.The R&S is new, so no worries there if you can get access to their support system to download firmware.Thanks,Josh

author: KungFuJosh
author_rank: Super Contributor
timestamp: September 27, 2025, 03:20:34 pm
content: For a functional comparison, here's the Keithley. A ton more options for secondary measurements. It has a nice web console with a virtual front panel for remote control. The graphing features are excellent too. Also, standard jacks.Since i have the DAQ version, there are scanner cards available which greatly expands what you can do. Some versions use relays, some use silent switching.Thanks,Josh

author: 2N3055
author_rank: Super Contributor
timestamp: September 27, 2025, 09:12:43 pm
content: Quote from: pdenisowski on September 27, 2025, 07:37:52 pmWhat I understood is that HMC8012 was switching. Maybe not with clicking relay, but not simultaneously sampling but alternate. With single ADC.If you keep ranges relays steady and then solid state switch A/V that is very good solution for wear.For measuring DC current/voltage of some DUT that is pretty good enough. If I am wrong and there are 2 ADCs please correct me.If new DMM does have dual ADC and can sample current and voltage simultaneously, that is very good and very interesting feature.That would make difference if it has fast sampling mode, where you could look at faster changes, and then simultaneous sampling would be more needed.Please let us know.Best,

author: Kean
author_rank: Unknown
timestamp: September 28, 2025, 06:33:43 am
content: In dual measurement mode it does seem that the HMC8012 alternates dual measurements, because the sample rate drops.I was going to run a test on mine when in the lab this evening, but I came across this older video that showed what we need.Interestingly, in the video description it states:QuoteBut it seems to me the facts show something different if you watch the video closely.The first 50-ish seconds are measuring DCV & DCI in Slow mode. Slow mode is normally 5 readings per second.Using the stats panel, you can see the stats count increases from about 620 to 745 in 50 seconds, so an increase of 125 or 2.5 readings per second.Starting at about 54 seconds into the video, it is switched to Fast mode which is normally 200 readings per second in DCV or DCI.The stats count increases to 1000 after approx 20-23 seconds, so this appears to be only 50 readings per second (possibly a little less).This is about 1/4 the normal reading rate, so maybe some extra sampling delay was introduced for the higher resolution readings.I might do a short test myself just in case newer firmware gives a different result.

author: pdenisowski
author_rank: Super Contributor
timestamp: October 01, 2025, 06:29:16 pm
content: So the word I got back from R&D is that yes, the UDS is switching (single ADC) between voltage and current measurements. I don't have numbers for the switching speed, but it is an electronic (not mechanical) relay.

author: 2N3055
author_rank: Super Contributor
timestamp: October 01, 2025, 07:14:15 pm
content: Quote from: pdenisowski on October 01, 2025, 06:29:16 pmPaul,thank you for the effort and the update. And comforting confirmation that I am not (yet) crazy...Like I said, it is clever way of doing it, and if you avoid ranging (that does use relays) there is no additional wear.For DC and slow moving processes that is good enough most of the time.Best,Siniša

author: KungFuJosh
author_rank: Super Contributor
timestamp: October 01, 2025, 08:04:02 pm
content: Quote from: pdenisowski on October 01, 2025, 06:29:16 pmThat's good. The Keysight has a mechanical relay.

author: salomonander
author_rank: Regular Contributor
timestamp: October 02, 2025, 05:43:38 pm
content: I use a hmc8012 that i like a lot. But i would like it a lot more, if r&s would ever implement a percent math function as in the keithleys. Actually im thinking sbout selling the r&s and getting the dmm6500 for this very reason… or is there any chance this will be added to the r&s dmms at some point? Should be doable in a software upgrade i guess.

author: pdenisowski
author_rank: Super Contributor
timestamp: October 02, 2025, 06:32:54 pm
content: Quote from: salomonander on October 02, 2025, 05:43:38 pmIt's a good suggestion - I'll pass it on to the product line managers. Thanks!

author: salomonander
author_rank: Regular Contributor
timestamp: October 02, 2025, 09:17:05 pm
content: Awesome. It would be such a great help for all kinds of scenarios. During calibration, measuring of components and so on. Please also suggest for the hmc8012