Keysight DMM - Yay or nay?

[Electro Fan]

I spent a lot of time considering the 34465A, the 6500, and some other bench DMMs.  I went with the 34465A.

I also am not a huge fan of touch screens but I believe that done well they can be not only be good but for some functions better than buttons.  While so far I'm mostly into buttons, based on some other products I own I believe that with a well done UI a combination of touch screen and buttons might be ideal.  If you can do everything you want with buttons and then also do more with the touch screen you can easily and enjoyably grow into the use of the touch screen.

As for accuracy I think both the 34465A and the 6500 would have likely been more than sufficient for my needs.  On the 34465A, for example, I can get to roughly 1 milliohm with some good confidence.  My experience with 4 wire resistance measurements is that in addition to the kelvin clips and the DMM itself, the room temperature is going to need to be controlled pretty tightly if you want to successfully measure to a milliohm or maybe to 100s of microohms.  I made a bunch of simple 4 wire resistance tests that I posted on the forum if you are interested.

For me, the basic measuring functionality, precision and accuracy, ease of use, reliability, and KS support were the main drivers but I think all of those would probably be good with 6500 too - with the touch screen being an unknown/TBD for me as a first time bench top DMM user, but again, I suspect the touch screen would turn out to have both some negatives and some positives. 

What I think would have tipped me toward the 6500 was if I was more inclined to dive deeply into the software functionality of the 6500.  I think for someone who is reasonably to highly adept with software the 6500 would be an outstanding unit. The only other unknown for me was the occasional report of 6500 bugs.  I think with all the 6500 software flexibility you might have to wrestle a machine that starts to feel a bit like a computer, but again, if you are strong with software maybe no problem, as in no pain no gain.  I'm sure it would be nice to have both the 34465A and the 6500. 

[Kleinstein]

At the very low ohms end it can be relevant what test current is used (3446x use 1 mA, DMM6500 goes upt to 10 mA) and if they offer a offset compensated mode to eliminate the error from thermal EMF. With some resistors the thermal EMF can be quite some problem if the there are temperature gradiends (e.g. hold probes with the hand or not enough waiting after handling).
The 1 Ohms range with the DMM6500 looks more like a digital zoom and is likely of very limited value.
Much of the DMM6500 SW problems have been resolved to some degree, so many of the initial problems are no longer present.

There are already at least 2 other thereads about the KS ACAL problems.

[HighVoltage]

The 1 Ohms range with the DMM6500 looks more like a digital zoom and is likely of very limited value.

The low ohm feature of the DMM6500 is much better than one would expect.

As I have said in other threads before, both instruments are great.

[Kleinstein]

The 1 Ohms range with the DMM6500 looks more like a digital zoom and is likely of very limited value.

The low ohm feature of the DMM6500 is much better than one would expect.

As I have said in other threads before, both instruments are great.

Low ohms is good, but the 1 Ohms range would be 10 mV max for the measured voltage and I don't think there is a real 10 mV range, more like just a digital x 10.
The 10 Ohms range with 10 mA test current is already good - though 10 mA with up to 12 V could be a problem for some tiny resistors / transistors.

[Dr. Frank]

Hi,

First I want to make this clear, I can still recommend Traceless the 34465a from Keysight it is not a bad DMM!

The things I show below like this concern small deviations at the PPM level when using the Autocal function.
...
So I paid the higher price, but the function doesn't work well, and I find that a bit sad.

I can still take accurate measurements as needed as I also have an Agilent 3458a standing by. but for good stability this DMM will need to be on for at least 12 hours,
...

Here you can see the drift on my 34465a after using the autocal function.



.

...
It may well be that the few PPM I have experienced is the "base" drift and if the ambient temperature is e.g. 25 degrees higher in a 19-Inch rack that this base drift I am measuring will cancel out against e.g. 15PPM drift that the Autocal function corrects.
I have no way to check this, I do not own a climate box to do good measurements in this regard.


I hoop this helps and if there are question, i like to hear them. 

Kind regards,
Bram

Hello Bram,
I also have the 3458A, the 34401A and bought the 34465A in 2015 as an improved version to the latter.
I already identified several bugs around the ACAL and calibration functions, which went into two improved FW versions.
I also can confirm your observation, that meanwhile after an ACAL a 10Vdc measurement drifts about -1ppm before stabilizing.. this did not happen when the instrument was new. But I find that you have totally exaggerated expectations on your 34465A, and you know that yourself, I assume.
 
