Author Topic: New EEVblog BM786 Multimeter  (Read 53347 times)

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Online bdunham7

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Re: New EEVblog BM786 Multimeter
« Reply #400 on: March 27, 2021, 01:40:08 am »
Fluke also does not allow this.

I'm not clear--Fluke does not allow what?
A 3.5 digit 4.5 digit 5 digit 5.5 digit 6.5 digit 7.5 digit DMM is good enough for most people.
 

Offline wizard69

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Re: New EEVblog BM786 Multimeter
« Reply #401 on: March 27, 2021, 02:50:12 am »
compared to the old 34401A.  They provide regular firmware update without the need to recalibrate.

I can't imagine what you would want to update on a 34401A.   :)
Adding features is a nice idea, but I'm not so thrilled about manufacturers shipping half-baked stuff knowing they can maybe fix it later if they have to--if they are still around and if they still care. 

That is not the point and never has been the point of having upgradeable software.   Are you seriously implying you want to be stuck with bugs forever.
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Dave, I like the meter, perhaps one thing you could communicate back to the manufacturer is the ability to do field firmware upgrade would have provided a great differentiation that all buyers would love to have, and helps to reduce their warranty cost.

I think the issue is that they want their code protected.

I don't doubt that one bit.    However It would be nice to see somebody offer up an open sourced DMM.   We need this as users because of the one problem that is rather huge in the test equipment industry, that is a lot of manufactures just don't last.   That is a company will flop before its hardware has ran through a reasonable life span.    Beyond that I'm still amazed that we don't have scriptable instruments from the big manufactures.
 

Offline vishkas

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Re: New EEVblog BM786 Multimeter
« Reply #402 on: March 27, 2021, 03:21:19 am »
Good One  :-DMM
 

Offline Kleinstein

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Re: New EEVblog BM786 Multimeter
« Reply #403 on: March 27, 2021, 06:36:02 am »
A DMM should have reliable software from the start.  Wrong reading may pose a safety problem, so it needs some security measures.  This would be a problem with a open source DMM, or even one with open access to the software.

At least the basic functions of a handheld DMM are not that complicated and can be tested relatively easy. It gets more complicated only with more special functions like graphing, statistics and similar.
If really wanted a suitable place for a connector to allow a SW update would be in the battery compartment.
Not having the possibility to change the SW easy forces the manufacturers to get it right. For a limited SW complexity there is a chance to have bug free software.

Getting intermediate numbers when changing the input signal is normal. The DMM reading is an average over some time and some intermedate number is correct - not random, just hard to control manually. The bench DMMs tend to be faster in the default settings and thus have the transients less visible.
 

Offline 2N3055

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Re: New EEVblog BM786 Multimeter
« Reply #404 on: March 27, 2021, 08:40:57 am »
I don't doubt that one bit.    However It would be nice to see somebody offer up an open sourced DMM.   We need this as users because of the one problem that is rather huge in the test equipment industry, that is a lot of manufactures just don't last.   That is a company will flop before its hardware has ran through a reasonable life span.    Beyond that I'm still amazed that we don't have scriptable instruments from the big manufactures.

There are literally hundreds of open source multimeters on the Internet. And they all went nowhere. Not to mention how safe is to make something you poke into dangerous voltages that Arduino maker will "hack and make better".

And what's with "don't have scriptable instruments"? All of them are, if they have any kind of interface. You need Raspberry PI, small screen, and write Python scripts for days... Graphing, logging, everything. I have a network share mapped, so files are accessible from PCs too... Ethernet, serial, Bluetooth, GPIB connectivity, you name it.
Also, DMM6500 from Keithley has built in scripting language and rather big screen.   OTOH, unfortunately, it is also a living proof that Linux can also bluescreen all the time if you write crappy software...
 
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Offline wizard69

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Re: New EEVblog BM786 Multimeter
« Reply #405 on: March 27, 2021, 09:48:50 pm »
I don't doubt that one bit.    However It would be nice to see somebody offer up an open sourced DMM.   We need this as users because of the one problem that is rather huge in the test equipment industry, that is a lot of manufactures just don't last.   That is a company will flop before its hardware has ran through a reasonable life span.    Beyond that I'm still amazed that we don't have scriptable instruments from the big manufactures.

