Author Topic: BM235 vs BM867s  (Read 5517 times)

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Offline robdejongeTopic starter

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Re: BM235 vs BM867s
« Reply #25 on: April 07, 2023, 08:57:56 am »
But as often happens, I found imperfections that I cannot "unsee" - even if they are actually of little consequence.  Kind of like when a stupid song gets into your head and just plays itself over and over. It took me more than a year before I tried to light up an LED - and I probably wouldn't do it again for another year.  On the plus side, it actually won't happen again, because every time I pickup the meter now the earworm of "oh yeah - this doesn't light LEDs" pops into my head.  Even though lighting up LEDs was (until that moment) the furthest thing from my mind.  (Cripes - I just wrote an entire paragraph about lighting up LEDs... :palm:)
I think we might be on to something here. In our next session, I'd like to explore if your obsession with lighting up LEDs may be linked to your childhood in some way. But I think that's all the time we have for our session today.  :-/O
 
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Offline Fungus

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Re: BM235 vs BM867s
« Reply #26 on: April 07, 2023, 01:09:45 pm »
every time I pickup the meter now the earworm of "oh yeah - this doesn't light LEDs" pops into my head.

It's an important function for many people. Some meters even have special "LED testers" on the front.

Me? I wouldn't buy a meter that can't light up a big white LED.

...Fungus' excellent idea of an extra long button press to turn on the backlight with no timeout

I'm for hire.

It could even flash the battery warning indicator at you in that mode if it makes the designers feel better.
 
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Offline mwb1100

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Re: BM235 vs BM867s
« Reply #27 on: April 07, 2023, 03:48:01 pm »
Some meters even have special "LED testers" on the front.

Makes me imagine some future Dave multimeter review:
Quote
Arrgh!  They put a bloody hFE LED tester on there!  What the?!... Who tests LEDs anymore?!?  It's just a waste of space on an otherwise pretty nice meter.  Crikey - it just goes to show that they don't understand their market... Rrrrr...  That's a fail.  (tosses meter aside)
 

Offline HKJ

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Re: BM235 vs BM867s
« Reply #28 on: April 07, 2023, 04:19:11 pm »
every time I pickup the meter now the earworm of "oh yeah - this doesn't light LEDs" pops into my head.

It's an important function for many people. Some meters even have special "LED testers" on the front.

Me? I wouldn't buy a meter that can't light up a big white LED.

A special LED test socket may be a safety concern (Probably not on the Fluke).
A diode voltage that can light white leds can sometimes be useful, I have two meters can optionally use considerable higher voltage for diode testing (121GW & CA5293) they are most for testing zener diodes (I have used the higher low current voltage for other purposes also). There are also isolation testers that can use up to 1000V for ohm test.
Generally I would recommend having multiple DMM's and not all of them need all the functions.
 

Offline Fungus

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Re: BM235 vs BM867s
« Reply #29 on: April 07, 2023, 05:36:39 pm »
Some meters even have special "LED testers" on the front.

Makes me imagine some future Dave multimeter review:
Quote
Arrgh!  They put a bloody hFE LED tester on there!  What the?!... Who tests LEDs anymore?!?  It's just a waste of space on an otherwise pretty nice meter.  Crikey - it just goes to show that they don't understand their market... Rrrrr...  That's a fail.  (tosses meter aside)

But... it's yellow! He can't say bad things about yellow meters,


It's not much use for testing star LEDs though...


A special LED test socket may be a safety concern (Probably not on the Fluke).

If any sparks are big enough to come flying out of those LED test holes then you've probably got more important things to worry about.
« Last Edit: April 07, 2023, 05:43:27 pm by Fungus »
 

Offline HKJ

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Re: BM235 vs BM867s
« Reply #30 on: April 07, 2023, 06:43:58 pm »
A special LED test socket may be a safety concern (Probably not on the Fluke).

If any sparks are big enough to come flying out of those LED test holes then you've probably got more important things to worry about.

It is more about isolation distance, CAT III 600V means the isolation must handle 6000V, i.e. a finger on top of the LED socket must not get zapped if 6000V is applied to the measurements inputs.
 

Offline Fungus

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Re: BM235 vs BM867s
« Reply #31 on: April 07, 2023, 07:01:57 pm »
If any sparks are big enough to come flying out of those LED test holes then you've probably got more important things to worry about.
It is more about isolation distance

I think that's what I said...  :-//

If any sparks are big enough to get past the input protection components and make it all the way to the top of the meter then you've probably got more important things to worry about.
 

Offline HKJ

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Re: BM235 vs BM867s
« Reply #32 on: April 07, 2023, 07:12:09 pm »
If any sparks are big enough to come flying out of those LED test holes then you've probably got more important things to worry about.
It is more about isolation distance

I think that's what I said...  :-//

If any sparks are big enough to get past the input protection components and make it all the way to the top of the meter then you've probably got more important things to worry about.

You obvious do not get it. The 6000V may come in on the black terminal and it is probably connected with a fairly low impedance to the LED test terminals. The only practical way to protect is distance from terminals inside the meter to the front place. Impedance and/or isolation is not practical in a cheap meter.
 

Offline Fungus

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Re: BM235 vs BM867s
« Reply #33 on: April 07, 2023, 08:03:23 pm »
You obvious do not get it. The 6000V may come in on the black terminal and it is probably connected with a fairly low impedance to the LED test terminals. The only practical way to protect is distance from terminals inside the meter to the front place. Impedance and/or isolation is not practical in a cheap meter.

Why do you imagine the LED test holes are directly connected in any way to the input jacks? It's not necessary.

(and it's Fluke, they think of these things...)

