EEVBlog 121GW Multimeter Firmware Details - Page 1
Forum section: electronics / testgear

author: gnif
author_rank: Unknown
timestamp: January 12, 2018, 12:42:41 pm
content: Figured this would be of interest to some, I was expecting to see the firmware that this meter came with to be encrypted with at the very least some very basic xor, but turns out the 'EEVBlog.bin' firmware on the SD card is just the plain firmware, with what looks like a calibration file appended to the end of it (cal.dat)Code:geoff@sarah-xen:~/Projects/121GW$ arm-none-eabi-objdump -D -b binary -marm -Mforce-thumb EEVBlog.bin | head -n 21EEVBlog.bin: file format binaryDisassembly of section .data:00000000 <.data>:0: 4b78 ldr r3, [pc, #480] ; (0x1e4)2: 2000 movs r0, #04: 2879 cmp r0, #121 ; 0x796: 0802 lsrs r2, r0, #328: 0e35 lsrs r5, r6, #24a: 0802 lsrs r2, r0, #32c: 0e37 lsrs r7, r6, #24e: 0802 lsrs r2, r0, #3210: 0e39 lsrs r1, r7, #2412: 0802 lsrs r2, r0, #3214: 0e3b lsrs r3, r7, #2416: 0802 lsrs r2, r0, #3218: 0e3d lsrs r5, r7, #241a: 0802 lsrs r2, r0, #32...To explain:Code:0x20004b78 - The main stack pointer0x08022879 - The reset vector (this is thumb, so the address is actually -1)... etcI am yet to look more into this, but it's good news from the point of view of writing custom firmware for the meter.

author: dr.diesel
author_rank: Super Contributor
timestamp: January 12, 2018, 12:48:02 pm
content: That is good news!Since we now have a FW thread, my 121 came with v1.01 and I've seen references to 1.02? Considering the FW resides on the SDcard I guess someone with a 1.02 could post it for us on 1.01 to upgrade.

author: gnif
author_rank: Unknown
timestamp: January 12, 2018, 12:50:24 pm
content: Quote from: dr.diesel on January 12, 2018, 12:48:02 pmIndeed, mine has 1.01 on it, it would be interesting to compare the two.

author: Iagash
author_rank: Regular Contributor
timestamp: January 12, 2018, 02:15:08 pm
content: Quote from: gnif on January 12, 2018, 12:50:24 pmI attached version U-1.02 as zip file (at least I hope, since it is from my sd-card).I suggest not to upgrade from this file. It might contain cal-data only suitable for my meter.Just use it to compare against your files.

author: amspire
author_rank: Super Contributor
timestamp: January 22, 2018, 04:21:16 am
content: Gnif, from what you currently know, does it look like we can add our own firmware using the existing bootloader and binary update mechanism? In other words, can we load new experimental firmware and easily return to the official firmware?

author: EEVblog
author_rank: Unknown
timestamp: January 22, 2018, 06:03:07 am
content: FYI, as mentioned in another thread, v1.02 has a small bug fix for the calibration SD card import/export feature.

author: gnif
author_rank: Unknown
timestamp: January 22, 2018, 11:25:33 am
content: Quote from: amspire on January 22, 2018, 04:21:16 amIt seems so, I have been on break though and have not had an opportunity to play more with this yet. If the base address can be figured out there should be nothing stopping custom firmware being flashed into the device, it seems it has a boot loader that then hands over control to the program in ROM, but at this time I can not confirm if this bootloader contains the flash utility.When I find some more time I will attach to the JTAG port on the STM32 and see what I can do with it, if we get lucky they may have not set the read protection bit and we can dump the entire firmware out. If that doesn't work it shouldn't be hard to compile some code to dump it all out to the SD card or UART, etc...Note: I am very familiar with the STM32F1xx series chips, they remain my favorite micros, I am excited to see what I can make this meter do.PS: Thanks for the sticky Dave

author: mikeselectricstuff
author_rank: Super Contributor
timestamp: January 22, 2018, 12:17:40 pm
content: It would be very useful for someone to extract the bootloader, as during software development, for speed you'd want to flash the application code directly with a programmer rather than via SD card, but you'd want the ability to put the bootloader back agaon afterwards.

author: amspire
author_rank: Super Contributor
timestamp: January 22, 2018, 12:27:54 pm
content: I am just hoping that the IAP Binary update mode (Turn on with HOLD and MEM pressed) is completely in the bootloader. It would make sense for this to be so.If it is, we should be able to switch between the official firmware and experimental with the need of JTAG.

author: EEVblog
author_rank: Unknown
timestamp: January 22, 2018, 01:07:48 pm
content: Quote from: amspire on January 22, 2018, 12:27:54 pmYes, I believe that's how it works. Stock standard ST Micro IAP bootloader (with code to drive the LCD and buttons). I've taken out the SD card during firmware update and it recovers just fine.

author: tpw_rules
author_rank: Regular Contributor
timestamp: January 23, 2018, 03:13:13 am
content: I've set up a GitHub repository for future development and information,located here. The wiki on it is free to edit for anyone with a GitHub account. I plan to upload my IDA database tomorrow or so and work on documenting what I've found on the wiki. If you would like to help, please check out theQuestionspage. I haven't got my meter yet so I can't answer them.I've got pretty much the entire thing documented in terms of variables and functions. Some algorithms I don't know yet and would like help with. But there's a hell of a lot of information we can use to start our own firmware, which I also hope to do on perhaps a bit of a longer timescale.And as I mentioned previously, I have some firmwares edited with bugfixes, if anyone would like to test them out?

author: BU508A
author_rank: Super Contributor
timestamp: January 23, 2018, 07:09:31 am
content: Is it possible to put this information into the very first posting of this thread?Could be helpful finding it more easily imho.Thanks.

author: Mr.B
author_rank: Unknown
timestamp: January 23, 2018, 08:23:54 am
content: I don't have my meter yet.I will be in wave 2 of the shipping (March?).However, I am very interested in following the firmware thread - bookmarked, so to speak.

author: Iagash
author_rank: Regular Contributor
timestamp: January 23, 2018, 04:20:14 pm
content: Dave, could you provide us with the pinout of the jtag connector, so I could try to read out the bootloader and the option byte values with my ST-Link dongle?

author: tpw_rules
author_rank: Regular Contributor
timestamp: January 23, 2018, 09:17:45 pm
content: I've uploaded the database now. There's a lot more documentation to come too. I will really need y'all's help figuring out the reasoning behind the measurements. If we need to reimplement logging, whatever, but I'd really like to learn how and why the meter e.g. does frequency dependent offset for AC mode. Glance at theQuestionspage and see if you can figure something out.By the way, thank you to GitHub users htro for determining the chip and c-MM for finding the clock crystals (though I have a hunch there's still an oscillator somewhere).

author: tpw_rules
author_rank: Regular Contributor
timestamp: January 23, 2018, 09:19:41 pm
content: Quote from: Iagash on January 23, 2018, 04:20:14 pmI'd bet money it's ARM SWD. I don't think these smaller parts use JTAG. The pin list is in thedatasheetsomewhere; the meter uses the LQFP144 package. You're looking for SWCLK, SWDIO, NRST, VCC, and GND.Edit: I know you meant the pin header on the accessible side of the board, but if you have some time this would give the answer without waiting for Dave. Be sure to add it to the wiki!

author: ez24
author_rank: Super Contributor
timestamp: January 23, 2018, 09:36:26 pm
content: Reading(Interesting to see what happens with this meter and what members can do with it. My guess it is going to become a great meter because of the firmware updates)

author: Scottjd
author_rank: Frequent Contributor
timestamp: January 23, 2018, 10:08:03 pm
content: So what does Dave say, “For those who want to play along at home”....Well if the picturemin the other thread is correct the this is the data sheet.It’s the LQFP144 package, page 35 has the pinouts.http://www.st.com/content/ccc/resource/technical/document/datasheet/58/e3/b5/60/88/c8/4b/1b/DM00034689.pdf/files/DM00034689.pdf/jcr:content/translations/en.DM00034689.pdfUpdate: I guess I shouldn’t have kept my post in draft so long, lol. I was busy reading the data sheet myself and forgot to click post.

author: EEVblog
author_rank: Unknown
timestamp: January 23, 2018, 10:59:21 pm
content: Here is the schematic which may helpDavid2 is working on seeing what we can provide in terms of documentation to help people who want to write their own firmware.http://www.eevblog.com/files/121GW%20EEVBlog%20Circuit%20diagram.pdf

author: hwti
author_rank: Contributor
timestamp: January 24, 2018, 01:53:57 am
content: Quote from: EEVblog on January 23, 2018, 10:59:21 pmThe CN2 connector seems to be a debug interface for the BLE module.Can the STM32 update the bluetooth firmware with the serial port ?

author: Iagash
author_rank: Regular Contributor
timestamp: January 25, 2018, 06:23:34 pm
content: I hooked up the 121gw to my st-link and seem to be able to dump the flash.I also tried to read out the option bytes from the cpu.

author: chefkoch84
author_rank: Contributor
timestamp: January 25, 2018, 07:13:21 pm
content: I am a backer for the 2nd batch ... and looking forward to the new toy.I did have some look at the firmware and had it decompiled here:https://retdec.com/decompilation/I was surprised how easy and straightforward that was. - Of course, the code is not very readable... but in combination with know-how on the hardware, it should be possible to have some improvements.e.g. finding the function for the buzzer should be quite doable.I myself could not have a very detailed look yet.p.s. - perhaps somebody finds the source for this firmware on a USB-stick in the dumpster (next to a 500k$ scope or something ;-)If so... it would be a very nice move to upload it here...Edit: if you wanna use the attachments: remove the ".zip" extension from the filenames and process with 7zip. (The forum does not allow bigger files... nor files ending with .7z.001 )

author: Iagash
author_rank: Regular Contributor
timestamp: January 25, 2018, 07:25:05 pm
content: Quote from: Iagash on January 25, 2018, 06:23:34 pmHere is the openocd config file I used to dump the data:Code:# 121gw.cfg openocd configsource [find interface/stlink-v2.cfg]set WORKAREASIZE 0x4000source [find target/stm32lx_dual_bank.cfg]# use software resetreset_config noneinitreset haltflash probe 0Here is how I connected the meter. I didn't use the reset line.Code:/ 1 Vcc -------- 8 3.3V \| 2 Reset ------ NC |121gw - + 3 TMS/SWDIO -- 4 SWDIO + ST-Link-v2 miniCN3 | 4 TCK/SWCLK -- 2 SWCLK |\ 5 VSS -------- 6 GND /This way the meter is powered by the ST-Link and you need to make sure to switch it on or the CPU will be kept in reset mode.I used the LowZ range, but other ranges will probably work too.Start openocd with:Code:sudo openocd -f 121gw.cfgAnd the connect to it in another terminal with:Code:telnet localhost 4444

author: tpw_rules
author_rank: Regular Contributor
timestamp: January 25, 2018, 10:24:51 pm
content: Quote from: chefkoch84 on January 25, 2018, 07:13:21 pmIf I may toot my own horn a little bit, I'm already ahead of you. If you're interested, check it outhereand feel free to contribute to the wiki.Quote from: Iagash on January 25, 2018, 06:23:34 pmThank you so much for both of those (along with the cal data from earlier) and the detailed instructions you provided on doing it yourself. I've added all three things to the GitHub. By the way, your meter has version 1.02, correct? That's what the dump seemed to indicate.

author: Iagash
author_rank: Regular Contributor
timestamp: January 25, 2018, 10:59:03 pm
content: Quote from: Iagash on January 25, 2018, 06:23:34 pmI'm not sure about these if I did it right. I'll look into them tomorrow with the datasheet to see if they make sense.This is my first encounter with STM32, I just used AVRs up to now. I'll have to do a lot of reading.Quote from: tpw_rules on January 25, 2018, 10:24:51 pmYes this is correct.Thank you a lot for your work investigating the firmware! This is very interesting.I get you are also one of the early backers and you meter is stuck at UEi in the US. If you don't mind a wobbly switch, Dave might be able to poke them a bit to send your meter out early.Edit:And also a lot of thanks to Dave and UEi for not setting the readout protection on the STM32! I sincerely hope they don't regret it.

author: tpw_rules
author_rank: Regular Contributor
timestamp: January 25, 2018, 11:27:31 pm
content: Quote from: Iagash on January 25, 2018, 10:59:03 pmAs far as I can tell, you did. Most of the memory should be 0s as it's not actually mapped to anything. The rest of them are two-byte complement pairs. I didn't actually decode them to see what they mean. Page 73 of the reference manual has all the details.And welcome to ARM! I made that transition a year or so ago and it's great. Everything is more complicated and there's more reading to do, but you get a heck of a lot of cool stuff and power in return.Quote from: Iagash on January 25, 2018, 10:59:03 pmMe too. Thanks also to UEi for not encrypting the firmware and for not using compiler optimizations. That's being extremely nice to hackers

author: bicycleguy
author_rank: Frequent Contributor
timestamp: January 28, 2018, 02:43:46 am
content: Quote from: tpw_rules on January 23, 2018, 03:13:13 amLooked at your github and am really amazed at all you have figured out and documented. Looks better documented than most new code!I have a few questions if you don't mind. Most are not about the 121GW but about the process. I've done a lot of micro coding but never decompiling.1. Looks like C++ because I see the word 'class' around a lot. Is this why you commented 'everything is global' ie. the decompiler put all the class object data in one big pile?2. Since you have modified firmware already (and tested by Dave somewhere) does that mean you were able to recompile the code. I don't see how that could happen without all the object definitions, headers ect. Could you illuminate further. Is the binary just patched ? I didn't see any C++ code.thanks

author: amspire
author_rank: Super Contributor
timestamp: January 28, 2018, 03:05:10 am
content: Fantastic, I have just cloned your repository.Ages since I have used a decompiler. Did you rebuild the C++ code from the assembler? That seems to be pretty amazing.

author: tpw_rules
author_rank: Regular Contributor
timestamp: January 28, 2018, 03:09:52 am
content: Quote from: bicycleguy on January 28, 2018, 02:43:46 amThank youI made great use of IDA 6.6 and the Hex-Rays decompiler. It automated all the disassembly and decompilation; my job was going and figuring out what e.g. the functionsub_801C504and variabledword_20003908did.Quote from: bicycleguy on January 28, 2018, 02:43:46 amUm I'm not sure where you've seen the word 'class'. I did a search of the repo and could not find that word anywhere. What I mean by 'everything is global' is that there are several functions (e.g.meas_ohms_calc_50M_offset(digits, factor)) where all the intermediate variables are stored as globals and only read/written in that function. This makes no sense and I'm pretty sure it can't be caused by the compiler.Quote from: bicycleguy on January 28, 2018, 02:43:46 amNo, I'm not yet able to recompile the code. I do want to have that available so everyone can play with the firmware, but I haven't taken the time to try it, see what's missing, etc. It's definitely possible, but may be a crazy amount of work. And I still would have no way to test it. For now, I just hand-assembled ARM instructions and patched the binary. It's a lot easier because the compiler wasn't very efficient and so space can easily be made for new code.is the assembly for the bit I patched, andis it after the patch. You can see I was able to make more efficient use of registers and fit in an extra test, store, and branch that doesif (autorange_changed_range) meter_mode_range_change_delay = 0;

author: tpw_rules
author_rank: Regular Contributor
timestamp: January 28, 2018, 03:11:49 am
content: By the way, Dave, if you're reading this, I sent you a PM a couple days ago? I sent an e-mail to dave@eevblog.com as well. It might have got lost in the shuffle.

author: Brumby
author_rank: Unknown
timestamp: January 28, 2018, 11:58:11 am
content: Quote from: tpw_rules on January 28, 2018, 03:09:52 amIt's been a lot of years since I've done that - and it was on a systems module on an IBM mainframe.Making the change isn't all that difficult - it's knowing that you haven't broken something in doing so that is the challenge. The decompile would have helped immensely ... I had to do mine from a hex dump.The big thumbs up comes from doing this without being able to test it on meter.Champion stuff.

