Agilent 34461a - Fluke 8846A opinions & recommendations welcome

[BVH]

I’ve been looking at specs and video reviews on 6 ˝ digit DMMs for the last 4 days.  I don’t “need” a 6.5 digit meter but I am very interested in electrical and electronics and I “want” one.  Some background.  I’m 61, retired and my most enjoyable hobby is finding, acquiring and repairing older 1960’s – 1980’s vintage military long-range Short Arc searchlights and modern day aviation Short Arc searchlights.   These lights produce laser-like beams down to 1 degree and project that beam for 2+ miles – much further than the unaided eye can see.  As such, I do some basic troubleshooting, parts testing and replacement and re-wiring on the lights themselves and on the short arc power supplies including their 35KV to 45KV ignition systems.  I also enjoy finding “for parts” variable DC power supplies and trying to repair them.

I want a bench meter capable of absolute 3-decimal place accuracy.  When performing the posted accuracy calculations for the Fluke 8846A and the Agilent 34461A, my net results show that even when using the 1-year maximum error percentage factors, the result will not impact the 1st, 2nd & 3rd Decimal digits.   Is this correct?

I’ve tentatively narrowed my search to the Fluke 8846A or the Agilent 34461A.  From what I can see, the Fluke is capable of a bit better accuracy over the Agilent 34461A but I love the tft screen on the Agilent and if it can give me that guaranteed 3-place accuracy, then I would lean towards that meter.  The software for the Agilent units also seems to be much more user-friendly and feature-rich when used on a PC.

I’m guessing that any of these units would be very much overkill for my novice needs but all the same, I would appreciate thoughts and opinions as I enjoy hearing what others with much more experience have to say.  Thank you in advance.

[TechJunkie]

I have the Agilent 34401A which is still in mint condition and running like a champ! The accuracy is still spot on with minor drift in the 1st and 2nd digit occasionally. I was considering upgrading to the 34461A in the next month or two. I also looked at the Fluke but with a $1500 dollar price tag the Agilent was much more appealing. Since I run most of my instruments in my lab with software (When Capable), I really like using BenchVue from Agilent. It works very well and I feel it's much better then FlukeForms. Plus the Agilent has a better display with a wider range of info available. Although the Fluke 8846A has a 34401A emulation mode which allows it to work with BenchVue, I still prefer the Agilent over the Fluke for a bench DMM.

[MJLorton]

I second what TechJunkie has posted.

Even though I don't have any of the Agilent bench meters (I want one!...Don't need it ;-) ) I would go with the 34461A over the Fluke.
Another consideration is the Rigol DM3068 which is priced really well and I prefer to my Fluke 8846A.

But if you have the budget I would go with the Agilent.

Your calculations about relying on the first 3 decimal places are correct. I talk about this in some of the videos I've done on the higher count bench meters I have.

Cheers,
Martin.

[BVH]

Thank you both!  Not having bought any test equipment of this caliber, I would appreciate some guidance.  It would appear that most of the vendors are posting the same price within a few dollars.  Some indicate that a "calibration certificate" is included but I get the idea that this certificate just says the instrument was calibrated on such-an-such a date but gives no data.  To get a certificate with data seems to add $125+ to the price and if it's NIST, then it could be more.

Again, just being a hobbiest, can I expect the meter to be within it's published accuracy spec when received and for the next 12 months or so or should I consider getting it a NIST cert for the added price.  I've asked two different vendors this question:  If I buy one today, can you give me the date of calibration of the instrument you will actually send me.  Both give the same excuse that the "meter is warehoused in a different location" so they cannot give me the date.  In some of these cases, I would guess that they don't stock any and that they will order the unit drop shipped from the factory.   I don't want to buy a unit that was calibrated a year or more ago.  How do I do my due diligence and get one recently factory calibrated?  Any other tips would be greatly appreciated and even a vendor recommendation if appropriate.

Milli-ohm measurements are good enough for me so should I forget about buying the 4-wire test lead set?  (Not that I really understand this measurement process well at this point.)

[TechJunkie]

BVH,

  If you get a chance to see the BnechVue in action I think this will help your decision. It is a superb piece of software which will add much more functionality and precision data logging and analysis to your DMM. One of the really cool features of BenchVue is the ability to drag and drop signals from various devices onto other compatible devices. For example, you have your Agilent DSO  with a waveform captured and you want to easily reproduce it on your Agilent Arbitrary waveform generator, all you do is drag the scope window onto the waveform gen and it is reproduced instantly. BenchVue also has an extensive library which depending on the connected equipment provides manuals, specs, videos, app notes, demos, FAQ's, downloads and much more. There is also a Data Manager which keeps a database of all your runs so they can be reviewed, emailed, analyzed at a later time. The GUI is very well built and provides all the functionality you would need for data logging, realtime monitoring and more. Not to mention multiple pieces of gear can be monitored and logged simultaneously with  bench layout function. I guess I'm sounding like an Agilent rep, but I really do like their gear, If I can answer any questions for you, please don't hesitate to message me.

Good Luck!

[BVH]

Thanks Techjunkie.  I've decided to go with the Agilent 46A but am just after a bit of advice from those who are more knowledgeable than myself  on how best to buy one that is fresh/recently built and factory calibrated so I can have close to a year without thinking of re calibrating.  Do you re-cal your meters annually or is every couple of years fine?  I just want to buy smart, not like a newby.  Then again, I may be way over-thinking this and maybe all this thought is not really applicable to my simple hobbiest use of the meter since it would probably take quite a while for calibration error factor to affect the 3rd Decimal digit - and even then, the 3rd digit accuracy is not "really" a big deal for my use.  I just enjoy really getting into specs and want to buy smart.

