Author Topic: EEVblog #933 - Keysight U1272A EMC Issue  (Read 150249 times)

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Online BravoV

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #125 on: October 30, 2016, 07:53:30 am »
I think the entire T&M market is moving from building "permanent asset" to building "3-year lifetime consumable".

For sure, Agilent (pre Keysight) did it long time ago , not a big deal though, but just look at the label at my 3 yrs old U1242B, no harsh nor field used, only at the lab all the time.  :palm:

Heck, even screen printing at common cheap 2 dollars DMM like DM803's label don't wear of that easily.


Offline WackyGerman

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #126 on: October 30, 2016, 07:58:06 am »
Maybe they dropped the price for some other stuff , but here in Germany the price for the U1272A is close to the Fluke 87V . Fluke did do their work and fixed the emc issue , Keysight didn t . When buying a multimeter for 460 € you can expect more customer service that that
 

Offline EEVblog

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #127 on: October 30, 2016, 08:00:13 am »
They'd only be expected to do that for a safety issue, which this isn't likely to be.  (Admittedly, anything that causes a DMM to display a grossly incorrect value under reasonable operating conditions has the potential to be a safety issue.) 
What will probably happen is that they'll develop a fix internally, and issue a service bulletin -- which may or may not be public -- that says "Apply this fix on customer request."

Yep, I think they will quietly fix this in a future design revision.
I suspect they came to the conclusion that it's better to give the nothing response they gave and take the heat for that, then issue a notice admitting a major issue and risking any legal consequences. When they basically said "It meets the specs", that covers their arse fairly nicely legally, and gives them a long time to fix it on the quiet.
Classic corporate response.
 

Offline blueskull

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #128 on: October 30, 2016, 08:02:45 am »
Maybe they dropped the price for some other stuff , but here in Germany the price for the U1272A is close to the Fluke 87V . Fluke did do their work and fixed the emc issue , Keysight didn t . When buying a multimeter for 460 € you can expect more customer service that that

U1272A is supposed to be compared with F289, not F87V.
 

Offline WackyGerman

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #129 on: October 30, 2016, 08:19:31 am »
Really ? I think that s a personal opinion . For me the F289 plays in it s own ligue with its dot matrix display
 

Online BravoV

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #130 on: October 30, 2016, 08:23:41 am »
Really ? I think that s a personal opinion . For me the F289 plays in it s own ligue with its dot matrix display

+1, the logging and capability of displaying it at the meter, this alone made the F289/287 is more like a hand held ultra high resolution oscilloscope, not high speed though.

Offline blueskull

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #131 on: October 30, 2016, 08:47:08 am »
+1, the logging and capability of displaying it at the meter, this alone made the F289/287 is more like a hand held ultra high resolution oscilloscope, not high speed though.

While Keysight meters cannot plot on meter, but they can display individual data points on meter.
Also, there are a few OLED models that are dot-matrix based.
 

Online BravoV

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #132 on: October 30, 2016, 09:12:19 am »
+1, the logging and capability of displaying it at the meter, this alone made the F289/287 is more like a hand held ultra high resolution oscilloscope, not high speed though.

While Keysight meters cannot plot on meter, but they can display individual data points on meter.
Also, there are a few OLED models that are dot-matrix based.

Dot matrix ? Yeah, still no where near plotting this kind of graph on the spot "at the handheld".

Example -> -> F28X log example
Its temperature log for 8 hours that can be zoomed down to seconds, made this log while ago to check the newly installed air con unit.

Imo, the dot matrix model you mentioned is not even the same league, c'mon, you own F289 as well, you have to agree F287/289 is like handheld scope, but with 1000V capability and the whole shebangs built in it.

Offline madires

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #133 on: October 30, 2016, 09:23:38 am »
You cannot really expect competitive price plus good quality plus decades of experience plus good customer service.

