BM235 vs BM867s - Page 1
Forum section: electronics / testgear

author: robdejonge
author_rank: Regular Contributor
timestamp: April 05, 2023, 05:34:52 am
content: For some more on-point arguments, it was recommended to me that I post this question here.A decade ago I bought a $5 multimeter to keep around for occasional use like checking a battery voltage or how fast a phone was charging.A few years ago I bought a 40,000 count multimeter for ~$60. I had started getting into electronics a bit. Low voltage stuff, mostly surrounding home automation and other simple circuits. The occasional more challenging gig. The meter still measures within spec, but I’ve noticed odd behavior. Mechanical issues perhaps.Now, I'm in the market for a 'proper' multimeter. My initial selection thoughts:No need for it to be yellow for reasons Dave made a video aboutReliable manufacturerLong-term reliable sellerNo more than €150Comfortable to stick the leads into mains6000-60000 countVoltage, current, frequency, resistance, capacitance, diode, continuityTemperature is *not* important to meI decided on Brymen. Their meters get great reviews, they seem to build quality products and I'm able to buy them through some reliable sellers in Europe when I visit there this summer.I'm now trying to decide between the BM235 and the BM867s; for the extra €60 I'd get:An extra digit that I know I don't really need, but might be a 'nice to have' feature to, for example, see gradual changes in battery voltage or something like thatDual 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.'Analog' type bar graph is a feature I could see being useful. I'm just not sure how to quantify how valuable exactly.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.I *think* it can detect one-of pulses better? That could be useful.Duty cycle seems useful if it can be measured without having to set up my scope.I really like all the whitespace on the meter display, for some reasonNeither nS or dBm, or LoZ are things I've ever needed.The meter will land on a hobby bench that has an oscilloscope, bench power supplies, other cheaper multimeters, logic analyser, soldering gear, etc. that is all used by a curious but decidedly ignorant individual. I am by no means qualified to be using any of this stuff, just like learning. Most of what I do is home automation stuff, plus the odd repair around the house.I'm curious what arguments you all would offer up in deciding between these meters.

author: Fungus
author_rank: Super Contributor
timestamp: April 05, 2023, 06:42:01 am
content: Quote from: robdejonge on April 05, 2023, 05:34:52 amMe? I'd get an "industrial" BM857s. They're square and chunky. I like that. They're also quite a lot smaller than those massive curvy ones (literally half as thick... probably 1/3 of the volume of the 867s).Also: The dial is simpler - less function overload on the ranges. The only thing I really need to switch is resistance/continuity. Beware that the pic on the Brymen web site is wrong, it shows the 859s which has temperature where the 857s puts the diode function.It has the 500000 count mode and bar graph, etc. It's not dual display but I can switch between values with a button press (eg. press the Hz button to see frequency of an AC signal).Quote from: robdejonge on April 05, 2023, 05:34:52 amBar graph is useful.Dual display? I'm never sure. It's OK when you're actually using it but otherwise it's just clutter. Me? I wouldn't use it much so that's why I go for the 857.Brymen protocol is discussed here:https://www.eevblog.com/forum/testgear/brymen-ir-connection-protocol-anyone-sniffed-it-yet/msg208747/#msg208747The 235 is a good meter but it has a lot less counts and no bar graph. To me it seems more like an electrician/workshop meter than en engineering meter. It also does a lot of things I'd never use like LoZ and VFD. All those functions clutter up the dial.Bottom line: I guess I'm a low-clutter person. I don't see the point in having lots of extras that I'll never use but are constantly distracting me.

author: sonpul
author_rank: Regular Contributor
timestamp: April 05, 2023, 08:06:13 am
content: 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.

author: 2N3055
author_rank: Super Contributor
timestamp: April 05, 2023, 02:47:14 pm
content: Temperature measurement is useful. Also with two probes for a measuring of temperature difference between 2 points.And so is Lo-Z. For those occasional moments where you measure mains it is very useful..Dual screen? It depends.. Measuring 2 things at the same time can be useful. Not necessary but useful.Also I would take a look at BM257...

