Author Topic: EEVblog 121GW Multimeter Issues  (Read 83289 times)

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Offline joeqsmith

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Re: EEVblog 121GW Multimeter Issues
« Reply #75 on: January 13, 2018, 12:02:58 am »
I did run VA logging for about 9h over night.
It produced a logfile with  130662 entries, which is about 4 lines per second.
So this seems fine.

Should I try something else?


Thanks for running these longer tests!  I know a bit of a pain.   Glad to hear they have it working.   It's been some time since I did anything with the prototype and I can't remember any other real major functional problems with it.  I remember most were simple problems.   If you check my main thread where I post my results, some of the problems were discussed there but my guess is they have been corrected.   

What's the open circuit HV diode test putting out now? 
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Offline Iagash

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Re: EEVblog 121GW Multimeter Issues
« Reply #76 on: January 13, 2018, 12:16:04 am »
What's the open circuit HV diode test putting out now?

17.332V
 

Offline joeqsmith

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Re: EEVblog 121GW Multimeter Issues
« Reply #77 on: January 13, 2018, 01:43:50 am »
What's the open circuit HV diode test putting out now?
17.332V
That's interesting.  I think the prototype was under 17.   I was a bit concerned with the mux they were using had an absolute max rating.  It looked like they stayed with the same part in Dave's close up video showing the board.   Maybe they came up with a better way to protect it.   From what I saw, the mux was the weak point as far as the transient tests I run.    That mux is an HEFxxxx  located near the edge of the PCB if you wanted to pull the datasheets to have a look.   I think its an absolute max of 18 on that one.  You can drive it a little above the rail.   Easy enough to trace the path to the input pin to see how it is being protected.   Again, hard to say if you would call it a bug or issue anyway.  Maybe just something to be aware of.   
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Offline Scottjd

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Re: EEVblog 121GW Multimeter Issues
« Reply #78 on: January 13, 2018, 01:59:55 am »
What's the open circuit HV diode test putting out now?
17.332V
That's interesting.  I think the prototype was under 17.   I was a bit concerned with the mux they were using had an absolute max rating.  It looked like they stayed with the same part in Dave's close up video showing the board.   Maybe they came up with a better way to protect it.   From what I saw, the mux was the weak point as far as the transient tests I run.    That mux is an HEFxxxx  located near the edge of the PCB if you wanted to pull the datasheets to have a look.   I think its an absolute max of 18 on that one.  You can drive it a little above the rail.   Easy enough to trace the path to the input pin to see how it is being protected.   Again, hard to say if you would call it a bug or issue anyway.  Maybe just something to be aware of.   
Good question, it was claimed to be 15V, so if it has the room maybe a good TVS diode could go in and even with the voltage drop it would still be above 15V. But I don’t know if a TVS diode would even stop your transients Joe. But it would be better then nothing.
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Online dr.diesel

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Re: EEVblog 121GW Multimeter Issues
« Reply #79 on: January 13, 2018, 02:02:20 am »
What's the open circuit HV diode test putting out now?

17.332V

000063 = 16.3V
000061 = 17.8V

Offline mikeselectricstuff

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Re: EEVblog 121GW Multimeter Issues
« Reply #80 on: January 13, 2018, 02:04:49 am »
What's the open circuit HV diode test putting out now?

17.332V

000063 = 16.3V
000061 = 17.8V
Is it significantly dependent on battery voltage ?
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Online dr.diesel

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Re: EEVblog 121GW Multimeter Issues
« Reply #81 on: January 13, 2018, 02:09:57 am »
Bug, FW 1.01.

Switching to diode test mode, the secondary display continues to show temp, not 3/15v like it should, until the Range button is cycled.

Online dr.diesel

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Re: EEVblog 121GW Multimeter Issues
« Reply #82 on: January 13, 2018, 02:17:50 am »
What's the open circuit HV diode test putting out now?