author: Fungus
author_rank: Super Contributor
timestamp: January 28, 2018, 03:30:22 pm
content: Quote from: Brumby on January 28, 2018, 11:58:11 amBonus points for doing it in a EPROM where you can only change 1s to 0s.(I did that once)

author: bicycleguy
author_rank: Frequent Contributor
timestamp: January 28, 2018, 06:24:17 pm
content: Quote from: tpw_rules on January 28, 2018, 03:09:52 amI'm not sure where I got that from either, probably a brain fart although the vapors are still hanging, sorry.The top of the 'EEVBlog-102.c':Code:/* This file has been generated by the Hex-Rays decompiler.Copyright (c) 2007-2014 Hex-Rays <info@hex-rays.com>Detected compiler: GNU C++*/I guess this means the GNU C++ compiler was used, not that the code is C++ ?

author: exe
author_rank: Unknown
timestamp: January 30, 2018, 09:16:03 am
content: Sorry, I'm a bit late to the party. Is there a version of decompiled sources that could be modified a compiled? Or people directly modify binary code?

author: tpw_rules
author_rank: Regular Contributor
timestamp: January 30, 2018, 05:45:59 pm
content: Quote from: exe on January 30, 2018, 09:16:03 amIt would in theory be possible to recompile the source from the decompiler but I don't know how actually feasible it is. I've just been hand-assembling and patching the binary. I would like to see the sources recompiled at some point though.

author: exe
author_rank: Unknown
timestamp: February 01, 2018, 08:26:30 pm
content: chefkoch84, thanks for providing decompiled FW. Do you know how to compile it back? I believe this should be possible. Unfortunately, I don't have much experience with ARM (I do software for web-servers). So, I picked some random gcc flags used by CubeMX from one of my old project, gcc still complains. I don't bother with missing main function (I believe it just has a wrong name), but I'm worried about other functions missing. How come they are not present in the code?I also tried snowman, another ARM decompiler, but it seems it expects and ELF executable, not raw FW binary. Too bad, that tool produced a useful result to me. May be it's time to roll a completely new FW written from scratch? I'll try to start with an empty CubeMX project... when time permits. Since now we have schematics it should be relatively easy to create a proof of concept (I'm not talking about correct measurements or display working).Code:arm-none-eabi-gcc -mthumb -mcpu=cortex-m4 -mfpu=fpv4-sp-d16 -mfloat-abi=hard --specs=nosys.specs ./EEVBlog.c(.text+0x44): undefined reference to `main'/tmp/ccgtjcep.o: In function `function_117dc':EEVBlog.c:(.text+0x21f0a): undefined reference to `unknown_117bc'/tmp/ccgtjcep.o: In function `function_158ec':EEVBlog.c:(.text+0x294c4): undefined reference to `unknown_ff696e8c'EEVBlog.c:(.text+0x299dc): undefined reference to `unknown_ff696ed4'EEVBlog.c:(.text+0x299e4): undefined reference to `unknown_ff397cfc'/tmp/ccgtjcep.o: In function `function_16ac0':EEVBlog.c:(.text+0x367d6): undefined reference to `unknown_fff9a9c0'EEVBlog.c:(.text+0x36812): undefined reference to `unknown_fff982e8'/tmp/ccgtjcep.o: In function `function_1a4e8':EEVBlog.c:(.text+0x43928): undefined reference to `unknown_fff9b7bc'/tmp/ccgtjcep.o: In function `function_1b872':EEVBlog.c:(.text+0x48054): undefined reference to `unknown_110c4c'EEVBlog.c:(.text+0x48060): undefined reference to `unknown_ffe3ac50'EEVBlog.c:(.text+0x48068): undefined reference to `unknown_fff71c54'EEVBlog.c:(.text+0x48074): undefined reference to `unknown_ff6b4c58'EEVBlog.c:(.text+0x4807c): undefined reference to `unknown_ff801c5c'EEVBlog.c:(.text+0x4809e): undefined reference to `unknown_fff59c60'/tmp/ccgtjcep.o: In function `function_1beee':EEVBlog.c:(.text+0x48934): undefined reference to `unknown_1bf4c'collect2: error: ld returned 1 exit status

author: exe
author_rank: Unknown
timestamp: February 01, 2018, 09:12:07 pm
content: I just sacrificed one meter, the chip is STM32L152ZDT6 . Too bad this is not specified on schematic.UP: looks like LCD is driven directly. So, no fancy proprietary drivers or something. Damn, wtf UEI does not release their crappy firmware opensource, I don't believe it is too difficult to write a firmware.

author: firewalker
author_rank: Super Contributor
timestamp: February 01, 2018, 09:33:24 pm
content: We knew the mcu part number.https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/msg1406994/#msg1406994Alexander.

author: exe
author_rank: Unknown
timestamp: February 01, 2018, 10:10:07 pm
content: That's the problem, information is spread all over three threads. Unfortunately, I don't follow all of them, nor I have enough memory to remember who said what and where.Anyway, following the instructions here I have openocd working:Code:Escape character is '^]'.Open On-Chip Debugger> dump_image dump.bin 0x08000000 0x1ffffdumped 131071 bytes in 6.293624s (20.338 KiB/s)I'll try to make a hello world over weekend, if time permits. Although, I don't mind if somebody else will do this ahead of me.

author: cwalex
author_rank: Frequent Contributor
timestamp: February 02, 2018, 03:38:00 am
content: Does anyone know if there has been an official firmware update released that fixes the slow auto range we can download and use to update our multimeters?It would be nice if there was a support web page that we could go to for news and updates on current issues being worked on and official updates, instructions, info, etc. Does a page like this exist yet?

author: exe
author_rank: Unknown
timestamp: February 02, 2018, 08:25:28 am
content: To the best of my knowledge, there is no such page. AFAIK, All the news are here:https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/?topicseen. Short digest: many problems are acknowledge by the manufacturer, but no ETA yet. Dave does not post much, though. Perhaps, because there is nothing to say (and, I guess, to preserve good relationship with the manufacturer).My biggest concern is that we are not told what UEI is going to do. I don't want to spend a lot of time on FW if there is a new FW release solving all the issues. I also understand that doing software is not easy. There might be very nontrivial things like temperature and age compensation. Or workarounds for HW problems, etc.Quote from: cwalex on February 02, 2018, 03:38:00 am

author: exe
author_rank: Unknown
timestamp: February 02, 2018, 10:37:10 pm
content: I tried to generate some code with the latest CubeMX, looks like it has a bug: some source files are mentioned twice in generated Makefile. This causes "multiple definition of XXX" problem. But this is easy to fix.Now I'm trying to enable buzzer or lit some segments on LCD (assuming 1/4 duty cycle), no luck. I followed this instruction to setup openocd:https://sourcegate.wordpress.com/2012/09/18/getting-started-with-an-stm32l-discovery-with-linux-and-gcc/. According to GDB my program is up and running. Uhm, may be it's time to read some manuals... Concerning LCD, I found this one: "How to use the STM8AL3Lxx, STM8L152xx and STM8L162xx LCD controllers" (http://www.st.com/content/ccc/resource/technical/document/application_note/0d/99/cb/9c/dc/73/42/52/CD00257713.pdf/files/CD00257713.pdf/jcr:content/translations/en.CD00257713.pdf)I keep trying.UP: buzzer (PE7) works! I had to disable LCD driver. Cool, now it's time to figure out what's wrong.

author: exe
author_rank: Unknown
timestamp: February 02, 2018, 11:02:23 pm
content: Alright, now I know what's happening (sort of). HAL_LCD_Init() returns HAL_TIMEOUT. Looking at the code, it seems that more initialization is needed. Perhaps, it's really time to open the manual (or find a working example on stackoverflow).Catch you next time!

author: tpw_rules
author_rank: Regular Contributor
timestamp: February 05, 2018, 04:11:20 am
content: Just as a reminder, the 121GWreverse engineering information repositoryis available. There's a new update with some more juicy hardware bits.But now, there's also anIDE template already set upfor you to write your own firmware. Instructions for setting it up are in the repository README. The best part is that you don't even need a programmer!If you'd like to say hello to your meter too:Put the EEVBlog.bin on your meter's SD card in a safe place (or get a copy of v1.02here)Copy the built EEVBlog.bin from the template onto the SD card (or get a pre-built copyhere)Execute the IAP procedure as detailed in the user manual (boot with MEM and HOLD buttons held, then press SETUP)To restore the official firmware, just put it back on the SD card and execute IAP again. Calibration EEPROM data will not be touchedNote that the IAP procedure requires the firmware on the SD card to be named EEVBlog.bin; you might have to rename files.

author: exe
author_rank: Unknown
timestamp: February 05, 2018, 02:01:54 pm
content: Thanks a lot! Would it be useful if I try writing a buttons driver?The way I see it: timer polls button state (polling is for debouncing). Pressed buttons go into a queue (here some de-duplication needed if button remains pressed for several polling periods). If button remains pressed for more than certain time then this is a "long press". The keypress is logged at button release. At the moment only single key press would be supported to make life easier. The "queue" is a simple array with a few pointers and item counter. May be no need for a queue, just remember the last press.I'm not sure how this fits the overall architecture of the FW though. I mean, menus, etc.

author: TD-Linux
author_rank: Contributor
timestamp: February 11, 2018, 12:28:17 pm
content: Quote from: tpw_rules on February 05, 2018, 04:11:20 amHave you decided on a license for your code? FYI, most of the newer ST code is under a 3-clause BSD, but the SD card code in Src/ is not.

author: tpw_rules
author_rank: Regular Contributor
timestamp: February 12, 2018, 03:29:24 am
content: Quote from: TD-Linux on February 11, 2018, 12:28:17 pmI was thinking about something GPLey, as I'd rather like to avoid UEI just taking it and folding it into their meters.All the code I can see looks to have the same license? At least it's got the same header as the others. I'm not experienced in such matters. I was just going to drop the GPLv3 in LICENSE in the root but I'm not sure if that is safe.

author: amspire
author_rank: Super Contributor
timestamp: February 12, 2018, 04:05:06 am
content: It may be not a bad idea to use a permissive license that allows UEi to freely use the open source code in their multimeters.For one thing, it may have the effect that people such as EEVBLOG forum members start getting better multimeters. With a permissive license, any or every multimeter company could use parts of our 121GW code if they want.Also, if we implement some new Bluetooth communications protocols for the 121GW and the same protocol starts appearing in many other multimeters, is that a bad thing?There are aspects of GPL that are impossible for many companies to live with in their products. GPL does do a bit of "You have to do exactly what I tell you to do" and that is not exactly free.Is the point of the code to allow 121GW owners to reprogram their meters which only needs a permissive license, or are there other goals in mind that require a GPL license?

author: exe
author_rank: Unknown
timestamp: February 13, 2018, 09:16:16 pm
content: Shame on me, guys, I don't have free time at the moment to work on this. Hope to get back in a few weeks. Sorry. I also have to learn a lot since my experience with MCU is very limited.

author: Yannik
author_rank: Unknown
timestamp: February 15, 2018, 10:36:58 am
content: With a GPL license, UEI and other companies can still use the code. However, they need to share their improvements to the code, which is just fair. Therefore, I strongly support the use of a GPL license for this.

author: amspire
author_rank: Super Contributor
timestamp: February 15, 2018, 11:29:42 am
content: Quote from: Yannik on February 15, 2018, 10:36:58 amIf for internal reasons which is their business, UEi just cannot GPL code, is it better if they can make use of our code and so everybody gets our improvements, plus their secret source, or is it better that they ignore our code.In projects like this, there will always be one person who does the bulk of the work and I am totally happy if that person picks any license they want to. However GPL is open, but it is very dictatorial. There are many open source projects that pick permissive license for the reason that they want others to be able to use the code without any demands. It may be UEi have some secret source relating to their in-house calibration methods that they absolutely cannot make open source.Remember, UEi are giving us something - they designed the meter with the features Dave asked for and they have given us the schematic. Through Dave, we have direct contact with someone who can talk to the developers. That is probably more then any other multimeter company has given. We want to encourage UEi to continue to make the meter, otherwise any code we produce will only be useful to a few hundred people (assuming most only use official firmware) and the project may die in a year or two.

author: glarsson
author_rank: Frequent Contributor
timestamp: February 15, 2018, 11:32:24 am
content: The GPL license also requires them to share everything the GPL code is linked to. In the case of this multimeter it is everything. If they can't share everything (licensed 3:rd party libraries) then they can't use the GPL code, will not make improvements and have nothing to share. A loss for everyone.

author: Brumby
author_rank: Unknown
timestamp: February 15, 2018, 01:54:44 pm
content: There is an alternative...They can take the improvements as seen from the User perspective - and then code their own changes to deliver the same, or similar (or better?) benefits.While they may not have the benefit of the coding, they will have the benefit of knowing something is possible and - as is typical of this community - the issues addressed along the way.As a further advantage and incentive - by seeing what features/fixes get support here, they will have a better idea of what is worth the effort.

author: cjs
author_rank: Contributor
timestamp: February 18, 2018, 05:20:31 am
content: One more thing to keep in mind with your license:Unless you're getting copyright assignments forallcontributed code, that code not assigned to you or your project remains owned by the contributor and only he or she can relicense it under any other terms. Once your project starts to grow this can effectively preclude changing the license even if everyone agrees that they want to change it. This happened to us withNetBSD; although everybody wants to move all the code to a two-clause BSD license (in part because the advertising clause of the 4-clause license is especially annoying) there is a great deal of code that cannot have the licence changed because we can't track down the owners of the copyright. (The owner may not even be the author, such as in cases where the author is deceased.)Regarding inability to use GPL code, that can go beyond amspire's points that a company may have internal reasons that they don't want to open all the source in their devices. Source code licensed from external vendors may not allow it even if the company would prefer to do it. Or, worse yet, certain open source licences are incompatible with the GPL, meaning that there are cases where you can't combine code from two different open source projects.Personally, as someone who's been writing both opens-source and commercial software for a couple of decades now, I use GPL and accept only code with a copyright assignment to me when I'm interested in preserving my own ability to exploit the code commercially at a later date. The GPL in this case is essentially a commercial profit protection mechanism. If I don't anticipate that I'd want to commercialize a product, I use a much less restrictive license so that the code can do maximum good in the world.

author: amspire
author_rank: Super Contributor
timestamp: February 18, 2018, 06:03:58 am
content: Quote from: cjs on February 18, 2018, 05:20:31 amIf the GPL license is used, this is the exact model I would like to see. Almost certainly, one person will be responsible for making this code into a quality reality and they deserve to have the copyright assignment. It would mean that they would be able to offer companies an alternate paid commercial license if that is what the companies need.It might be that the SQLite3 model is the best one to follow. SQLite is open source but is not open contribution. They do not even accept patches. With this model, anyone can go and make their own variant, but if you want to use the official SQLite code, you are using code that has almost fully been written by just two people.With one person or one team writing the 121GW code, you can get a consistent coding quality and the finally reliability is totally in the hand of the programmers who know the code the best. They can take suggestions and bug reports, but they then make the changes themselves.One direction this code could go would be towards general purpose multimeter code with a big config.h file which allows you to set pin assignments, multimeter A/D chip choice and so on. The code does not have to be only for the 121GW multimeter. Something like the OpenWRT project that at the start only worked on one Linksys WRT54 router. Now it works on many different processors with many different chipset options.

author: tpw_rules
author_rank: Regular Contributor
timestamp: February 18, 2018, 05:46:17 pm
content: So I've been looking and a BSD 3-clause license doesn't seem entirely unreasonable. I thought GPL initially because I didn't really want UEI taking our code for nothing in return to improve their meters, but if they can't do that I guess it becomes a kind of pointless exercise.Now how do I license the code under that? Can I just drop LICENSE.md in the Git root? How does this affect all the STMicro library code?