author: mwb1100
author_rank: Frequent Contributor
timestamp: April 05, 2023, 03:20:03 pm
content: Quote from: robdejonge on April 05, 2023, 05:34:52 amEEVblog user HJK has written a logging program that supports a wide range of meters, including the BM867s. The software supports Linux, Windows, and Mac (it's written in Java).-https://www.eevblog.com/forum/testgear/program-that-can-log-from-many-multimeters/-https://lygte-info.dk/project/TestControllerIntro%20UK.htmlIf you look at the eevblog thread you will see that HJK actively supports the program.Disclaimer: I have never actually used the program, but have no reason to believe it doesn't do what HJK says it does.

author: robdejonge
author_rank: Regular Contributor
timestamp: April 06, 2023, 02:06:55 am
content: Quote from: Fungus on April 05, 2023, 06:42:01 amWhat a delightfully odd protocol indeed. Haha!Quote from: mwb1100 on April 05, 2023, 03:20:03 pmFantastic, that will prove to be super useful! Thanks for sharing. Will for sure check it out. A quick search also foundthis Python script, which looks useful.

author: robdejonge
author_rank: Regular Contributor
timestamp: April 06, 2023, 02:13:56 am
content: Quote from: Fungus on April 05, 2023, 06:42:01 amWhat do you say to the "6000 count is more than enough for a hobby user" comments I read here all the time?

author: robdejonge
author_rank: Regular Contributor
timestamp: April 06, 2023, 02:17:42 am
content: Quote from: 2N3055 on April 05, 2023, 02:47:14 pmInteresting suggestion. That looks like a BM235 with data logging. Thanks!

author: Fungus
author_rank: Super Contributor
timestamp: April 06, 2023, 03:17:21 am
content: Quote from: robdejonge on April 06, 2023, 02:13:56 amFor real work? I agree with it.6000 counts is ~0.02% accuracy. That's plenty. Most components are 5% tolerance and I never saw a 5V power supply that was exactly 5.00V under all loads.But ... hobbies are supposed to beentertaining. Volt-nuttery is fun and a 50,000 count meter doesn't hurt.It's also good to have a reference meter to compare all your other meters against.

author: robdejonge
author_rank: Regular Contributor
timestamp: April 06, 2023, 03:59:19 am
content: Quote from: Fungus on April 06, 2023, 03:17:21 amExcellent arguments to be added to my "this vs. that" list! Thanks ;-)

author: mwb1100
author_rank: Frequent Contributor
timestamp: April 06, 2023, 06:44:20 am
content: Regarding the BM257s there are two nitpick things which have bugged me about the meter:1. it can only measure plain silicon diodes - it cannot light up even a red LED. I knew this when I bought it and figured I didn't need that capability. But then came a day when I actually tried to test an LED and I had forgotten about the limitation...2. the backlight remains lit for only 30 seconds. This is something many users don't care about, but I find myself using the backlight a lot. And the short duration drives me a bit crazy.

author: 2N3055
author_rank: Super Contributor
timestamp: April 06, 2023, 07:08:04 am
content: Quote from: Fungus on April 06, 2023, 03:17:21 am6000 count is 0,016%resolution... Accuracy is specified separately.And 6000 count is good enough for very professional work.. If that work does not require more...Professional - hobby distinction comes in play with imperative to perform at different contractual level.You can do same thing at home for fun and be hobby user, or if you do exactly same type of work for other people and get paid for it you are pro.There are many professionals that can perform their contractual obligations with simple meters with 3.5 digits and 0.3% accuracy with no TrueRMS. And they do it well and reliably. Professionally. Because that meter is good enough for the job they do..

author: robdejonge
author_rank: Regular Contributor
timestamp: April 06, 2023, 07:08:50 am
content: Quote from: mwb1100 on April 06, 2023, 06:44:20 amYou can’t just turn the backlight on permanently? Hm.I believe these also apply to the BM867 / BM869. Can someone confirm?

