Author Topic: Finally received my Uni-T UT17B Pro, I'm pleasantly surprised  (Read 2585 times)

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Online joeqsmith

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Re: Finally received my Uni-T UT17B Pro, I'm pleasantly surprised
« Reply #25 on: August 11, 2020, 12:31:38 am »
I see many people excited  but this meter has the crappiest AC bandwidth , no bargraph , so beside beeing cheap what is the point  buying it for electronics ? And I doubt  any professional electrician would trust a company like this for his life ...  :--
At this price the quality can't be good , I'm sorry but good things don't come free ... I don't want to be evil >:D but first check if those fuses are't just chinese fakes . They know by now how much people love big fuses  ;D

To be fair, I don't trust Uni-T either, but the actual physical construction and the PCB are made to a higher standard than a lot of their previous models. I was just curious as to what the meter feels like so I bought it to check it out. If you wanna depend your life on it? That'd be crazy, and I wouldn't do that either, but for someone who's looking for a cheaper alternative with relatively good quality (compared to those absolute cheapies), it does feel a lot better in the hand, and the measurements are consistent, screen is big and fonts are bold, not to mention the great backlight feature and the beeping diode mode.

I see nothing wrong with these cheaper alternatives. They have a place in the market, and I see no prob Uni-T actually try to improve the quality of their cheapies.

EDIT:
Again, is 500Hz bandwidth too different from 800Hz? Is a crappy bargraph worth having? Name me a few meters that have decent bargraph in the $60-$70 range that has similar fit and finish and construction? The UT61E seems to be a lot better in this regard, but it was not built in the same way. Nothing is free I guess as you said.

What I'm really trying to say is, nothing is free. You get something, you lose something. I don't believe you'd be able to get a UT61E successor in this kind of build quality for a similar price. Well that hasn't happened yet, so we'll see.


Looks like it would be around $100 USD with tax and shipping, for a 6000 count UNI-T.   What's this great back light feature you keep mentioning?  The fact it actually has one?  Or can you leave it on forever until the battery drains?


It has an ETL certification, as embossed at the back of the meter and as stated in the Chinese user manual.
(Intertek's Electrical Testing Labs)

After seeing Dave's 121GW get ETL cert and not even be able to do simple autorange, I have little confidence in their ability. 

It's interesting that Fluke used to send them to several agencies, I suspect partly to avoid having a test house that replaced their senior staff with fresh outs who have no idea what a DMM is, just to make more profit.   Surely this couldn't happen.

With Dave's new meter having a UL cert, it will be interesting to see if it follows a similar path.   So far, that lack of transparency and leaking a little bit here and there, it sure seems like this it the path it is heading down. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline Corner

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Re: Finally received my Uni-T UT17B Pro, I'm pleasantly surprised
« Reply #26 on: August 11, 2020, 02:27:42 am »
Looks like it would be around $100 USD with tax and shipping, for a 6000 count UNI-T.   What's this great back light feature you keep mentioning?  The fact it actually has one?  Or can you leave it on forever until the battery drains?

Well, it's only $100 AUD shipped including the Australian GST: https://www.aliexpress.com/item/4001122129754.html?spm=a2g0o.productlist.0.0.7a03270aUPB6rp&algo_pvid=7ae98d28-1bcf-44b5-9978-2913752e273b&algo_expid=7ae98d28-1bcf-44b5-9978-2913752e273b-0&btsid=0ab6d59515971125434111042e2898&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

And this one is $94 AUD shipped including our tax: https://www.aliexpress.com/item/4001253921623.html?spm=a2g0o.productlist.0.0.7a03270aUPB6rp&algo_pvid=7ae98d28-1bcf-44b5-9978-2913752e273b&algo_expid=7ae98d28-1bcf-44b5-9978-2913752e273b-2&btsid=0ab6d59515971125434111042e2898&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_

The backlight is way more convenient to use than their other models. It's light sensing. It'll stay on forever if ambient environment is dark enough. It'll time out in maybe 20 seconds if not, then enabling it again is not as gruelling as the 139C/E models where you have to hold a button for 2 seconds. Just cover the light sensor and it'll come on. Completely disabling it is just a press of a button.
« Last Edit: August 11, 2020, 02:46:35 am by Corner »
 

Offline CDaniel

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Re: Finally received my Uni-T UT17B Pro, I'm pleasantly surprised
« Reply #27 on: August 11, 2020, 06:23:40 am »


EDIT:
Again, is 500Hz bandwidth too different from 800Hz? Is a crappy bargraph worth having? Name me a few meters that have decent bargraph in the $60-$70 range that has similar fit and finish and construction? The UT61E seems to be a lot better in this regard, but it was not built in the same way. Nothing is free I guess as you said.