For nearly EUR 500 I expect good quality plus decades of experience plus good customer service. After Keysight's response I wouldn't pay more than EUR 200 for the U1272A. Somehow I got the feeling, that Keysight just discounted everything they sell by 50%.
 

Offline blueskull

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #134 on: October 30, 2016, 09:35:13 am »
Imo, the dot matrix model you mentioned is not even the same league, c'mon, you own F289 as well, you have to agree F287/289 is like handheld scope, but with 1000V capability and the whole shebangs built in it.

Not saying they are the same, but I think 87V should not be compared with U1272A as U1272A has so many features that 87V does not, although 289 is even better.
Also, in terms of customer care, Fluke never addressed the leaky super cap issue on 289/287. My 289 has 2.4V residual voltage in LoZ mode, and Tektronix calibration center (same owner as Fluke) told me that's normal.
 

Offline alouko

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #135 on: October 30, 2016, 10:19:20 am »
As far as I have understood, the problem is also in some other series, like 1240 and 1280.  They have not addressed that at all, yet.

And LPF doesn't really help.  I just tested with my U1273A and with 10MHz sine wave with 3V amplitude it still gives about -0.2A readings.  I would like to see the new spec sheet where they state +- 0.1% -2000 digits!  10MHz 3V sine is completely feasible voltage in many everyday circuits, not something extreme.

Well, I have my case in local Keysight office and I will probably suggest that they either fix my DMM or replace it with a working one with similar specs, be it either Keysight or Fluke or Metrahit!

If messieurs Hewlett and Packard were still alive, they would probably suffer a stroke because of how Keysight is handling this.

P.S.

At Keysight.com, you can see ad stream, first one stating "Capture Every Signal".  Well, at least that promise holds, even for DMMs  ;)

 

Offline Brumby

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #136 on: October 30, 2016, 11:33:06 am »
Since turning on LPF solves the problem,

That's not how I read it.  Turning on the LPF simply reduces the problem, not solve it - unless I've missed something.
 

Offline Brumby

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #137 on: October 30, 2016, 11:35:08 am »
They'd only be expected to do that for a safety issue, which this isn't likely to be.  (Admittedly, anything that causes a DMM to display a grossly incorrect value under reasonable operating conditions has the potential to be a safety issue.) 
What will probably happen is that they'll develop a fix internally, and issue a service bulletin -- which may or may not be public -- that says "Apply this fix on customer request."

Yep, I think they will quietly fix this in a future design revision.
I suspect they came to the conclusion that it's better to give the nothing response they gave and take the heat for that, then issue a notice admitting a major issue and risking any legal consequences. When they basically said "It meets the specs", that covers their arse fairly nicely legally, and gives them a long time to fix it on the quiet.
Classic corporate response.

Classic indeed.
 

Offline blueskull

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #138 on: October 30, 2016, 11:45:19 am »
Since turning on LPF solves the problem,

That's not how I read it.  Turning on the LPF simply reduces the problem, not solve it - unless I've missed something.

Correct. I should say ... solves the problem to a degree.
 

Offline Fungus

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #139 on: October 30, 2016, 11:45:37 am »
All firmware released since version 2.04 has the DC low pass filter turned “on” by default.

I wonder why...  :popcorn:

 

Offline TheAmmoniacal

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #140 on: October 30, 2016, 11:54:20 am »
All firmware released since version 2.04 has the DC low pass filter turned “on” by default.

I wonder why...  :popcorn:

So will they send me a free USB-IR cable so I can upgrade to the new firmware? Like they did with the erratic display problem?
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Offline joeqsmith

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #141 on: October 30, 2016, 03:31:40 pm »
Thanks to those on this thread for pointing out a potential EMC issue on the U1272A family of handheld multimeters. We have our best EMC technical experts at Keysight doing a deep dive to replicate the problem and determine its root cause. We expect them to complete the investigation within the week, and we’ll get back to the community on what we’ve found and any follow-up actions we may decide to take.