author: Diosol
author_rank: Newbie
timestamp: February 19, 2018, 10:17:51 pm
content: I'm kinda blind and don't know how to use google. But I just haven't found where to download the newest firmware. Like 1.05 shown in newest video. At the moment this is just a blue expensive brick in my hands.Does anyone have a link where the newest firmware's are hosted or can be downloaded?

author: lowimpedance
author_rank: Super Contributor
timestamp: February 19, 2018, 11:04:43 pm
content: The later revision firmware is being tested and refined thus has not been released yet, so no download links exist. (vers 1.05 may even be no longer the current one).The meter is still usable and is hardly a complete brick. As stated this testing (inside UEI currently) takes time and its best to wait for the currently reported bugs to be fixed.And then a new much improved firmware be made available.

author: Yannik
author_rank: Unknown
timestamp: February 24, 2018, 09:50:39 am
content: I'd still be in favour of a copyleft license. Maybe LGPL is a good compromise?

author: newbrain
author_rank: Super Contributor
timestamp: February 25, 2018, 08:26:29 am
content: Quote from: Yannik on February 24, 2018, 09:50:39 amIt could be used, but given that static linking is used:QuoteUEI (or anyone else using the code) would be forced to distribute the objects from its application (and possibly any special tool needed for the relinking, but not 100% sure).This is not an unreasonable burden, but can still be seen as showstopper in a corporate environment.LGPL is ok when you can dinamically link or use a form of IPC, but that rarely applies to embedded code.

author: Halcyon
author_rank: Unknown
timestamp: May 17, 2018, 05:59:56 am
content: On the subject of firmware, has there been any official/stable release of firmware beyond 1.01? Forgive me if details have been posted elsewhere.

author: firewalker
author_rank: Super Contributor
timestamp: May 17, 2018, 07:47:04 am
content: Quote from: Halcyon on May 17, 2018, 05:59:56 amYes. 1.15https://www.eevblog.com/wp-content/plugins/download-attachments/includes/download.php?id=12211

author: Candid
author_rank: Regular Contributor
timestamp: May 24, 2018, 03:19:28 pm
content: 1.17 is out but no changelog:https://www.eevblog.com/wp-content/plugins/download-attachments/includes/download.php?id=13009And new manual dated 24th May 2018:https://www.eevblog.com/wp-content/plugins/download-attachments/includes/download.php?id=13012

author: ChunkyPastaSauce
author_rank: Unknown
timestamp: May 24, 2018, 03:40:23 pm
content: Change log is in new manual 1.17: "Improved accuracy of voltage measurement in AC and DC VA modes."

author: Candid
author_rank: Regular Contributor
timestamp: June 15, 2018, 10:01:15 am
content: 1.21 is out but no change log (manual still 24th May):https://www.eevblog.com/wp-content/plugins/download-attachments/includes/download.php?id=13372

author: Dampmaskin
author_rank: Newbie
timestamp: June 22, 2018, 01:18:31 pm
content: I wonder what's new in 1.22.https://www.eevblog.com/wp-content/plugins/download-attachments/includes/download.php?id=13423

author: Seppy
author_rank: Unknown
timestamp: June 25, 2018, 02:07:27 am
content: Manual has been updated with the changes that occured in 1.21 and 1.22.

author: Jon.C
author_rank: Unknown
timestamp: June 25, 2018, 05:39:59 am
content: Quote from: Dampmaskin on June 22, 2018, 01:18:31 pm

author: tpw_rules
author_rank: Regular Contributor
timestamp: August 05, 2018, 04:33:49 pm
content: Quote from: joeqsmith on August 01, 2018, 10:17:49 pmFor the record, there's nothing particularly interesting in the BLE112, but I believe it is 121GW specific. The STM32 talks to it over RS232 at 19200 baud using the following format (sans quotes): "=<packet data as documented, in hex>\r\n". It can also receive raw bytes from the bluetooth connection. I imagine this firmware is an example somewhere in the SI stuff, but I haven't found it.

author: Candid
author_rank: Regular Contributor
timestamp: August 07, 2018, 02:47:41 pm
content: v1.25 is out and new manual with changelog...https://www.eevblog.com/product/121gw/

author: cmumford
author_rank: Contributor
timestamp: August 07, 2018, 03:46:12 pm
content: Quote from: Candid on August 07, 2018, 02:47:41 pmChanges since 1.22:Auto-ranging loop in M Ohms range resolved..Burden Voltage glitch resolved.

author: 1anX
author_rank: Regular Contributor
timestamp: August 11, 2018, 10:25:18 am
content: I just tried loading in the latest V1.26 but unfortunately after many attempts had to give up on it.Loaded V1.25 back on to the SD card and it loaded onto the meter without a problem.Maybe the image of the V1.26 file Dave has placed to download is the problem?Anyone else tried to install the new firmware yet?

author: firewalker
author_rank: Super Contributor
timestamp: August 11, 2018, 10:51:54 am
content: No problem for me. Did you rename the file to EEVBlog.bin?Alexander.

author: 1anX
author_rank: Regular Contributor
timestamp: August 11, 2018, 11:11:08 am
content: Quote from: firewalker on August 11, 2018, 10:51:54 amYep your right, it was my mistake after numerous updates I managed to forget to drop off the version number from the bin file

author: Zkronk
author_rank: Newbie
timestamp: August 12, 2018, 08:43:55 am
content: What is new in the 1.26 firmware?The bin-file is available on the EEVBlog-site, but the change log in the PDF-manual is not updated

author: firewalker
author_rank: Super Contributor
timestamp: August 12, 2018, 09:03:12 am
content: Quote from: EEVblog on August 11, 2018, 07:59:24 am

author: firewalker
author_rank: Super Contributor
timestamp: August 14, 2018, 08:01:28 pm
content: Have anyone decoded the binary file with the calibration data?Alexander.

author: tpw_rules
author_rank: Regular Contributor
timestamp: August 14, 2018, 08:04:29 pm
content: Quote from: firewalker on August 14, 2018, 08:01:28 pmSure have. If you've got python 3 or above, runthis scriptwith the first argument pointing to the file.

author: firewalker
author_rank: Super Contributor
timestamp: August 14, 2018, 08:19:20 pm
content: Thank you!!! <3 <3 <3Alexander.

author: firewalker
author_rank: Super Contributor
timestamp: August 14, 2018, 08:26:43 pm
content: The offset number is directly added to the adc result? Is the function that involves the values read form the adc, the calibration data and the displayed number known?Alexander.

author: tpw_rules
author_rank: Regular Contributor
timestamp: August 14, 2018, 09:04:24 pm
content: Quote from: firewalker on August 14, 2018, 08:26:43 pmYeah, it's all detailed in the reverse engineering. I suggest you consult that if you are curious because I'm too lazy to explain everything. But to put it in a sentence, bargraph = (ADC - offset) * gain, and screen = smooth(average(bargraph) - nonlinearity_corr), where average is the average of 8 or 16 bargraph samples, nonlinearity_corr is some nonlinearity offset calculated using some data tables and the listed coefficients in a manner that I don't entirely understand, and smooth is a rolling average that resets if the difference between samples is too large.May I ask why you are interested in knowing all this?

author: firewalker
author_rank: Super Contributor
timestamp: August 14, 2018, 09:12:55 pm
content: I was wondering if it is possible to recalibrate offset by hand editing the calibration data. Because someone (Dr. Frank) mentioned that someone might have to complete and the full scale gain calibration in order the meter to save and accept the zero offset data. But this mean specialized equipment.Alexander.

author: tpw_rules
author_rank: Regular Contributor
timestamp: August 14, 2018, 09:18:59 pm
content: Quote from: firewalker on August 14, 2018, 09:12:55 pmIt would be possible. However, according to my knowledge of the firmware, the corresponding factor is saved before the G-END or OFF-E message is displayed. So you can just turn off the meter after offset calibration to skip gain calibration. But of course, the offset factor is used when calibrating the gain factor, so one would be advised to do gain as well. Maybe someone can work out the math to adjust the gain factor, and hand edit that in.

author: Lion_Tamer
author_rank: Contributor
timestamp: September 02, 2018, 07:54:57 pm
content: Hi allI have finally had time to sit down and start playing with the meter properly, although I would love to have completely open source firmware I also know that I don't have the skill or knowledge to write it, I also don't have the time or equipment to do the extensive testing required but thought that I could contribute by at least dumping out the firmware from the BLE112 blue tooth module (I know that at least Joe has a meter with an un-programmed module and though it would be useful in case anyone bricks one).I did this using the "Texas Instruments Smart RF Flash Programmer" software with a "CC Debugger" connected to the CN2 port in the 121GW - connections as below:121GW <=> CC DebuggerPin 1 <=> Pin 7Pin 2 <=> Pin 2 + 9Pin 3 <=> Pin 1Pin 4 <=> Pin 3Pin 5 <=> Pin 4In time I may try to reverse engineer it a bit more but I suspect that my lack of expertise will hinder me there.JemP.S. this was dumped from meter no 180701854 running firmware version 1.26

author: Lion_Tamer
author_rank: Contributor
timestamp: September 27, 2018, 09:14:56 pm
content: I found that I was struggling to understand the official Packet protocol document so as I don't currently have a blue tooth interface for the PC I have been looking at the UART streams between the STM32 processor and the BLE112 blue tooth interface on the meter and am slowly creating a more detailed document about the 19 byte packet.I have attached what I have got so far below along with a screen shot of a packet as captured from my meter.Note: Meter Firmware Version 1.51Jem

author: Lion_Tamer
author_rank: Contributor
timestamp: September 27, 2018, 10:12:07 pm
content: Its a 19 byte packet from the STM32 to the BLE112 inside the meter, I don't know if the BLE112 adds any packets before it transmits it to the receiving device, I intend to try and look at the transmitted data as well at some point to see if it does add stuff but don't have a compatible blue tooth receiver for the PC.Jem

author: Dampmaskin
author_rank: Newbie
timestamp: October 30, 2018, 11:59:37 am
content: Now version 1.51 is gone fromthe product page, and 1.26 is the newest. What happened?

author: Candid
author_rank: Regular Contributor
timestamp: October 30, 2018, 04:48:10 pm
content: So as a 121GW user I would like to hear about the reason or at least if I should downgrade to 1.26.

author: GeoffreyF
author_rank: Regular Contributor
timestamp: November 01, 2018, 02:06:56 pm
content: I figured it was just an oversight with managing the web page. Possibly still there may be problems with attending to this due to the move. I wish someone would comment on this matter. I did install 1.51 in my meter. I see no problems but I'm wondering what's what.

author: MrPeak
author_rank: Newbie
timestamp: November 03, 2018, 06:06:36 pm
content: I've installed the 1.51 FW, a month ago, without any issues. I want to know why the FWwas removed. There is another thread, where a user complains that the calibration data ispartly wrong after upgrade to 1.51.Maybe someone can bring a little bit clarity about the background. I'm afraid that my calibrationdata is also corrupt.

author: cmumford
author_rank: Contributor
timestamp: November 05, 2018, 01:00:23 am
content: I also upgraded to 1.51, but didn't use the meter post upgrade. I'd love to know if I should downgrade.

author: gdewitte
author_rank: Unknown
timestamp: November 05, 2018, 09:16:17 pm
content: And now 1.52 is out there. Could someone please give us an update?

author: GeoffreyF
author_rank: Regular Contributor
timestamp: November 05, 2018, 10:48:41 pm
content: Being of an empirical and somewhat adventurous nature, I decided to install the firmware labeled 1_52. The meter started back up just fine but comedy ensued, the firmware revision is reported as 1_53. I checked this several times lest my eyes deceived me. 1_53. I suppose I can state the result is better than expected, at least numerically.Cursory examination, the meter seems OK. I'm still wondering if, after 1_51, it's still calibrated. but I think it is. I'd like a way to verify that - what a "bricked calibration" looks like is not what mine looks like. I'm thinking that the incident that initiated pulling 1_51 was fairly anomalous but can we get confirmation?

author: CDaniel
author_rank: Frequent Contributor
timestamp: November 05, 2018, 11:35:14 pm
content: I installed v1.52 , so far I see a big improvement in reducing the 50Hz noise in resistance mode , now when measuring Mohm resistors you can touch the probes and cables .The beep sound in diode mode is still laggy ...

author: GeoffreyF
author_rank: Regular Contributor
timestamp: November 06, 2018, 02:14:31 am
content: Quote from: CDaniel on November 05, 2018, 11:35:14 pmDid it report 1.53 when when you first started it? I think resistance resolution seems faster. I don't think that beep is supposed to happen with all diodes. Beep happens only when resistance is very low. It's responding to apparent continuity.

author: CDaniel
author_rank: Frequent Contributor
timestamp: November 06, 2018, 07:13:32 am
content: Quote from: GeoffreyF on November 06, 2018, 02:14:31 amYes of course it display 1.53 ...The beep when you are shorting the probes is laggy , so when measuring a shorted transistor or diode you have to wait a moment ... not good at all . Every other multimeter is much responsive .In continuity mode the beep is very fast responding , so I don't see any reason why in diode mode is laggy .

author: GeoffreyF
author_rank: Regular Contributor
timestamp: November 06, 2018, 02:56:01 pm
content: Quote from: CDaniel on November 06, 2018, 07:13:32 amI am using Probemaster probes but even with the ones which came with (that I believe are UEI Test) - I have found no lag at all on beep, simply striking the probe tips against one another or bring the tips together, is an immediate beep. Something may be off with your unit. When you short the probes, what is the resistance reading?

author: CDaniel
author_rank: Frequent Contributor
timestamp: November 06, 2018, 04:03:53 pm
content: The beep lag is only in diode mode ( maybe 0.5sec ) , in continuity mode is very fast .Resistance is zero when shorting the probes

author: GeoffreyF
author_rank: Regular Contributor
timestamp: November 06, 2018, 04:44:34 pm
content: There is no mention of diode beep in the manual. According to the manual there is a 2.2k resistor and a PTC in series with the DUT. Literally the diode test is not supposed to Beep except that is a side effect of the continuity function for diodes with low enough forward current to trigger it. It's hardly surprising that when the beep happens - it is "laggy". it's not a simple continuity test.You are wanting something to work that is not part of the published feature set.

author: CDaniel
author_rank: Frequent Contributor
timestamp: November 06, 2018, 05:03:01 pm
content: Every decent multimeter has the beep in diode mode ... and is fast , feature or notIf you really work with the multimeter repairing something you will know why .

author: GeoffreyF
author_rank: Regular Contributor
timestamp: November 06, 2018, 07:38:53 pm
content: Quote from: CDaniel on November 06, 2018, 05:03:01 pmI have repaired a lot of things. I have repaired many things for many weekly pay checks. I like numbers a lot. I like to see that the device has the numbers it should. A beep is simply low resistance. Do you get a reassuring "unbeep" when you measure in the opposite polarity?If it doesn't say it on the tin (and it doesn't in this case) then you have no right to expect it. What I have learned is to read the manual before I make a purchase. If it says "it beeps for diodes" on some other device, I would want to know EXACTLY what constitutes "beep worthy". What would a diode beep mean to me diagnostically?Can you offer a link to a multi-meter online manual (or spec) that satisfies your diode beeping needs? I'd be interested to see how it is specified.

author: tautech
author_rank: Super Contributor
timestamp: November 06, 2018, 07:49:41 pm
content: Quote from: GeoffreyF on November 06, 2018, 07:38:53 pmI agree.Diode beep is BS, it's more likely the beep is issued when a stable measurement is seen/known.

author: CDaniel
author_rank: Frequent Contributor
timestamp: November 07, 2018, 06:24:58 am
content: A delayed beep is annoying , or is fast or not at all ... Fluke behavior is what should be expected from a decent multimeter .When you work on a board you want to find fast the shorted semiconductors , you don't have time dicking around waiting for the meter ... and you don't want to switch all the time to continuity mode and back because is faster or has the beep.For those who don't like the beep should be very easy to add a way to disable/enable it .

author: GeoffreyF
author_rank: Regular Contributor
timestamp: November 07, 2018, 01:08:42 pm
content: Quote from: CDaniel on November 07, 2018, 06:24:58 amYou are repeating yourself. Go buy the Fluke.