I can order a unit from a vendor who indicates there is stock on-hand or I can order from a vendor who indicates units are back-ordered and are due first week of Sept.  Logic would tell me to back-order because I would assume that the units that will arrive are freshly built and factory calibrated very recently.  Is this a reasonable approach?

[TechJunkie]

Do you re-cal your meters annually or is every couple of years fine?

No, I can easily get away with every couple years, even a few depending on the drift. Agilent is about 185 dollars for a basic calibration on there DMM. If you get an NIST and want to keep the cal cert valid then you will need to do it yearly but for your purpose I don't think that would be necessary. The drift I see is negligible and does not effect measurements with most of my projects. Occasionally I am doing something that requires great precision and the Agilent is what I use and it performs well. I do have some small voltage ref modules that I check my meters from time to time and record that data to see if there are any changes, but short of having a calibrated professional reference standard, that's about all you can do at home. I think Martin has a nice HP reference standard, don't know the model of the top of my head.

I can order a unit from a vendor who indicates there is stock on-hand or I can order from a vendor who indicates units are back-ordered and are due first week of Sept.  Logic would tell me to back-order because I would assume that the units that will arrive are freshly built and factory calibrated very recently.  Is this a reasonable approach?

Depends on whom you order from. I get test equipment from several different sources. For general gear and a few specialty items I have used Amazon. Although, Amazon is a warehouse and product can sit for quite some time before being sold. I have received out of date gear from Amazon before. Still new, just the prior model. Another place is TEquipment, I have a particular rep I speak with and their product is rotated and kept "Fresh". During the whole Rigol issue with DP32A heatsink problem that was discovered by Dave at the EEVblog, TEquipment promptly had Rigol swap out there affected stock of DP832A units with updated units which had the new bigger heatsink. They guaranteed me that I would not get a unit with the defect. Honestly, it would really depend on how bad you need it or want it. Getting a unit with an MFG date only a few months apart may not really be a big deal, plus a reputable supplier will cycle its stock fairly quick so the products are usually up to date anyway.

We had once a brand new never used Agilent DMM produced in I believe it was 2006 or 2007. Opened the box in 2012, turned it on and allowed a 30 minute warm-up and would you believe, it was still in spec! I think your going to be very happy with your new Agilent. Make sure you get BenchVue (Free Download), if you have any questions about it, don't hesitate to ask.

[BVH]

OK, all of your info really helps put things in perspective. 

I watched 8 of the short Agilent BenchVue videos yesterday and even with not having any experience with precision DMMs and some of the other equipment they used for the demos, I could follow along fairly easily to get an idea of the power and ease-of-use of the software.  This is going to be fun!

[TechJunkie]

Great! I am excited for you. Datalogging is high on my list for some of the research I do. I have quite a few hardware/software combinations which allow me to collect data. I spent a considerable amount of time and money into collecting measurement data for analysis. I won't go into details because much of it may bore you and I don't think I could put it all in a single post! 

[BVH]

Got it ordered from TEquipment.  Now the two-week wait but at least it will ship fresh direct from the factory/MFG.

[TechJunkie]

Got it ordered from TEquipment.  Now the two-week wait but at least it will ship fresh direct from the factory/MFG.

Awesome! If you have any questions about BenchVue, feel free to post a message. Just a note, allow a warmup of at least 30 minutes before doing any Vref tests, you will get the best accuracy then.

[BVH]

Got the meter on Thursday and installed all the software libraries and drivers including BenchVue.  The software communicates with the meter as it should.  Two questions so far, When connected in Remote, the initial BenchVue screen resembles the trending screen with a grid versus the numbers screen that was on the meter when the connection took place.  I do not see any way to change meter screens within BenchVue?  I'm fairly sure I remember seeing the numbers screen on BenchVue when I watched those 8 videos, but not 100% sure.  Maybe it was in the WEB UI mode of remote control.

When in remote mode, I measured a single Lithium-Ion battery cell and the BenchVue trending-like screen on the PC does what it's supposed to do but on the meter, the meter screen remains static with all the ....... big dots that appeared when the connection took place.  However there are very brief moments (maybe 2 per second) when the Voltage numbers flash visible but are not readable.  When connected to BenchVue, is the meter screen non-functional?

Really looking forward to playing with the meter.

[TechJunkie]

BVH,

  During data acquisition or "Remote" mode the front panel displays and controls are disabled. My 34461A will display a "Remote" label in the upper right corner of the display. My 34401A will display an "RMT" in the lower left of the display to denote remote mode. Changing modes of measurement is done from the software, make sure you "Stop" data acquisition and simply select the Measurement Dropdown menu and all the modes of operation that meter is capable of are displayed for selection. After selecting the mode, start data acquisition again and your ready to go.

Keep in mind that it is normal for the front panel to flash a value every so ofter. All the 34461A's will do this. The proper use when in "Remote" mode is to use the BenchVue software. Priority is given to the USB or whatever com bus your are using to allow for the faster sampling updates through the software.

I have attached a couple photos for clarification. A photo of the units before "Remote" mode and after enabling "Remote" mode. I also attached a screenshot of my BenchVue with both DMM's active in remote mode.

[BVH]

OK based on your post above, everything is working just as it should.  I did more research and found that I was remembering features from the WEB based remote control method of accessing the meter, not BenchVue.  Thanks for confirming!

[BVH]

With the screen saver enabled, what is the period of idle time before it goes into saver mode?  I've left mine on for 70 minutes and it has not gone into save mode - that I can tell.  Does it blank the screen or dim it and if dimming, by about how much?