Looking for a bench reference standard, thoughts on this Keysight 34465A?

[bsodmike]

Hi all,

What do you think about the Keysight 34465A as a bench reference standard, it is 6.5 digits DMM.

https://export.farnell.com/keysight-technologies/34465a/digital-multimeter-bench-6-1-2/dp/2467508?st=34465a

Thanks, Mike.

[Grandchuck]

Basic DC accuracy is 30 parts per million.  Not quite good enough to qualify as a "bench reference standard".

I have one and it is a fine meter!

[Electro Fan]

I spent about a year thinking about bench meters (and went round and round - see below).

The 34465A is my first bench meter so I don't have anything to compare it to (other than handhelds).  Only had it a few weeks but so far so (very) good.

Depends on what you want the meter to do.  The 34461A would save some $ but I'm glad I went with the 65A.  The other meter that definitely warrants consideration is the Keithley 6500.  And the Siglents are worth a look too, I think.  There are several threads around here on the 6500, and the Siglents - worth reading if you haven't already found them.

I've made some posts on the 34465A, mostly regarding 4 wire resistance measurements in case my simple tests shed any insight.

If you have any specific questions feel free to ask and if I can address them I will do my best.  Lots of other Keysight users here so you can probably get an answer to almost anything. 

[bdunham7]

It's overkill and then some for the vast majority of users.  Go for it! 

[bsodmike]

Basic DC accuracy is 30 parts per million.  Not quite good enough to qualify as a "bench reference standard".

I have one and it is a fine meter!

As for a transfer reference, I was thinking of also grabbing a PDVS2mini (as it is calibrated with a Keysight 3458A) and use that as a "cheapish" transfer reference with the 34465A.  I plan to be doing some work on high-efficiency MCUs - measuring low-low current draw would be important.

Also toying with DIY precision references, I have a couple projects in mind for that space as well.

[bsodmike]

It's overkill and then some for the vast majority of users.  Go for it! 

Totally agree haha 

[bsodmike]

I did some research and wanted to compare the Keithley (Textronix???) DMM6500 (https://export.farnell.com/keithley/dmm6500/digital-multimeter-bench-6-5-digit/dp/2840447) vs. the Keysight (ex Agilent, ex HP) 34465A (https://export.farnell.com/keysight-technologies/34465a/digital-multimeter-bench-6-1-2/dp/2467508?st=34465a).

The Keithley unit is almost 2/3rds the cost.  I couldn't figure out how they are dropping the price so much, but here are some observations:

• Keithley DMM6500 has a higher burden voltage at the lower ranges.
• Both offer 3-year manufacturer warranty
• Keithley PC software looked dated
• Not sure if it is TrueRMS?
• Cut corners with calibration certification/standards?

Any ideas how this is cheaper?

Thanks!

[HKJ]

Keithley DMM6500 has a higher burden voltage at the lower ranges.

DMM6500 have a shunt for each range, this may make it more precise, but also means each range has about 0.1V in burden voltage at full current.

Not sure if it is TrueRMS?

It is, but the RMS converters is not as good as Keysights.

Where the DMM6500 has advantages is in fast sampling, lots of buffer memory and possibility to run programs.

I have both and use both.

[Hexley]

I plan to be doing some work on high-efficiency MCUs - measuring low-low current draw would be important.

If the current level of interest is tens of microamps or more, you can use the 34465A's 6.5-digit resolution to measure on the 10 Amp range. That reduces the burden voltage to quite a small amount.

At 1 Amp, the 34465A drops about 25 mV.  Lower currents have even less drop, of course., which makes this setup usable for low-voltage battery-operated device tests. My old 3478A drops 160 mV at 1 Amp, as a point of comparison.

The charting feature of the 34465A is not going to replace an oscilloscope, but it can give good insight into where one should start investigating. Here, for example, is a supply current waveform from an IOT device. One can clearly see the change in current between various states.

[bdunham7]

DMM6500 have a shunt for each range, this may make it more precise, but also means each range has about 0.1V in burden voltage at full current.

This is absolutely the best way to go, IMO.  If you need to lower the burden voltage, you can just manually kick it up a range and lose one digit resolution, which on 6.5 digit DMM is not a huge problem. 

Not using one shunt per range results in some ranges becoming very noisy.  My 8846A is good on some ranges and crap on others for this very reason.

[chewmanfoo]

Guys who own both: if your budget afforded one, which one would you choose?  DMM6500 or 34461A?

[Grandchuck]

Basic DC accuracy is 30 parts per million.  Not quite good enough to qualify as a "bench reference standard".

I have one and it is a fine meter!