author: CDaniel
author_rank: Frequent Contributor
timestamp: November 08, 2018, 10:08:50 am
content: Maybe I wasn't clear enough for you , a laggy beep ( 0,5sec or more ) is not something good or normal . If a meter has the beep it should be as fast as possible so you can't feel a big lag , or you think otherwise or don't care ? Thats the issue with 121GW , I want the beep response in diode mode to be faster , not lightning fast but decent enough . The discusion about other meters , who has the beep and how is implemented is useless at this point . You can complain about that if you want something different .And for sure this can be corrected in firmware with a little effort ... just one more small issue on the list

author: PeterL
author_rank: Regular Contributor
timestamp: November 08, 2018, 11:22:47 am
content: Quote from: joeqsmith on November 08, 2018, 03:26:33 amI have a agilent u1252b which does this as well. I don't have it at hand atm so I can't check how fast it is or at which voltages. But I like this option a lot, it let's you easily spot diode's while probing around.As for the speed I agree the 121GW(v1.51) feels very slow. I measured it, and came to 0.5 +/- 0.1 second, where in resistive mode it's more like 30msec. Also the bar graph is very fast in diode mode, so I'd say it should not be difficult to make it beep much faster.

author: GeoffreyF
author_rank: Regular Contributor
timestamp: November 08, 2018, 01:15:22 pm
content: Quote from: CDaniel on November 08, 2018, 10:08:50 amYou have been perfectly clear - redundantly clear, repetitively and tediously clear. It's not an issue because the 121GW is not specified to do what you want and never was. The unnamed models you like were probably specified to do it. They also probably have a higher price point,and generally a different feature set than this one. In future purchase decisions, read the specs compare the feature sets and price before making your purchase. (Is that clear?) I also expect that it cannot be corrected with firmware that this has something to do with the settling time for the A-D. Why do you need to be clear? None of us work for EEVBlog or write firmware for the product and are in no position to do what you endlessly ask. Still you go on and on. Speculating about others repair styles etc. So please stop.

author: CDaniel
author_rank: Frequent Contributor
timestamp: November 08, 2018, 01:26:21 pm
content: Your comments are not helpfull , if you don't care about an issue don't imply it's not a feature ...This is a firmware bug like many others , this has nothing to do with price , brand ( Fluke ) or anything else .It is laughable that you imply that someone should buy a very expensive meter just to have fast responding beep in diode mode. Then how is possible to be fast in continuity mode ? It's the same ADC . Please stop the nonsense and watch your own business .

author: GeoffreyF
author_rank: Regular Contributor
timestamp: November 08, 2018, 03:48:09 pm
content: Quote from: CDaniel on November 08, 2018, 01:26:21 pmHow is continuity, passive device and active device measurement different? Checking a diode or junction is different from checking a passive resistor has been explained and actually you should have known it given any of your claimed expertise. You didn't read what was written to you god knows how many redundant posts back. As for nonsense: Nobody you are arguing with can change the firmware for you. You missed that point completely. You insist that this is an "Issue" not an add on to what was specified. I don't think you really have thought much about any of the responses you got. Other than insults, none of your posts have either responded to others or introduced a new point to what you repeat. There is no purpose to your continuing with this.

author: Sharp
author_rank: Contributor
timestamp: November 08, 2018, 08:44:14 pm
content: Just received my 121GW it has v1.54 FW - just for info - I have no idea what have been changed in the FW

author: 1anX
author_rank: Regular Contributor
timestamp: November 08, 2018, 09:33:14 pm
content: Quote from: CDaniel on November 07, 2018, 06:24:58 amHi CDaniel, can I suggest that you move your comments and feedback to the "121GW Issues" thread. That thread is for reporting issues that you would like to see addressed.https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/This thread is for "Firmware Details" and would be the right thread if you were to offer up the firmware code for the meter operation you describe. Try the Issues thread and you may get your issue with the meter considered!

author: lowimpedance
author_rank: Super Contributor
timestamp: November 08, 2018, 10:41:51 pm
content: Quote from: Sharp on November 08, 2018, 08:44:14 pmOr perhaps you have 1.53 going by the recent 1.52 release reporting as 1.53.Seriously though if true that's a short life for1.521.53. Some release notes may be handy here.

author: gdewitte
author_rank: Unknown
timestamp: November 09, 2018, 03:00:06 am
content: Second the call for release notes. Could someone please tell us what the hell is going on?

author: exe
author_rank: Unknown
timestamp: November 09, 2018, 09:40:35 am
content: BTW, I wonder if someone wants to actually write some firmware for it.I recently tried ChibiOS and made a very trivial hello-world interface using threads+queues. So far I like it much more than CubeMX. I may want to try to write firmware using it, threads and C++. If someone wants to join let me know.

author: PeterL
author_rank: Regular Contributor
timestamp: November 10, 2018, 05:05:54 pm
content: Quote from: exe on November 09, 2018, 09:40:35 amDid you actually run your own code on the 121GW? And if so can you revert back to stock firmware afterwards?If that's possible, and you could provide some instructions to do so, I'll bet it would just be a matter of time before others hop on.

author: exe
author_rank: Unknown
timestamp: November 10, 2018, 05:34:16 pm
content: Quote from: PeterL on November 10, 2018, 05:05:54 pmWell, actually, this thread used to be about development. Just read a few pages back, Mr. @tpw_rules did a great job at reverse engineering firmware, dumping calibration data, and even prepared a demo firmware with an lcd driver using cubemx. I tried to continue development, but cubemx and C is just not my thing.

author: PeterL
author_rank: Regular Contributor
timestamp: November 10, 2018, 07:31:38 pm
content: Quote from: exe on November 10, 2018, 05:34:16 pmOh great! I totally missed that one (here:https://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-firmware-details/msg1418335/#msg1418335)I don't have a lot of time for doing serious things for this, but I will have a look at it.I have never used cubemx, but I have done stm32 C development with atollic.And I hadn't even heard of ChibiOS. Can you share what you have so far?

author: hammy
author_rank: Unknown
timestamp: November 13, 2018, 12:12:18 pm
content: Third call for release notes and clarification about the version number.Some DMM are already shipped with firmware version 1.54? Is this confirmed?

author: Terry01
author_rank: Frequent Contributor
timestamp: November 20, 2018, 05:59:44 pm
content: I received mine today with 1.54 on it. Bought new from Welectron on the 15th. So.… confirmed

author: gdewitte
author_rank: Unknown
timestamp: November 20, 2018, 06:04:34 pm
content: And, again, could someone please enlighten us regarding firmware versions? What's going on?

author: gdewitte
author_rank: Unknown
timestamp: November 21, 2018, 03:17:52 am
content: Seriously folks: Is someone going to address this or are we to just sit in the dark and act like mushrooms?

author: gnif
author_rank: Unknown
timestamp: November 21, 2018, 03:35:01 am
content: This thread isn't supposed to be about the changes in the official firmware, it's about the firmware format and reverse engineering efforts.If you want a change log, please start a thread asking for it, it's entirely up to Dave if he wishes to provide one, but to be completely honest he has zero obligation to state what the differences are between versions.

author: ggchab
author_rank: Frequent Contributor
timestamp: November 21, 2018, 07:14:03 am
content: This is a somewhat surprising answer. We trusted Dave when we bought this multimeter and today, we might think he lost interest in the instrumentalthough we understand that he is very busy right now.There may be no obligation but there should be some enthusiasm to communicate improvements.I hope enthusiasm is still there

author: 1anX
author_rank: Regular Contributor
timestamp: November 21, 2018, 07:58:38 am
content: This thread is titled"...Firmware Details" so I don't think it is unreasonable to ask if the version changes can listed. Dave in his earlier replies in this thread did in fact provide some detail on version update changes.Dave2 seems to update the manual with the changes from version to version, so maybe Dave2 (Seppy) can help?

author: newbrain
author_rank: Super Contributor
timestamp: November 21, 2018, 08:50:28 am
content: Quote from: ggchab on November 21, 2018, 07:14:03 amI hope improvements are still there

author: Terry01
author_rank: Frequent Contributor
timestamp: November 21, 2018, 10:58:40 am
content: I know this is a tiny bit off topic for this particular thread but for those who are interested in V 1.54 firmware, I just did a quick check of all the modes and ranges on my new 121GW that came with the V 1,54 firmware installed from Welectron yesterday.I tested it alongside 6 other meters doing a general function test, i checked caps, resistors, diodes, voltages and currents of all different values and sizes and it was very close in every test same as the rest of the meters were. I didn't expect them to match exact to the last digit.I didn't notice it to be particularly slow either or anything like that in any particular mode.The only thing I didn't test was the mvA/VA feature as I don't know exactly how it works to test it. I'll learn that soon enough though.To sum up i am happy with the meter so far in how it performs.Hope this is of interest to someone.

author: thaistatos
author_rank: Contributor
timestamp: November 21, 2018, 11:53:45 am
content: is there an improvement of the slow reading of resistance?

author: rattnallen
author_rank: Contributor
timestamp: November 21, 2018, 02:19:25 pm
content: Firmware version 1.57 athttps://www.eevblog.com/product/121gw/

author: Terry01
author_rank: Frequent Contributor
timestamp: November 21, 2018, 02:26:51 pm
content: Quote from: rattnallen on November 21, 2018, 02:19:25 pmI saw that but there was no V 1.54 which I thought was a bit strange. I'll wait and see as I am happy with it just now.

author: exe
author_rank: Unknown
timestamp: November 21, 2018, 03:33:52 pm
content: Quote from: PeterL on November 10, 2018, 07:31:38 pmUhm, not much, just a proof of concept for another project:https://github.com/kopchik/psu_firmware/blob/master/main.cpp. I use ChibiOS because:1) reasonably simple API2) Supports Linux (and any other sensible OS)3) Provides threads and queue support. This is a must for me for any async UI development.4) Sources are written by humans, not a typical autogenerated rubbish5) I don't care about power consumption, if a DMM gonna work 50hrs from batteries instead of 600h it's still fine provided firmware is better than the stock one.PS I think I'll finish my other projects first before jumping on this train. Don't want to spread too much.

author: Dirk C.
author_rank: Newbie
timestamp: November 21, 2018, 05:18:33 pm
content: Quote from: thaistatos on November 21, 2018, 11:53:45 amIn Auto Mode it is not fine, slow.In manual mode the measurements are very fast.Version 1.57Dirk

author: chronos42
author_rank: Regular Contributor
timestamp: November 23, 2018, 05:39:20 pm
content: Hi,there is indeed an extra digit.I have made some test and found this:In the higher ranges the meter is still slow but accurate and has a higher resolution.DER EE 5000 as reference meter, 100nF (MKT type capacitor) @1khz : 113.68nFAgilent 1252B : 114.2nFBrymen BM869S : 114,4nFUNI-T UT201E (cheap clamp meter) :114.4nF121GW: 0.1129µFSo far so good, all meters are doing a good job.Next with a 220pF ceramic NP0 capacitor:DER EE 5000 as reference meter, 220pF@10khz : 238.3pFAgilent 1252B : 0.234nFBrymen BM869S : 0.24nFUNI-T UT201E (cheap clamp meter) : 0.240nF121GW: 0.165nFAll meters are spot on, except of the 121GW which is way off and not even close to 220pF. It seems that the low capacitance range now is messed up. Can sombody reproduce this issue?

author: exe
author_rank: Unknown
timestamp: November 23, 2018, 07:02:35 pm
content: There is a separate thread for reporting bugs, and another one for general discussion. It's unlikely to get much support in this thread.

author: CDaniel
author_rank: Frequent Contributor
timestamp: November 23, 2018, 10:21:47 pm
content: Sub 1nF readings drift and are affected by noise , if you touch the probes , etc , this must be investigated further . I don't think it is normal ... another issue maybe . If I used REL just before the measurement and I didn't touch anything was accurate for low capacitance ... but needs more testing .If you touch only the red probe tip you can get a reading of a few nF , this it is not scientific but an indication that is not very ok .

author: chronos42
author_rank: Regular Contributor
timestamp: November 24, 2018, 07:44:17 am
content: Quote from: joeqsmith on November 23, 2018, 09:09:25 pmHi,sorry, I forgot the version information.It is 1.57.

author: chronos42
author_rank: Regular Contributor
timestamp: November 24, 2018, 08:09:46 am
content: Hi joeqsmith,I can repeat this and get the same result every time.Now with a 0.39 nF NP0.DE EE 5000: 392.6pF @ 10kHz121GW (Firmware 1.57) : 0.316nF.The meter is about 80pF too low in the lowest range, capacitors lower than 81pF are shown as 0.000.Unfortunately I don't know from which Firmware on the problem started, maybe I have lost a small part of the calibration. The other ranges are spot on as mentiond before.Seems that I am the only one whith this problem?

author: chronos42
author_rank: Regular Contributor
timestamp: November 24, 2018, 11:13:43 am
content: Hi,I did some more tests and found that this seems to be a problem only for my 121GW, it has nothing to do with the firmware.My meter reads about 80pF too low in the lowest capacity range. It does this also with firmware 1.26 and the original calibration data, saved on the SD card.Update:After I have played with different firmware versions, I went back to 1.57, restored the original cal data again and made a new offset correction for all current ranges, because there was a large offset since firmware 1.5X.And now the low capacity range works, it is only off for some pF.WHAT???This is really strange, I have no idea what happend, something in the calibration seems to be mixed up by some firmwareupdate in the past.

author: CDaniel
author_rank: Frequent Contributor
timestamp: November 24, 2018, 12:56:37 pm
content: It is not working reliable for small capacitors , sometimes a remanent value of 20-60 pF remain on display . Disapear only if I switch to resistance and back .I assume this can be negative as well but you can't see it ( below 0 ) and substracts from real value , sometimes I can get -80pF lower reading like in your case .

author: chronos42
author_rank: Regular Contributor
timestamp: November 24, 2018, 01:59:03 pm
content: Hi CDaniel,thanks for the answer, so it seems I am not the only one with this issue.Update:I could repeat this behavior.100pF capacitor:I switched on the meter, it showed 0.100 nF, first time spot on!Switching off and on again, now it showed 0.082nF.Switched to Ohms an back to capactity: Now it showed 0.021nF, after switching off and on again sometimes 0.014nF, sometimes 0.021nF, but never again 0.100nF.Does the 121GW only one time per day show the correct value in the pF range?...

author: CDaniel
author_rank: Frequent Contributor
timestamp: November 24, 2018, 06:30:38 pm
content: If I just put the fingers on buttons the value is changing by ~60pF ... so about what precision we are talking about ?Measuring a precision capacitor the displayed value is drifting in time (10min) by at least 50pF .This is again a problem with AC noise , like it was in resistance mode ( now resolved )The behaviour can be somewhat different because everyone's lab is different , probably even the spot where it sits counts ...

author: CDaniel
author_rank: Frequent Contributor
timestamp: November 24, 2018, 07:58:51 pm
content: No , I don't touch or move anything and it drifts .You don't use the probes , that is a very big difference .The problem is not how you should measure for maximum precision pF capacitance , we know and we have RLC bridges for this , but if the meter is comparable with other good multimeters ... who we presume should not drift much and you can use the probes just in case you need to measure something accurate . This is a portable handheld multimeter after all , not to sit in the best conditions

author: chronos42
author_rank: Regular Contributor
timestamp: November 24, 2018, 10:32:43 pm
content: Hi joeqsmith,to make that more clear: Normaly I do not use a multimeter for measuring low pF values, I have other instruments for this.But that is not the point. Also the drift is not my major problem.The problem is: I Connect a capacitor in the pF range to my meter, switch it on and it shows (mostly) the correct value at the first try. Then I switch it off and on again while not touching anything except the switch and now I get a totally different value. Do the same again and I get another different value. When I switch off the meter again, wait some time, switch it on I get the correct value ....and so on...That is a very strange behavior. I don't know whether this issue was from begin on or not, because I had never tried to measure a capacitor in the low pF range. I noticed this first time after you have mentioned the higher resolution in the capacitor mode and I checked this to look how the 121GW now performs compared with my other meters.Just for fun.. I did not expect such a crazy behavior.First I thougt that is a firmware bug of rev. 1.57, but it seems not so.Your meter seems not affected from this issue as I can see in your video. But CDaniel seems to have the same problem like me.BTW: Try also the mode button, does this also not affect your meter?

