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Author Topic: Multimeter Review: Agilent U1272A  (Read 20630 times)

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Offline mjlorton

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Multimeter Review: Agilent U1272A
« on: February 23, 2012, 04:34:28 PM »
Here is my initial review of the U1272A.

A quick summary of my findings:

* Look and feel: Good to very good
* Test leads / probes: Not good
* Accuracy: Excellent
* Resolution: Very good
* Continuity tester: Very good
* Features: Excellent
* Robustness as an industrial multimeter: Good

I need more time to play with the extended features and to do a comparison with the Fluke87-V.



Review Index:
Introduction - 00:00:05 to 00:01:17
General look and feel - 00:01:19 to 00:06:03
Auto range, display resolution and update speed - 00:06:05 to 00:09:32
Accuracy, calibration and voltage reference test - 00:09:33 to 00:11:44
Current and resistance reference tests - 00:11:46 to 00:15:27
Continuity tester - 00:15:30 to 00:16:39
Min, Max, Average feature - 00:16:41 to 00:17:57
Trig Hold and Auto Hold Feature - 00:17:59 to 00:18:59
Multimeter teardown - 00:19:01 to 00:24:00
Low battery warning test - 00:24:02 to 00:26:26
Final Conclusion - 00:26:28 to 00:28:37


Cheers,
Martin
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Offline ron

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Re: Multimeter Review: Agilent U1272A
« Reply #1 on: February 23, 2012, 05:48:33 PM »
Well done!  Good tempo and concise.  Great review.  :)

The lead compensation feature is interesting and might bear further investigation.

One question--why did the battery test start at ~9v instead of 6v ?
 

Offline mjlorton

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Re: Multimeter Review: Agilent U1272A
« Reply #2 on: February 23, 2012, 11:53:09 PM »
Well done!  Good tempo and concise.  Great review.  :)

The lead compensation feature is interesting and might bear further investigation.

One question--why did the battery test start at ~9v instead of 6v ?
Thanks Ron...I hope to continue improving with you kind guidance ;-)

Yes...that 9v!!! Very silly me...I was in a rush and forgot it should have been 6v...I have added an annotation to the video...thankfully the 1272A survived.

The lead compensation certainly is interesting, I will post a little more on it in the video on the extended features.

Thanks again for your input.

Cheers,
Martin.
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Offline saturation

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Re: Multimeter Review: Agilent U1272A
« Reply #3 on: February 24, 2012, 12:26:30 AM »
Most excellent. Thanks for doing it.  Its been ?~ 1 year since I did mine, there were some significant v1.x bugs, what firmware version is shipped with the new 1272a?

Early models have a defective nub on the stand, it wears out very fast. 

The cal certificate is great if you need such; its fully automated so the cost to do it is fairly small done the Agilent way.  However,  one 1272a I received with a certificate was out of cal, and the values the meter provided on some ranges and the certificate did not match.  Agilent sent me another test meter thereafter.

On an 1252a DMM, same thing on the 5V range, and both meters still had valid cal certificates.

So always good to performance test your new DMMs to insure it meets specs.




Best Wishes,

 Saturation
 

Offline TerminalJack505

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Re: Multimeter Review: Agilent U1272A
« Reply #4 on: February 24, 2012, 12:45:20 AM »
Good timing as I'm in the market for another meter.  I was looking at this one just yesterday.  Thanks for the review.
 

Offline mjlorton

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Re: Multimeter Review: Agilent U1272A
« Reply #5 on: February 24, 2012, 01:25:56 AM »
Most excellent. Thanks for doing it.  Its been ?~ 1 year since I did mine, there were some significant v1.x bugs, what firmware version is shipped with the new 1272a?

Thanks for the feedback. Mine came with firmware version 2.00

The cal certificate is great if you need such; its fully automated so the cost to do it is fairly small done the Agilent way.  However,  one 1272a I received with a certificate was out of cal, and the values the meter provided on some ranges and the certificate did not match.  Agilent sent me another test meter thereafter.

On an 1252a DMM, same thing on the 5V range, and both meters still had valid cal certificates.

So always good to performance test your new DMMs to insure it meets specs.
Interesting info on the calibration service...looking at the print out I figured it must be automated but good to know the cost should be reasonable as well.
It's a little concerning that a valid cert is not reflecting what the meter should be....and I guess most folks are never going to realise that...

Cheers,
Martin.
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Offline mjlorton

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Re: Multimeter Review: Agilent U1272A
« Reply #6 on: February 24, 2012, 01:28:11 AM »
Good timing as I'm in the market for another meter.  I was looking at this one just yesterday.  Thanks for the review.

