EEVblog Electronics Community Forum
Electronics => Metrology => Topic started by: ebclr on December 25, 2017, 02:01:48 pm
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I'm really thinking in forget my order of keysight 34465 in favour off Rigol DM3058, will save-me 500 USD, and adds a lot of flexibility.
What I will miss ??
https://www.youtube.com/watch?v=eR0TM3eitNk (https://www.youtube.com/watch?v=eR0TM3eitNk)
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You will only miss the large screen of the 34465A with a really nice trend chart capability, after you have used it once!
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Better documentation ("Please send it to Rigol for calibrating" is a joke for a precision instrument), a better pedigree, better UI, better software support (although not sure how much functionality is available from BenchVue without paying $$$), better tech support in many regions.
See also these past threads:
https://www.eevblog.com/forum/testgear/rigol-dm3068-vs-agilent-34461a/ (https://www.eevblog.com/forum/testgear/rigol-dm3068-vs-agilent-34461a/)
https://www.eevblog.com/forum/testgear/6-5-digit-dmm-keysight-34461a-or-rigol-dm3068-or/ (https://www.eevblog.com/forum/testgear/6-5-digit-dmm-keysight-34461a-or-rigol-dm3068-or/)
Edit: this post was mostly about the DM3068, which is closer in features to the 34461A/34465A. But many arguments equally apply to the DM3058E, in addition to differences like communication interfaces, resolution, accuracy and trend plotting.
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500$ different is only to 3058E, which is 5.5 digit and no interfaces.
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@tin
in EU 34465 is 1150-1200€ , DM3068 is 699€ (VAT free). so yeah, that's almost 500 €, which buys you a scope...
@ebclr
To be honest, nobody really ever proved DM3068 to be really bad or good..
Voltnuts that have equipment, knowledge and patience snobbishly discount it as something without pedigree and not even worth their time.
Everybody just presumed it's bad.
Other ones that speak against it mainly come from position of ether better pedigree of big brands (which has it's merits for sure), or the facts like bigger graphical screen and colours, or something on usability side.. Or they bought it directly from China from who knows who, and got something suspicious (rejects, reworks, repaired).
Those threads mentioned, they have no useful information, they end up talking about everything except DM3068..
That being said, 34465 is a better specced instrument, with better screen, from a reputed company, with global premium support and calibration network. It is almost twice the price too, but if you can pay for it, you can't go wrong with it.
On the other hand, DM3068 is more like 34461 specs vise, and in my experience, holds it's ground well against it, and is better than 34460 that's still a slightly more expensive. But some will say that for the price difference (700€ DM3068 vs. 890€ 34461 VAT free) they still will get Keysight because it's less than 200€ more .. I say that's 30% more.. And screen aside, not much going on for 34461 spec vise, except brand.
But that is a problem with precision instruments. Reputation and repeatable quality (ie. every one made by factory should be uniform quality and live up to specs..) is important..
If you plan to give around 1200 € and you don't care much about graphical screen, Fluke 8846A has even better 1 year accuracy specs than 34465..
Pick your poison.
Or you can think like I did: Keysight 34450A is a 5 1/2 digits (100 000 counts), 0.015% and costs the same as DM3068... And that is a no brainer..DM3068 is much better instrument..
I'm so amused when those that don't like chinese equipment compare it to to big brands, they go straight to comparing it to the best ones.. That cost twice as much...
If you compare it on a basis of price, it looks much better.
But all that is moot... Better question is, and what you had to start with was: what do you plan to do with it. Do you really need 6.5 digit DMM in a first place?
Regards,
Sinisa
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Just tossing this out there. If you want the 34465A's features but it was not in the budget, look at the Siglent SDM3065x. Its very similar in operation and features and is a very fine meter for the price IMHO (yes, I had one and also have a 34465A). The 34465A is just a pleasure to use from all aspects, its a quality meter.
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What I will miss ??
Professional after-sales services. In my experience there are light-years between Rigol and the tier one T&M manufacturers.
Fine for hobbyists (as long as you are aware of the fact). A No-Go for use in a professional environment IMHO.
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What I will miss ??
Professional after-sales services. In my experience there are light-years between Rigol and the tier one T&M manufacturers.
Fine for hobbyists (as long as you are aware of the fact). A No-Go for use in a professional environment IMHO.