What I'm really trying to say is, nothing is free. You get something, you lose something. I don't believe you'd be able to get a UT61E successor in this kind of build quality for a similar price. Well that hasn't happened yet, so we'll see.

At least 20KHz bandwidth for audio purpose I would say is enough for electronics ...
When buying a multimeter you shouldn't think how cheap it is even if you are poor , a good brand could last for life and have all the fuctions you need .
 

Online joeqsmith

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Re: Finally received my Uni-T UT17B Pro, I'm pleasantly surprised
« Reply #28 on: August 11, 2020, 11:16:43 am »
Looks like it would be around $100 USD with tax and shipping, for a 6000 count UNI-T.   What's this great back light feature you keep mentioning?  The fact it actually has one?  Or can you leave it on forever until the battery drains?

Well, it's only $100 AUD shipped including the Australian GST:

And this one is $94 AUD shipped including our tax:

The backlight is way more convenient to use than their other models. It's light sensing. It'll stay on forever if ambient environment is dark enough. It'll time out in maybe 20 seconds if not, then enabling it again is not as gruelling as the 139C/E models where you have to hold a button for 2 seconds. Just cover the light sensor and it'll come on. Completely disabling it is just a press of a button.
I would have guessed you would find it for less.   

Four years ago I had modified a UT61E to demonstrate how backlight's intensity could be controlled  based on the ambient light.   It took them long enough to copy the concept.     

While they are pretty good at copying.   The UT181A is a decent clone of the Fluke 289 with some added bling.  It's too bad that when it comes to actually improve the UT181A they fall way short.    I was told that the 181A was now certified to the 61326 EMC standards and so I looked it up (see attached).   Intertek wrote up a cert for it but having that paper means less and less to me.   Do I actually believe a brand new UT181A would survive even the most basic of tests?  If I did, I would have one! 

Old video showing the adaptive backlight control....
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Online Wytnucls

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Re: Finally received my Uni-T UT17B Pro, I'm pleasantly surprised
« Reply #29 on: August 11, 2020, 12:20:56 pm »
The automatic backlight feature, triggered by ambient light intensity has been around for a while:
Appa 507 505 503 since 2011
Holdpeak  HP770D

Some meters have a backlight with voice activation.
 

Offline rsjsouza

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Re: Finally received my Uni-T UT17B Pro, I'm pleasantly surprised
« Reply #30 on: August 11, 2020, 02:30:29 pm »
Hard to say how it would hold up.  It looks like the high speed clamps are tied to the return path for the MOVs.
That is a sin of the cheap meters - it seems they copy each other's mistakes.

If this is true, it's interesting that they would talk about the 30K cycle test. We could run it to 50K full cycles and see if there is anything left.
Well, truth be told, either 30k or 50k is a very respectable lifetime for the switch. The issue is believing if they are a design feature or instead simply a "prepared" unit.

If the whimmpy grill starter didn't damage it and it survived my smaller generator (6KVish), that would be a big improvement for UNI-T.  The 138C can't come anywhere near that.   
Are you referring to the UT139C? If so, in your tests it went up to 5kV. I wouldn't necessarily classify it as "can't come anywhere near that".

It has an ETL certification, as embossed at the back of the meter and as stated in the Chinese user manual.
(Intertek's Electrical Testing Labs)

After seeing Dave's 121GW get ETL cert and not even be able to do simple autorange, I have little confidence in their ability. 
We mentioned this somewhere else; there is a possibility the test procedure does not exercise or cover this scenario. It is a somewhat CYA operation.