17.332V

000063 = 16.3V
000061 = 17.8V
Is it significantly dependent on battery voltage ?

From 5-6.5V battery voltage has no impact.

Offline hwti

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Re: EEVblog 121GW Multimeter Issues
« Reply #83 on: January 13, 2018, 02:30:27 am »
What's the open circuit HV diode test putting out now?

17.332V
Here 15.45V (and 3.23V for the 3V mode), FW 1.02
 

Offline hwti

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Re: EEVblog 121GW Multimeter Issues
« Reply #84 on: January 13, 2018, 02:44:49 am »
  • The range switch is unreliable, you sometimes need to poke it a bit until the meter behaves properly.
  • The inability to disable the excessive beeping or at least lowering the volume get's annoying fast.
  • Autoranging speed in Ohms is way too slow.

I just had the range switch issue : after switching from V to Low-Z, it stayed in volts mode, I had to move the switch a little bit.

+1 for the annoying beeps and slow autoranging
 

Offline lewis

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Re: EEVblog 121GW Multimeter Issues
« Reply #85 on: January 13, 2018, 04:08:02 am »
Beep beep. Beep. Beep. Beep. Beep!

FOR THE LOVE OF GOD....

Skip to 6min 32sec


« Last Edit: January 13, 2018, 04:11:30 am by lewis »
I will not be pushed, filed, stamped, indexed, briefed, debriefed or numbered.
 
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Offline joeqsmith

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Re: EEVblog 121GW Multimeter Issues
« Reply #86 on: January 13, 2018, 11:38:51 am »
What's the open circuit HV diode test putting out now?
17.332V
That's interesting.  I think the prototype was under 17.   I was a bit concerned with the mux they were using had an absolute max rating.  It looked like they stayed with the same part in Dave's close up video showing the board.   Maybe they came up with a better way to protect it.   From what I saw, the mux was the weak point as far as the transient tests I run.    That mux is an HEFxxxx  located near the edge of the PCB if you wanted to pull the datasheets to have a look.   I think its an absolute max of 18 on that one.  You can drive it a little above the rail.   Easy enough to trace the path to the input pin to see how it is being protected.   Again, hard to say if you would call it a bug or issue anyway.  Maybe just something to be aware of.   
Good question, it was claimed to be 15V, so if it has the room maybe a good TVS diode could go in and even with the voltage drop it would still be above 15V. But I don’t know if a TVS diode would even stop your transients Joe. But it would be better then nothing.

I assume 15 would be the minimum.  It really would not matter to me anyway, if it ran a little hot (higher).  Actually, I would prefer it.   It the part has an absolute max of 18 and they are running it a bit over 17, there is not a lot of wiggle room.  You don't want it to leak and you don't ever want to exceed that absolute value.   I don't know if they made improvements to the released meter or not and am only assuming it's the same based on the comments.   They may have found a better way to protect it.   

There was a third video of my final mods as well. I damaged that prototype a few times before settling in on part selection.  I don't remember how high I went up to with it before calling it good enough.  I can tell you I never put the grim reaper on it with 14KV or bust.   :-DD       
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Offline ChrisG

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Re: EEVblog 121GW Multimeter Issues
« Reply #87 on: January 13, 2018, 10:58:53 pm »
Received mine on 12th Jan in Netherlands. Auto ranging is ridicuously slow. None of my other DMM’s 869, 235 and an old Metrixc 53c are so slow. Is this an issue or by design?

Apologies.  Just noticed it has been mentioned already many times. V 1.02 is my firmware. Will do more tests later.
« Last Edit: January 13, 2018, 11:16:31 pm by ChrisG »
 

Offline joeqsmith

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Re: EEVblog 121GW Multimeter Issues
« Reply #88 on: January 14, 2018, 04:35:22 am »
When I first released that video where I had repaired the prototype meter the first time, someone had commented how the period calculation was not correct and I explained how I look for a deviation in how the meter behaves and with it being a prototype, I was expecting some problems.  I assume people have checked the basic functions like this to make sure they now work.   