There are literally hundreds of open source multimeters on the Internet. And they all went nowhere. Not to mention how safe is to make something you poke into dangerous voltages that Arduino maker will "hack and make better".
That pretty much highlights that there are no true open source multimeters.   Further there is a lot more to the world of open source and even open hardware than Arduino.   I sometimes see Arduino as enablement for idiots but that doesn't mean everybody that put an Arduino to good use is an idiot.
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And what's with "don't have scriptable instruments"? All of them are, if they have any kind of interface.
Having an interface doesn't make the meter itself scriptable.
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You need Raspberry PI, small screen, and write Python scripts for days... Graphing, logging, everything. I have a network share mapped, so files are accessible from PCs too... Ethernet, serial, Bluetooth, GPIB connectivity, you name it.
Also, DMM6500 from Keithley has built in scripting language and rather big screen.   OTOH, unfortunately, it is also a living proof that Linux can also bluescreen all the time if you write crappy software...
So you have one high end meter to consider here.   As for a blue screens you are right that crappy software is a problem, but even quality software will have bugs.   That is why field up-gradable instruments makes lots of sense to me.    It is almost impossible to ship reasonably complex software without bugs.

What is interesting to me, with respect to Linux and much of the software that runs there, is just how good it has become.    Yes there are crappy apps, that are delivered by rather poor programmers, but that stuff doesn't stay in circulation long.    Either programmer (often the project leader) gets better at programming or something turns up to replace it.    Contrast this with Windows when you can get stuck with a crappy app with no replacement in sight, nor a way to get it fixed.

Is open source always the right answer, nope not saying that.   However it has done really well in some case such as low end logic analyzers.   The industry would benefit from more such successes.
 

Offline EEVblog

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Re: New EEVblog BM786 Multimeter
« Reply #406 on: March 28, 2021, 10:33:41 am »
Dave, I like the meter, perhaps one thing you could communicate back to the manufacturer is the ability to do field firmware upgrade would have provided a great differentiation that all buyers would love to have, and helps to reduce their warranty cost.

I've already did that when I first heard that it was possible with gthis new design (the BM235 and others use OTP parts). But they clearly don't want users upgrading the firmware. If you want an answer on why you'll have to ask them directly, I don't know.
Ultimately I (as a dealer) will have the ability to do firmware upgrades once I get the hardware to do so, but it's all under NDA I'm afraid.
 
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Offline EEVblog

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Re: New EEVblog BM786 Multimeter
« Reply #407 on: March 28, 2021, 10:36:11 am »
They can't provide an external USB port for safety reasons, and few people would be able to open up the case, connect to an internal programming header, and use a special programmer to burn the new firmware (at the risk of bricking the device if they got it wrong).

For some reason I thought this meter had PC-COM.  But are the PC-COM equipped Brymen meters
 flashable?

No they aren't. I believe the BM78x series is the first to use a re-programmable processor.
 
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Offline EEVblog

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Re: New EEVblog BM786 Multimeter
« Reply #408 on: March 28, 2021, 10:40:31 am »
I doubt Brymen is using OTP, but instead Flash with a burned JTAG fuse to prevent any access.

Maybe, but I have been told the BM235 is OTP. And given that during development they were wondering if they could fit a couple of extra features I wanted in the IIRC hundred bytes or something they had left in the memory, I'm fairly confident it's one of those little known smal memory OTP processors.
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Offline EEVblog

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Re: New EEVblog BM786 Multimeter
« Reply #409 on: March 28, 2021, 10:43:34 am »
If really wanted a suitable place for a connector to allow a SW update would be in the battery compartment.

That's where it is on the BM786. Or at least that's what I assume it is they haven't given me the programmer hardware or instructions yet. But there is a mystery header in the battery compartment.
 
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Offline ogdento

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Re: New EEVblog BM786 Multimeter
« Reply #410 on: April 17, 2021, 06:22:18 am »
I saw that Dave and some others checked various headers on the unit and got no data coming out, but I noticed that the lcd driver (HY2613C) has an i2c interface... are the sda/scl lines exposed on any pads/test points? 