As mentioned in our earlier post, we asked our EMC technical experts to look into this – and they were able to replicate the symptom. Keysight engineers found the majority of U1272A measurement modes and ranges meet published specifications in the presence of an RF field, but the product is susceptible to RF fields in certain measurement modes.

......  we are characterizing the accuracy of the U1272A’s performance in the presence of an RF field, and will revise the product’s data sheets accordingly. We will let you know via this blog when we have posted the revised datasheets on Keysight’s website.

I would be interested in knowing if Keysight's experts were unable to find a solution or if higher up they decided it was not worth going after.
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Online BravoV

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #142 on: October 30, 2016, 04:05:33 pm »

......  we are characterizing the accuracy of the U1272A’s performance in the presence of an RF field, and will revise the product’s data sheets accordingly. We will let you know via this blog when we have posted the revised datasheets on Keysight’s website.

I would be interested in knowing if Keysight's experts were unable to find a solution or if higher up they decided it was not worth going after.

To me, its clear enough, they will not do anything about it, and that direction is clearly came from top management.

The highlighted words above is crystal clear .. its like fridge you bought, the spec and brochure when you purchased it said it was able to chill down to below freezing point, that turns water into ice in the freezer section.

Now, it will be revised "accordingly", its like ... "Sorry, the spec changed, your water will not turn into ice in the freezer, and enjoy chilled drink .. oh yeah ... your ice cream will melt if you put in there" ... go figure.  :palm:
« Last Edit: October 30, 2016, 04:09:46 pm by BravoV »
 

Offline joeqsmith

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #143 on: October 30, 2016, 05:09:03 pm »

......  we are characterizing the accuracy of the U1272A’s performance in the presence of an RF field, and will revise the product’s data sheets accordingly. We will let you know via this blog when we have posted the revised datasheets on Keysight’s website.

I would be interested in knowing if Keysight's experts were unable to find a solution or if higher up they decided it was not worth going after.
To me, its clear enough, they will not do anything about it, and that direction is clearly came from top management.

They are doing something about it, they are changing the datasheet.  To be clear, that's not my question.  I want to know if their EMC experts have a solution and the company will not correct the design for reasons like loss of profits.   Is this a technical problem or a money problem?   
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Online Neilm

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #144 on: October 30, 2016, 06:16:23 pm »
They'd only be expected to do that for a safety issue, which this isn't likely to be.  (Admittedly, anything that causes a DMM to display a grossly incorrect value under reasonable operating conditions has the potential to be a safety issue.) 
What will probably happen is that they'll develop a fix internally, and issue a service bulletin -- which may or may not be public -- that says "Apply this fix on customer request."

Yep, I think they will quietly fix this in a future design revision.
I suspect they came to the conclusion that it's better to give the nothing response they gave and take the heat for that, then issue a notice admitting a major issue and risking any legal consequences. When they basically said "It meets the specs", that covers their arse fairly nicely legally, and gives them a long time to fix it on the quiet.
Classic corporate response.

It says it meets "Commercial limits compliance with EN61326-1"

Ether they have to open the spec really wide (it measures current to +/- 5A) or they have to remove the CE mark and withdraw from sale in those parts of the world that require compliance to that standard (Europe certainly, I think Australia and don't know about US).
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Offline joeqsmith

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #145 on: October 30, 2016, 07:02:56 pm »
They'd only be expected to do that for a safety issue, which this isn't likely to be.  (Admittedly, anything that causes a DMM to display a grossly incorrect value under reasonable operating conditions has the potential to be a safety issue.) 
What will probably happen is that they'll develop a fix internally, and issue a service bulletin -- which may or may not be public -- that says "Apply this fix on customer request."

Yep, I think they will quietly fix this in a future design revision.
I suspect they came to the conclusion that it's better to give the nothing response they gave and take the heat for that, then issue a notice admitting a major issue and risking any legal consequences. When they basically said "It meets the specs", that covers their arse fairly nicely legally, and gives them a long time to fix it on the quiet.
Classic corporate response.