It's interesting that Fluke used to send them to several agencies, I suspect partly to avoid having a test house that replaced their senior staff with fresh outs who have no idea what a DMM is, just to make more profit.   Surely this couldn't happen.
I wouldn't be surprised that Fluke, having created or shared a great deal of the practices and design rules that inspired the standards, would get these certifications done for pennies on the dollar.  :-+

With Dave's new meter having a UL cert, it will be interesting to see if it follows a similar path.   So far, that lack of transparency and leaking a little bit here and there, it sure seems like this it the path it is heading down. 
Just like you, I think that a decent equipment is mostly tied to the OEM than to the standard itself.
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Online joeqsmith

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Re: Finally received my Uni-T UT17B Pro, I'm pleasantly surprised
« Reply #31 on: August 11, 2020, 03:29:56 pm »
If this is true, it's interesting that they would talk about the 30K cycle test. We could run it to 50K full cycles and see if there is anything left.
Well, truth be told, either 30k or 50k is a very respectable lifetime for the switch. The issue is believing if they are a design feature or instead simply a "prepared" unit.

They may spit shine them every 5,000 cycles like Dave demonstrated.   I don't think I ever life cycled a UNI-T product.   The fact they even mention it for this particular meter seems like it would be a good choice.


If the whimmpy grill starter didn't damage it and it survived my smaller generator (6KVish), that would be a big improvement for UNI-T.  The 138C can't come anywhere near that.   
Are you referring to the UT139C? If so, in your tests it went up to 5kV. I wouldn't necessarily classify it as "can't come anywhere near that".

Yes.  Just a typo.  An old story...  When I ran that first set of $50 meters, the AMPROBE AM510 was the runner up, if you want to call it that.   The Fluke 101 surpassed it by a very large margin.  Still to this day, I am not sure by how much as the 101 has yet to be damaged.    I consider anything that can't compete with the AMPROBE AM510 not to be robust.   So moving forward, when the I designed the new generator, I based it off what the AM510 could survive.   

I know many people whined about how the 139C performed.  I gave it a second chance on the new generator where it was again damaged at levels below what both the AM510 and Fluke 101 could easily survive.   

You may see these numbers as being too harsh.  It makes no difference to me if you felt the free Harbor Freight meter was a great meter.  I could care less.  My goal was never to sell meters but rather just benchmark them.  The 139C did poorly, twice. 

It has an ETL certification, as embossed at the back of the meter and as stated in the Chinese user manual.
(Intertek's Electrical Testing Labs)

After seeing Dave's 121GW get ETL cert and not even be able to do simple autorange, I have little confidence in their ability. 
We mentioned this somewhere else; there is a possibility the test procedure does not exercise or cover this scenario. It is a somewhat CYA operation.
Yes we did and I pointed out key parts of the standards.  But there was no conclusion.  Me personally, I don't trust them to do their job.   Seeing that Gossen get through with such obvious problems, I don't trust them as well.   If the agencies want to dilute their value, I'm fine with it. 

It's interesting that Fluke used to send them to several agencies, I suspect partly to avoid having a test house that replaced their senior staff with fresh outs who have no idea what a DMM is, just to make more profit.   Surely this couldn't happen.
I wouldn't be surprised that Fluke, having created or shared a great deal of the practices and design rules that inspired the standards, would get these certifications done for pennies on the dollar.  :-+

With Dave's new meter having a UL cert, it will be interesting to see if it follows a similar path.   So far, that lack of transparency and leaking a little bit here and there, it sure seems like this it the path it is heading down. 
Just like you, I think that a decent equipment is mostly tied to the OEM than to the standard itself.
Yeah when that person had brought up HIOKI being self certified, it's a good case and point.   

***

Was going to mention that I believe the AMPROBE AM-510 was certified by Intertek and made by UNI-T (see attached).  Of course, the same companies produced and certified the AM-530.    The 510 far surpassed the 530 in my testing.   Just shows that if you make enough products, eventually you may stumble on a combination that is better than others.   Design by random chance.   

« Last Edit: August 11, 2020, 11:48:40 pm by joeqsmith »
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline rsjsouza

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Re: Finally received my Uni-T UT17B Pro, I'm pleasantly surprised
« Reply #32 on: August 12, 2020, 01:00:25 am »
If this is true, it's interesting that they would talk about the 30K cycle test. We could run it to 50K full cycles and see if there is anything left.
Well, truth be told, either 30k or 50k is a very respectable lifetime for the switch. The issue is believing if they are a design feature or instead simply a "prepared" unit.

