Author Topic: EEVBlog 121GW Discussion thread  (Read 331213 times)

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Re: EEVBlog 121GW Discussion thread
« Reply #1725 on: January 25, 2020, 12:20:30 am »
A basic robustness test I’ve seen Dave use a couple of times is to put mains 240VAC into whatever mode the mode switch can be placed in, perhaps for a couple of seconds or so. I do my damndest trying to avoid doing a “mistake” like that. But still not an unreasonable test to do and see if the meter survives. So in this scenario the meters clamps, PTC’s and other input series resistors have to cope with the stress resulting from about 340V peak to peak, there can of course be some nasty overlayed transients on top of that but unless you’re monitoring the VAC with a scope you have no clue if this is the case.
Anyway, I can’t really remember if Dave also did this test on the 121gw, but I think so, in its original configuration anyway with the 4007‘s. But has he also done it with the new clamp configuration i.e. to show that it’s just as robust as it was before. If it isn't perhaps mentioning this in the next user manual revision is a good idea.

Yes, done that (245VAC) countless times on every design variant.
I also do +/-1100V DC and 1100V AC as well, but both of my high voltage supplies will go into current limit mode when the meter is on the ohms range.
Survives all this just fine.
 

Offline dcac

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Re: EEVBlog 121GW Discussion thread
« Reply #1726 on: January 25, 2020, 03:59:22 pm »
A basic robustness test I’ve seen Dave use a couple of times is to put mains 240VAC into whatever mode the mode switch can be placed in, perhaps for a couple of seconds or so. I do my damndest trying to avoid doing a “mistake” like that. But still not an unreasonable test to do and see if the meter survives. So in this scenario the meters clamps, PTC’s and other input series resistors have to cope with the stress resulting from about 340V peak to peak, there can of course be some nasty overlayed transients on top of that but unless you’re monitoring the VAC with a scope you have no clue if this is the case.
Anyway, I can’t really remember if Dave also did this test on the 121gw, but I think so, in its original configuration anyway with the 4007‘s. But has he also done it with the new clamp configuration i.e. to show that it’s just as robust as it was before. If it isn't perhaps mentioning this in the next user manual revision is a good idea.

Yes, done that (245VAC) countless times on every design variant.
I also do +/-1100V DC and 1100V AC as well, but both of my high voltage supplies will go into current limit mode when the meter is on the ohms range.
Survives all this just fine.



There are many manufactures of the 4053 type mux, all with slightly different spec. but they all seem to quote this +/- 10mA as absolute maximum input current.

As I understand it, in the original 121gw with 4007's diode clamps, this would have limited the current to just around those 10mA as you'd have about 1V over the diodes and then R82 100 ohms resistor in series with the mux input.

But with the transistor type clamps that i.e. Joe’s production 1-2 had, the current into the mux can be as much as 250mA, so way over the suggested limit by the manufactures.

So it seems even if the mux ‘survives’ an over current event, you have no idea if it will do so the next time or if it perhaps has degraded its performance in other aspects.

I my experience integrated type diode clamps, like the ones in the 4053 mux are very rarely precisely specified as to what current they really can withstand or for how long. I think you’re actually not even to regard them as 'clamping’ diodes.

 

Offline joeqsmith

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Re: EEVBlog 121GW Discussion thread
« Reply #1727 on: January 25, 2020, 05:37:01 pm »
Someone's digging in...

Something to keep this in mind is there are other difference between what Dave sold me and the last schematics besides removing the two diodes and changing to the transistor clamp.   Off the top of my head, I know the 10ohm was removed.    I was hoping they would supply an up to date schematic.   

Because they have even newer hardware, there really wasn't much point in reversing what I purchased as the new may have other changes beyond the clamp. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline dcac

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Re: EEVBlog 121GW Discussion thread
« Reply #1728 on: January 25, 2020, 07:37:31 pm »
No not really...

I’m just perplexed, like I think many 121gw owners are. Mostly perhaps as you mentioned by the lack of information.

And just to be clear I’m not trying to put any blame on Dave, I’ve no idea what deal he has with UEi, but I got a feeling he’s not really in a position to put any pressure on them or is free to release information as he pleases. And this seems to leave quite a gap between 121gw users and the manufacture.

But I am interested in what clamping solution can be used instead of the leaky 4007's. Perhaps specially selected TVS diodes could be an option after all.
 

Offline joeqsmith

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Re: EEVBlog 121GW Discussion thread
« Reply #1729 on: January 25, 2020, 08:05:03 pm »
For the prototype,  I clamped it on the other side of R82.    The resistor limits the current to the mux.  I did have a TVS across the mux's supply but again, my goal wasn't to achieve anything outside of seeing what the next failure point would be.  In other words, protect that mux at all cost.   