My pleasure and thanks for the feedback.

Cheers,
Martin.
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Offline Richard W.

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Re: Multimeter Review: Agilent U1272A
« Reply #7 on: February 24, 2012, 01:53:47 AM »
Hello Martin,

nice review, but 9V is a little bit to much for a circuit which is designed for 4 AAA batteries  ;D
I'd not dare on my 289 to try this experiment.
but the meter obviously survived (due to it's swichmode voltage regulators?!) that's nice.

Have you noticed the bargraph at 25:30? It goes up and up..


regards
 

Offline saturation

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Re: Multimeter Review: Agilent U1272A
« Reply #8 on: February 24, 2012, 01:58:54 AM »
Thanks.  Yes, whenever I receive a new instrument, its best to do a performance test to check it meets the specs.  Most folks simply assume its factory perfect and begin using it.  Most of your video tests are akin to select samples of performance tests, but there are detailed sets somewhere in most service manuals.  Some of the higher levels of the tests require more equipment, but just try to get as many done as possible.  In the 1272a service manual, it begins at page 10.  It opens:

"The performance verification tests are recommended as
acceptance tests when you first receive the instrument. The
acceptance test results should be compared against the one
year test limits. After acceptance, you should repeat the
performance verification tests at every calibration interval.
If the multimeter fails the performance verification tests,
adjustment or repair is required."

In the case of a new DMM, it just gets shipped back to the seller.



Most excellent. Thanks for doing it.  Its been ?~ 1 year since I did mine, there were some significant v1.x bugs, what firmware version is shipped with the new 1272a?

Thanks for the feedback. Mine came with firmware version 2.00

The cal certificate is great if you need such; its fully automated so the cost to do it is fairly small done the Agilent way.  However,  one 1272a I received with a certificate was out of cal, and the values the meter provided on some ranges and the certificate did not match.  Agilent sent me another test meter thereafter.

On an 1252a DMM, same thing on the 5V range, and both meters still had valid cal certificates.

So always good to performance test your new DMMs to insure it meets specs.
Interesting info on the calibration service...looking at the print out I figured it must be automated but good to know the cost should be reasonable as well.
It's a little concerning that a valid cert is not reflecting what the meter should be....and I guess most folks are never going to realise that...

Cheers,
Martin.
Best Wishes,

 Saturation
 

alm

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Re: Multimeter Review: Agilent U1272A
« Reply #9 on: February 24, 2012, 02:26:06 AM »
Shifting the burden of QA to the consumer is a very lame excuse, and should result in the customer black-listing that manufacturer for some period of time. It's good to trust AND verify, but that doesn't mean the manufacturer isn't 100% responsible for screwing up.

What does the list of recommended equipment for a performance test look like, and what percentage of the price of the DMM does it represent? Assume you buy a DMM calibrator and its manual contains a similar notice, now what?

Should one just discard the Agilent cal certificate and budget for third-party calibration? That's going to make Fluke pricing look very attractive.
 

Offline lavo-1

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Re: Multimeter Review: Agilent U1272A
« Reply #10 on: February 24, 2012, 04:07:41 AM »
Excellent review as ever ;) I have watched your Youtube channel for some time now and I always look forward to your reviews.
This does look a nice meter, but I will always stick with Fluke 87 series as it has stood up to my job working off shore in the oil industry which I think is possibly one of the harshest environments any test equipment could ever take.
Look forward to more vid's :)
 

Offline mjlorton

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Re: Multimeter Review: Agilent U1272A
« Reply #11 on: February 24, 2012, 06:20:43 PM »
Excellent review as ever ;) I have watched your Youtube channel for some time now and I always look forward to your reviews.
This does look a nice meter, but I will always stick with Fluke 87 series as it has stood up to my job working off shore in the oil industry which I think is possibly one of the harshest environments any test equipment could ever take.
Look forward to more vid's :)

Thanks for your feedback. I concur with your view of the Fluke 87 being more robust in harsh environments. This should come out in a side by side review.
Thanks for your support.
Martin.
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Solar Power and Electronic Measurement Equipment
 

Offline benemorius

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Re: Multimeter Review: Agilent U1272A
« Reply #12 on: February 25, 2012, 10:31:50 AM »
It didn't seem to do so well on the supply voltage test after considering that there are 4 cells instead of 6. It started demanding new batteries at a very healthy 1.05V per cell and the bar graph started acting up immediately thereafter. By the time you actually reached  a dead state of 0.8V per cell, the display was pretty much gone entirely and the bar graph had long since become useless. That isn't very acceptable, and it's certainly nothing to be proud of. Perhaps in your extended review you can shed some light on the situation and hopefully Agilent will step up their game a bit. Assuming it withstands the test of time, it looks like they're very close to having a damn good meter here.
 