author: CDaniel
author_rank: Frequent Contributor
timestamp: November 25, 2018, 01:01:18 am
content: Yes , more or less I see the same behaviour like you , but not allways . The drifting I see is maybe that difference ...With short probes it is not sensitive to touching the buttons ... but an issue is an issue , you can't make it dissapear . If you put the hands near the probes ... it's a messAnd of course you can see the problem with larger capacitors 1nF-10nF , you don't have to measure something really small .I doubt it's a hardware issue , they don't know very well to control the chip HY3131 with the firmware ... and if STM32 microcontroller is also new for them it's a very bad combination

author: 1anX
author_rank: Regular Contributor
timestamp: November 25, 2018, 04:02:17 am
content: Quote from: chronos42 on November 24, 2018, 10:32:43 pmHey chronos what happens if you short the capacitor leads each time before turning on the meter?By turning the meter on the first time I assume you are charging a discharged cap, but each time you turn off and test again, the cap is already charged from the previous test.Could this account for the behavior you are seeing?

author: 1anX
author_rank: Regular Contributor
timestamp: November 25, 2018, 06:39:42 am
content: I thought I would run a couple of low cap tests on my meter with V1.57 firmware.Measured 2 caps of given values, 15pF and 22pF which are at the extreme end of what the meter is capable of measuring and checked values against my DER EE DE-5000 LCR meter.The GW121 displayed a combined meter and leads, (with alligator clips) capacitance of 0.175nF when turned on. I used the REL function to zero out the combined meter and lead capacitance and then measured each cap. I repeated the turning off and on of the meter and zeroing using the REL function before taking each measurement.The 15pF cap measured 15.7pf on the DE-5000 and 0.018nF for the first 121GW test measurement and then 0.014nF for the second test.The 22pf cap measured 22.9pf on the DE-5000 and 0.025nF for the first 121GW test measurement and then 0.021nF for the second test.Considering the +-2.5%+5, I was pretty pleased with the meter's performance!

author: chronos42
author_rank: Regular Contributor
timestamp: November 25, 2018, 10:06:30 am
content: hi joeqsmith and 1anX,i noticed this issue first with firmware 1.57 and blamed this firmware, but i was wrong in this point, sorry for the missleading.I also can get very accurate values in the low pF range, but only one time after the meter was laying around unused for some time. After switching on the first time it is within its specs.So far so good.But from now on the behavior is not predictable.When I switch off and on it sometimes is spot on again, sometimes it reads about 80pF too less. When I use the mode button and step through the different modes until I am back to capacity mode it also reads 80pF too less. Switching off and on in this state does not reset the meter to a correct reading. I have to wait some time, then it comes back. The reading counts up with about 1pF all 15 seconds until it has reached the correct value again.That makes it so hard to find out a predictable behavior.For me that looks like a port that is not correctly set and floates in tristate mode. In this case there is no stable operation possible and everything can happen and also every meter can behave different.

author: CDaniel
author_rank: Frequent Contributor
timestamp: November 25, 2018, 06:33:29 pm
content: Sorry about the pictures being tiltedSo , meter on the bench , no probes , no powerfull electric field nearby ( everything was shut down )At first was 0.000 , and then slowly is drifting up ( in maybe 30min ) . Doesn't matter if is on or off . With leads connected is much faster and bigger . This offset is adding when I measure a real capacitor .This is not something heating up inside , it is like some capacitor in the measurement path is charged by external electromagnetic field .If I switch the rottary selector to off and then on again to capacitance nothing is changing .To zero out this offset I have to cycle through cap manual ranges or to switch to resistance and back ...I see that you are curious about the shim , my multimeter was bought from Welectron with it already installed ( I looked inside ) . And is working just fine ... for now

author: CDaniel
author_rank: Frequent Contributor
timestamp: November 25, 2018, 07:03:52 pm
content: Mister joeqsmith , if you read my post carefully I said that with leads the drift is faster and bigger .I tested without probes on purpose so you can't say that I moved them or I did something ... or my test capacitors are not good enoughIf you don't observe anything wrong doesn't mean that everybody else is stupid ...

author: CDaniel
author_rank: Frequent Contributor
timestamp: November 25, 2018, 07:31:47 pm
content: Some issues are hard to replicate if you don't have the exact meter , it was pre-production or modified in any way .And the firmware was released just recently , before this , with low resolution , was useless to test small capacitors .So be patient , if there are contradictions is because we are testing right now , ideas and observations can change . Probably many others will test and share the results .

author: CDaniel
author_rank: Frequent Contributor
timestamp: November 25, 2018, 08:58:30 pm
content: OK , I have read the HY3131 Configuration , but we can't know yet how the firmware is implemented . How the configuration bits are .For the noise in resistance mode I discovered that they didn't used the input low pass capacitor C21 , now they fixed that . That's like using an ADC for DC without any capacitor at input , any electomagnetic field will make the reading to fluctuate .Maybe this is something simple , or not ... if it is something hardware after all , that CMOS 4053 switch leakeage current is the first suspectIn my shoping list are some MAX4053 low leakeage switch

author: Lion_Tamer
author_rank: Contributor
timestamp: November 25, 2018, 10:09:45 pm
content: I have just tested my meter on the capacitance mode to see what sort of drift it has with results as below:Set-up = The meter was placed in front of me between my keyboard and 2 monitors, probes were plugged in and clipped in to the holder on the back with nothing else connected and the excess lead laying on the bench. Blue tooth and logging was turned off. I left the meter in auto range mode on capacitance mode. Test length was 30 minutes each time.Test 1:Firmware Version 1.51Available Resolution 10nFStarting value 0.00nFEnd value 0.00nFComment: At no point in the test did I see the meter value change.Test 2:Firmware Version 1.57Available Resolution 1nFStarting value 0.000nFEnd value 0.002nFComment: The meter drifted up to 1pF after about 5 minutes and 2pF after 10 minutes, at one point during the test I did see 3pF on the display but it only lasted a couple of minutes.I also tried touching but not pressing the buttons and leads during both tests with no noticeable changes to the displayed value.Meter Serial No:180701854I may have to look and see if I have any low value caps to test with when I can get a chance to sort my workbench out after recent building work.Jem

author: CDaniel
author_rank: Frequent Contributor
timestamp: November 25, 2018, 11:01:51 pm
content: For capacitance there is not a zero offset calibration in the manual , anyway with or without the leads connected is showing 0.000Interesting ...

author: lowimpedance
author_rank: Super Contributor
timestamp: November 26, 2018, 01:44:56 am
content: *********************************************************************************************************Jan 8th 2019EDIT : Just for clarity of my posts and further down in relation to the problem found with the capacitance measurement.Below was in response to a previous members post relating to a bug (as noted above, and yes this is not the correct thread for this stuff but anyway..).A number of posts by another member were removed by them which generally makes the thread seem disjointed with my responses.But as the detail of my posts are still of interest I will leave them here.I did ask in the other thread when the discussion moved there to move the posts from here but that did not happen and that time window has long passed.*********************************************************************************************************Okay I updated my kickstarter meter (1st batch) to firmware 1.57. And tested some lowish value capacitors. All connected to the meter via short leads and croc. clips.The Meter was in Auto ranging mode and gave quick measurements on the three capacitor values when connected.first value100pF silver mica.Initial connection showed 0.100 nF +/- 1pF -2 pF. With no capacitor connected the meter reads 0.000 nFRepeated disconnect and reconnect gave same result. Leaving the cap connected and then turning meter OFF then ON from the RH OFF position did not affect the measurement.Now using the LH OFF position introduced errors into the measurement, which then also persisted when also using the RH OFF then back to ON. A 100 pF with a variable readingaround 30 pF (not consistent).Also cycling through the modes on that switch position did not restore correct measurement.1 nF polystyreneInitial connection showed 0.990 nFRepeated connection gave the same result. Leaving the cap connected and then turning meter OFF then ON from the RH and the LH OFF position did not affect the measurement.10 nF silver mica (a L&N standard cap !)Initial connection showed 10.110 nF. Cycling through the modes back to capacitance again now gave a reading of 10.040 nF. (This value corresponded to my Fluke 87V after I REL the 0.26 nf Offset out.)Repeated connection gave the same result. Leaving the cap connected and then turning meter OFF then ON from the RH and the LH OFF position did not affect the measurement.Last test was to 'pad' the input capacitance with the 1 nF and REL it out then connect the 100 pF and repeat that a number of times.The measured value was 0.100 nF and was the same each time it was re connected.No drift measurement done*******************************************************NOTE :When I went to the firmware download page I noted a message above the firmware list saying quote:"NOTE: This version has a change that will not function correctly with the app in capacitance range. An update to the app will be released soon."Its not clear if this refers to the current firmware on the list with the DMM and the logging app or just the capacitance mode on the meter itself.Or this message has been there for many firmware revisions !, as I only just updated from 1.17 its been a while since I looked at the firmware page.

author: lowimpedance
author_rank: Super Contributor
timestamp: November 26, 2018, 02:29:14 am
content: Yeah , not sure what to make of the initial success with using the RH OFF only, as it generally went (and stayed) pear shaped after using the LH OFF.Will try to repeat after the meter has been off for some time.My testing was with a pair of DIY short leads so not much to twist so thats why I used the 1 nF to get of the measurement 'floor' !. Seemed to give good results after the REL.I had quite a lot of issues directly attributable to the sloppy switch which I resolved with similar shimming before the official shim was released.Still not convinced this switch design is issue free yet.

author: lowimpedance
author_rank: Super Contributor
timestamp: November 26, 2018, 05:37:11 am
content: Re test of 100 pF after more than an hour turned off. Result was a correct reading of 0.100 nF when connecting / remove and re connect to the croc. clips.Next leaving connected and turning OFF/ON from both directions initially gave correct reading but a short time later the reading started to display approx 82 pF instead.I then cycled through the modes on that switch position and then re measured the 100 pF with the result now down around 25 pF or so as previously tested.So a sort of repeatable result.Noted that the larger capacitance measures start a bit higher as well and then drop a small amount and could correlate to the same amount observed with the 100 pF. Needs further testing.At this stage I have no plans to remove the switch, which considering the amount of usage I have given it would probably not show to much wear.They did appear to be quite clean at the time I had the switch out, (nice gold plating).However I will keep this in mind for when I do feel motivated to get in there again

author: Terry01
author_rank: Frequent Contributor
timestamp: November 26, 2018, 08:38:33 am
content: Quote from: joeqsmith on November 26, 2018, 06:32:50 amI got a 121GW new a few days ago with v1,54 firmware installed and noticed the internal temp is around 2.5C higher than the internal temp in my U1273 when the temp is around 15C. As the temp gets nearer 20C it wanders to being around 3C higher. The 121GW also wanders quite a bit more on start up where as the U1273 is a lot steadier. The 121GW changes from anywhere around .5C to 1C in the first minute after start up.

author: lowimpedance
author_rank: Super Contributor
timestamp: November 26, 2018, 09:15:34 am
content: @Joe, I have not watched the video yet but I will and comment then.When measuring the 100 pf after the unusual drift to the lower value I did not observe a further drift of more than a few LSD. I will check for drift tomorrow with the 100 of from the first start.I will also pay attention to the measured temperature compared to other meters for any differences from the lab temperature.

author: lowimpedance
author_rank: Super Contributor
timestamp: November 26, 2018, 11:06:54 pm
content: Okay this morning I turned the 121 on an noted an initial reading of 0.012 nF with no connected cap. Which is what I had observed previously.Next I connected the 100 pF and the reading was 0.111 pF then over the next 10 minutes that slowly drifted down to 0.109 pF as the 121 warmed up !. No further significant change observed.The meter was kept in a temp. controlled lab overnight and is sitting at 21.40 deg. as recorded on a Guildline 9540 PRT temp. meter. The 121 secondary temp. reading was also 21.4 deg.Now the interesting bit, with the 100 pF still connected I cycled through the modes on that switch position and now the 100 pF measured as 25 pF and would stay at the value when eitherturning on or off or disconnecting or reconnecting the cap.Leaving the unit off for a short time and then turning back on shows the measured value to be increasing back to the correct value !!. just like something has a residual charge being slowly bled away.At re-switch on it showed approx. 68 p and after 10 or so minutes was up to 93 p, and now at 103 pF after 20 plus minutes......Interestingly the display will show 0.000 nF with no connection, when the 121 starts to give wrong measurements. (mode cycling).Perhaps the firmware hides all negative readings and just gives all 0.@Joe , Looking at your video I would say the behaviour was consistent with mine when measuring a 1 nF cap although I did note a change from the initial value down from 1.016 n to 0.977 nF after mode cycling.OT:, and yay post 1000 !..........only took 7 years

author: CDaniel
author_rank: Frequent Contributor
timestamp: November 26, 2018, 11:58:01 pm
content: If you have some initial reading when you cycle through modes will clear that ... in my case anyway .There has to be some kind of automatic zeroing when switching to capacitance , otherwise there is no way to read 0.000nF with or wihout leads ( long , short or how you want ) . If you put the probes close but not twisted together the capacitance is at least 10pF .So if you leave something connected at start-up will screw-up the auto calibration ... my theory .Maybe this feature is not well design and is responsible for what we observe . Why some meters don't have the issue is interesting , the external electromagnetic fields may play a role .

author: lowimpedance
author_rank: Super Contributor
timestamp: November 27, 2018, 12:04:17 am
content: Additional info:I cycled the modes on the switch position to get the wrong capacitance reading of 24 pF with a 100 pF silver mica capacitor connected, then I left the meter running and waited.The meter did auto power off but on restarting the meter using a key press the reading was correct at 109 pF. The time that passed was at least 30 minutes.So all I did was to return after a half hour and turn the mater back on to now show the correct value.Mode cycling will fully cause the issue to present itself each and every time on my meter.

author: Lion_Tamer
author_rank: Contributor
timestamp: November 27, 2018, 12:25:07 am
content: I had a dig through my parts bin and found a 27pF ceramic capacitor to try drift testing with tonight - so far I have only tried V1.57Using a peak LCR meter the cap measured at 22.5pFThis time I also turned on logging (Results below). The maximum value that I obtained was 21pF with a minimum of 0.15pF in a non temperature controlled environment (probably only changed by a couple of degrees).After the drift test I tried turning the meter off then back to capacitance mode several times, initially the read value would drop by a couple of pF before suddenly dropping to zero after which it did not seem to matter what I did with the meter it would not read any pF value for about 30 minutes.Jem

author: lowimpedance
author_rank: Super Contributor
timestamp: November 27, 2018, 01:32:09 am
content: I would say that behaviour is consistent with my meter. Could you also cycle through the modes on that switch position, (from capacitance through ohms etc and back to capacitance), when starting with 21 pF.What reading do you get after the mode cycle ?.

author: Terry01
author_rank: Frequent Contributor
timestamp: November 27, 2018, 12:30:04 pm
content: Hi Joe can I ask a very beginner question? Do you use the 2 x BNC to 4mm connectors to give a more stable reading of the cap under test and eliminate the capacitance that would be in the leads if you used them? Sorry for the dumb question but I would like to learn these things.

author: Terry01
author_rank: Frequent Contributor
timestamp: November 27, 2018, 03:03:11 pm
content: Quote from: joeqsmith on November 27, 2018, 02:17:44 pmCool...thanks for the explanation.

author: chronos42
author_rank: Regular Contributor
timestamp: November 27, 2018, 03:42:09 pm
content: Good to see that I am finally not the only one with this odd problem...And to joeqsmith: You had every reason to ask, i did not belive it too after I saw this behaviour the first time.

