Siglent SDM 3065X or Keithley DMM 6500 as a new DMM? - Page 1
Forum section: electronics / testgear

author: chephato
author_rank: Contributor
timestamp: August 16, 2020, 09:37:43 pm
content: I am looking for a new digital multimeter and am not sure which one to get:Siglent SDM3065X which looks like it can get the job done but the refresh rate is pretty slow- OR -Keithley DMM 6500 which is about 25% more expensive but has a much faster refresh rate but is pretty long lengthwise for a bench topPost your vote.

author: jjoonathan
author_rank: Frequent Contributor
timestamp: August 16, 2020, 10:40:10 pm
content: You know in your heart that you want the DMM6500. The warp-speed refresh rates and "half way to an oscilloscope" plots will bring joy every time you use them. Treat yourself!

author: chephato
author_rank: Contributor
timestamp: August 16, 2020, 10:58:17 pm
content: It might sound like that but I actually like the user interface of the Siglent more. I'm not a fan of unnecessary gradients and rounded corners on small screens like on the Keithley. I mean seriously, who does the UI design there? Aren't solid colored boxes easier to implement than silly gradients?So genuinely, I am neutral when it comes to this decision.

author: jjoonathan
author_rank: Frequent Contributor
timestamp: August 16, 2020, 11:58:32 pm
content: I'm all about responsiveness. The theme plays no part in my preferences. Your call, of course, just make sure you haven't missed this dimension by limiting yourself to static pictures, spec sheets, and videos at slow NPLC settings.

author: Electro Fan
author_rank: Super Contributor
timestamp: August 17, 2020, 12:05:07 am
content: How often are you going to collect and post-process data or automate data collection and data processing vs. mostly making attended measurements? How much do you like to write programs and scripts?

author: ercapoccia
author_rank: Regular Contributor
timestamp: August 17, 2020, 08:44:42 pm
content: I'd consider also the 34461A as alternative of the DMM6500If you like Siglent UI you will like the Agilent/Keysight better. Check Dave's review.

author: Sighound36
author_rank: Frequent Contributor
timestamp: August 17, 2020, 08:53:48 pm
content: Having had both units the DMM6500 is another league altogether itsca rather spiffing dvm

author: Electro Fan
author_rank: Super Contributor
timestamp: August 17, 2020, 10:06:25 pm
content: Quote from: Sighound36 on August 17, 2020, 08:53:48 pmSighound36, just to confirm/clarify, both units meaning the 6500 and the 3065X? or the 6500 and something else? Thx

author: Tabian
author_rank: Newbie
timestamp: March 21, 2021, 10:19:41 pm
content: Hi I’m in the same position. Which one did you go for in the end. Are you happy with your decision?

author: ComradeXavier
author_rank: Contributor
timestamp: March 22, 2021, 08:54:48 pm
content: Quote from: Tabian on March 21, 2021, 10:19:41 pmI have an SDM3065X but kind of wish I'd paid up for the DMM6500 instead. On paper, the SDM3065X is more than good enough for my (quite modest) needs, but Siglent have been slow to fix a lot of rough edges in the firmware. See the mainSDM30XX-series threadfor a bunch of bugs others have documented.

author: tautech
author_rank: Super Contributor
timestamp: March 22, 2021, 09:28:00 pm
content: Quote from: ComradeXavier on March 22, 2021, 08:54:48 pmAre you on the latest firmware: V3.01.01.08R1 ?

author: ComradeXavier
author_rank: Contributor
timestamp: March 23, 2021, 12:14:12 am
content: Quote from: tautech on March 22, 2021, 09:28:00 pmYes, I have V3.01.01.08R1.I haven't tried anything fancy since installing the update (modest needs, etc.) and in any case I haven't had any problems that weren't reported by someone else first.No doubt a SDM3065X bought now has better firmware for the price than what I got in January 2020. It's just that watching the pace of bugs reported vs. bugs fixed in the main Siglent meters thread has persuaded me that in retrospect I could have been happier opening my wallet a bit wider.

author: JoeRoy
author_rank: Regular Contributor
timestamp: October 28, 2023, 06:38:39 pm
content: Nobody commented, but I wonder why Agilent/Keysight and Tektronics/Keithley 6 1/2 DMMs have a max range of "1", while Siglent is "2".e.g.: you can measure "2.000'000", "20.000'00", "200.000'0" in a Siglent while with the Same Resolution in a Keysight/Keithley would be "1.000'000", "10.000'00", "100.000'0".AFAIK, even though both DMMs are 6.5 Digit, one has 2 Million Counts and another just 1 Million Counts.There are a lot of voltage standards around 1.5V, 1.8V, 12V, 15V, 120V, etc which will be more precise on a 2 Million counts DMM.(I'm just reading the Datasheet, I never had those DMMs, sorry if I made some misinterpretation).sources:https://siglentna.com/USA_website_2014/Documents/DataSheet/SDM3065X_DataSheet_DS06036-E02C.pdfhttps://download.tek.com/datasheet/1KW-61315-0_DMM6500_Datasheet_050523.pdf

author: mawyatt
author_rank: Super Contributor
timestamp: October 28, 2023, 07:19:11 pm
content: Siglent uses a Sigma-Delta ADC (believe ADI chip), while KS and Keithley utilize custom combinational multi-slope integrating ADC circuit with an external ADC chip (also believe an ADI chip). These more complex overall ADC methods enable KS and Keithley to "extend" resolution, the Siglent does not have such capability.Siglent is good value, we have one, but not in same class as latest, more feature rich (and expensive) KS and Keithley DMMs like KS34465A and DMM6500 respectively (have these also).For GP use the Siglent is fine, however for more involved use we lean towards the KS or Keithly.Best,

author: Kleinstein
author_rank: Super Contributor
timestamp: October 28, 2023, 07:46:13 pm
content: Many modern higher grade DMMs use an ADC that is working with an input range of a little over 10 V (e.g. 12 V or so). This makes it a natural choice for a +-10 V nominal range. Another point is than many CMOS switches and OP-amps are available for some +-15 or +-18 V supply, but only few for something like +-24 V. So there is quite some extra effort to make a high impedance 20 V range. There are / were a few other DMMs with a 20 V range (e.g. Datron 1271, Fluke 8840, Keithley 2001, Keithley 192) and in the old days quite some with only 2 or 3 V high Z ranges (like the SDM3055).The SDM3068 uses a clever way to generate a 20 V high impedance range: the low side is not identical to the circuit ground but driven to about the opposite of the high input. So 20 V is measured as difference from +10 V to -10V. The ADC is a SD type with a differential input and anyway a smaller input range of some +-2.5 V or so. So the 2 V range may actually be the more stable range for the gain.The high grade reference voltages were at some 1.018 V (Hg cells) in the old times and are now at some 7 V, often scaled to some 10 V. For more practical use 2.5 V and 5 V reference are also common. So for this tasks a 10 V and 1 V range are perfectly fine. There is always the problem of finding voltages that are just a bit too large for the range.

author: exe
author_rank: Unknown
timestamp: October 29, 2023, 08:12:51 pm
content: Rumors say DMM6500 cannot measure resistance of transformers:https://www.eevblog.com/forum/testgear/keithley-dmm6500-strange-beahavor-measuring-transformer-resistance/Another thing I don't like about DMM6500 is that there is not thousands separator. For me it's hard to read all the digits without any separation. Or they fixed that already?