This instrument is neither intended, nor specified to make precision measurement below 13ppm stability (24h spec), in contrast to the 3458A.

We both know, that it performs better than specified. E.g. my unit is still inside 1y spec. in most of the modes, although I experimented and modified a lot on my instrument.

The ACAL function does of course not work like the one in the 3458A, that was also never promoted that way.

It only corrects for T.C. effects, and that really works very well, of course inside its specification limits.
I did such temperature tests several times, easy in winter time, i.e. let it cool outside, power on inside directly, and attach a 10V reference. Initial reading will be far off, still in spec though, by including T.C. of course, but after ACAL, it will display within 5ppm or so, I don't remember exactly. Repeat that ACAL during warm up, it'll still always be below spec. limits. That also works at elevated room temperatures, like in my bureau, instead in my  basement lab which has R.T. = 22 +/-1°C over the year. I also can't confirm that the 34465A needs 12hours for stabilization, it's warmed up after 2h.

For the other DMMs I have no experience at all, but I suggest to make fair comparisons based on the specifications only: Do they really perform better than the 344465A for such parameters?

In this context, the relevant features why I bought the 34465A are: Offset Compensation for Ohm modes, long term data acquisition and digitizing modes, low DCI ranges (pA resolution), temperature measurement, and other useful features compared to the 344401A. So I also recommend to buy the 34465A, but get the MEM option for free, because that is needed for proper use of the built in DIG function.

Frank 
 

[Traceless]

So I also recommend to buy the 34465A, but get the MEM option for free, because that is needed for proper use of the built in DIG function.

Frank

You can get that for free? I checked and that seems to be sold as an 250€ upgrade.

[Dr. Frank]

So I also recommend to buy the 34465A, but get the MEM option for free, because that is needed for proper use of the built in DIG function.

Frank

You can get that for free? I checked and that seems to be sold as an 250€ upgrade.

I had to buy both options at that time, plus the GPIB interface.
The DIG option is included since FW 3.0.
KS offered the MEM option for free several times over the last years as a sales deal, so you have to look out, also on the American site, or ask your German distributor, if they can offer that for free, if you buy the instrument.

PS: Currently they include BenchView for free (forget it!), so maybe you can deal-in this for the MEM option. 
Maybe the other colleagues can tell something about the Keithley SW in comparison?

Frank

[HighVoltage]

The 1 Ohms range with the DMM6500 looks more like a digital zoom and is likely of very limited value.

The low ohm feature of the DMM6500 is much better than one would expect.

As I have said in other threads before, both instruments are great.

Low ohms is good, but the 1 Ohms range would be 10 mV max for the measured voltage and I don't think there is a real 10 mV range, more like just a digital x 10.
The 10 Ohms range with 10 mA test current is already good - though 10 mA with up to 12 V could be a problem for some tiny resistors / transistors.

Well, one would always use a milli ohm meter or instrument that is used for low ohm measurements.
However, I was really surprised how spot on the DMM6500 is in low ohm measurements.
And this experiment can be repeated with success, the instrument really shines here unexpectedly.

[HighVoltage]

I also can confirm your observation, that meanwhile after an ACAL a 10Vdc measurement drifts about -1ppm before stabilizing.. this did not happen when the instrument was new.

Frank

I had the horrible ACAL drift experiences with the 34470A and that was never really fixed by Keysight.

The ACAL drift of the 34465A is not bad in comparison.
Here is the ACAL drift test of my 34465A from 2018.

[nctnico]

The 1 Ohms range with the DMM6500 looks more like a digital zoom and is likely of very limited value.

The low ohm feature of the DMM6500 is much better than one would expect.

As I have said in other threads before, both instruments are great.

Low ohms is good, but the 1 Ohms range would be 10 mV max for the measured voltage and I don't think there is a real 10 mV range, more like just a digital x 10.
The 10 Ohms range with 10 mA test current is already good - though 10 mA with up to 12 V could be a problem for some tiny resistors / transistors.

Well, one would always use a milli ohm meter or instrument that is used for low ohm measurements.

Yes. But it is nicer if you have instruments that can at least help you out when in a pinch. In my case I suddenly needed to measure a resistor in the range of 500 micro-Ohm with 1% accuracy. A 100 Ohm range is not doing much good in such a case.