author: lowimpedance
author_rank: Super Contributor
timestamp: November 29, 2018, 05:00:55 am
content: Quote from: joeqsmith on November 26, 2018, 04:22:01 amI actually had an occasion to have the switch out and not having any means to take a high res pic. I tried to get the best with the crummy camera I had to hand. See image attached.Looking as close as I could with a magnifying glass I cannot see any notable wear on my meter.Butthen again it has not reached 50000 rotations.

author: nonentity
author_rank: Newbie
timestamp: November 29, 2018, 08:04:36 am
content: I'm wondering if the administrator has considered combining some of these threads with the issues section. It started out with discussions about firmware metadata, but looks like it has morphed into issues.Topics I would expect to see in firmware details discussions would be:Design Requirements, i.e., what things is it supposed to do and will those things be tested?Configuration Management/Control, i.e., what really is in V 1.57 and what should go into 1.58 and why?Test methods and results, i.e., how is it going to be tested? Was it tested? And where are the reports?DocumentationQuality Control

author: lowimpedance
author_rank: Super Contributor
timestamp: November 30, 2018, 05:41:22 am
content: @JoeI used the Mantis at work to inspect the switch pattern and I could not determine if the black material was metallic in nature , quite possible there is some.The reason is after a good clean I could see (using a 10X mag. eye loupe) that there was notable wear on some of the dimples on the switch fingers in the rotor.Ie: the dimples that were a bit higher and thus had more pressure on them had worn down through the gold plate to the copper underneath. And this could well be the source of the black material on the PCB.The PCB switch pattern however looked perfectly fine with minimal wear after cleaning.I will try to get hold of a USB microscope to take some pictures (Monday!).

author: CDaniel
author_rank: Frequent Contributor
timestamp: December 02, 2018, 08:19:26 pm
content: My meter 180701918 from Welectron

author: Terry01
author_rank: Frequent Contributor
timestamp: December 02, 2018, 08:42:20 pm
content: I got mine around a week ago from Welectron too but it's only been used a few times since so the contacts will still probably be "as new" so hardly worth showing just yet. I'll wait till I've had it for 6 months or so then i'll open it up and post a few photos.

author: gnavigator1007
author_rank: Unknown
timestamp: December 02, 2018, 09:33:41 pm
content: Quote from: Terry01 on December 02, 2018, 08:42:20 pmMight be worth it to open it now and grab some pics to compare down the road. Obviously, should still look new with no wear, but you don't really know without a peek.

author: Terry01
author_rank: Frequent Contributor
timestamp: December 02, 2018, 11:15:36 pm
content: Quote from: gnavigator1007 on December 02, 2018, 09:33:41 pmVery true, I never thought of it like that. I'll open it up when I get up in the morning and post a couple of the pics I take.

author: CDaniel
author_rank: Frequent Contributor
timestamp: December 03, 2018, 12:44:18 am
content: Quote from: joeqsmith on December 02, 2018, 10:55:12 pmThat is "black dirt " , after a wipe with alcohol looks like new , no sign of wear on pads .But I didn't work with it much , as we know has "some" bugs and I don't like this ...I'm more worried about this issues ...I would like to see a comparation with other multimeters using HY3131 , Keysight U1282A for example ...

author: Terry01
author_rank: Frequent Contributor
timestamp: December 03, 2018, 01:11:42 am
content: Quote from: CDaniel on December 03, 2018, 12:44:18 amI have Keysight U1273A...does that have HY3131?

author: lowimpedance
author_rank: Super Contributor
timestamp: December 03, 2018, 01:20:13 am
content: I have taken some pictures of my 121 ontacts using a USB microscope and attached for your ref.note its quite hard with the gear I had to hand to get the best contrast, so may not be the absolute best representation.The wear appears to be uniform across most of the dimples. The cotton tip I used for cleaning only shows the 'black stuff' and no discernible metallic debris.The PCB traces look good with no obvious 'wear track' forming.

author: CDaniel
author_rank: Frequent Contributor
timestamp: December 03, 2018, 08:11:12 am
content: Quote from: Terry01 on December 03, 2018, 01:11:42 amYes , it should have HY3131 , but I think you can easily take a peek inside to confirm .

author: ChrisG
author_rank: Unknown
timestamp: December 03, 2018, 10:51:46 am
content: I upgraded the 121GW regularly and now from 1.51 to 1.57 it's done. It stuck for 20 minutes without any progress. So I did need to switch it off (sorry). Wanting to go back to 1.51 is to no avail and it seems bricked now. What should I do? What should I check? The download option is still available though.

author: GeoffreyF
author_rank: Regular Contributor
timestamp: December 03, 2018, 12:56:53 pm
content: Quote from: ChrisG on December 03, 2018, 10:51:46 amDid you leave the back off while you did this?

author: ChrisG
author_rank: Unknown
timestamp: December 03, 2018, 03:08:18 pm
content: I tried both options. First it was on and then it was off. The batteries were still very good. However I thought I'd change them for the fun of it. No difference. Until..... I accidentally touched with the cover off with my hand the back of the SD card. I guessed it got wiggled side to side and presto.... (perhaps there is dust in?) On the other hand I've reinserted the card 10 times or more. Perhaps the gold-fingers of the slot are not that great ?So I managed to do it in the end but this is a weakpoint in the design.

author: GeoffreyF
author_rank: Regular Contributor
timestamp: December 04, 2018, 02:52:57 am
content: If the cover is not in place then the batteries are not securely in place. If the battery is interrupted for even a moment while loading, that would explain your issue. Remove the cover and check how well the batteries stay in. You will see what I mean.I had a close call on that myself once. Keep the cover on when installing new firmware.

author: Terry01
author_rank: Frequent Contributor
timestamp: December 04, 2018, 09:04:22 am
content: Quote from: CDaniel on December 03, 2018, 08:11:12 amSorry was busy yesterday. I have a while today to spare. What was it you were wanting to see between these 2 meters again?

author: CDaniel
author_rank: Frequent Contributor
timestamp: December 04, 2018, 09:17:32 am
content: I think everybody wants to know if the issues with 121GW ( from the issues topic ) are hardware related ( HY3131 limitations ) or software ( implementation ) , a direct comparison with a similar meter is usefull , maybe Keysight is worse , we don't know ...

author: Terry01
author_rank: Frequent Contributor
timestamp: December 04, 2018, 09:31:57 am
content: Ah ok, I can do that no probs at all but you'll have to just take my word for the results as I don't have any recording gear to make a decent video of the outcome.

author: ChrisG
author_rank: Unknown
timestamp: December 04, 2018, 10:01:19 am
content: Joe, I agree with you and the batteries were perfectly okay in the box and solid enough. I'm now wondering if I should retry with the former batteries although they seem perfectly fine. My take on things is that there is crud from the wipers on the SD card slot or the slot itself is not great.

author: CDaniel
author_rank: Frequent Contributor
timestamp: December 04, 2018, 10:30:18 am
content: Quote from: Terry01 on December 04, 2018, 09:31:57 amTerry01 , we don't need proofs , user observations and feeling is enough .

author: Terry01
author_rank: Frequent Contributor
timestamp: December 04, 2018, 01:50:23 pm
content: Quote from: CDaniel on December 04, 2018, 10:30:18 amI spent 45 mins or so there with my 121GW and U1273a just measuring lots of different things between the two meters. I used 2 sets of the same leads in both meters depending what I was measuring. So the test was as fair as I could make it leads wise.First off before I say anything when I first got the 121GW with firmware v1.54 installed I tested a load of resistors, caps, diodes and anything else I had laying around and I thought it wasn't that bad.Today with it side by side with another meter it was awful! Very slow in everything apart from DC volts where it was ok or as good as the U1273a and it also jumps around quite a bit.When measuring resistance it always jumps to between 20-40k and then settles on a more realistic number where the U1273a just lands on the measure and stays there solid.On AC volts it's a wee bit slower than the U1273a but settles fine after a couple seconds.I also measured the A ranges with a couple 9v batteries, 1 has been used a little and 1 is quite quite badly depleted which was very strange.I used a 3.9 ohm power resistor as a load. Both meters showed around 87mA on the A range when measuring the newer battery but when i then changed range to mA range the 121GW would not read it and kept showing OFL where the U1273a measured it no problems in either A or mA. I found that very strange! The dud battery measured 200-300 uA or there abouts and both meters measured this no problems in the mA range.When i tested the 121GW on it's own when i first got it it really didn't seem that bad, maybe my inexperience played a part in thinking that too though.A couple things to sum up... the U1273a is around £100+ more expensive and has had time to iron out all the teething problems etc and also Keysight has much more experience and has made loads of previous other meters to gain knowledge from along the way. I think the 121GW will catch up in time but we'll just have to wait and see. I still use the 121GW at my bench just because i like the meter and a couple seconds extra to wait here and there doesn't matter to me.I can see where it would matter to someone who needs quick measures dead on every time though. It's funny how a couple seconds extra makes the 121GW seem painfully slow beside the Keysight!

author: CDaniel
author_rank: Frequent Contributor
timestamp: December 04, 2018, 03:50:39 pm
content: Thx for the honest opinion , can you verify the autorange hysteresis ?121GW has a huge hysterezis in resistance mode , switch in upper range at 55000 counts and at 40000 counts in lower range , and very big in voltage mode 55000 counts up and 45000 down if I remember correctly .

author: Terry01
author_rank: Frequent Contributor
timestamp: December 04, 2018, 04:31:42 pm
content: How do you mean? How would I test that to get the answer your looking for?Sorry i'm still learning things...

author: CDaniel
author_rank: Frequent Contributor
timestamp: December 04, 2018, 04:53:04 pm
content: With a power supply adjust the voltage up and down to see when is switching ranges .For resistance you need a potentiometer or some kind of variable resistor .Of course the multimeter must be left connected all the time , not adjust and then measure .

author: Brumby
author_rank: Unknown
timestamp: December 05, 2018, 12:38:46 am
content: Quote from: CDaniel on December 04, 2018, 04:53:04 pmTo be clear here:Step 1: Use an adjustable power supply that can at least go from 3V to 7V. Start at 3V or so andincreasethe voltage until you see the range change on the meter (watch the units and decimal point). Make a note of the voltage when this happens.Step 2: Continuing on from Step 1 - From the 7V level,decreasethe voltage until you see the range change. Make a note of this voltage.The difference between these two voltages is the "hysteresis". This is a designed behaviour meant to stop the frequent range changes you would get from a meter without this feature when a measured voltage fluctuates either side of the range switching point.The issue is the magnitude of this hysteresis. If it's too big then you could have a transient (for example) trigger a switch to a higher range and when the voltage settles it is under that "range up" switching point, but not below the "range down" switching point. As well as being visually distracting, it also means you lose a whole digit of resolution.This behaviour and the issues associated with it apply to all measurements and ranges - whether voltage, current, resistance or whatever. I just used an easily achievable example for voltage.

author: Terry01
author_rank: Frequent Contributor
timestamp: December 05, 2018, 08:29:54 am
content: Quote from: Brumby on December 05, 2018, 12:38:46 amThanks for the explanation. I understand now what hysteresis is and can do this later this morning and will post the results.Is anyone else having the problem I had yesterday with their meter not measuring in mA range? My 121GW was measuring 87mA in the A range but when I changed range to mA it would not measure. It kept showing OFL.I have v1.54 firmware installed as it came from Welectron around a week ago.

author: ChrisG
author_rank: Unknown
timestamp: December 05, 2018, 10:31:38 am
content: Quote from: joeqsmith on December 05, 2018, 02:26:28 am

author: exe
author_rank: Unknown
timestamp: December 05, 2018, 11:32:45 am
content: Quote from: Terry01 on December 05, 2018, 08:29:54 amDid you change the current socket on the meter?

author: exe
author_rank: Unknown
timestamp: December 06, 2018, 02:57:56 pm
content: Quote from: joeqsmith on December 05, 2018, 12:46:26 pmUhm, it's a standard stm32 mcu, can be reprogrammed via the swd intarface using a $5 programmer (but header is not soldered). I did brick it many times and was able to restore the original firmware and bootloader. Just be sure to dump the calibration table, I lost mine during experiments.

author: Terry01
author_rank: Frequent Contributor
timestamp: December 06, 2018, 05:38:54 pm
content: Quote from: exe on December 05, 2018, 11:32:45 amYes, just did it again and also with my 87v too. The Fluke did it no probs and the 121GW showed OFL. I used a half-"ish" used 9v battery and a 4 ohm power resister as a load.I have another much more depleted 9v battery that is down to 200-300 uA using the same set up. Both meters measured this no problem.I have just read that you are not supposed to use fresh lithium in the 121GW which i have so it may be my fault. I'll change them out later for normal batteries and see if it fixes it.I'll let you know how I go with that.

author: HKJ
author_rank: Super Contributor
timestamp: December 06, 2018, 05:44:09 pm
content: Quote from: Terry01 on December 06, 2018, 05:38:54 pmYou are aware that maximum for mA input range is 55mA on the 121GW, for larger current you must use the A input.

author: Terry01
author_rank: Frequent Contributor
timestamp: December 06, 2018, 05:50:05 pm
content: Well there's why it won't measure 90 mA in the mA range then!

author: HKJ
author_rank: Super Contributor
timestamp: December 06, 2018, 06:40:23 pm
content: Quote from: Terry01 on December 06, 2018, 05:50:05 pmThat is part of the "Low burden voltage", the high mA range is moved to the A input.It is not that the meter is missing a range, it has one or two current ranges more than most other multimeters. It has 7 current ranges, typically a meters has 5 or 6 current ranges.

author: Terry01
author_rank: Frequent Contributor
timestamp: December 07, 2018, 02:44:22 pm
content: Quote from: HKJ on December 06, 2018, 06:40:23 pmCool, thanks for the information. I would never have guessed that as there is no indication on the meter around the jacks and I haven't read the manual.Thanks again

author: HKJ
author_rank: Super Contributor
timestamp: December 07, 2018, 03:08:08 pm
content: Quote from: Terry01 on December 07, 2018, 02:44:22 pmThere is a indication, the A terminal is marked "A 500mA", because it is both ampere and 500mA range.

author: Terry01
author_rank: Frequent Contributor
timestamp: December 07, 2018, 04:42:20 pm
content: Quote from: HKJ on December 07, 2018, 03:08:08 pmI agree that 500mA is clearly marked on the A jack but can't see how that would indicate the mA jack is only good for 55mA.I also see no one else has told me that and I have made a couple of posts about trying to feed 90mA into the mA jack so it can't be that obvious or well know or someone else would have said.

author: darik
author_rank: Regular Contributor
timestamp: December 07, 2018, 05:56:00 pm
content: Quote from: Terry01 on December 07, 2018, 04:42:20 pmThe "OFL" that the meter displayed means exactly that you have exceeded the current limit in the selected range. What else could OFL mean in an amps setting? That was a good indication, but you incorrectly assumed the meter was lying to you.

author: Terry01
author_rank: Frequent Contributor
timestamp: December 07, 2018, 06:14:02 pm
content: Quote from: darik on December 07, 2018, 05:56:00 pmYes I agree. I incorrectly assumed the meter was lying to me but lets be clear the meter is hardly 100% trust worthy is it? There are loads of posts of the meter lying or not doing what it's supposed to or whatever. I can hardly be faulted for thinking it was just something else wrong with it.I have a few other meters that are not limited to 55mA in the mA range and I haven't read the manual for the 121GW. Like I say too, I posted a couple other times about this problem and no one else knew this so if it was that obvious someone else would have knew and told me.You think it's obvious, I don't. I can't see how "OFL" would translate into "55mA is the max this jack will read"

author: Terry01
author_rank: Frequent Contributor
timestamp: December 07, 2018, 06:59:26 pm
content: I will read the manual for this meter next time I have a while to take it in for sure. I have MS and sometimes I need to read the same thing 3 or 4 times for it to register. Things like user manuals and the likes I read on days where I feel like my memory will co-operate with me.The meter has a few nice features for sure. 1 of the other things I got caught out with was, I put fresh lithium in it when I got it and another forum member pointed out to me the little bit extra voltage "fresh" lithium have is enough to affect the diode and resistance mode so it's not a good idea.Something else that is probably clearly stated somewhere and I never read it or whatever but I would say is not obvious too.Something that is obvious..... I need to RTFM!!My lack of knowledge probably plays a huge part too but hey ho!