author: Fungus
author_rank: Super Contributor
timestamp: April 06, 2023, 07:32:48 am
content: Quote from: 2N3055 on April 06, 2023, 07:08:04 amWe weren't talking about any specific model so I assumed an ideal multimeter.

author: 2N3055
author_rank: Super Contributor
timestamp: April 06, 2023, 07:35:12 am
content: Quote from: Fungus on April 06, 2023, 07:32:48 amYour numeric estimate was correct enough.. I just wanted to point out difference between accuracy and resolution. As a clarification, nothing more..

author: sonpul
author_rank: Regular Contributor
timestamp: April 06, 2023, 08:07:30 am
content: Each brand has an engineer on the team who brings some kind of dirty trick to the ideal development.For example, they make the backlight only 15 seconds, or wedged nS between measurement and continuity modes.Probably in Briman this developer was fired. In recent versions, 869 has about 3 minutes. And the BM789 finally did the right thing, 30 minutes of backlighting. But they still left the catch, did not remember the previous state of the backlight when turned on. Тhat would be ideal.

author: mwb1100
author_rank: Frequent Contributor
timestamp: April 06, 2023, 08:52:59 am
content: Quote from: robdejonge on April 06, 2023, 07:08:50 amNot that I'm aware of. If that can be done, I hope someone can fill me in.Quote from: robdejonge on April 06, 2023, 07:08:50 amAccording to the manual the BM867s/BM869s models have a 256 second backlight. 4+ minutes seems reasonable to me.

author: robdejonge
author_rank: Regular Contributor
timestamp: April 06, 2023, 09:07:13 am
content: Quote from: mwb1100 on April 06, 2023, 08:52:59 amI'd agree. I thought I had seen comments about shot backlight times somewhere, but looks like that was in older firmware versions.

author: HKJ
author_rank: Super Contributor
timestamp: April 06, 2023, 09:17:45 am
content: Quote from: mwb1100 on April 05, 2023, 03:20:03 pmTestController only support HID interfaces on Windows and BM867 uses HID.But BM257 has serial interface and works on any OS (Windows, Mac, Linux) supported by TestController.

author: Fungus
author_rank: Super Contributor
timestamp: April 06, 2023, 04:25:31 pm
content: Yeah, the backlight thing is completely stupid, I don't know what goes through their heads. Let us choose!Why can't we hold the "light" button for three seconds to make it stay on forever? (or something like that)

author: J-R
author_rank: Super Contributor
timestamp: April 06, 2023, 07:40:57 pm
content: Running the backlight on the Brymen DMMs pulls a lot of extra power (2x-4x depending on the model), so the already short battery life would be greatly reduced. It was perhaps a wise marketing decision to have a short backlight timeout to avoid having the Brymens be labelled as excessively battery hungry.

author: Fungus
author_rank: Super Contributor
timestamp: April 06, 2023, 08:09:29 pm
content: Quote from: J-R on April 06, 2023, 07:40:57 pmInstead they get labelled as having useless backlights?I don't see how that's better.

author: J-R
author_rank: Super Contributor
timestamp: April 07, 2023, 06:25:51 am
content: 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...

author: Fungus
author_rank: Super Contributor
timestamp: April 07, 2023, 06:40:21 am
content: Quote from: J-R on April 07, 2023, 06:25:51 amBy that logic they should make flashlights with auto-power-off...

author: mwb1100
author_rank: Frequent Contributor
timestamp: April 07, 2023, 08:47:53 am
content: Just for the record, the BM257s is a fine multimeter.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...)And in principle I have no problem with auto shutoff for backlights. But the 15s timer that many meters implement is just plain stupid. And 30s is irritating (bordering on stupid). Give meat leasta minute, or implement Fungus' excellent idea of an extra long button press to turn on the backlight with no timeout (or a 10 minute timeout if the meter's designer is really concerned that I'll use up too many ofmybatteries).