[Traceless]

@nctnico, @HighVoltage: I was about to pull the trigger on the 34465A but due to your comments, the positive things reported before and another video (link below) someone sent me via DM I'm reconsidering the DMM 6500 now. The video is german but showed at least two occasions where the DMM 6500 was clearly superior to a 34461A. I doubt though that the test results would have looked different on a 34465A:

1. at 7:03 the peak-to-peak current while switching on a light bulb is measured. Due to the super high sampling rate the Keithley caught the inrush current, which was missed by the Keysight.

2. 8:04 Because of the larger display and zoom the Keithley can display even weak signals that show as flat line on the 34461A. The Keithley also seems to offer higher resolutions on the time axis.

[mawyatt]

We did a couple quick low ohms Kelvin (0.1 & 1 Dale 1% Chassis mount type) measurements 1/27 and 2/4 with a 2 year old and new KS3465A, a 6 month old DMM6500 and a 8 month old Tonghui TH2830 LCR meter. All meters used cheap Kelvin probes for measurements of low ohms (TH use supplied Kelvin probes), the 1 ohm resistor all readings agreed under ~1000ppm, 0.1 ohms under ~7000ppm. Repeatability from two dates was; older KS 5000/288, new KS 6300/400, DMM 2300/262, TH was 1900ppm/90ppm for 0.1 and 1 ohms respectively. No attempt was made to record the setup, temp or exact probes used, so variations were highly likely between dates.

Anyway YMMV,

Best

[Kleinstein]

In that German video they just used a wrong PLC setting to do the peak current test. With a more reasonable setting the 34461 would have been done better and OK for the lamp. The 34465 is faster, than the 34461, though still not as fast as the 2nd ADC in the conversion rate as the DMM6500. However the DMM6500 has a limited BW (in some ranges relatively slow) and thus can not make full use of the high sampling speed of the 2nd ADC (digitizer mode). The faster ADC also has limited accuracy. At least the 2nd ADC allows a good digital AC mode.

The screen resolution is a bit limited for the KS meters and thus the somewhat limited screen shots.

[Traceless]

In that German video they just used a wrong PLC setting to do the peak current test. With a more reasonable setting the 34461 would have been done better and OK for the lamp.

I see, thanks for clarifying that.

[Electro Fan]

Traceless, some more considerations for your decision.

Regarding capacitance which you mentioned in your original post, if you don't already have a LCR meter, the DER DE-5000 is an excellent meter that won't add a lot of expense on top of either a 34465A or a 6500.  It's always good to have a second device that can help you gauge the sanity if not the accuracy and precision of another device's measurements and the DE-5000 not only give you some reasonable accuracy, it will also measure some values that neither of the bench meters will measure.

If you can get the extra memory for the 34465A at no extra charge (if KS happens to be running the special or if you can persuade them or a distributor to throw it in) that would of course be good.  Having said that some considerations:  1) I think you can add the memory later.  2) with the standard memory you can still do a lot; I ran a test for about a week (probably more than most tests will need) with the standard 50k readings memory:
https://www.eevblog.com/forum/testgear/4-wire-2-wire-resistance-tests-various-cheap-kelvin-clips-various-meters/msg3256942/#msg3256942

And 3) if you have to pay 250€ or so for the extra memory that should be more than enough to buy a DE-5000.

Having said all that, I'm just an enthusiast and there are some much more experienced and capable folks here that can give you more insight on the details and the tradeoffs.

[blackdog]

Hi Frank,

Autocal 34465a
My expectations of the 34465A was that the Autocal worked well at the 10V DC range and that is what you also point out, was not executed properly bij Keysight and I do blame Keysight for that, do it right or don't do it.
The autocal is usable, do an autocal read within 15 seconds(and with my 34465a it is within 1PPM on 10V DC range)

As I mentioned, I am certainly happy with the filter operation that is available as an extra in the 34465a, also the extra possibilities for temperature measurements are appreciated, and the 34465a is used here almost daily.
This is because in temperature measurements with the TEK DMM4050 with a resolution of 0.001C there is a lot of noise present and the 34465a has the extra filter and less noise.

34465a VS 3458a
As you yourself pointed out I am aware that it is not a 3458a. 
My two Keysigt 34461a are still within specs as far as DC is concerned and my two 34461a meters drift on the DC 10V range no more than 3 to 5PPM / year, and that is very good.

34401a
Even my 34401a after 8 years is still within 6PPM the specified value of course around the calibration temperature.
The 34401a is a bit more sensitive to ambient temperature variation, this for the meter I have here, I have no knowledge of other meters of this model.