Offline samgab

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Re: Multimeter Review: Agilent U1272A
« Reply #13 on: February 25, 2012, 10:39:51 AM »
The battery life isn't as bad as it seems. Due to hysteresis in Alkaline and NiMH cells, when the current draw is very low, such as in this device, the (essentially "resting") voltage remains above ~1.2V until the cells are almost spent. It only dips below that substantially (with capacity still remaining in the cells) when there is a high current load, which doesn't happen even with the backlight on in this meter. I'd be comfortable running this meter on eneloops.
 

Online IanB

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Re: Multimeter Review: Agilent U1272A
« Reply #14 on: February 25, 2012, 01:56:56 PM »
Just making comments as I watch. At 7m30s, with that fast update speed: how would you read a fluctuating or rapidly changing signal? The digits would become blurred and hard to read. Is there a "slow it down" mode so you get a chance to read the (average) value?
I'm not an EE--what am I doing here?
 

Online IanB

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Re: Multimeter Review: Agilent U1272A
« Reply #15 on: February 25, 2012, 01:59:08 PM »
At the beginning: do the probe tip guards really not unscrew to expose the whole length of the metal probes?
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Offline samgab

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Re: Multimeter Review: Agilent U1272A
« Reply #16 on: February 25, 2012, 02:29:44 PM »
Just making comments as I watch. At 7m30s, with that fast update speed: how would you read a fluctuating or rapidly changing signal? The digits would become blurred and hard to read. Is there a "slow it down" mode so you get a chance to read the (average) value?

If the reading was fluctuating that much, to make it unreadable, probably the best thing to do would be use the averaging feature. That would smooth the reading out nicely.
(Readings are 7 per second on many of the ranges, and I believe the screen is updating that quickly too.)

Edit: RE the probe tips... Yeah, I thought the same thing when I first saw them. I thought "oh, they just unscrew and you haven't discovered that yet"... But NO! They don't unscrew, they are permanently affixed like that!
See the kit they sell with probes with both 4mm (for CAT IV 600V) and 19mm tips:
http://www.home.agilent.com/agilent/product.jspx?cc=US&lc=eng&nid=-536902470.892751
« Last Edit: February 25, 2012, 02:32:30 PM by samgab »
 

Offline grenert

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Re: Multimeter Review: Agilent U1272A
« Reply #17 on: February 25, 2012, 05:00:02 PM »
It's too bad that Fluke/Danaher own Pomona now - HP/Agilent used to get their probes from them and they are definitely better than the Chinese probes included with Agilent kit now.
 

Offline mjlorton

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Re: Multimeter Review: Agilent U1272A
« Reply #18 on: February 26, 2012, 01:48:41 AM »
Just making comments as I watch. At 7m30s, with that fast update speed: how would you read a fluctuating or rapidly changing signal? The digits would become blurred and hard to read. Is there a "slow it down" mode so you get a chance to read the (average) value?

You make a valid point as I can see the pros and cons of a display that updates that quickly. I had an interesting scenario yesterday where I was trying to measure a rapidly fluctuating mA reading and I had both the Fluke 87-V and the U1272A taking the reading at the same time and using MIN / MAX / Ave  to "smooth" it. I hope to post a video soon showing that senario as it makes for an interesting comparison on several points.
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Offline mjlorton

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Re: Multimeter Review: Agilent U1272A
« Reply #19 on: February 27, 2012, 12:51:13 AM »
Just making comments as I watch. At 7m30s, with that fast update speed: how would you read a fluctuating or rapidly changing signal? The digits would become blurred and hard to read. Is there a "slow it down" mode so you get a chance to read the (average) value?

Have a look at this video and see what you think?



Cheers,
Martin.




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Online IanB

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Re: Multimeter Review: Agilent U1272A
« Reply #20 on: February 27, 2012, 05:44:00 AM »
Have a look at this video and see what you think?

I think that I don't like the Agilent. If you consider ergonomics or human usability, a digital display should not update more frequently than the eye and brain can absorb the numbers. Practically speaking, this means the display should freeze the current reading for at least a quarter of a second before moving on to the next reading. Any faster than this and you tend to see a blur--any advantage is lost.

