Products > Test Equipment
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:
--- Quote from: Kleinstein on March 04, 2022, 09:06:28 am ---The 1 Ohms range with the DMM6500 looks more like a digital zoom and is likely of very limited value.
--- End quote ---
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:
--- Quote from: HighVoltage on March 04, 2022, 09:29:46 am ---
--- Quote from: Kleinstein on March 04, 2022, 09:06:28 am ---The 1 Ohms range with the DMM6500 looks more like a digital zoom and is likely of very limited value.
--- End quote ---
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.
--- End quote ---
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:
--- Quote from: blackdog on March 03, 2022, 11:23:08 am ---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
--- End quote ---
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
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