Could you please explain what exactly does that mean, after sales service? Not being facetious, but I hear that phrase but no explanation what it means.
Do they help you with setting up measurements, explaining things from user manual that kind of things.. Or it means that you setup something according to the manual and it doesn't function as explained so you call them for clarification.? In which case is it good support or bad manual or instrument... ?
What part of after sales service was most important to you and it was worth the price?
I never had much (in professional environment) use of after sales service, except bug reports, repairs in and out warranty, and calibration...
Rigol, in my experience is nowhere near Keysight in customer service, but it was adequate so far...
Mind you, my experience was in small environments, I have no idea what it looks like when you have 250 8 1/2 digit meters and need to keep them running..
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600E is still a lot for a meter, especially for a voltnut hobby, so many folks are instead hunting down older but top-tier brand meters, like 34401/10A, K200x, 345x that are well proven by time, have very clear calibration information in public, have lot of various software options to use in datalogging/automated rigs and still have parts support in case something goes bad.
Since you touched voltnuts, same reason why nearly nobody from this crowd get Rigol/Siglent have that much of free time to waste testing inferior meter (by design) to prove it's specs. Even with 5.5 digits verifications is NOT the simple plug a reference into meter, get few readings, and viola, test done. Multiply check points for various functions and ranges, you just to test if meter in spec or not you will end up with few weeks of full-time job timeframe, which usually cost more then meter itself.
Yet, nothing is lost, and if you like risks and gamble, you can still have ebay and hunt for much lower prices than 600E, and still get 6.5d meter. Some of 34401A/K2000/K2015's go for less than 300$USD if you patient and don't care than much of nice fancy screen (which is overrated in my pov anyway, since you want remote interface to perform datalogs anyway!).
34461A is quite similar to 34465A/70A, if you look at Dave's video you'll notice that even PCB is 99% same. So 34461 is underestimated meter in a way, and still in current support.
If you want to buy benchtop DMM, then perhaps you buying it for stability, accuracy and reliability, for which items it usually worth to spend 100-200E more and sleep well at night.
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On the other hand, DM3068 is more like 34461 specs vise, and in my experience, holds it's ground well against it, and is better than 34460 that's still a slightly more expensive. But some will say that for the price difference (700€ DM3068 vs. 890€ 34461 VAT free) they still will get Keysight because it's less than 200€ more .. I say that's 30% more.. And screen aside, not much going on for 34461 spec vise, except brand.
Regardless of quality and trustability of specifications, compared to Keysight 3446xA, DM3068 has much less sophisticated true RMS measurement. And many times higher injection current when high input impedance mode is used. Also it's strange that it is compared to 34465A when it's not even direct competitor unlike 34461A. If it's not a typo about DM3058 and not DM3068 as in the video, then it does not make sense at all.
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DM3058 is a completely different meter to the DM3068 that Shahriar reviewed, they just look similar.
If you want a 5.5 digit cheap chinese DMM then don't touch DM3058 with a bargepole, go for the Siglent SDM instead. (It's cheaper too!)
Rigol still sell the DM3058(E) but absolutely do not support it. Last firmware update 2.2 back in 2015.
ETA: I would not bother with any new Chinese meters, just go for a used Keithley 2000/2015, HP/Agilent 34401 instead and get trusted 6.5 digits for half the cost of new China 5.5 digits. ;)
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500$ different is only to 3058E, which is 5.5 digit and no interfaces.
To be fair to my 3058E, it does have USB and RS232 interfaces for SCPI, the higher spec 3058 (non "E") has GPIB and LXI and includes its own webserver too as a nice gimmick.
Though the SCPI is broken and I have raised this with Rigol but they just gaslight me and say nobody cares that it claims to be Agilent 34401A compatible and it patently isn't.
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That windows CE inside Keysight is the thing that I didn't like, long boot time, and slow screens, In some years the nand will crash, and will be a nightwhere to replace it with a windows version who will no more be available, Rigols on the otjher hand is bare metal and will not have this kind of trouble. Also that kids play screens is quite useless for a instrument with 1000000 count an a 300 pixels graphics, it's much better using LXI on a 4k computer screen and matlab The point that I liked is Rigol is the sensor scale, emulation of 3 kinds of instruments for automation, and very low current scales together with a strong capacimeter,
I would agree that the keysigth is a very beauty design. But will be a instrument to work , not a piece of art.