They may spit shine them every 5,000 cycles like Dave demonstrated. 
I didn't remember this. If they did so, then it would not be very realistic.

The Fluke 101 surpassed it by a very large margin.  Still to this day, I am not sure by how much as the 101 has yet to be damaged.
Yes, the little Fluke is still the one to beat. However, I had a few quality problems with two very different units built with two different date codes that it reduced my trust significantly on them.

  I consider anything that can't compete with the AMPROBE AM510 not to be robust. 
(...)
I know many people whined about how the 139C performed. 
(...)
You may see these numbers as being too harsh.
I have zero skin in the game. I don't care one way or another either, but my comment is about words, not numbers. Thanks for providing the parameter of "joeq's standard of robustness" (TM) :-+

Yeah when that person had brought up HIOKI being self certified, it's a good case and point.   

***

Was going to mention that I believe the AMPROBE AM-510 was certified by Intertek and made by UNI-T (see attached).  Of course, the same companies produced and certified the AM-530.    The 510 far surpassed the 530 in my testing.   Just shows that if you make enough products, eventually you may stumble on a combination that is better than others.   Design by random chance.
I was going to comment that as well. The AM530 seems quite alright w.r.t. input protection but it may simply be a weakness brought by the added features.
« Last Edit: August 12, 2020, 01:26:49 am by rsjsouza »
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Online joeqsmith

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Re: Finally received my Uni-T UT17B Pro, I'm pleasantly surprised
« Reply #33 on: August 12, 2020, 03:22:02 am »
If this is true, it's interesting that they would talk about the 30K cycle test. We could run it to 50K full cycles and see if there is anything left.
Well, truth be told, either 30k or 50k is a very respectable lifetime for the switch. The issue is believing if they are a design feature or instead simply a "prepared" unit.

They may spit shine them every 5,000 cycles like Dave demonstrated. 
I didn't remember this. If they did so, then it would not be very realistic.
Yeah, he kept pulling it apart.  Then in the end proceeded to explain how to properly test a switch.  It's interesting how much that plastic had wore down on the 121GW I ran.  I piked that meter up the other day and forgot just how little resistance there is from the detent now.   It's shot.   In more ways than one!

The Fluke 101 surpassed it by a very large margin.  Still to this day, I am not sure by how much as the 101 has yet to be damaged.
Yes, the little Fluke is still the one to beat. However, I had a few quality problems with two very different units built with two different date codes that it reduced my trust significantly on them.

  I consider anything that can't compete with the AMPROBE AM510 not to be robust. 
(...)
I know many people whined about how the 139C performed. 
(...)
You may see these numbers as being too harsh.
I have zero skin in the game. I don't care one way or another either, but my comment is about words, not numbers. Thanks for providing the parameter of "joeq's standard of robustness" (TM) :-+

The second 139C was damaged at 5KV but had survived 4K.  Somewhere in 1-2KVish off the mark.  We've seen meters that couldn't even make it to 2KV.   Hard to say what it would take to improve it.  The secondary clamps on the 139C were not good enough to save the IC, unlike the AM510 which could be repaired.   


Yeah when that person had brought up HIOKI being self certified, it's a good case and point.   

***

Was going to mention that I believe the AMPROBE AM-510 was certified by Intertek and made by UNI-T (see attached).  Of course, the same companies produced and certified the AM-530.    The 510 far surpassed the 530 in my testing.   Just shows that if you make enough products, eventually you may stumble on a combination that is better than others.   Design by random chance.
I was going to comment that as well. The AM530 seems quite alright w.r.t. input protection but it may simply be a weakness brought by the added features.

I've seen similar comments about the added features being to cause of the weakness.  I never understood that.  If UNI-T wants to design products that survive, then they just need to put the effort in.   I've looked at a lot of meters with far more features than the 139C that could easily survive that 6KV transient and weak grill starter.   Pretty much every Brymen and Fluke I have looked at had no problems.   Even that Gossen Ultra with it's lack of shields survived everything I put it through.  I would imagine the difference is the skill set of their designers compared with UNI-T is all.   That or the designers are not asked to come up with robust designs.  That's certainly possible.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline rsjsouza