Of course the bar graph is different. This is an "analog" display, and it should update as close to real time as the display permits before burring occurs. Obviously a better LCD display with fast pixel response and low persistence would be ideal here. Those ancient slow displays with long persistence are no good at all. They have long since been abandoned on computer or smartphone displays.

Getting back to the display of numerical readings, the ideal situation would be to show three numbers on the display. Every quarter of a second the display should update to show the average over the previous quarter of a second, but simultaneously it should show the high and low values instantaneously measured over that same quarter of a second. The spread of the high and low would give you a measure of the noise, fluctuation or uncertainty on the signal.

This is an interesting situation in that I don't think my ideal meter exists out there at any price point. The Fluke 289 has some nice features, but it is way too big and has that horribly inconvenient soft menu system. Not to mention the appetite for batteries. The Fluke 87V is old technology and is overpriced for what it offers. The Agilent is interesting, but not quite there yet. The designers have built a few too many usability flaws into it. I wonder if the U1251B is any better?
« Last Edit: February 27, 2012, 07:58:06 AM by IanB »
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alm

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Re: Multimeter Review: Agilent U1272A
« Reply #21 on: February 27, 2012, 07:26:39 AM »
Many bench meters, with much faster update rates, implement a configurable windowed averaging, which resets the window of the new reading deviates significantly from the average. This offers a compromise between fast transient response, stable readings for stable values and an indication the fluctuations for unstable values. I find the difference between only a few readings per second and tens of readings per second quite noticeable, at least with fast VFD displays. You can't distinguish the individual values if they're unstable, but the number of fluctuating digits also provides information.

One example is adjusting a trimmer for a voltage of 5.00 V. Quick feedback is essential since humans aren't PID controllers, but the bar graph is useless due to its limited resolution. If the meter is 20 V full scale, the resolution will only be about 0.4 V. Some sort of zoom feature would be convenient. I find it quite easy to judge if the value is above or below 5.00 V, even if it's fluctuating due to my turning of the trimmer.

I haven't used the Agilent handhelds, so I can't comment on their usability.
 

Online IanB

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Re: Multimeter Review: Agilent U1272A
« Reply #22 on: February 27, 2012, 08:04:16 AM »
I find it quite easy to judge if the value is above or below 5.00 V, even if it's fluctuating due to my turning of the trimmer.

I suspect this might be because of the change in the most significant digit. Would you find it as easy to set a value of, say, 4.096 V? Also there is a difference between stable voltages and noisy signals such as from a switching regulator. If the number stops fluctuating as soon as you let go of the adjustment pot that is going to be much easier to deal with.
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alm

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Re: Multimeter Review: Agilent U1272A
« Reply #23 on: February 27, 2012, 09:47:49 AM »
Yes, the change of the most or second-to-most significant digit helps. In the case of 4.096 V, it would be easy to determine whether it would be between 4.090 V and 5.000 V, but the last digit would be harder. The time it takes to display the correct value depends on the transient response, which is improved by a faster update rate. The averaging takes care of displaying a stable value once you stop adjusting.

Using a DMM with an update rate of 3 readings/second for the same job was much harder. It also was completely unable to sense that another signal was quickly fluctuating, it displayed some sort of stable average. The DMM with the much faster sampling rate immediately indicated the fluctuations. A bargraph would probably have been sufficient in the latter case, since the fluctuations were quite large.
 

Offline Adrien

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Re: Multimeter Review: Agilent U1272A
« Reply #24 on: February 27, 2012, 02:17:22 PM »
Hi,
Great videos indeed both of them.
I see most of the feedback is from "pro" Fluke users, as an everyday DMM user and a Fluke user I would like to say that Fluke has to up their game. Agilent just made a remarkably good meter. If the only bad thing about it is the probes and how fast it actualizes the display so what? can we actually read and write that fast? When was the last time someone needed to record measurements of that accuracy? We all know here that electronics measurements are never exacts, passive components have tolerances, then temperature, noise, etc... Plus if I was in the need to get that kind of reading I would use the average function.
Don't get me wrong, I see that feedback very useful, but in saying that, would I buy a 87V over a U1272A today, probably not so far I haven't been convinced that spending the extra money for a 87V is worth it. The 87V look old, the display isn't as clear and is quite small. Agilent is very competitive, what meter today matches its performance with its price? I think Fluke are living on their reputation and that's fine, but it is very good to see that Agilent is having a go at them and to be fair they are on the right track.
"I can't blow my 400mA DMM fuse I am only using 10V from the bench top power supply" says the electronics lecturer
 


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