BENNING MM 12 (APPA 506B) – my experience (with pictures) - Page 1
Forum section: electronics / testgear

author: Cymaphore
author_rank: Regular Contributor
timestamp: March 13, 2021, 12:47:50 am
content: If your DMM never leaves the comfortable environment of a lab bench with nice lighting and no real hazard sources, you’ll probably be more happy with another meter than this one. Otherwise this might be interesting for you.At my job I work in the automotive industry on electric vehicles and components (BEV and hybrid alike) and with electric cabinets and HV battery testers at up to 1000V, so my requirements on measurement equipment are a bit different than that of a “pure” electronic environment.You might imagine that using those shiny “aliexpress-class” / mainland chinese meters at my job is completely out of the question and pure suicide.For quite a while now I own aBENNING MM 12(a.k.a.APPA 506B,Sefram 7352B). I originally purchased it for private use after my old personal meter didn’t survive an unintended drop test, but the MM 12 quickly became my favorite and most used meter overall.That’s mainly because of it being a very unique combination of features in one single handy device, making it pretty much perfect for my purposes.It can be operated single handed in either hand with 1000V insulation gloves on. You can also operate the buttons and the rotary switch easily single handed by thumb while holding it. It has a good and reliable CAT IV rating. The automatic backlight feature is something I really got accustomed to and that I now constantly miss on other meters.It has a dual display, so that I can read min/max/avg/peak/auto hold/etc. simultaniously with the current measurement value.No more loosing the Display (I talk to you, F233) or bulky BLE-Adapter on top (I talk to you, F289). It has built-in BLE-support and you can get the screen reading with a lightweight Android and iOS-App for remote monitoring of the display readings. At the same time someone else can still directly watch and operate the meter.It also has an integrated data logging feature that I frequently use. Stored data can be read on the device itself or downloaded via USB or Bluetooth LE to another device. Settings are accessible over a menu and funny two-handed „Turn on while pressing button“ action to change something is not needed thanks to a setup menu.Of course, it lacks some of the features of other meters since it’s purposed for electrical engineering and it’s precision, speed and display count is in the „just enough“ range of things, but that’s quite okay for me. But by my experience, even if it is only 4000/40000 counts, it’s precision matches in practise close enough that of those native 40000 or 50000 count meters well enough. And it’s continuity test could be considered to be not the fastest one, but that’s also not an issue for me at all.Data cable, windows-software and magnetic holder is included. It has a hole in the back where you can hang it on a screw or something similar. There is free space in this spot of the sleeve where I put a magnet in to just “stick” the meter to some cabinet wall or vehicle frame or whatever metal is nearby, without any additional strap.It cannot do duty cycle and automatic calculation of conductance and loop current percentage like other meters, but that’s not a problem for me. It also doesn’t have a fancy graphic screen, but I actually prefer it that way.Pictures are attached below.I created a sigrok-driver to be able to monitor it from the command line or with SmuView, over USB and Bluetooth LE,see here.If it is of interest for someone here, I could do a full review or perform some specific tests on it.

author: PushUp
author_rank: Regular Contributor
timestamp: February 09, 2022, 04:38:43 am
content: Hello Cymaphore,thank you very much for your exchange of experiences of the "Benning MM12"!It would be nice to see a picture of the dual display, showing AC+DC in Volt and Ampere. How does it look like? Are there any combinations like Keysight or Fluke offers?Do you have a linux setup, to test it with TestController by HKJ? I know, that TestController will work with VirtualBox and Windows, but I prefer not using WinDoof at all.I have the "Benning IT 101" and "Voltcraft LCR-400", which do have the same origin and design: The build quality is very good and I do like the sense of touch.However, I don't like the wide digits of the display, but what is more is the weired automatic light: I had to put 3 layers of black tape over the light detection point, so that it is always on; however there are still some lighting conditions, such as under a very bright LED lamp, which makes the detection freak out by getting the backlight always on and off continously.In the manual it says according to the "Benning MM12", that you have the "Auto (automatic)" backlight mode and that you can turn it "ON" or "OFF" manually? Is this correct, because I cannot believe it...or do I misunderstand the wording...?!Thank you very much & best wishes!

author: joeqsmith
author_rank: Super Contributor
timestamp: February 09, 2022, 07:37:32 am
content: While they had enough foresight to offset the vias on the switch contacts, the off position seems like it was tossed in as an after thought.Note how the contact is riding over the top of that trace. How long until it cuts the trace? Once the copper is exposed, can that trace short to the other switch pads and does it cause problems? What function do those two pads that straddle the one off pad provide? I would have like to have see what the contacts themselves looked like. How are they held into place? What does the detent spring area look like?Looking at the mezzanine board, are they counting on that screw to carry the current to the main PCB? It looks like a self tapping type but can't tell from the lack of pictures of the front case inside view. If that gets loose at all, what happens?On the input terminal, what is the black device (R85)? It looks like a third small PTC but I can't tell. Looks like an after thought but would be curious how it connects. Could you trace this area out?

author: cspy777
author_rank: Newbie
timestamp: February 28, 2022, 12:25:56 am
content: Quote from: joeqsmith on February 09, 2022, 07:37:32 amIt is obvious that the contacts do not slide over this area, since this is the end position, and the switch is not able to turn 360° around the axis due to the limiters. Do not panic, traces are safe)..Contacts are used to short pads according to configuration and switch position. These contacts are somehow connected under the plastic, I think.The screw is not used as a conductor, it acts as a screw only).I use APPA77 true RMS meter for many years, it's very reliable and accurate enough according to it's price (it cost approximately €100 about 15 years ago). It also measures frequencies up to 64MHz which has been very helpful for me on in many cases. Now i need to be able to take more accurate measurements in my home workshop and intend to purchase APPA506 (for about €150), hope it worth it...