Has anyone checked to see if they still limit the frequency counter to 1MHz?   Again, not really a bug perhaps but more a slight oversight.   
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Offline mikeselectricstuff

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Re: EEVblog 121GW Multimeter Issues
« Reply #89 on: January 14, 2018, 07:03:35 am »
Has anyone checked to see if they still limit the frequency counter to 1MHz?   Again, not really a bug perhaps but more a slight oversight.
Or maybe there are issues like jitter or miscounts that make higher frequencies subject to errors?
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Offline joeqsmith

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Re: EEVblog 121GW Multimeter Issues
« Reply #90 on: January 14, 2018, 07:07:00 am »
Has anyone checked to see if they still limit the frequency counter to 1MHz?   Again, not really a bug perhaps but more a slight oversight.
Or maybe there are issues like jitter or miscounts that make higher frequencies subject to errors?

If you watch the video, it just over ranges.  They cap it for some reason. 
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Offline hwti

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Re: EEVblog 121GW Multimeter Issues
« Reply #91 on: January 14, 2018, 07:47:21 am »
Has anyone checked to see if they still limit the frequency counter to 1MHz?   Again, not really a bug perhaps but more a slight oversight.
It's still limited.
It's in the manual : "99.999 Hz to 999.99 kHz" ranges.
 

Offline The Soulman

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Re: EEVblog 121GW Multimeter Issues
« Reply #92 on: January 14, 2018, 08:29:59 am »
NOTE: Can we please limit this thread to reporting and confirmation of bugs and issues, any discussions should be on the discussion thread.
Thanks.
 

Offline Scottjd

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Re: EEVblog 121GW Multimeter Issues
« Reply #93 on: January 14, 2018, 11:21:52 am »
NOTE: Can we please limit this thread to reporting and confirmation of bugs and issues, any discussions should be on the discussion thread.
Thanks.
I didn’t know we were keeping score.
One point to you!
Who is winning?

Wait, that’s your signature, not your post. That doesn’t count then.
So if this is the bugs only (some know about before the release and never fixed?) the What thread is the shipping only? Does anyone know, I tried searching but their is so many threaded mentioning the 121GW in then. Most old threads before the Kickstarter even launched.
« Last Edit: January 14, 2018, 11:26:20 am by Scottjd »
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Offline The Soulman

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Re: EEVblog 121GW Multimeter Issues
« Reply #94 on: January 14, 2018, 11:48:24 am »
Well maybe this one is actually monitored by Dave and he gets a notification for every single reply here so he can gather data
to form statistics and eventually can act accordingly?
Don't pollute it.
 

Offline 1anX

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Re: EEVblog 121GW Multimeter Issues
« Reply #95 on: January 14, 2018, 12:15:35 pm »
For those looking for another place to post, there is a discussion thread up and running on the meter here!
http://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/
 

Offline Kal

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Re: EEVblog 121GW Multimeter Issues
« Reply #96 on: January 14, 2018, 12:49:01 pm »
I can aslo confirm that v1.02 autoranging is very slow, especially measuring low ohms or higher voltages. Compared to BM235 its about 16 times slower worst case (0.5s vs 8s, short circuit measurement) which makes those modes basically unusable at the moment. I'm expecting this should be easily fixable in firmware so not too worried, just looks like it's always measuring at full precision starting from Mohms range and not doing fast range checking measurments at first.
 

Offline idpromnut

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Re: EEVblog 121GW Multimeter Issues
« Reply #97 on: January 15, 2018, 02:49:15 am »
@Dave: when you get the chance, can you see about getting the firmware update v1.02 published for those of us that have only v1.01?  Thanks!
 