As for a transfer reference, I was thinking of also grabbing a PDVS2mini (as it is calibrated with a Keysight 3458A) and use that as a "cheapish" transfer reference with the 34465A.  I plan to be doing some work on high-efficiency MCUs - measuring low-low current draw would be important.

Also toying with DIY precision references, I have a couple projects in mind for that space as well.

You do realize that you are entering the rabbit hole of volt-nutery

I also have the PDVS2mini and also can recommend it. 

[bsodmike]

You do realize that you are entering the rabbit hole of volt-nutery

I also have the PDVS2mini and also can recommend it.

As far as nutery and "costly" rabbit holes go, YES 

Within the past 4-6 months I've re-built my workbench (due to a move).  Apart from the bottom two, the rest have been ordered new from Farnell

• Rohde & Schwarz RTM3004
• 2x Fluke 87V
• 1x Fluke 287
• Keysight E36313A Bench PSU
• Keysight 33521B Arb Waveform generator
• Keysight 34465A (just ordered)
• Old Metcal SMD rework station
• Decade old Tektronix scope

[VK5RC]

As a student volt-nut, my basic 34461 punches remarkably above its weight in my studies (yet to be published) of about 12 ltz references of various constructions (TiN and Dr Franks pcbs different resistors and different temp settings 12k 13k etc) looking for long term stability /accuracy. This has been going for about 2 1/2 years now. The reason for so many ltz is so that if my meter/s drift, all my ltzs results will drift the same amount.
 I have an old and calibrated (just out) 3458 and the 34461 is and has been remarkably close for a fraction of the $. The 34465 would be better than the 34461 I suspect.  The specs 3458 is 8ppm/yr, the 34461 38ppm/yr, 34465 30ppm/yr.
My rough impression is that the 3458 is good for 1-2ppm/yr and 34461 about 10ppm/yr but I am relying on averaging the better ones of the multiple ltz as a 'true' reference - quite a bit of a 'dodge' but I can't afford a Josephson Junction array.
The user interface of the 34461 is excellent, it did have an early bug re continuity - but a software upgrade fixed that.
In a round about way - I am saying I think a 34465 would actually be a good reference - especially considering the $.
Rob

[bsodmike]

As a student volt-nut, my basic 34461 punches remarkably above its weight in my studies (yet to be published) of about 12 ltz references of various constructions (TiN and Dr Franks pcbs different resistors and different temp settings 12k 13k etc) looking for long term stability /accuracy. This has been going for about 2 1/2 years now. The reason for so many ltz is so that if my meter/s drift, all my ltzs results will drift the same amount.
 I have an old and calibrated (just out) 3458 and the 34461 is and has been remarkably close for a fraction of the $. The 34465 would be better than the 34461 I suspect.  The specs 3458 is 8ppm/yr, the 34461 38ppm/yr, 34465 30ppm/yr.
My rough impression is that the 3458 is good for 1-2ppm/yr and 34461 about 10ppm/yr but I am relying on averaging the better ones of the multiple ltz as a 'true' reference - quite a bit of a 'dodge' but I can't afford a Josephson Junction array.
The user interface of the 34461 is excellent, it did have an early bug re continuity - but a software upgrade fixed that.
In a round about way - I am saying I think a 34465 would actually be a good reference - especially considering the $.
Rob

Thanks a lot Rob, appreciate your detailed response.

I agree, I am also quite happy with ease of use aspect of the Keysight firmware; in terms of menu options etc, it is similar to the software on my Keysight E36313A bench PSU.

One thing I do appreciate, over the long term as well, is being really familiar with my equipment so that when I'm working the instrument aids me in whatever process I'm working on rather than being a further barrier to progress etc.

I'm hoping to get my hands on a PDVS2mini but the order list is "email only".  The advantage of having this is that shipping the unit-back/forth for re-calibration would be quite handy, plus it is calibrated on a reference that has ~0.1 ppm/year drift. Update: see next post for correct drift specification.

[Grandchuck]

I think Ian is using a 3458A DMM to calibrate the PDVS2minis.  The accuracy of that meter in PPM (values in () are for opt. 002):

Range    24 hour            90 day                    1 year            2 year
10 V    0.5 + 0.05    4.1 (2.6) + 0.05    8 (4) + 0.05    14 (10) + 0.05

So guessing 90 days since calibration, one could assume 2.6 to 4.1 parts per million.  Not sure what you are referring to with 0.1 ppm/year drift?

[bsodmike]

Corrected my post to refer to yours, my mistake.  Thanks!

The datasheet opened with:

Select a reading rate of 100,000 readings/second for maximal test throughput. Or achieve highest levels
of precision with up to 8.5 digits of measurement resolution and 0.1 part per million transfer accuracy.