I believe that the venerable 34401A is a proven good instrument, but those new ones isn't the same instrument and we can't assume that they will do the same on the long run I really expect that a "blue screen " is waiting for me.
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Why anyone would need to replace windows CE version :-//, it's not desktop windows. Rigol is not bare metal but runs Linux IIRC. I won't disassemble Rigol to look what flash it uses but it could be NAND as well.
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Why anyone would need to replace windows CE version :-//, it's not desktop windows. Rigol is not bare metal but runs Linux IIRC. I won't disassemble Rigol to look what flash it uses but it could be NAND as well.
DM3058:
Flash is Spansion S29GL032N90TFI04 - and the Rigol fuckwits appear to have locked the lower 2 sectors with a password for no good reason whatsoever which hasn't helped my friend ralphrmartin at all in flashing a new firmware.
FWIW, The VREF is MAX6325 and the ADC is AD7799.
The DM3068 does use an LM399, not sure what the ADC is.
ETA: Just checked my notes. The DM3068 ADC is ADS1256. The Siglent SDM3055 has the same MAX6325 as DM3058 but the superior AD7190 ADC. ;)
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DM3058:
Flash is Spansion S29GL032N90TFI04 - and the Rigol fuckwits appear to have locked the lower 2 sectors with a password for no good reason whatsoever which hasn't helped my friend ralphrmartin at all in flashing a new firmware.
FWIW, The VREF is MAX6325 and the ADC is AD7799.
The DM3068 does use an LM399, not sure what the ADC is.
ETA: Just checked my notes. The DM3068 ADC is ADS1256. The Siglent SDM3055 has the same MAX6325 as DM3058 but the superior AD7190 ADC. ;)
FWIW
SDM3065X VRef LM399H
https://www.eevblog.com/forum/testgear/siglent-new-bench-dmm-sdm3055/msg1329966/#msg1329966 (https://www.eevblog.com/forum/testgear/siglent-new-bench-dmm-sdm3055/msg1329966/#msg1329966)
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600E is still a lot for a meter, especially for a voltnut hobby, so many folks are instead hunting down older but top-tier brand meters, like 34401/10A, K200x, 345x that are well proven by time, have very clear calibration information in public, have lot of various software options to use in datalogging/automated rigs and still have parts support in case something goes bad.
Since you touched voltnuts, same reason why nearly nobody from this crowd get Rigol/Siglent have that much of free time to waste testing inferior meter (by design) to prove it's specs. Even with 5.5 digits verifications is NOT the simple plug a reference into meter, get few readings, and viola, test done. Multiply check points for various functions and ranges, you just to test if meter in spec or not you will end up with few weeks of full-time job timeframe, which usually cost more then meter itself.
Yet, nothing is lost, and if you like risks and gamble, you can still have ebay and hunt for much lower prices than 600E, and still get 6.5d meter. Some of 34401A/K2000/K2015's go for less than 300$USD if you patient and don't care than much of nice fancy screen (which is overrated in my pov anyway, since you want remote interface to perform datalogs anyway!).
34461A is quite similar to 34465A/70A, if you look at Dave's video you'll notice that even PCB is 99% same. So 34461 is underestimated meter in a way, and still in current support.
If you want to buy benchtop DMM, then perhaps you buying it for stability, accuracy and reliability, for which items it usually worth to spend 100-200E more and sleep well at night.
My english is failing me when I try to be precise.. Maybe if I try to organize it like this:
1. I simply pointed at correct prices.. Price difference between DM3068 and 34465A is around 450€. That statement is correct. Difference to DM3058E full 750€
2. I said that 34465A is much better instrument and pointed out I find it absurd that people are comparing it to DM3068
3. I said that DM3068 seems to be comparable to 34460 in specs. Which is maybe 100€ more expensive, and at that price difference many would choose 34460A if nothing else for being Keysight.
4. Leaning to that "by design flawed" opinion, it is very logical to understand nobody would loose time to characterise instrument they think have no chance of exceptional performance..