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Re: Finally received my Uni-T UT17B Pro, I'm pleasantly surprised
« Reply #34 on: August 12, 2020, 03:19:10 pm »
I've seen similar comments about the added features being to cause of the weakness.  I never understood that.  If UNI-T wants to design products that survive, then they just need to put the effort in.   I've looked at a lot of meters with far more features than the 139C that could easily survive that 6KV transient and weak grill starter.   Pretty much every Brymen and Fluke I have looked at had no problems.   Even that Gossen Ultra with it's lack of shields survived everything I put it through.  I would imagine the difference is the skill set of their designers compared with UNI-T is all.   That or the designers are not asked to come up with robust designs.  That's certainly possible.   
We talked about this somewhere else as well: the standard seems to not give a damn for the survivability of the circuit itself, as long as the damage does not cause harm to the operator. Sure, the more intact the meter is after an event, the better, but it is impossible to have a 1:1 correlation between your tests and whatever the cert agencies put out.

(Special case for the Gossen, which actually changes its status due to magnetic forces, showing an incredible gap in testing).

However, my comment is that the survival chances of a circuit can be due to many factors, ranging from improper input protection to changes on the IC design. The IC used on the AM510 could be borderline above the input transient, while the AM530 could be internally weakened by an internal switch, mux or even a floating GPIO or anything else, really. That could be evidenced by your tests if a simple Ctrl-C+Ctrl-V of the input protection circuitry was done across these two models. Given the amount of damage between the two could simply be a small "poof" on the main IC and the physical integrity is intact, that becomes a non-issue for the manufacturer.

I always recall an ancient video of Dave and Doug blowing up meters with a 40J pulse, where the most potentially dangerous was indeed a Fluke 7x series (it was a 75 IIRC), where the rotary dial flew off at a high speed.
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Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 

Online joeqsmith

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Re: Finally received my Uni-T UT17B Pro, I'm pleasantly surprised
« Reply #35 on: August 12, 2020, 05:10:07 pm »
I've seen similar comments about the added features being to cause of the weakness.  I never understood that.  If UNI-T wants to design products that survive, then they just need to put the effort in.   I've looked at a lot of meters with far more features than the 139C that could easily survive that 6KV transient and weak grill starter.   Pretty much every Brymen and Fluke I have looked at had no problems.   Even that Gossen Ultra with it's lack of shields survived everything I put it through.  I would imagine the difference is the skill set of their designers compared with UNI-T is all.   That or the designers are not asked to come up with robust designs.  That's certainly possible.   
We talked about this somewhere else as well: the standard seems to not give a damn for the survivability of the circuit itself, as long as the damage does not cause harm to the operator. Sure, the more intact the meter is after an event, the better, but it is impossible to have a 1:1 correlation between your tests and whatever the cert agencies put out.

(Special case for the Gossen, which actually changes its status due to magnetic forces, showing an incredible gap in testing).

However, my comment is that the survival chances of a circuit can be due to many factors, ranging from improper input protection to changes on the IC design. The IC used on the AM510 could be borderline above the input transient, while the AM530 could be internally weakened by an internal switch, mux or even a floating GPIO or anything else, really. That could be evidenced by your tests if a simple Ctrl-C+Ctrl-V of the input protection circuitry was done across these two models. Given the amount of damage between the two could simply be a small "poof" on the main IC and the physical integrity is intact, that becomes a non-issue for the manufacturer.

I always recall an ancient video of Dave and Doug blowing up meters with a 40J pulse, where the most potentially dangerous was indeed a Fluke 7x series (it was a 75 IIRC), where the rotary dial flew off at a high speed.

Still to this date, I couldn't tell you if the spirit of the standards is that the meters must survive or not.  I have presented sections from the standards that I would tend to interpret that the must survive.  Obviously a lot of meters would not, at least the way I test them.  Some have UL approval.  So yeah, hard to say.  Again talking directly with Fluke, I was told they design them to survive these test.   I spoke with another large company who were on the opposite end of the spectrum. 

"...but it is impossible to have a 1:1 correlation between your tests and whatever the cert agencies put out." 
It's good to finally see comments like this echoed.