author: robdejonge
author_rank: Regular Contributor
timestamp: April 07, 2023, 08:57:56 am
content: Quote from: mwb1100 on April 07, 2023, 08:47:53 amI 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.

author: Fungus
author_rank: Super Contributor
timestamp: April 07, 2023, 01:09:45 pm
content: Quote from: mwb1100 on April 07, 2023, 08:47:53 amIt'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.Quote from: mwb1100 on April 07, 2023, 08:47:53 amI'm for hire.It could even flash the battery warning indicator at you in that mode if it makes the designers feel better.

author: mwb1100
author_rank: Frequent Contributor
timestamp: April 07, 2023, 03:48:01 pm
content: Quote from: Fungus on April 07, 2023, 01:09:45 pmMakes me imagine some future Dave multimeter review:Quote

author: HKJ
author_rank: Super Contributor
timestamp: April 07, 2023, 04:19:11 pm
content: Quote from: Fungus on April 07, 2023, 01:09:45 pmA 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.

author: Fungus
author_rank: Super Contributor
timestamp: April 07, 2023, 05:36:39 pm
content: Quote from: mwb1100 on April 07, 2023, 03:48:01 pmBut... it's yellow! He can't say bad things about yellow meters,It's not much use for testing star LEDs though...Quote from: HKJ on April 07, 2023, 04:19:11 pmIf 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.

author: HKJ
author_rank: Super Contributor
timestamp: April 07, 2023, 06:43:58 pm
content: Quote from: Fungus on April 07, 2023, 05:36:39 pmIt 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.

author: Fungus
author_rank: Super Contributor
timestamp: April 07, 2023, 07:01:57 pm
content: Quote from: HKJ on April 07, 2023, 06:43:58 pmI 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.

author: HKJ
author_rank: Super Contributor
timestamp: April 07, 2023, 07:12:09 pm
content: Quote from: Fungus on April 07, 2023, 07:01:57 pmYou 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.

author: Fungus
author_rank: Super Contributor
timestamp: April 07, 2023, 08:03:23 pm
content: Quote from: HKJ on April 07, 2023, 07:12:09 pmWhy 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:

author: HKJ
author_rank: Super Contributor
timestamp: April 07, 2023, 08:45:42 pm
content: Quote from: Fungus on April 07, 2023, 08:03:23 pmFrom 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.

author: J-R
author_rank: Super Contributor
timestamp: April 08, 2023, 12:18:01 am
content: Quote from: Fungus on April 07, 2023, 06:40:21 amIt'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.

author: Fungus
author_rank: Super Contributor
timestamp: April 08, 2023, 01:12:31 am
content: Quote from: J-R on April 08, 2023, 12:18:01 amNobody's arguingagainstthat, we're arguingforthe 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.

author: robdejonge
author_rank: Regular Contributor
timestamp: April 08, 2023, 01:31:52 am
content: Quote from: Fungus on April 08, 2023, 01:12:31 amGreat idea!

author: mwb1100
author_rank: Frequent Contributor
timestamp: April 08, 2023, 02:45:55 am
content: Quote from: Fungus on April 08, 2023, 01:12:31 amGW121 beat you to it (but you have to search it out - it's not continuously displayed):Quote

author: GuidoK
author_rank: Regular Contributor
timestamp: June 22, 2023, 03:20:47 am
content: Quote from: robdejonge on April 05, 2023, 05:34:52 amThe dual display is super handy, especially to see for instance AC+DC and the AC component in one glance.QuoteBesides 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?!?

author: HackedFridgeMagnet
author_rank: Super Contributor
timestamp: June 22, 2023, 04:01:03 am
content: 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.

author: Electro Fan
author_rank: Super Contributor
timestamp: June 22, 2023, 04:12:11 am
content: Quote from: sonpul on April 05, 2023, 08:06:13 am+1 for BM789https://brymen.eu/wp-content/uploads/biall/102222/102222.KARTA_EN..2020-10-26.1.pdf