5. It wasn't my intention to "call out" neither you personally or Voltnuts in general. I don't presume to tell people what to do with their time. I merely pointed out my regret that Voltnuts have no interest in that, as they would be great bunch to prove how good or bad DM3068 is. I'm very grateful for huge amounts of hard earned knowledge Voltnuts share here..
6. You explained to me (thanks for that !) that consensus between Voltnuts that DM3068 is "inferior meter by design" and that is the reason nobody wanted to test it.
Fair enough, but that also confuses me, because for the love of God, i can't find any published technical explanation as to why.
Not that I'm contesting your opinion, you and other our Voltnut friends here are much more knowledgeable and qualified than me about this topic. Is the choice of monolithic A/D converter as opposed to discrete A/D solution main reason, or you have some other compliant (reference circuit, input circuits, general design of board that point to unsophisticated design ...) I'm merely curious.
7. I'm in EU. Those magical 300USD instruments are not possible here.. 150USD instrument became 450USD to my door. And then I have still have no clue if it even works right unless I send it for a factory calibration. In which case, i think it is smarter to just buy a new 34461A and be done with it.. And have warranty..
8. My personal take on DM3068 is that you can buy one for the price of 5 1/2 digit from Keysight. And in that comparison DM3068 is much better instrument. I don't think DM3068 is a PPM chasing device..
Best regards,
Sinisa
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That windows CE inside Keysight is the thing that I didn't like, long boot time, and slow screens, In some years the nand will crash, and will be a nightwhere to replace it with a windows version who will no more be available, Rigols on the otjher hand is bare metal and will not have this kind of trouble.
But Keysight plan on selling and supporting this model for a very long time, that you can bet the house on.
This means they will find a solution to the WinCE issue and will offer upgrades in the future.
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Just tossing this out there. If you want the 34465A's features but it was not in the budget, look at the Siglent SDM3065x. Its very similar in operation and features and is a very fine meter for the price IMHO (yes, I had one and also have a 34465A). The 34465A is just a pleasure to use from all aspects, its a quality meter.
And the "bonus" is that Siglent completely copied the Keysight UI, practically menu option for menu option :--
So in effect the Siglent is as close to a clone of the Keysight as you'll get.
But you know, imitation and flattery and all that right.
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Some subjektive thoughts:
because in the analog world i'm playing arround with some lm399, ltz1000, kx'es and some adc's, dac's, precise resistors, i'm in love with the direct graphical and statistical possibilities of the 6.5 digit 34461a. But in retrospect, i wish i had the 34465a from the beginning. I buy it as a new meter, because i have no other reliably calibrated meter in my hobby-lab for now.
As to its accuracy and graphical presentation, this meter shows also his own sensitivity to the ambient temperature as well as the TC sensitivity of the DUT. So, one is sensitized to take that into account as an additional learning effect with this type of meter, as otherwise you can see always only digits. The possibility to see the last measurements from sample and hold directly in a table on screen, is an other feature, which I often use, and do not want to miss anymore. Maybe the siglent 6.5 meter is similarly good, but I decided for the original one.
My conclusion: i don't want to to miss such a meter anymore.
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I don't know how much (if any) this helps since I don't have any metrology grade equipment nor the knowledge to accurately use it but I do have a DM3068 which I bought new in 2013. I've also got one of those cheap Chinese AD584 based reference modules (also bought in 2013) which I now and then run across my meters. This thread reminded me that perhaps it was time to do it again so I did and here are the results from the three times that I've done it on the DM3068.
The "actual" voltage is what it says on the little "calibration certificate" that came with the voltage standard. It was supposedly calibrated using a 34401A. Temperature in the "lab" is within 5°C
"Actual" 2013-08-14 2017-01-10 2017-12-26
2.49901 2.49898 2.49901 2.49904
5.00025 5.00024 5.00031 5.00035
7.49933 7.49933 7.49942 7.49946
10.00011 10.00013 10.00025 10.00029
It was in pretty good agreement with the "standard" when it was new. Now, 4.5 years later it's drifted 160uV on the 10V reading provided the reference hasn't moved. The next best thing I've got is a FLUKE189 and it shows the same reading within a single digit today as it did the other two times but its resoultion obviously isn't even close to the DM3068.
If I read the datasheet on the DM3068 correctly it's still well within specification - for this single range...
Again, I make no claims that this is valid and/or solid proof of anything, it's just my own datapoints so take it for what it is.