Offline nuclearcat

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Re: EEVblog 121GW Multimeter Issues
« Reply #98 on: January 15, 2018, 04:26:48 am »
BLE data corruption issue:
Code: [Select]
#!/usr/bin/python
from bluepy import btle
from bluepy.btle import UUID, Peripheral,DefaultDelegate
import binascii
import array
from struct import *

def parse_data(x):
    xlen = len(x)
    for offset in range(0,xlen):
        if (ord(x[offset:offset+1]) == 0xF2):
            # Process accumulated data
            print ("Accumulated data(%d): %s" % (len(parse_data.accumulated_data), str(parse_data.accumulated_data)))
            parse_data.accumulated_data = array.array('c')
        else:
            parse_data.accumulated_data.append(x[offset:offset+1])

class MyDelegate(btle.DefaultDelegate):
    def __init__(self):
        btle.DefaultDelegate.__init__(self)

    def handleNotification(self, cHandle, data):
         parse_data(data)


parse_data.accumulated_data = array.array('c')
# Put your multimeter mac here
p = btle.Peripheral("88:6B:XX:XX:XX:XX", btle.ADDR_TYPE_PUBLIC)
p.setDelegate( MyDelegate() )

print('Ready!')
p.writeCharacteristic(0x9, "\x03\x00")

while True:
    if p.waitForNotifications(1.0):
        continue

    print("Waiting...")

with this script it is easy to reproduce data corruption over BLE, length is changing and bits are flipping.
For example:
Code: [Select]
31373038303030303030313031343041451b34303130304537303130383038343030303030300a
3137303830303030303031300c343041453634303130304537303130383038343030303030300a
31373038303030303030313031343041453634303130304537303130383038343030303030300a
31373038303030303030313031343041453634303130304537303130383038343030303030300a
31373038303030303030313031343041453607303834303030303030303030303030303030300a
31373038303030303030313031343041450d74373031303830383430303030303030303030300a
3137303830303030303031303134304145360a
31370638303030303030313031343041453634303130304537303130383038343030303030300a <-- here is a "06" at pos 5,6 where I expected "30"
31373038303030303030313031343041453634303130304537303106383038343030303030300a
31373038303030303030313031343041453634303130534537303130383038343030303030300a
31373038303030303030313031343041453634303130304537303130383038343030303030300a
3137303830303030303031303134304145360c304537303130383038343030303030303030300a
3137303830303030303031303134304145360630303030303030303030303032440d0a
313730383030303030303130313430414536343031300a
31373038303030303030313031343041453634303130304537303130383038343030303030300a
31373038303030303030313031343041453634300330304537303130383038343030303030300a
31373038303030303030313031343041453634303130304537303130383038343030303030300a
31373038303030303030313031343041453634303130304537303130383038343030303030300a
31373038303030303030313031343041453634303130304537303130383038343030303030300a
31373038303030303030313031343041453681303030303030303030303030303030303030300a
313730383030303030303130313430414536303032440d0a
3137303830303030303031303134304145363430313030453730313038303834300a
31373038303030303030313031343041453634303130304537303130383038343030303030300a
31373038303030303030313031343041453634303130304537303130383038341830303030300a
 

Online IanB

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Re: EEVblog 121GW Multimeter Issues
« Reply #99 on: January 15, 2018, 04:53:25 am »
The data is corrupted as bellow in the middle of the data.
59625,DCV,049.997,V,,,,,,,,
59626,DCV,049.997,V,,,,,,,,
59627,DCV,049.996,V,,,,,,,,
59628,DCV,049.997,V,,,,,,,,
59629,DCV,                                                                                                                                                                                        59641,DCV,050.001,V,,,,,,,,
59642,DCV,049.996,V,,,,,,,,
59643,DCV,049.996,V,,,,,,,,
59644,DCV,049.998,V,,,,,,,,
59645,DCV,049.996,V,,,,,,,,

The garbled line only happened in one line out of four files of data logging.

It looks to me as if samples 59629 through 59640 are missing from the file? So it's not just a garbled line, it's some dropped data.
I'm not an EE--what am I doing here?
 
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