author: HKJ
author_rank: Super Contributor
timestamp: December 07, 2018, 07:10:03 pm
content: Quote from: Terry01 on December 07, 2018, 06:14:02 pmI have not seen that, in some extreme cases the meter shows wrong values, in normal usage it may be slow or it may be unstable, but it do not show wrong values.This is something you have to know about every meter you use, where is it correct and stable, wheremayit show wrong value and where is it wrong most of the time. I do not remember it for all my meters, but if the value is outside expected values I check with another (or more, even a scope) meter.

author: gdewitte
author_rank: Unknown
timestamp: December 07, 2018, 07:24:06 pm
content: Quote from: joeqsmith on December 07, 2018, 06:40:56 pmWhere in the manual is it clearly stated? I just searched the latest manual (revised 04 Dec. 2018) for things like "55" and "current" and had no returns relating to a 55 mA maximum.

author: darik
author_rank: Regular Contributor
timestamp: December 07, 2018, 07:30:55 pm
content: Quote from: gdewitte on December 07, 2018, 07:24:06 pmIn the version 1.22 manual I have on my drive it states it on page 16, where it details the current ranges, and on page 32, where it details the different jacks.And of course since taking current measurements that are out of range is one of the easiest ways to damage a meter or at least blow a fuse, we _all_ familiarize ourselves with the limitations of the current ranges before using them. Right?

author: HKJ
author_rank: Super Contributor
timestamp: December 07, 2018, 07:40:53 pm
content: Quote from: Terry01 on December 07, 2018, 07:29:58 pmIt may show wrong value at high megaohms. In current it may have a zero offset (As I note in my review), this is not ideal, but easy to handle. The low burden voltage has a price.In some ranges the auto range do not work, this is easy to fix: Use manual range.The meter is not perfect, but I do not see it as unreliable. I hope it will get better with some software updates, making it easier to use in all situations.Note: For me a unreliable meter is a meter where you cannot see that it is showing a wrong value (when you are within specifications).

author: HKJ
author_rank: Super Contributor
timestamp: December 07, 2018, 09:01:51 pm
content: Quote from: Terry01 on December 07, 2018, 08:30:26 pmJust to clarify (Others can add more points):Offset do not make a meter unreliable, but is inconvenient, even if the meter has a REL function.Measuring frequencies (including harmonic) outside the specifications is not expected to show correct values, but high sensitivity for specific frequencies may rate as slightly unreliable. Like changing reading when a mobile phone is near the meter (I would rate it as silly to measure with high RF fields around).Auto range jumping around, this is a software fault in the meter, but do not make it unreliable.Problems with mixed AC+DC signals. I do not really now how to rate this, as long as they are of similar amplitude I expect the meter to handle it, but when there is a huge difference most meters will be unreliable.Sensitive to hands near the meter, this is easy to see and do not make the meter unreliable, but is very inconvenientAs can be seen from the list, there is a lot of stuff I do not like, but I would not call the meter unreliable due to it.The 121GW is not my main meter and will probably never be, it is too slow. But is has some functions that I like and this means I keep it within easy reach and do use it.

author: HKJ
author_rank: Super Contributor
timestamp: December 07, 2018, 09:56:59 pm
content: Quote from: Terry01 on December 07, 2018, 09:33:34 pmI have way to many meters for that, I have a few hand held meters I use for checking stuff (That includes the 121GW) and some bench meters I use when I want precise result (Keithley, Fluke and Keysight).

author: CDaniel
author_rank: Frequent Contributor
timestamp: December 07, 2018, 10:23:05 pm
content: Unreliable is just a word , at the end of the day the firmware is at least very "unfinished" after 1 year in production ...Even the sensitivity to noise could be just software related ...

author: HKJ
author_rank: Super Contributor
timestamp: December 07, 2018, 10:36:20 pm
content: Quote from: CDaniel on December 07, 2018, 10:23:05 pmIt is not just a word, a long time ago I bought a fairly fancy multimeter. When I got it the mains was maybe 10V (I do not remember the exact values) and other voltage readings was also very far off, I decided that it was definitely a bad meter and it had to be returned. I was (as usual) rater busy and left it alone for a couple of days, then I got around to it again, this time it was very precise.I did not return the meter and have never used it, for me it is unreliable (And some lost money).

author: CDaniel
author_rank: Frequent Contributor
timestamp: December 07, 2018, 11:07:40 pm
content: Ok , we will use "unreliable" only for defective meters then

author: bicycleguy
author_rank: Frequent Contributor
timestamp: December 08, 2018, 01:42:29 am
content: Quote from: Terry01 on December 07, 2018, 04:42:20 pmThought you'd figure it out. Didn't want to make you feel like an idiotDon't feel bad though, Iv'e done the same thing a few times but usually RTFM.

author: EEVblog
author_rank: Unknown
timestamp: December 08, 2018, 03:07:12 am
content: For those interested, we (Kane & EEVblog) are now setting up a shared git (not public) for firmware version control with the intention that we (EEVblog) now have full visibility on all firmware changes, and in time will be able to make our own changes and compile ourselves etc.At present we have almost no real visibility into their internal firmware environment.

author: 1anX
author_rank: Regular Contributor
timestamp: December 08, 2018, 03:31:43 am
content: Quote from: EEVblog on December 08, 2018, 03:07:12 amThats great news Dave!This meter carries your name and brand, (EEVBlog) so its good that you are in the loop with the development of the firmware. It seems to me that with responsible management this meter could develop to its true potential.The hardware too requires your input and direction toward meeting quality and performance requirements. If UEI want to carry on with 700 out of spec PCBs requiring shims then maybe they should put their brand on it. IMHO get quality into the meters that carry your branding and be prepared for a lot more sales.

author: EEVblog
author_rank: Unknown
timestamp: December 08, 2018, 03:36:05 am
content: Quote from: 1anX on December 08, 2018, 03:31:43 amI've heard you a dozen times now, no need to continue to repeat it.

author: 1anX
author_rank: Regular Contributor
timestamp: December 08, 2018, 04:29:39 am
content: Quote from: EEVblog on December 08, 2018, 03:36:05 amIts called customer feedback Dave!I've never seen you shy away from voicing your opinions on products. I was suggesting something a little different in my last post and that was to separate the out of spec PCBs from the meters carrying your brand.You have said before that UEI are engineering the meter that incorporates some of your design ideas, (good ideas) all I'm suggesting is that if you have some control in the manufacture then opt for quality. Sure they are built to a cost of around $300, but hell, how much does the PCB cost as a percentage of the bill?I'm participating in the forum and if you dont like my suggestions thats fine, but I dont think I'm repeating myself as much as many others do around here.

author: Brumby
author_rank: Unknown
timestamp: December 08, 2018, 05:53:26 am
content: Dave's heard you, I've heard you and I'm sure there are a bucketload of other members who have heard you - so give it a rest, please!As for the PCB's - what is the problem? The fact that they aren't picture perfectly identical to the original?If I could be so bold (as a person who does not own a 121GW - buthasreadallthese threads) - from what I've read to date - IT DOESN'T MATTER!There is a mechanical requirement in the range switch and PCB which is accomplished by one of two configurations:1. Thicker PCB and no shimor2. Thinner PCB with a shimEither appear to be as good as the other

author: Brumby
author_rank: Unknown
timestamp: December 08, 2018, 06:02:41 am
content: Quote from: 1anX on December 08, 2018, 04:29:39 amA crapload more than a shim, that's for sure.BUT that isn't the sole reason.Many meters were sent out with the thinner PCB and the shim solution dealt with the problem with a user serviceable field change. The alternative would be a complete recall - as I don't think Dave or UEI would be sending out replacement PCBs - populated, tested and calibrated!Sending out the shim with instructions as to how to fit it was simple, inexpensive and only inconvenienced the user for the length of time it took to fit the shim.The shim solution was found to be good enough to be used in the construction of new units out of the factory - so the engineering has been proven.Your pedanticism is inappropriate here. The shim solution works well. Please .... move on.Edit:Dave: If I've overstepped the mark or got something wrong, please feel free to castigate and correct me!

author: EEVblog
author_rank: Unknown
timestamp: December 08, 2018, 08:33:14 am
content: Quote from: 1anX on December 08, 2018, 04:29:39 amYou are repeating yourself constantly, and you've ironically just done it again. I get it, please stop now.

author: ggchab
author_rank: Frequent Contributor
timestamp: December 08, 2018, 10:06:09 am
content: Quote from: EEVblog on December 08, 2018, 03:07:12 amMy only concern was that Dave lost enthusiasm and interest in the meter because of other projects.Very happy he has now full access to the firmware and will even compile and test his own versions

author: exe
author_rank: Unknown
timestamp: December 08, 2018, 11:40:32 am
content: Quote from: joeqsmith on December 07, 2018, 02:13:56 pmJust to be clear, I bricked it with own firmware, not with the stock one.Concerning stm32 programming, any generic "st-link v2" adapter will do. I have similar to this one:https://www.ebay.com/itm/ST-Link-V2-Programming-Unit-mini-STM8-STM32-Emulator-Downloader-M89-New/401088363326?hash=item5d62babb3e:rk:1:pf:0. Also any stm32 development board will work as they have st-link interface on the board.Software... I'm on Linux, so I use openocd andhttps://github.com/texane/stlink. In general, any IDE supporting stm32 should have support for st-link, so software not a problem. Just use whatever is available for your OS. Here is the list of what's available:https://www.st.com/en/development-tools/stm32-ides.html?querycriteria=productId=LN1200. People often use Keil and Attolic TrueSTUDIO. There are trial and free versions available.

author: EEVblog
author_rank: Unknown
timestamp: December 09, 2018, 02:26:39 am
content: Quote from: exe on December 08, 2018, 11:40:32 amJust beware, I think the pinout is different, but otherwise, yes, compatible with ST-Link-V2

author: CDaniel
author_rank: Frequent Contributor
timestamp: December 09, 2018, 09:41:41 am
content: Quote from: joeqsmith on December 08, 2018, 11:11:17 amYou forgot that the switch assembly is mounted on the PCB through a hole and has plastic clamps on the other side . If the PCB is thicker the switch contact spings will be pushed harder into the PCB . So now not the shim and the upper case will push the switch to make good contact , but will stay itself closer to the PCB .And the PCB doesn't have to be thicker by the shim thickness , is much less , much of the shim thikness is for the normal space between the case and the switch ( they are not supose to be touching )

author: HKJ
author_rank: Super Contributor
timestamp: December 09, 2018, 03:54:44 pm
content: Quote from: Terry01 on December 09, 2018, 03:47:39 pmPage 32: mA / μA Jack: This input jack is used for the 50 mA, 500 μA and 50 μA current ranges. It is 400 mA HRC fused. An input warning alert functions for this jackBut I am missing the 5mA range in that list.

author: fboehle
author_rank: Newbie
timestamp: December 09, 2018, 04:01:06 pm
content: It is written on page 32 (File Version 04.12.2018)"This input jack is used for the 50 mA, 500 µA and 50 μA current rangesThis input jack is used for the 10 A, 5 A and 500 mA current ranges. "But yeah, a bit hidden...Quote from: Terry01 on December 09, 2018, 03:47:39 pm

author: CDaniel
author_rank: Frequent Contributor
timestamp: December 09, 2018, 04:54:34 pm
content: It's unusual to have 500mA in the amps jack ( because of low burden ) , but on older multimeters is written " A 500mA " so you can see even if you didn't read the manual or you forgot .I think they removed this on newer models , just " A " ... as in the picture from the manual .

author: HKJ
author_rank: Super Contributor
timestamp: December 09, 2018, 05:05:38 pm
content: Quote from: Terry01 on December 09, 2018, 04:34:16 pmThe actual limit is 55mA, but in many multimeter specifications values are rounded down.

author: n3mmr
author_rank: Regular Contributor
timestamp: December 10, 2018, 01:13:46 pm
content: A question about logging:Is it possible to log both frequency and voltage simultaneously in ac mode and automatic logging?

author: bicycleguy
author_rank: Frequent Contributor
timestamp: December 10, 2018, 05:25:50 pm
content: Quote from: n3mmr on December 10, 2018, 01:13:46 pmyesCode:START2018/12/10102124ID170800121INTERVAL10secMAINSUB-1SUB-2RemarkNo.Func.ValueUnitFunc.ValueUnitFunc.ValueUnit1ACV0.0046VFREQ.0Hz2ACV0.0114VFREQ.0Hz3ACV0.0122VFREQ.0Hz4ACV0.027VFREQ.0Hz5ACV0.0413VFREQ.0Hz6ACV0.2659VFREQ.59.996Hz7ACV0.2724VFREQ.59.999Hz8ACV0.0245VFREQ.0HzMAX7ACV0.2724VMIN1ACV0.0046V

author: n3mmr
author_rank: Regular Contributor
timestamp: December 12, 2018, 10:15:22 am
content: Quote from: bicycleguy on December 10, 2018, 05:25:50 pmCould you then make the app plot voltage against frequency?

author: EEVblog
author_rank: Unknown
timestamp: December 15, 2018, 12:47:05 pm
content: Can you please take this overload talk elsewhere, this thread is for firmware stuff only. Thanks.

author: joeqsmith
author_rank: Super Contributor
timestamp: December 15, 2018, 03:10:27 pm
content: No problem. I will clean up my mess.About two pages cleaned up for you. If others word do the same we could get it down even lower.

author: jancumps
author_rank: Unknown
timestamp: January 09, 2019, 01:12:15 am
content: With the v1.58 beta, I can't get the min/max/avg to work.Pressing the button changes the AUTO label on the display, but min/max/avg don't cycle anymore for me.PEBKAC

author: alex-sh
author_rank: Regular Contributor
timestamp: January 29, 2019, 03:53:43 pm
content: Anyone extensively tested 1.58 beta please? Any drawbacks?

author: bicycleguy
author_rank: Frequent Contributor
timestamp: January 29, 2019, 05:35:06 pm
content: Best yet, no regression AFAIK

author: Alex Rodriguez
author_rank: Newbie
timestamp: February 25, 2019, 12:30:09 am
content: The burden voltage I think is a little off. Using a 25Ω/5W resistor in series with 12V DC, the 121GW shows 18.3mV burden voltage. The FLuke 28II connected in parallel to the voltage input of the 121GW shows 21.96mV. I followed page 41 burden voltage measurement instructions. Of course, there is no mention to use another DMM to confirm results. The 121GW current measurement is right on the spot. Firmware 1_58 beta

author: Candid
author_rank: Regular Contributor
timestamp: February 25, 2019, 07:44:58 pm
content: You may have a look on this concerning burden voltage:https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg2213955/#msg2213955

author: Alex Rodriguez
author_rank: Newbie
timestamp: February 25, 2019, 11:30:12 pm
content: Quote from: Candid on February 25, 2019, 07:44:58 pmMy friend, yes I watched your video, but I hate to tell you that you might have to re-do your video. Have you looked very carefully page 41 (121GW User Manual - Last Revised: 08 February 2019)? You are usingmVA/VA, and that is for something else. To measure burden voltage, you must use mA or A.By the way, the mVA/VA is working just fine.Page 41 says:To measure theburden voltagean additional lead is required, this must beconnected between the activecurrent terminaland the voltage input, as shown below:

author: Uksa007
author_rank: Contributor
timestamp: March 06, 2019, 06:28:49 am
content: Quote from: alex-sh on January 29, 2019, 03:53:43 pmCan't find any change-log details in the manual about what 1.58 beta fixes, in fact the manuals last entry is v1.51.Did the app get updated to support the latest versions?Whats the best stable version that works with ios app, V1.57?