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I used the DM3068 now for several years for hobbiest use and I'm very happy with it. The only thing really bothering me is, that you can't calibrate it, without sending it to Rigol -.- :--
The big display is fancy, but I don't value it as much as the cal option.
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It was in pretty good agreement with the "standard" when it was new. Now, 4.5 years later it's drifted 160uV on the 10V reading provided the reference hasn't moved.
Your reference is useless for such meter, as it's much worse than the meter itself. You can calibrate your reference by using DM3068 as a standard but not the other way around.
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I used the DM3068 now for several years for hobbiest use and I'm very happy with it. The only thing really bothering me is, that you can't calibrate it, without sending it to Rigol -.- :--
The big display is fancy, but I don't value it as much as the cal option.
Does the DM3068 not have a "user cal" option? The DM3058 does - you can switch cal back and forth between factory and user cal.
Unfortunately the method employed requires constant entering of the cal password on the front panel (so I changed mine to '0') for every single range and is a PITA. It also doesn't allow you to enter the exact value of the references you provide, it demands 19.00000V exactly for example.
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............................... The only thing really bothering me is, that you can't calibrate it, without sending it to Rigol -.- :--
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You have to send ANY 6 1/2 digit meter to someone for calibration....
Even if you knew how to do it, you don't have equipment to do it properly at home...
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Hmm, any good DMM >= 5.5 DMM (HP, Fluke, Keithley) can be calibrated everywhere with the right calibrators. When Rigol states that the DMM can only be calibrated by Rigol, then they
1. didnt bother to implement a simple calibration routine or
2. want to get more money through calibrations.
Either way: enjoy your missing freedom, but hey, its cheap right. :palm:
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Of course it can be calibrated and verified at any facility that can calibrate other instruments ot that accuracy..
There is a Service manual with clear instructions how to perform instrument performance verification.
The fact that you cannot adjust it except in Rigol is annoying. You also have to send it to them for service. No third party service exist that I know of.
Why they do it, I don't know. It might be to monopolize service income, or something else. It might even be that they want to gather service and calibration statistics.. HP ran it's calibration service both as income source but also as a way to gather statistical info on devices and their real (not estimated) stability, drift etc... They use that data all the time, they even use it to prolong calibration intervals on some equipment ...
Maybe Rigol decided to start gathering such data ... Who knows.
All I know I have to send it somewhere anyways, and Rigol quote to do it was actually very good. So I might as well send it to Rigol.
Regards,
Sinisa
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Hmm, any good DMM >= 5.5 DMM (HP, Fluke, Keithley) can be calibrated everywhere with the right calibrators.
Do not confuse "calibration check" with "calibration adjustment".
Any good calibration house will NOT calibration "adjust" your instrument unless you specifically ask and pay for that.
When you send your meter off for "calibration" it is is only "checked", not adjusted.
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I meant adjusting, sorry if i didnt make that clear in my post.
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Of course it can be calibrated and verified at any facility that can calibrate other instruments ot that accuracy..
There is a Service manual with clear instructions how to perform instrument performance verification.
The fact that you cannot adjust it except in Rigol is annoying. You also have to send it to them for service. No third party service exist that I know of.
Well, I can send a Rigol meter to a cal lab where they may find out it is out of specs. Then, I have to send it to Rigol to adjust it. I would not call it annoying I would call it fail, because such procedure would cost definitely more money. All reputable T&M manufactures allow third-party adjustment of their 6.5 digit multimeters...
Obviously, Rigol is able to implement user calibration - DM3058 series supports it: http://beyondmeasure.rigoltech.com/acton/attachment/1579/f-059c/1/-/-/-/-/DM3058%20Calibration%20Guide.pdf (http://beyondmeasure.rigoltech.com/acton/attachment/1579/f-059c/1/-/-/-/-/DM3058%20Calibration%20Guide.pdf), so I only wonder why they didn't not implement it in DM3068 series too.
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@saturnin (by the way, "Saturnin" by Zden?k Jirotka is my favorite book :-)
As always with calibration, we have a terminology problem as well as freedom / economy problem ...
End user 99.999 % of the time cannot make adjustments of 6.5 digit meters that will not make it worse than it was.