Again, that prototype has some different circuits.   U9 used to be supplied for VDD through D9, or through R81 when U10 was active.   I noticed R81 was missing and assumed they power it another way.  I would see if you can get your hands on the version they are now selling and reverse engineer the design.  Then you could take look at how to protect  it based on your personal goals. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline e0ne199

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Re: EEVBlog 121GW Discussion thread
« Reply #1730 on: January 26, 2020, 12:11:33 am »
No not really...

I’m just perplexed, like I think many 121gw owners are. Mostly perhaps as you mentioned by the lack of information.

And just to be clear I’m not trying to put any blame on Dave, I’ve no idea what deal he has with UEi, but I got a feeling he’s not really in a position to put any pressure on them or is free to release information as he pleases. And this seems to leave quite a gap between 121gw users and the manufacture.

But I am interested in what clamping solution can be used instead of the leaky 4007's. Perhaps specially selected TVS diodes could be an option after all.

probably dave cannot control that meter development at all and after all it is just a UEi meter with EEVBLOG logo sticking on it to make people belive that it is dave who designed it.. cmiiw
 

Offline jancumps

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Re: EEVBlog 121GW Discussion thread
« Reply #1731 on: January 26, 2020, 12:19:48 am »
There are several videos discussing design decision between UEi and Dave.
 

Offline dcac

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Re: EEVBlog 121GW Discussion thread
« Reply #1732 on: January 26, 2020, 01:32:54 am »
No not really...

I’m just perplexed, like I think many 121gw owners are. Mostly perhaps as you mentioned by the lack of information.

And just to be clear I’m not trying to put any blame on Dave, I’ve no idea what deal he has with UEi, but I got a feeling he’s not really in a position to put any pressure on them or is free to release information as he pleases. And this seems to leave quite a gap between 121gw users and the manufacture.

But I am interested in what clamping solution can be used instead of the leaky 4007's. Perhaps specially selected TVS diodes could be an option after all.

probably dave cannot control that meter development at all and after all it is just a UEi meter with EEVBLOG logo sticking on it to make people belive that it is dave who designed it.. cmiiw

I know you're joking, but.

Just to be even clearer, I don't think Dave is in a position to put pressure on UEi to fix things, that is i.e. to make them fix problems with the meter's basic functionality. Like this logging issues people are having, or the worrisome high voltage ranging and warning issue. Just to name a couple (lol).

 

Offline joeqsmith

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Re: EEVBlog 121GW Discussion thread
« Reply #1733 on: January 26, 2020, 02:01:42 am »
I had looked up the Intertek cert.  Looks like more than UEi are involved. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

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Re: EEVBlog 121GW Discussion thread
« Reply #1734 on: January 26, 2020, 08:25:52 am »
I had looked up the Intertek cert.  Looks like more than UEi are involved.

Kane own UEi and Finest.
The meter was designed and is manufactured by Finest in South Korea. UEi is basically the US brand they bought in 1992, and Finest is the Asian brand they recently acquired.
 

Offline joeqsmith

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Re: EEVBlog 121GW Discussion thread
« Reply #1735 on: January 26, 2020, 04:13:37 pm »
I tried to look up the IN address.    Maybe a rented office of sorts.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Re: EEVBlog 121GW Discussion thread
« Reply #1736 on: January 26, 2020, 04:24:17 pm »
UEi also appears to have a brand in IN.  It's at a different address than what was listed.  Maybe a warehouse?   

Dave had mentioned about working with someone in the USA to design it.  Maybe the design house is in Portland.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Re: EEVBlog 121GW Discussion thread
« Reply #1737 on: January 26, 2020, 04:31:13 pm »
Looking at the address Dave provided,  maybe the shipping and receiving warehouses.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline joeqsmith

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Re: EEVBlog 121GW Discussion thread
« Reply #1738 on: January 26, 2020, 04:37:38 pm »
Maybe Fine Instruments Corp is not the same as Finest.   Looks like an apartment building rather than a manufacturing house. 

Makes me wonder where the meters were produced.  Judging by some of the soldering, maybe they were made in an apartment. 
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

Offline dcac

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Re: EEVBlog 121GW Discussion thread
« Reply #1739 on: January 26, 2020, 07:37:23 pm »
My KS #924 121gw meter is reasonable well built, just had to clean up some flux residues. So perhaps it was manufactured before they moved to the apartment.