If so, maybe the data going to the lcd could be read??  (sortof how you can read the older brymens lcd data via the IR adapter)
 

Online Microdoser

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Re: New EEVblog BM786 Multimeter
« Reply #411 on: April 17, 2021, 11:42:49 am »
Dave, I like the meter, perhaps one thing you could communicate back to the manufacturer is the ability to do field firmware upgrade would have provided a great differentiation that all buyers would love to have, and helps to reduce their warranty cost.

I've already did that when I first heard that it was possible with gthis new design (the BM235 and others use OTP parts). But they clearly don't want users upgrading the firmware. If you want an answer on why you'll have to ask them directly, I don't know.
Ultimately I (as a dealer) will have the ability to do firmware upgrades once I get the hardware to do so, but it's all under NDA I'm afraid.

I suspect that, in part, they don't want third party firmware being installed.
 

Offline Fungus

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Re: New EEVblog BM786 Multimeter
« Reply #412 on: April 17, 2021, 12:06:23 pm »
I suspect that, in part, they don't want third party firmware being installed.

I suspect that the meter's CAT rating depends on the firmware so they don't want anybody compromising that.

 

Online Microdoser

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Re: New EEVblog BM786 Multimeter
« Reply #413 on: April 17, 2021, 04:39:45 pm »
I suspect that, in part, they don't want third party firmware being installed.

I suspect that the meter's CAT rating depends on the firmware so they don't want anybody compromising that.

That would be one of the reasons they don't want third party firmware installed, yes.
 

Offline EEVblog

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Re: New EEVblog BM786 Multimeter
« Reply #414 on: April 19, 2021, 01:17:30 am »
If really wanted a suitable place for a connector to allow a SW update would be in the battery compartment.
That's where it is on the BM786. Or at least that's what I assume it is they haven't given me the programmer hardware or instructions yet. But there is a mystery header in the battery compartment.

Mystery battery compartment header confirmed as the programming port (obviously).
I am also now in possesion of the programmer so am able to update stock on hand if a firmware update comes out. Have not tried it yet though.
Please do not ask for any details, I am not able to reveal any info about it.
 
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Offline EEVblog

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Re: New EEVblog BM786 Multimeter
« Reply #415 on: April 19, 2021, 01:22:51 am »
I saw that Dave and some others checked various headers on the unit and got no data coming out, but I noticed that the lcd driver (HY2613C) has an i2c interface... are the sda/scl lines exposed on any pads/test points? 
If so, maybe the data going to the lcd could be read??  (sortof how you can read the older brymens lcd data via the IR adapter)

Photos: https://www.flickr.com/photos/eevblog/albums/72157718973141297
 
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Online AVGresponding

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Re: New EEVblog BM786 Multimeter
« Reply #416 on: April 19, 2021, 05:32:37 pm »
If really wanted a suitable place for a connector to allow a SW update would be in the battery compartment.
That's where it is on the BM786. Or at least that's what I assume it is they haven't given me the programmer hardware or instructions yet. But there is a mystery header in the battery compartment.

Mystery battery compartment header confirmed as the programming port (obviously).
I am also now in possesion of the programmer so am able to update stock on hand if a firmware update comes out. Have not tried it yet though.
Please do not ask for any details, I am not able to reveal any info about it.

I am curious about the position on non-updated meters already existing in the wild. Do you anticipate some sort of shipping-them-there-and-back program to update them, or would that be logistically impossible?
nuqDaq yuch Dapol?
Addiction count: Agilent-AVO-BlackStar-Brymen-Fluke-Hameg-HP-Keithley-IsoTech-Mastech-Megger-Micronta-Racal-Solartron-Tektronix-Thurlby-Time Electronics-TTi-UniT
 

Offline ogdento

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Re: New EEVblog BM786 Multimeter
« Reply #417 on: April 19, 2021, 06:46:26 pm »
Thanks Dave,
I can see the SCL/SDA lines going from driver pins 9/10 to the R210/R211 (1k?) resistors on the board bottom.  Not sure if those are pullups, but I can't see where they go after.  I guess it would be interesting to play around with, but may be silly to hack in a data-output port.