Third party accredited labs can. Fact that Rigol didn't publish adjustment procedure publicly is annoying. It impedes my freedom. I don't like it.
But instruments like DM3068 don't go out of calibration that easy.. Adjustments are only needed after many years (if any) or after damage/repair. Some users don't want meters to adjusted at all.. THey just send them on regular calibration checks, keep history, and mathematically correct measurement results..
In case of repair, where would you send your Keysight meter? I would send it to Keysight anyways.. In Croatia we have a proverb: " If it cries, give a child to it's mother.. She'll know what to do.." It is usually a good advice..
I would have huge problem if Rigol would monopolize things and then tried to charge me 1000€ for calibration check... But they don't, prices I was sent were very good.
So while in theory, my freedom of choice is taken away from me, in practice I couldn't care less...Freedom of choice in business is all about not paying too much and power to negotiate for a good price for the service or product you need...
If price is OK in the first place no need to negotiate... Actually, I really don't like to haggle with salesmen...
Situation is what it is, right now. It is not ideal, but acceptable. If that changes to worse, i will deal with it accordingly.. But I don't think they will worsen their customer support. If anything, Rigol, Siglent and other Chinese manufacturers are demonstrating they are learning very, very fast...
As a side note, I will be sending my DM3068 for a ISO calibration at Rigol in months to come, and will document the experience and share it with forum, from customer experience, process, to results and documentation.
I'm also curious how will it go, I guess we will find out.
Regards,
Sinisa
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@saturnin (by the way, "Saturnin" by Zden?k Jirotka is my favorite book :-)
Good to hear the book found its fans abroad too. :) So, would you ever start "a doughnut fight" in a café? ;)
Back to the topic... I don't think it is so rare a multimeter needs adjustments after several years of service. 6.5 digit multimeters have quite tight specs and especially HV DCV and OHM ranges can drift out of them.
I don't know situation in your country, but here cal labs are accessible. I have two in close neighborhood (I don't live in a big city though). Both are well equipped (Fluke 8508A, Fluke 5720A, Datron 4708). I prefer to deliver my instruments personally to save shipping costs and to avoid a possible damage during transport by a courier. That's why I don't like Rigol's decision not to allow third-party adjustment of some of their instruments...
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@saturnin (by the way, "Saturnin" by Zden?k Jirotka is my favorite book :-)
i was reading the thread, and now i go to look for saturnin by zden ... and found it on youtube :D
i think rigol is not shy about their "copies". 2N3055 i think is quite right about monopoly, i think many (too many) chinese "copy" companies made alot of money using "copies". when they got rich enough, they eventually buy over the original company they copy from (you guys hear these stories before yes?). i guess the only way to know the difference, is for someone to post actual data about long term accuracy differences. which means, they probably should join some kind of hobby "calibration club" to economically obtain some form of knowledge about their accuracy drifts?
but since HO posted his drift findings, if we take it as it is. 35ppm drift per year for a cheapy DMM? i think is worse than used K2000?
it would be interesting if shahriar himself post some data about his rigol
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@saturnin, I'm not much of a "doughnut fight" guy, but I might have a spare binocular if you ever lose one while looking into water well... Cause, you know, that sort of thing happens all the time... :-) Also if you want to become shark hunter, maybe something can be arranged.. :-DD
But in all honesty, as I'm getting older, I would be more of a Doctor Vlach type..
I'm glad that you have calibration labs so available, and now understand your frustration. I would be too if I was in your situation. God, I wish I was in your situation... |O
Unfortunately, my nearest lab is in Zagreb, and that is not so close for me. And after entering EU, it is almost the same price to ship it to Zagreb as it is to Rigol Germany, or some other calibration lab..
I do agree that after some years you would need adjustments. My practice is to send new instrument after cca 2 years for full cal with adjustment. That will take care of most of accelerated initial drift. So adjusted instrument is quite ok to be sent only for performance verification afterwards for some years to come.. And then you can see how it drifts and plan to send it for adjustment when needed.
Of course, it depends on quality of instrument, environment etc etc..
Take care!!
Sinisa
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@saturnin (by the way, "Saturnin" by Zden?k Jirotka is my favorite book :-)
i was reading the thread, and now i go to look for saturnin by zden ...
Search for Zdenek Jirotka, "Saturnin".. It is good fun...