No doubt there can be many causes for damage.  Countless.  If the design goals are clear, I have no doubt that a team of  competent designers could achieve it assuming there is some give and take in cost and such.   The UNI-T 181A is a bothersome case.   It has some decent components and it certainly seems the intent was to have a very electrically robust design.  The odd thing it that it appears to have all fallen apart in the final stages of the design.  Maybe they can't test the layout before it goes into production.  I would have thought a senior EE could have spent an hour reviewing it and may have improved it before boards were ordered.  Who knows. 

It would be interesting to talk with UNI-T and get their insiders scoop.  Not the marketing / sales BS and not the engineering managers view but the actual designers.

The 121GW is also odd as in that case is we have Dave, the expert in DMMs and super critical of all poorly designed products approving it.  By approving, I mean allowing them use of his brand and also directly selling the product.  I wouldn't necessary have thought the meter would be robust but I would have expected it to be fairly solid from all other aspects.   
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline totalnoob

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Re: Finally received my Uni-T UT17B Pro, I'm pleasantly surprised
« Reply #36 on: August 12, 2020, 06:39:15 pm »

Still to this date, I couldn't tell you if the spirit of the standards is that the meters must survive or not.  I have presented sections from the standards that I would tend to interpret that the must survive.  Obviously a lot of meters would not, at least the way I test them.  Some have UL approval.  So yeah, hard to say.  Again talking directly with Fluke, I was told they design them to survive these test.   I spoke with another large company who were on the opposite end of the spectrum. 


Joe,

I don't have the expertise that you do, on this subject, as  a matter of fact, I am way out of my league.  I do not disagree that manufacturers cannot design and build resilient meters capable to surviving the conditions of the safety standards and keep on being used.  However, one thought that I have that manufacturers have a legitimate reason for having their meters NOT survive the conditions of the standard, but provide protection to the user.  That reason is that they likely cannot guarantee that the meter will survive multiple exposures to the standard.  To have a meter survive and remain in service (let's face it, an electrician is NOT going to replace a meter if it's not broken) after being exposed to the highest level of exposure of the standard is asking for a lawsuit should the meter not survive a subsequent exposure.  To give an analogous example, when I was involved in a car accident on my way home from work, I had a child seat in the back seat, but my child was not with me.  (Edit to add:  All the damage was to the front end, no damage to the back passenger area and there was nothing in the child safety seat. End Edit) Despite that, and because of the severity of the accident (the car was totaled) my insurance company said that I had to replace the car seat because they would not pay for medical costs to my child should I decide to re-use the car seat in my next car and if that car was involved in an accident while my child was in the child seat.  True story.  We did not hesitate to replace the car seat.  I can see meter manufacturers doing a similar calculation as my insurance company and deciding to make a meter that will protect the user for a one-time exposure, but after that exposure, the meter will not be usable.

Of course this does not absolve the manufacturers of meters who can't make a meter that at least protects the user from conditions in the standard or that lie about being tested to the standard. 

This is just another POV.  I'm not saying I'm right, just saying that there is likely more to the calculation than I have seen put forward until now. 
« Last Edit: August 12, 2020, 06:42:00 pm by totalnoob »
 

Offline CDaniel

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Re: Finally received my Uni-T UT17B Pro, I'm pleasantly surprised
« Reply #37 on: August 12, 2020, 08:59:09 pm »
Unfortunatly with some exceptions meters are seen just as consumer products ... so durability is not truly wanted .  Like the bilions of crappy staff  on the market . The owners of this companies who take decisions are by chance producing this , they could have been in business with pots or toilet paper , just the same  ;D
 

Online joeqsmith

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Re: Finally received my Uni-T UT17B Pro, I'm pleasantly surprised
« Reply #38 on: August 13, 2020, 12:20:28 pm »

Still to this date, I couldn't tell you if the spirit of the standards is that the meters must survive or not.  I have presented sections from the standards that I would tend to interpret that the must survive.  Obviously a lot of meters would not, at least the way I test them.  Some have UL approval.  So yeah, hard to say.  Again talking directly with Fluke, I was told they design them to survive these test.   I spoke with another large company who were on the opposite end of the spectrum. 