Edit: FWIW I found a picture of the PCB on the web. Judge for yourself if you think the LED socket is directly connected to the input jacks:
« Last Edit: April 07, 2023, 08:24:00 pm by Fungus »
 

Offline HKJ

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Re: BM235 vs BM867s
« Reply #34 on: April 07, 2023, 08:45:42 pm »
Why do you imagine the LED test holes are directly connected in any way to the input jacks? It's not necessary.

(and it's Fluke, they think of these things...)

Edit: FWIW I found a picture of the PCB on the web. Judge for yourself if you think the LED socket is directly connected to the input jacks:


From the picture it looks like there may be isolation, that is better than I expected, but as I stated initially I expected Fluke to be safe.
I am a bit impressed that Fluke would use money on isolation in a cheap meter (cheap for Fluke).

Without that DC/DC converter block there would not be more than a few kohm from minus input to one of the LED terminals. That would mean higher distances then class II main equipment (Due to the higher voltage). Here the limiting factor is probably creepage under the DC/DC converter.
 

Offline J-R

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Re: BM235 vs BM867s
« Reply #35 on: April 08, 2023, 12:18:01 am »
Brymen's backlight and auto-power-off behavior is similar to many DMMs where it is a common design choice in order to help the user avoid constantly picking up a tool expecting to be able to use it but instead finding a dead battery...

By that logic they should make flashlights with auto-power-off...  :-//

It's a fact that having the backlight on with battery-powered handhelds sucks the runtime significantly faster than with it off.  Furthermore, handhelds are frequently used by people who need them to do their job, so having a reliable device that you can use daily and still count on is important.  Most handheld DMM users pull it out of their bag, take some measurements, then put it away.  So it's far more user-friendly to have the auto-power-off function as it does now than not.  Also, if you need the backlight THAT BAD for THAT LONG, then your problem is lighting in general, so get a headlamp or work light so you're not probing in the dark.
 
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Offline Fungus

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Re: BM235 vs BM867s
« Reply #36 on: April 08, 2023, 01:12:31 am »
It's a fact that having the backlight on with battery-powered handhelds sucks the runtime significantly faster than with it off.  Furthermore, handhelds are frequently used by people who need them to do their job, so having a reliable device that you can use daily and still count on is important.

Nobody's arguing against that, we're arguing for the right to choose.

If you really want to be a nanny you could implement a feature that enables short backlight time when the battery reaches 30% or something like that.
Fresh battery? Backlight stays on if I want it to (long press of backlight button...)
Battery getting low? Backlight goes off after 20 seconds.

While we're here: That could give us another feature for our meters - display of current battery voltage. Maybe a "remaining battery" display on the bar graph.  :popcorn:
 

Offline robdejongeTopic starter

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Re: BM235 vs BM867s
« Reply #37 on: April 08, 2023, 01:31:52 am »
That could give us another feature for our meters - display of current battery voltage. Maybe a "remaining battery" display on the bar graph.  :popcorn:
Great idea!
 

Offline mwb1100

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Re: BM235 vs BM867s
« Reply #38 on: April 08, 2023, 02:45:55 am »
While we're here: That could give us another feature for our meters - display of current battery voltage. Maybe a "remaining battery" display on the bar graph.  :popcorn:

GW121 beat you to it (but you have to search it out - it's not continuously displayed):
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BATTERY VOLTAGE
To check the status of the batteries in the multimeter press the SETUP button until “Bat” is displayed. The Low Battery icon will come in when the batteries reach approximately 4.2 V
 

Offline GuidoK

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Re: BM235 vs BM867s
« Reply #39 on: June 22, 2023, 03:20:47 am »

  • Dual display that I've never had and so don't really know how useful it is. Comments have been made that I could just as easily add a second meter for the second parameter.
The dual display is super handy, especially to see for instance AC+DC and the AC component in one glance.

Quote
  • Data logging is a feature I would really like. I've read however that Brymen data is really weird, so I'm wondering if I'll be able to get it working on a Linux machine without having to write software myself.
Besides the brymen software (which is not that good), there are at least 2 free 3rd party programs that can log from the BM867/869:
TSDMMVIEWER:
https://www.ts-software-jp.net/index.html
(I think I use this one the most)
and Testcontroller (lot of functions):
https://www.eevblog.com/forum/testgear/program-that-can-log-from-many-multimeters/

Afaik both can log at 5x/sec in high resolution mode (500k counts) despite the brymen manual saying that update rate is only 1x/sec in 500k mode.

The only thing imho missing on the BM867/869 (and also on the bm235) is a good autohold function. And the 9V battery is...meh, but acceptable.
For that the BM786/789 is a good alternative as it has a very good autohold, but that has no dual display, no 500k high resolution mode and no logging/pc interface. Especially no logging possibility is I think a missed oppertunity in this day and age for a high spec meter. They gave the BM867/869 that functionality, and they are more or less the same price, so why not in the 78x series?!?
« Last Edit: June 23, 2023, 12:02:03 am by GuidoK »
 

Offline HackedFridgeMagnet

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Re: BM235 vs BM867s
« Reply #40 on: June 22, 2023, 04:01:03 am »
Another vote for the BM789. I use it at work all the time. Love it.
didn't read all your requirements but this is a great general purpose meter.
 

Offline Electro Fan

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Re: BM235 vs BM867s
« Reply #41 on: June 22, 2023, 04:12:11 am »
My opinion is this. If the wonderful BM859s do not suit you, do not torture yourself with doubts. Buy BM869s. Let him know everything. Don't trade for the BM867.
I saw that you are unsure about many of the functions listed. Let me remind you once again about the BM789. It is very compact, thin, comfortable in the hand and not bulky on the table. Knows a lot.

+1 for BM789

https://brymen.eu/wp-content/uploads/biall/102222/102222.KARTA_EN..2020-10-26.1.pdf
 


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