Considerations
If you don't think the interface is very important, then I would choose the Keithley 6500 over the 34461a.
But this is based on 1x Keithley 6500 and I have had 5 pieces of 3446x in here.
But 6500 VS 34465a everyone has to decide for themselves, my measuring sessions are certainly different from yours.

Service
The Service I have had from Keysight has been excellent, Service from Keithley I have fortunately not needed yet.
The 6500 is now almost three months old and as far as I have figured out, very stable.

Kind regards,
Bram

[Henry Finley]

Frakly I think we've past the point of diminishing returns on much gear. And one thing I can be sure of is that China is not contributory to advancement aside of what they can appropriate the proceeds of,  for their own purposes. And since most factory labor in the US is by refugees, expensive, and not even as wll made anyway then what's the point in frittering good money after bad? In concludion, if an old HP US-made machine still works quite well, why do I need all that crap foreign made (and often counterfeit). junk. As in JUNQUE, junk. From what I've seen, Mr Carlson seems to come up with some fine pieces of gear, available for us to fabricate for ourselves. There are 40 ways to test a cap. but if you are testing the cap because you suspect it, then wouln't just replacing it and seeing, be a better use of time?

[tautech]

Frakly I think we've past the point of diminishing returns on much gear. And one thing I can be sure of is that China is not contributory to advancement aside of what they can appropriate the proceeds of,  for their own purposes. And since most factory labor in the US is by refugees, expensive, and not even as wll made anyway then what's the point in frittering good money after bad? In concludion, if an old HP US-made machine still works quite well, why do I need all that crap foreign made (and often counterfeit). junk. As in JUNQUE, junk. From what I've seen, Mr Carlson seems to come up with some fine pieces of gear, available for us to fabricate for ourselves. There are 40 ways to test a cap. but if you are testing the cap because you suspect it, then wouln't just replacing it and seeing, be a better use of time?

Take that anti China crap elsewhere please.

[Traceless]

... if you don't already have a LCR meter, the DER DE-5000 is an excellent meter ...

I've seen and read quite a lot of good things about the DER DE-5000. I already own an LCR Meter, the DER DE-5000 was one of the candidates I considered but ultimately went with the 5200 model from Matrix.

If you can get the extra memory for the 34465A at no extra charge (if KS happens to be running the special or if you can persuade them or a distributor to throw it in) that would of course be good. 

KS offered the MEM option for free several times over the last years as a sales deal, so you have to look out, also on the American site, or ask your German distributor, if they can offer that for free, if you buy the instrument.

Thank you Dr. Frank and Electro Fan, I actually found out that the Keysight Memory Promotion is currently available. What is not clear (yet) is if I had to purchase through KS directly to qualify.

Still for basic use the purchase of say of a DMMCheck provides a sanity check that accuracy is appropriate for your needs...

It took me a bit of time to find out if/how to get a DMM Check here. Ordering directly from abroad involves considerable import fees, but it seems there is a german distributor assuming this is the DMM check you are talking about. Unfortunately the model with LC option is marked "out of supply".

Also thank you @tautech for pointing out the resource on Defpom's site.

otherwise the Voltnut rabbit hole awaits.

I'm trying to stay away from it, it is tempting though

[tautech]

Still for basic use the purchase of say of a DMMCheck provides a sanity check that accuracy is appropriate for your needs...

It took me a bit of time to find out if/how to get a DMM Check here. Ordering directly from abroad involves considerable import fees, but it seems there is a german distributor assuming this is the DMM check you are talking about. Unfortunately the model with LC option is marked "out of supply".

Yep, there's also thread about them here IIRC and I think it is Doug that makes them:
https://dmmcheckplus.com/

Also thank you @tautech for pointing out the resource on Defpom's site.

otherwise the Voltnut rabbit hole awaits.

I'm trying to stay away from it, it is tempting though

No worries, enjoy the voyage. 

[Dr. Frank]

@nctnico, @HighVoltage: I was about to pull the trigger on the 34465A but due to your comments, the positive things reported before and another video (link below) someone sent me via DM I'm reconsidering the DMM 6500 now. The video is german but showed at least two occasions where the DMM 6500 was clearly superior to a 34461A. I doubt though that the test results would have looked different on a 34465A:
1. at 7:03 the peak-to-peak current while switching on a light bulb is measured. Due to the super high sampling rate the Keithley caught the inrush current, which was missed by the Keysight.
2. 8:04 Because of the larger display and zoom the Keithley can display even weak signals that show as flat line on the 34461A. The Keithley also seems to offer higher resolutions on the time axis.