Joe,

I don't have the expertise that you do, on this subject, as  a matter of fact, I am way out of my league.  I do not disagree that manufacturers cannot design and build resilient meters capable to surviving the conditions of the safety standards and keep on being used.  However, one thought that I have that manufacturers have a legitimate reason for having their meters NOT survive the conditions of the standard, but provide protection to the user.  That reason is that they likely cannot guarantee that the meter will survive multiple exposures to the standard.  To have a meter survive and remain in service (let's face it, an electrician is NOT going to replace a meter if it's not broken) after being exposed to the highest level of exposure of the standard is asking for a lawsuit should the meter not survive a subsequent exposure.  To give an analogous example, when I was involved in a car accident on my way home from work, I had a child seat in the back seat, but my child was not with me.  (Edit to add:  All the damage was to the front end, no damage to the back passenger area and there was nothing in the child safety seat. End Edit) Despite that, and because of the severity of the accident (the car was totaled) my insurance company said that I had to replace the car seat because they would not pay for medical costs to my child should I decide to re-use the car seat in my next car and if that car was involved in an accident while my child was in the child seat.  True story.  We did not hesitate to replace the car seat.  I can see meter manufacturers doing a similar calculation as my insurance company and deciding to make a meter that will protect the user for a one-time exposure, but after that exposure, the meter will not be usable.

Of course this does not absolve the manufacturers of meters who can't make a meter that at least protects the user from conditions in the standard or that lie about being tested to the standard. 

This is just another POV.  I'm not saying I'm right, just saying that there is likely more to the calculation than I have seen put forward until now. 

I'm not sure how to respond other than I have seen others post similar comments and I am always having to pick my jaw up off the floor.   

I ride bikes and wear a helmet.  The helmets are certified for a limited number of years.  If you race, this is one of the things they will inspect.   If the helmet is exposed to any shock, say you drop it on the concrete, you should replace it.  They are designed for a single impact.   They cost a fair amount so it's best to take good care of them.   I personally trust Snell and have included a link for some basic background.   

https://smf.org/about

What's all this have to do with DMMs?  Nothing!  It's common for people to equate everything to automotive for some reason or another.  My guess is it stems from their lack of understanding of the subject. 

From my FAQ:
 
Quote
Q) These test are irrelevant over what is rated, is like you smash a car at 2 mach and say "ehh car not good, unsafe, bla bla" whats the point of using a meter over the rated point???

A)  Cars are subjected to some pretty harsh testing as well to insure the safety of the passengers.  Most of us don't drive our cars head on into concrete like the test dummies.  Maybe read the IEC standards or just do some simple Google searches on surge testing and what you are going to find out is the tests I show are a joke.  Not that they are as harsh as you make them out to be, but rather that they no where near as harsh as the real tests are.  And again, if I were interested in considering how safe a meter was, I would be testing differently but I'm only concerned with the robustness of the meter's front end.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline rsjsouza

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Re: Finally received my Uni-T UT17B Pro, I'm pleasantly surprised
« Reply #39 on: August 13, 2020, 01:51:29 pm »
Still to this date, I couldn't tell you if the spirit of the standards is that the meters must survive or not.  I have presented sections from the standards that I would tend to interpret that the must survive.  Obviously a lot of meters would not, at least the way I test them.  Some have UL approval.  So yeah, hard to say.  Again talking directly with Fluke, I was told they design them to survive these test.   I spoke with another large company who were on the opposite end of the spectrum.
I agree with you; the pieces of the standard are not terribly clear on this regard. It could be the case highlighted by totalnoob above (liability after an event) or perhaps one of the troubles of "industry standards" committees: it is an amalgam of various philosophies and interests that comprise the final text. Or, it could be something completely different.

"...but it is impossible to have a 1:1 correlation between your tests and whatever the cert agencies put out." 
It's good to finally see comments like this echoed.
Just for the record, I always said that.

No doubt there can be many causes for damage.  Countless.  If the design goals are clear, I have no doubt that a team of  competent designers could achieve it assuming there is some give and take in cost and such.
Unfortunately we may never know exactly what happened in this scenario. In my experience, a clear design specification is something achieved with a lot of experience, tenacity and a great number of iterations and feedback between field, design and test teams. This does not happen from day one.