I’ve also removed the pre-installed shim as Joe’s videos seemed to show this actually could cause more problems than it solved. When I removed it I also wanted to clean the PCB switch area as I noticed how incredible tight the switch holder hub was rotating in the PCB hole. it had even started to grind of some fiberglass dust that had contaminated the switch area. And my meter has not been used much at all, in fact mostly used for testing and hacking the FW as I feel the problems with this is simply making the meter too unreliable. But anyway, the switch was easy enough to clean up and I also gave the PCB hole a slight polish with a fine sandpaper to make it rotate more freely.

The switch now feels and sounds much better than before. And as long as it doesn’t get contaminated by more of this dust I think the contact pressure will be just fine.
 

Offline dcac

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Re: EEVBlog 121GW Discussion thread
« Reply #1740 on: January 26, 2020, 11:36:23 pm »
I had looked up the Intertek cert.  Looks like more than UEi are involved.

Kane own UEi and Finest.
The meter was designed and is manufactured by Finest in South Korea. UEi is basically the US brand they bought in 1992, and Finest is the Asian brand they recently acquired.

I’ve seen a few Finest and UEi branded multimeters and noticed the resemblance.





But with the 121gw and how it was presented I always got the impression UEi was the actual manufacture and responsible for the FW updates. But of course doesn’t really matter. But it would be interesting to know if the KS meters and the 121gw that's being sold now were manufactured in the same factories.

« Last Edit: January 26, 2020, 11:42:09 pm by dcac »
 

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Re: EEVBlog 121GW Discussion thread
« Reply #1741 on: January 27, 2020, 07:15:00 am »
But with the 121gw and how it was presented I always got the impression UEi was the actual manufacture and responsible for the FW updates. But of course doesn’t really matter. But it would be interesting to know if the KS meters and the 121gw that's being sold now were manufactured in the same factories.

Yes, same factory.
I'm not sure why the fuss over this. Companies in this sort of industry often have lots of complex relationships with part ownerships and branding etc.
I can assure you that the design and manufacturing has always been and is still done in South Korea by (formally) Finest (Fine Instrument Co) who is now wholly owned by Kane Test. They don't really use the finest brand any more that I am aware of, legally it's "Kane Asia" and that's who my purchase orders go to.
http://kanetest.co.kr/contact/
My point of contact for the design is the former CEO of Finest Instruments who now works for Kane Asia.
UEi are also another brand of Kane Test, and that is the brand they wanted associated with publicly for the project from day one, but that's the extent of "UEi" involvement with this project.
A lot of UEi stuff used Finest as the OEM, while other UEi stuff is designed and made in the USA.
If you want to go deeper down the rabbit whole, Klein Tools owned (or did own?) 50% of UEi, and that's actually how this whole thing started, I was talking to the head designer at Klein tools and down the rabbit whole it went to eventually Finest. They are all intertwined.
« Last Edit: January 27, 2020, 07:19:43 am by EEVblog »
 
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Offline dcac

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Re: EEVBlog 121GW Discussion thread
« Reply #1742 on: January 27, 2020, 04:13:33 pm »
But with the 121gw and how it was presented I always got the impression UEi was the actual manufacture and responsible for the FW updates. But of course doesn’t really matter. But it would be interesting to know if the KS meters and the 121gw that's being sold now were manufactured in the same factories.

Yes, same factory.
I'm not sure why the fuss over this. Companies in this sort of industry often have lots of complex relationships with part ownerships and branding etc.
I can assure you that the design and manufacturing has always been and is still done in South Korea by (formally) Finest (Fine Instrument Co) who is now wholly owned by Kane Test. They don't really use the finest brand any more that I am aware of, legally it's "Kane Asia" and that's who my purchase orders go to.
http://kanetest.co.kr/contact/
My point of contact for the design is the former CEO of Finest Instruments who now works for Kane Asia.
UEi are also another brand of Kane Test, and that is the brand they wanted associated with publicly for the project from day one, but that's the extent of "UEi" involvement with this project.
A lot of UEi stuff used Finest as the OEM, while other UEi stuff is designed and made in the USA.
If you want to go deeper down the rabbit whole, Klein Tools owned (or did own?) 50% of UEi, and that's actually how this whole thing started, I was talking to the head designer at Klein tools and down the rabbit whole it went to eventually Finest. They are all intertwined.

Thanks for the information Dave. it was just there’s been all this talk of UEi and now this Finest name suddenly was mentioned. So again thanks for clearing that up, how that name relates to the 121gw. And that the factory who’s actually making the 121gw is still the same.
 