[attach=1]

[attach=2]
« Last Edit: April 19, 2021, 06:49:28 pm by ogdento »
 
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Offline rsjsouza

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Re: New EEVblog BM786 Multimeter
« Reply #418 on: April 19, 2021, 08:51:52 pm »
Mystery battery compartment header confirmed as the programming port (obviously).
I am also now in possesion of the programmer so am able to update stock on hand if a firmware update comes out. Have not tried it yet though.
Aha! I called it!  ;D
(minus the blown JTAG fuse)

I doubt Brymen is using OTP, but instead Flash with a burned JTAG fuse to prevent any access.

Maybe, but I have been told the BM235 is OTP. And given that during development they were wondering if they could fit a couple of extra features I wanted in the IIRC hundred bytes or something they had left in the memory, I'm fairly confident it's one of those little known smal memory OTP processors.
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 EEVblog

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Re: New EEVblog BM786 Multimeter
« Reply #419 on: April 19, 2021, 11:05:15 pm »
I am curious about the position on non-updated meters already existing in the wild. Do you anticipate some sort of shipping-them-there-and-back program to update them, or would that be logistically impossible?

Logistically and financially not viable. Consider the BM78x series the same as all other Brymen meters, non-upgradable.
 

Offline jayjr1105

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Re: New EEVblog BM786 Multimeter
« Reply #420 on: May 01, 2021, 11:30:05 pm »
After regrettably selling my BM235, I bit the bullet on this meter.  Yes it's probably overkill for my hobby needs but I was sick of chasing the unicorn $50-100 "perfect" dmm.  BTW, is there no official eevblog video on this meter yet?  Would have been nice to see a thorough review of it even if it's your own product.
 

Offline rsjsouza

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Re: New EEVblog BM786 Multimeter
« Reply #421 on: May 02, 2021, 01:16:06 am »
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 wizard69

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Re: New EEVblog BM786 Multimeter
« Reply #422 on: May 03, 2021, 10:44:20 pm »
You will never regret having a "better than needed meter".   Even at the hobby end of the world a meter is such a basic instrument, that lasts a very long time, the cost isn't as big of a deal as it is with other products.   There are actually some very useful meters in the $50 to $100 range, for a beginner or hobbyist, but I still see benefit in moving up market.

I like to think of myself as being thrifty and cut corners on a lot of stuff for my pursuits.   However I'm pleased with my 786 as it is good product and I manage to support EEVblog a bit with the purchase.   Win Win. 

After regrettably selling my BM235, I bit the bullet on this meter.  Yes it's probably overkill for my hobby needs but I was sick of chasing the unicorn $50-100 "perfect" dmm.  BTW, is there no official eevblog video on this meter yet?  Would have been nice to see a thorough review of it even if it's your own product.
 
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Offline jayjr1105

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Re: New EEVblog BM786 Multimeter
« Reply #423 on: May 05, 2021, 11:58:50 pm »
You will never regret having a "better than needed meter".   Even at the hobby end of the world a meter is such a basic instrument, that lasts a very long time, the cost isn't as big of a deal as it is with other products.   There are actually some very useful meters in the $50 to $100 range, for a beginner or hobbyist, but I still see benefit in moving up market.

I like to think of myself as being thrifty and cut corners on a lot of stuff for my pursuits.   However I'm pleased with my 786 as it is good product and I manage to support EEVblog a bit with the purchase.   Win Win. 

After regrettably selling my BM235, I bit the bullet on this meter.  Yes it's probably overkill for my hobby needs but I was sick of chasing the unicorn $50-100 "perfect" dmm.  BTW, is there no official eevblog video on this meter yet?  Would have been nice to see a thorough review of it even if it's your own product.
Yeah you pretty much nailed it.  I'm frugal with a lot of things but some tools and toys I like to splurge on if it's going to be high quality and last a long time.  Here is my new "toy"
 
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Offline ceut

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Re: New EEVblog BM786 Multimeter
« Reply #424 on: May 31, 2021, 10:05:23 pm »
Hello,
I was about ordering the BM786, but when I saw the price difference with the BM789: I switched to the 789.
Also I use the Z-Low of my U1272A (very slowwww about 1read/s with low resolution, whereas all the other function are super fast with high resolution and I love that), and the "Auto" of my BM257s (full speed and resolution) for big capacitor discharge and other low-Z checking.

So here is my question: why EEVblog meter is not the 789 model ?  :(

And I like the blue thing very much... :-[
 


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