The 121GW is also odd as in that case is we have Dave, the expert in DMMs and super critical of all poorly designed products approving it.  By approving, I mean allowing them use of his brand and also directly selling the product.  I wouldn't necessary have thought the meter would be robust but I would have expected it to be fairly solid from all other aspects.
During the release process of the 121GW I was also working on a product release for work, and I ended up identifying myself with several mishaps during the wildly public product release, initial feedback and even the stock/HW version issues even you had gone through. It would be idiotic of me to say that I would never fall into the same traps that Dave did, so my stance is that it takes a lot of courage of him to take the design so openly from its early stances (with even a major design change such as the core processor) and, as I said before and you reiterated, take the harsh feedback from his crowd that were so reliant that something coming from him would be anything less than "a meter to rule them all". 😁

Vbe - vídeo blog eletrônico http://videos.vbeletronico.com

Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 

Offline CDaniel

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Re: Finally received my Uni-T UT17B Pro, I'm pleasantly surprised
« Reply #40 on: August 13, 2020, 02:33:02 pm »
If we deviate to David's meter , let's admit that he did't had time himself , then he should have done initial beta testing , simply borrowing some meters to serious hobbyists ( not fanboys to tell how good it is  ;D ) ... then all the issues should have been discovered and corrected  before releasing .
 

Offline rsjsouza

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Re: Finally received my Uni-T UT17B Pro, I'm pleasantly surprised
« Reply #41 on: August 13, 2020, 10:06:46 pm »
If we deviate to David's meter , let's admit that he did't had time himself , then he should have done initial beta testing , simply borrowing some meters to serious hobbyists ( not fanboys to tell how good it is  ;D ) ... then all the issues should have been discovered and corrected  before releasing .
If I understood correctly what you are saying, you mean that Dave should have kept a close circle of testers before spreading the word out, right? Well, that may well have been a much better alternative, but it was a rare time (outside of a crowd source project) that a DMM was so openly designed, tweaked, etc. Thus, my comment is that his attitude to be the guinea pig deserves at least some acknowledgment. Also, by sending one of the prototypes to Joe, it seems he was looking past the "yes men" you aluded  :-DD - the meter failed miserably in several fronts.

I am pretty sure that is the reason his new $150 meter is being kept under wraps this time.

At any rate, I suspect I am helping drift the discussion away from the main topic. Sorry, OP.
Vbe - vídeo blog eletrônico http://videos.vbeletronico.com

Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 

Online joeqsmith

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Re: Finally received my Uni-T UT17B Pro, I'm pleasantly surprised
« Reply #42 on: August 14, 2020, 01:54:25 am »
...
Also, by sending one of the prototypes to Joe, it seems he was looking past the "yes men" you aluded  :-DD - the meter failed miserably in several fronts.
...

I honestly don't think he knew or understood that I was benchmarking them while also dissecting them under the microscope.  Maybe people were filling his head with stories of meter exploding drama.   I know he was really just looking for me to blow the thing up and I was looking to what we could learn from it.   In the end, I think he felt it was a mistake and I can't say I disagree.   

I've said UNI-T had reached out to me at one point about looking at I think this meter.  I assume they were looking for some sort of unboxing, five star review where I talk about all the MOVs it has while pointing at the PTCs.   After explaining I would run it to failure, rank it against every other meter I had looked at and make it all public, that ended the conversation.   There's no free rides in my reviews.  You want a high rank, you earn it.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline rsjsouza

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Re: Finally received my Uni-T UT17B Pro, I'm pleasantly surprised
« Reply #43 on: August 14, 2020, 09:33:54 am »
...
Also, by sending one of the prototypes to Joe, it seems he was looking past the "yes men" you aluded  :-DD - the meter failed miserably in several fronts.
...

I honestly don't think he knew or understood that I was benchmarking them while also dissecting them under the microscope.  Maybe people were filling his head with stories of meter exploding drama.   I know he was really just looking for me to blow the thing up and I was looking to what we could learn from it.   In the end, I think he felt it was a mistake and I can't say I disagree. 
Interesting; I had some impression he was not entirely pleased after the fact, but I suspected he at least followed some of your videos to know what you usually do. Well, tough luck. In the end, we (consumers) are all much better for your efforts.

I would be very impressed if he, despite all this, would offer one of the new $150 meters for you to test it.
Vbe - vídeo blog eletrônico http://videos.vbeletronico.com

Oh, the "whys" of the datasheets... The information is there not to be an axiomatic truth, but instead each speck of data must be slowly inhaled while carefully performing a deep search inside oneself to find the true metaphysical sense...
 


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