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Offline joeqsmith

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Re: EEVBlog 121GW Discussion thread
« Reply #1743 on: January 28, 2020, 01:11:47 pm »
No fuss.  Just curious what their factory looked like to see what sort of capabilities they have.
How electrically robust is your meter?? https://www.youtube.com/channel/UCsK99WXk9VhcghnAauTBsbg
 

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Re: EEVBlog 121GW Discussion thread
« Reply #1744 on: January 28, 2020, 09:59:24 pm »
No fuss.  Just curious what their factory looked like to see what sort of capabilities they have.

I don't think I have any photos inside.
Kane Asia is somewhere in here:
 
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Offline DavidWC

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Re: EEVBlog 121GW Discussion thread
« Reply #1745 on: March 07, 2020, 10:33:10 am »
To anyone interested:

I've written an independent, third-party Android app for the 121GW called "Meteor".  It is a free app and you can get it from the Google Play Store:

https://play.google.com/store/apps/details?id=com.westerncomputational.meteor

It was designed to look and function much like the official EEVBlog app, with a few additions:

* Control buttons in landscape mode
* Long-press on control buttons to get alternate functions
* Option for spoken measurements (using Android voice synthesizer)
* Option for continuity tone and/or vibration
* Dark mode option
* Connect/disconnect button and connection-status label

There are a couple of features that the EEVBlog app has that Meteor doesn't (yet):

- Does not support two connected meters or math mode
- Does not capture or log measurements

As with all Android BLE apps, there is no guarantee that Meteor will work with your particular phone.  Try it out and see, especially if you've had trouble connecting with the EEVBlog app.  If you don't see your meter in the scan list, make sure it's not already connected to another phone or computer.   Turning the meter's BLE off and back on (with the 1ms button) can help, as can turning your phone's BLE off and back on again (in the Android Settings app).  Note that you will also have to grant Meteor location permissions on your phone, since Android requires this to scan for nearby BLE devices.

I've also written and released an iOS version, which I recently updated to v0.2:

https://apps.apple.com/us/app/meteor-for-121gw/id1452124710

This version adds automatic, continuous datalogging, so now any measurement you receive while connected with the app is automatically recorded for later export.  You can limit the number of samples recorded, or turn off logging, using the Settings page.  This version also adds some display options and fixes some bugs in some of the VA meter modes.

Both of these apps are still under development and should be considered beta quality.  Meteor is something of a testbed for my development on other BLE projects, so bug reports and feature suggestions are always welcome: support@westerncomputational.com.

Regards,
David Lavo
david@westerncomputational.com
 
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Offline pppopol

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Re: EEVBlog 121GW Discussion thread
« Reply #1746 on: March 07, 2020, 04:50:06 pm »
Hi DavidWC,

Thank you for this development of APPS which seems interesting.
But I have a problem.
The APP works 1/2 second, and closes immediately?
My Bluethoot is activated, as is my location.
I have firmware V2.02 on my 121GW.
Do you have any idea how to fix this problem?

Regards
 

Offline bateau020

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Re: EEVBlog 121GW Discussion thread
« Reply #1747 on: March 07, 2020, 07:48:01 pm »
@DavidWC also any chance you'd be able to create a MacOS app for logging?
Or anyone else, does that kind of app exist?

My reasons:

I would like to have logging to a desktop device. Don't need anything else like interaction with the meter or graphical stuff. Command line suffices, as long as it writes in a structured format.
  • Using the SD card is a mess since I have to open up the case for that.
  • Going via mobile apps is not great (the iOS app does some, but it is not easy to let it run for a long time, and the format is not really great.) 
  • And VMWare Fusion doesn't play well with BLE.
So in all, I now have to dig up a "real" windows machine to get the logging to a desktop device.

Not ideal.
 

Offline DavidWC

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Re: EEVBlog 121GW Discussion thread
« Reply #1748 on: March 07, 2020, 11:21:48 pm »
The APP works 1/2 second, and closes immediately?
This sounds like a crash, and definitely should not happen.  Which version is this - the iOS or the Android version?
 

Offline beanflying

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Re: EEVBlog 121GW Discussion thread
« Reply #1749 on: March 07, 2020, 11:25:12 pm »
Downloaded to my S7 from the store. Turned on the 121GW enabled BT, started the software and it happily found hooked up and ran  :-+

The ability to capture Logs is a must in your no doubt vast quantities of 'spare time'  ;)

Also important will be the ability to clear the data from the log or trigger a start of logging. Not sure what is possible but maybe even optional logging against the devices clock instead of the meters?

The pinch zoom vertically works fairly well but having the option or being able to show from the start of logging stay on screen would be great too rather than continual scrolling. That is assuming I didn't find a pinch zoom for that option that already exists?

 :-+ :-+ from me so far
Coffee, Food, R/C and electronics nerd in no particular order :)
 
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