It says it meets "Commercial limits compliance with EN61326-1"

Ether they have to open the spec really wide (it measures current to +/- 5A) or they have to remove the CE mark and withdraw from sale in those parts of the world that require compliance to that standard (Europe certainly, I think Australia and don't know about US).

Does the CE mark require the meter meet EMC standards or just the safety standards?   I always assumed it was safety only for the meters as most of the ones I have looked at do not reference the EMC standards. 

Would really like to see Dave do an Amp hour on these standards with they interview someone who dares interpret them.   I would guess the commercial limits are 3V/m 80MHz to 1G vs 10V/m for industrial.  The standards cover a wider range.  Even if we use the battery powered Annex A:
Quote
Examples for equipment included in the scope of this annex but not limited to, are: equipment covered by the scope of IEC 61326-2-2, digital multi-meters,
it calls out 3V/m. 

Looking at conducted (61000-4-6), this is 3V (150KHz to 80MHz), performance criterion A.   

Criterion A is defined as:
Quote
The equipment shall continue to operate as intended during and after the test. No degradation
of performance or loss of function is allowed below a performance level specified by the
manufacturer, when the equipment is used as intended. The performance level may be
replaced by a permissible loss of performance. If the minimum performance level or the
permissible performance loss is not specified by the manufacturer, either of these may be
derived from the product description and documentation and what the user may reasonably
expect from the equipment if used as intended.

The way I read this, they can do anything they want as long as they meet their specified performance level.   I guess I don't see a problem with them changing their spec to solve it.  I actually wonder how bad it really is if the test were done correctly.  It may be fun to run one and just see how bad it really is and what it would take to correct it, assuming it does not pass.

Typically there is a fair amount of variance chamber to chamber.  Just calibrating the RF level is not trivial.  They will need to make sure that what ever they come up with that the product passes with some margin.   Should be interesting.   
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Online Neilm

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #146 on: October 30, 2016, 07:11:47 pm »
Does the CE mark require the meter meet EMC standards or just the safety standards?   I always assumed it was safety only for the meters as most of the ones I have looked at do not reference the EMC standards. 

The CE marks shows that the product meets ALL relevant EU directives. Low voltage directive (safety) and the EMC directive plus any other relevant directive (Radio Equipment Directive if it has wireless capabilities, Machinery directive if it has moving parts). The Declaration Of Conformity should state all the directives it meets.
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Offline Dr.Trinity

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #147 on: October 30, 2016, 07:57:04 pm »
As mentioned in our earlier post, we asked our EMC technical experts to look into this – and they were able to replicate the symptom. Keysight engineers found the majority of U1272A measurement modes and ranges meet published specifications in the presence of an RF field, but the product is susceptible to RF fields in certain measurement modes.
Please tell me how to fix this problem.
We have many of the U1272A meters for teaching purpose and if this EMC problem is not solved for us, we have to replace all of them.

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Offline FrankT

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #148 on: October 30, 2016, 08:08:45 pm »
My U1272a beeped at me this morning when I switch to the voltage setting and I had the lead in the mA socket.

Could this be related to the problem we are seeing?  Does it rely on picking up stray noise to detect the leads are in the wrong spot?
 

Offline TheAmmoniacal

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Re: EEVblog #933 - Keysight U1272A EMC Issue
« Reply #149 on: October 30, 2016, 08:13:05 pm »
Poor Keysight..

I've had this meter for 3 years now and only had a measurement issue related to EMC twice, where I've had my function generator leads have been an entropic mess around my DMM and circuit. Now that I'm aware of it it's easy to avoid.

It's really a minor issue, not worth a recall or warranty replacement.. But it does change my impression of the Keysight brand somewhat.

I still think the slow audible continuity measurement is a much bigger issue, especially because it /has/ to be a damn firmware problem! (and fixable)
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