Please do not follow such completely incompetent videos or sites! 
These guys have obviously no clue what they are talking about, and in this case did not inform themselves at all about the KS instruments. I can only say: RTFM and RTFS
If a shorter sampling time had been used on the '461, 300µs is the fastest, instead of this NPLC 10, i.e. 200ms, as done on the Keithley DMM, then of course it would have caught the peak inrush current.

The 34465A of course is even faster than the '461, using its digitizing feature for DCV and DCI, which samples down to 20µs timely resolution. So yes this model is of course able to catch the inrush current also graphically and resolving it like the Keithley one, by simply using its button based ZOOM functions for time and volt axis.
That woman was simply not competent to use the KS correctly, and evidently she did not make herself familiar with it, neither with it's manual or specification.

Another hint: I regard the DMMcheck as a toy only, as you can't  really calibrate DMMs as it's got a few single ranges only.
So if you have the demand to check some of your other equipment, then either buy such a 6.5 digit DMM, or ask the volt-nuts community here in Germany, they are located all over the place, and all might give a practical help, w/o expecting you to become a volt-nut also. But you're of course very welcome, otherwise.

Frank

[Traceless]

Please do not follow such completely incompetent videos or sites! 

@Dr. Frank: Of course I take every information I find, espacially stuff on youtube, with a grain of salt. Luckily there is this awesome community which helps to identify such mistakes. Thank you for confirming that the 34465A can very well keep up with the DMM 6500 for those test cases.

@Everyone: I still have a few final questions, that may affect the purchase decision. Maybe the folks that have long-ish term experience with 34465A and the DMM-6500, can comment on some of them:

• Software/autocal issues aside, Are there any known weaknesses in any of the units (34465A, DMM 6500)? Example of issues that come to mind: Buttons not working properly/touchscreen becoming unesponsive after some time of use, input jacks wearing down fast or even breaking, issues with the power supply, fan bearings etc.
• How easy/hard is it to replace fuses, input jacks, fans? Are spare parts even available to "regular mortals" and is there a significant difference in sparpart prices between Keithley/Keysight?
• How well are the devices protected against a catastrophically misbehaving device under test (e.g. like the PSU shown in the video below)?
• Can I upgrade every option available for the devices after purchase or are there certain add-ons that can only be ordered with a new unit. (For instance the Siglent SDM3065X apparently can not be upgraded with a scanner card, instead one needs to purchase an SDM 3065X SC instead).
• Does any of the meters provide serious additonal value in terms of accessories. The A34465A comes with a "34138A test leads set", which I assume is decent. However if I'm not mistaken non of the meters comes with kelvin leads for 4-wire measurement. Looking for kelvin leads revealed they cost north of 450€ a pair on mouser (Are these made out of iridium threads handwoven by disney princesses, or what is going on here?). A more affordable pair from BK Precision (TLDK1) is available for ~100€, which still is a bit steep just for a set of leads.
• Does the DM-6500 come with a stylus?

[nctnico]

In my opinion you shouldn't care so much about repairs / spare parts. The bench DMMs discussed are high quality gear and will last a long time. The only fuse you can blow is the one for the current measurement and that is externally accessible. Other than that, the inputs are very rugged. Still, I wouldn't use a high end bench DMM like this on mains with all the nasty spikes that can ride on top of it.

[Kleinstein]

There are some complaints about the view angle on some of the meters. This is somewhat normal lmitiation with many LCDs as a larger viewing angle needs more power. AFAIR the angle on the 6500 is a bit limited.

For the DMM6500 there may be the option to install a scanner card (original and some plans around for a DIY solution).
Some early DMM6500 had roblems with transformer hum, but this problem should be fixed for newer units.

[Traceless]

@nctnico: I'd also rather keep the DMM away from dangerous stuff, but for me there is a catch here. As mentioned in the beginning of this thread the DMM I'm about to purchase is going to be the "swiss army knife" of my lab. As such it should (and has to) do basically everything well that includes PSU diagnosis. The alternative would be to use my Aneng 8009 for primary side PSU work. I also have two more handhelds very similar to these, which are cheap to replace, probably even cheaper then the fuse on a 34465A or the DMM-6500. Also they make mains work a lot more "exciting", but usually I try to keep the excitement level to a minimum during mains work .

@Kleinstein: Viewing angles are also a good point, thanks for bringing that up. Nice to hear that Keithley actually improves their devices if stuff like the transformer hum is discovered.