author: n3mmr
author_rank: Regular Contributor
timestamp: March 12, 2019, 11:51:05 am
content: Is the firmware source code available?Are the comments inside good?What development environment is best?

author: Brumby
author_rank: Unknown
timestamp: March 12, 2019, 01:44:40 pm
content: Quote from: n3mmr on March 12, 2019, 11:51:05 amNo, and it will likely never be. It contains proprietary content from UEI - and they are somewhat coy about sharing it.QuoteNo idea.

author: n3mmr
author_rank: Regular Contributor
timestamp: March 13, 2019, 04:18:45 pm
content: Quote from: Brumby on March 12, 2019, 01:44:40 pmSo it isn't hackable, then?

author: dcac
author_rank: Frequent Contributor
timestamp: March 13, 2019, 05:14:53 pm
content: Yeah - the 121GWishackable - just not by compiling a new FW from official FW source code.Though it's "simple" to do some "simple" changes by hexediting the FW bin files. Or you can do patching on assembly level using the IDA disassembler. But of course making any substantial changes this way will eventually drive you nuts.

author: GeoffreyF
author_rank: Regular Contributor
timestamp: March 13, 2019, 10:24:24 pm
content: When did "Hackable" imply complete information on what is to be hacked?Don't confuse user programmable (it isn't) with hackable (which most things actually are, this one more than others).

author: n3mmr
author_rank: Regular Contributor
timestamp: March 14, 2019, 02:19:07 am
content: Quote from: GeoffreyF on March 13, 2019, 10:24:24 pmPoint taken, of course.What I'm looking to do is actually to be able to automate measurements.I e be able to read data from the unit and possibly "press some buttons" from say a python program.Maybe something like this can be done via bluetooth?

author: GeoffreyF
author_rank: Regular Contributor
timestamp: March 14, 2019, 02:11:03 pm
content: You certainly can get a stream of data through bluetooth. The protocols for that are documented.pushing buttons - probably not so easy. You do have open schematics and so you could solder small wires to the button contacts or something like that. It seems to need reminding to some, for what it does the 121GW is not that expensive so - by all means hack the hardware. It won't be CAT anything if you do but it can be modified and then put into some kind of a case that supports the connections etc. That sounds like fun.

author: n3mmr
author_rank: Regular Contributor
timestamp: March 14, 2019, 05:05:25 pm
content: Stream of data is what is needed for using in automated setups, so if I look at that doc on BLE, and the app's source on git, supposedly I only need a way to talk to bluetooth from python."Pushing buttons" was just that the fw in tx3 lets you do just that over a serial connectionI wouldn't dream of "hacking the hardware". I want it to work reliably.

author: GeoffreyF
author_rank: Regular Contributor
timestamp: March 16, 2019, 12:36:52 am
content: Hacking (or modifying) the software can interfere with reliability as well. I think the real point here is that you need to acquire something other than a hand held DVM.

author: darik
author_rank: Regular Contributor
timestamp: March 16, 2019, 12:43:04 am
content: Quote from: n3mmr on March 14, 2019, 02:19:07 amDepending on the precision you are looking for, you may be able to accomplish what you want with one of these hooked up to an Arduino with an SD card.I've used the INA219 to log voltage, current, and burden voltage, worked great. Very easy to set up if you've done Arduino stuff before.https://www.adafruit.com/product/1164https://www.adafruit.com/product/904

author: n3mmr
author_rank: Regular Contributor
timestamp: March 17, 2019, 09:57:20 am
content: Quote from: GeoffreyF on March 16, 2019, 12:36:52 amOr:Since there is a way to transfer data over bluetooth, maybe I have no real.need for hacking either sw or hw...

author: newbrain
author_rank: Super Contributor
timestamp: April 25, 2019, 03:26:04 pm
content: The current FW is still 1.58beta, and has been for a long time.To this moment, it seems to be stable and probably the best one delivered.It does indeed look less beta than other versions.Is there any plan to make it "gold"?Is a new FW in the working?

author: btspce
author_rank: Contributor
timestamp: April 30, 2019, 06:34:24 pm
content: I just bought the 121GW from Welectron here in Europe and it came with firmware 1.61 so the 1.58 is already "old"

author: Roelof
author_rank: Newbie
timestamp: April 30, 2019, 06:42:02 pm
content: Also, as has been mentioned before, the manual only has changelog information up to 1.51. Would it perhaps be possible to give us an update on the firmware status?I do like my meter, but I'm very much looking forward to stable firmware with changelog information.

author: Roelof
author_rank: Newbie
timestamp: April 30, 2019, 06:43:38 pm
content: Quote from: btspce on April 30, 2019, 06:34:24 pmOh, nice, let's hope the firmware shows up on the EEVblog site soon.

author: Candid
author_rank: Regular Contributor
timestamp: April 30, 2019, 09:15:11 pm
content: Quote from: btspce on April 30, 2019, 06:34:24 pmOn the SD card you should finde a file called EEVBlog.bin that you may upload here for us. This is the firmware file.

author: 1anX
author_rank: Regular Contributor
timestamp: May 01, 2019, 12:01:55 am
content: Quote from: btspce on April 30, 2019, 06:34:24 pmInteresting!This firmware revision 1.61 is not available on Dave's website with the other firmware versions, latest on his site being 1.58.I cannot find anything on the Github under EEVBlog.Please attach a copy of firmware V1.61 if possible for the rest of us to try out.Whats happened to the firmware list on EEVBlog website for the 121GW being updated as new revisions become available ?

author: btspce
author_rank: Contributor
timestamp: May 01, 2019, 07:37:56 am
content: Just checked the sd card and it is empty. Did they leave a copy of the firmware on the sd card earlier ?@Dave what is the status on new firmwares? Why aren't the latest posted on the website (and the changelogs)?

author: Candid
author_rank: Regular Contributor
timestamp: May 03, 2019, 02:35:46 pm
content: Still no response here and no update on the official firmware support page. Hope that product support is not already suspended

author: exe
author_rank: Unknown
timestamp: May 03, 2019, 03:35:13 pm
content: Guys, this thread is not about stock firmware, nor about support. This thread is about developing a new firmware. So, Dave is not supposed to answer. Sorry for misleading title (it started as reverse-engineering of stock firmware). Please ask inhttps://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/orhttps://www.eevblog.com/forum/testgear/eevblog-121gw-multimeter-issues/

author: Alex Rodriguez
author_rank: Newbie
timestamp: June 04, 2019, 02:48:07 am
content: Just download firmware 2.0, unzip it, move it to the microSD card, but the meter keeps showing U-157, I was expecting to see U-2.0Never mind, I got it!

author: ddrulez
author_rank: Newbie
timestamp: June 12, 2019, 02:23:40 pm
content: I bought a new 121GW today and I have Firmware u-2.01 installed.Just wanted to mention it.

author: Candid
author_rank: Regular Contributor
timestamp: June 12, 2019, 05:20:33 pm
content: Is there a bin file called EEVBlog.bin on the internal microSD-Card?

author: ddrulez
author_rank: Newbie
timestamp: June 12, 2019, 07:27:03 pm
content: Sorry card is empty

author: hammy
author_rank: Unknown
timestamp: June 24, 2019, 11:19:00 am
content: Quote from: ddrulez on June 12, 2019, 02:23:40 pmAny news about the new 2.01 firmware? Changelog?Edit: typo

author: Perrin21
author_rank: Regular Contributor
timestamp: June 26, 2019, 05:13:05 pm
content: who is writing the firmware for this device? is it Dave or the manufacturer? has anyone created a hacked FW?

author: ggchab
author_rank: Frequent Contributor
timestamp: June 26, 2019, 06:45:45 pm
content: The manufacturer. Dave has a copy of the source files but I don't think he will ever something with the code. I guess this is probably far too much work.

author: Brumby
author_rank: Unknown
timestamp: June 27, 2019, 12:58:07 am
content: Quote from: ggchab on June 26, 2019, 06:45:45 pmCorrect.QuoteDoes he? I may have missed something, but I didn't think he did. As I understand it, the manufacturer has some "secret sauce" code that they are not willing to share (which, even if frustrating, is completely understandable).QuoteHaving the source code is only one part of the puzzle. You need to have a compatible development environment that has been configured appropriately before you start. Then you would need full details of every element of the hardware being controlled before even being able to code anything. Add to that the experience required to write effective and efficient code for this type of environment as well as dealing with idiosyncrasies of the component parts and you have quite the challenge.Quote from: Perrin21 on June 26, 2019, 05:13:05 pmWe have had some enterprising souls hack the binary from earlier versions - but I think the latest official manufacturer version makes them obsolete.

author: ggchab
author_rank: Frequent Contributor
timestamp: June 27, 2019, 07:14:24 am
content: I don't remember if this was in a video or in the forum, but I am 95 percent sure Dave said he received a copy of the source files (with a non-disclosure agreement). Not that long ago. A few months, maybe.Because of the work involved, I knew we would not see anything. Just fully understanding the existing code would probably already be a nightmare. So, UEI is not taking a big risk

author: exe
author_rank: Unknown
timestamp: June 27, 2019, 08:26:45 am
content: I think too he mentioned he has sources.I tried to write my own firmware, but failed due to underestimation of effort and lack of knowledge of stm32. I thought I'd write a basic firmware in a few evenings, but failed even to get LCD working :/. Then I realized that I don't know how to control the main IC, and its datasheet was uncomfortably big.... So, many things it seems need to be implemented from scratch, it's not like an arduino-style development when all it takes is just install libraries and bind them all together in main().

author: e0ne199
author_rank: Regular Contributor
timestamp: July 11, 2019, 12:58:26 pm
content: any info for new firmware?? 2.00 really is full of bugs anyway

author: firewalker
author_rank: Super Contributor
timestamp: July 11, 2019, 01:27:52 pm
content: Quote from: exe on June 27, 2019, 08:26:45 amThere is a basic open firmware with "Hello World" example.https://github.com/tpwrules/121gw-templateAlexander.

author: daveyk
author_rank: Frequent Contributor
timestamp: July 11, 2019, 04:37:50 pm
content: "I just bought the 121GW from Welectron here in Europe and it came with firmware 1.61 so the 1.58 is already "old""I just bought mine (June 2019) directly from Dave, and it is running 1.57 Firmware. I find the resistance mode very sluggish. Maybe new firmwar would fix that? I need to locate firmware and then I guess go buy a micro-sd card.

author: darik
author_rank: Regular Contributor
timestamp: July 11, 2019, 07:31:55 pm
content: Quote from: daveyk on July 11, 2019, 04:37:50 pm2.0 is definitely faster autoranging in resistance mode. To get it, go here and click on "firmware":https://www.eevblog.com/product/121gw/.I thought all the meters came with a micro-SD card. Or was that just the kickstarter? Anyhow, you should probably check and make sure there isn't already one in there.

author: 1anX
author_rank: Regular Contributor
timestamp: September 28, 2019, 07:11:53 am
content: I see firmware V2.02 is available!https://www.eevblog.com/product/121gw/

author: amspire
author_rank: Super Contributor
timestamp: September 28, 2019, 07:18:02 am
content: Quote from: 1anX on September 28, 2019, 07:11:53 amAnd a new manual update.Looks like they added a check of the battery voltage before doing a firmware update in the latest release. Sounds like a good idea.

author: daveyk
author_rank: Frequent Contributor
timestamp: November 13, 2019, 06:15:23 pm
content: I'm still not thrilled with resistance mode. It is still somewhat slow, but putting the two leads together, it takes 2.5 seconds and then readings float between .018 to .103 ohms. The longer you hold the leads together the more the resistance reading goes up. V2.02, I believe is better than v2.00 in resistance. I've swapped leads and same thing. Perhaps the leads I have are not ideal, but resistance readings so sluggish make it hard to use for trouble-shooting. Its hard to know when to press the REL button as it takes a while for the readings to settle down when shorting the leads together.On another subject, has anyone thought to do some customer firmware for working on older automobiles? I want to read RPM with a clamp-on probe (already have) and then drell angle (not real familiar with that). I am fixing-up (not down, but it is currently - lol) a 1974 Beetle as a hobby. I bought an automotive meter that is supposed to do this, but what a piece of fragile crap. RPM is basically reading frequency. I couldn't get that meter to read the RPM consistently. I have no idea what dwell angle is, but when I get to tuning the engine they say at a certain RPM set the timing for a dwell angle of xx. Anywho, I don't expect that, but did wonder if people have been doing customer firmware for this meter.Dave

author: npelov
author_rank: Frequent Contributor
timestamp: November 29, 2019, 12:25:06 pm
content: Since v2.0 the SD card logging stops working properly after a while. I haven't tried that in 2.02. The last time I recorded voltage for 19.5-20 hours with interval 2 seconds, fixed range. I monitored the display - the battery dropped gradually with cut off at about 10.8V. At about 19.5 hours the voltage was 11. At 19.0 hours - 11.8V. However since about 2h 40min (about 4800 recods) the value in csv is 12.529V +/- 3 LSD. The last digit keeps moving around like it's recording real data, but it has nothing to do with what's on the display.I've reported this before, but I don't see it in firmware change log. Is this fixed? Does anyone else have similar problems?Edit: Also since v2.0 the multimeter will occasionally freeze when I start logging - switching ranges, pressing buttons have no effect, until I turn it off.P.S. Yes, I know that bluetooth exists. I don't want to rely on wireless for long term logging.

author: eV1Te
author_rank: Regular Contributor
timestamp: December 02, 2019, 03:19:34 pm
content: Quote from: npelov on November 29, 2019, 12:25:06 pmThis sounds like a serious issue, however I am confused how to reproduce this...The total battery voltage in the 121GW should be about 6 V, not 10.8 to 11.8 as you mention. There are 4 batteries, not 8.What was the voltage source that you measured? Was it a constant voltage of 12.529 or did it change during the measurement? Did you check the voltage with a different meter during the test to confirm that the 121GW indeed measured/logged incorrect values?

author: fabrizio_fabrice
author_rank: Unknown
timestamp: December 14, 2019, 04:03:24 am
content: Can anyone who has updated to v 2.2 say how long to expect the process to remain in the "douun" mode?

author: Scottjd
author_rank: Frequent Contributor
timestamp: December 14, 2019, 05:47:44 am
content: Quote from: fabrizio_fabrice on December 14, 2019, 04:03:24 amI am assuming you mean firmware version 2.02?First make sure the new firmware file on the SD card is named “EEVBlog.bin” with no spaces in the file name or the meter might hang and just display down. If the current installed firmware is old then you might want to make sure you have a fresh set of batteries installed before running the firmware update. I think I’ve read the newer firmware will check the battery level first.1. Turn the meter off then hold down MEM and HOLD while turning on the meter. You will see IAP on the display.2. Press the “SETUP” button and it will display “DOWN / DOUUN” and after 5 seconds the meter bar should start rising from the left to right.3. Once the bar hits the end the meter will restart displaying the new version of firmware installed.This whole process after it displays “DOWN / DOUUN” shouldn’t take more then 15 seconds.

author: fabrizio_fabrice
author_rank: Unknown
timestamp: December 16, 2019, 04:51:27 am
content: Quote from: Scottjd on December 14, 2019, 05:47:44 amThanks, Scottjd, yes, I followed the instructions to a Tee, but it stayed in DOUUN mode for at least 6 hours. It started at 9 PM, but I couldn't sleep well, so up at 3 am to check. No change, still DOUUN, except the display contrast was changing as the batteries dropped from ~ 1.54 v at the start, to 1.47.With much trepidation I turned the meter off, then back on and it was still v. 1.57. I repeated the process with a different microSD using the same downloaded 2.02 .bin file, but this time it worked, and it was very quick. It immediately showed % progress and the analog bar incremented, too. 5 seconds, maybe, and it was done! A new set of batteries, and it's ready to go!Thanks again!

author: Sparky Faraday
author_rank: Regular Contributor
timestamp: February 09, 2020, 10:16:14 pm
content: Are all the functions reliable now? Anything crash?Thank you,Sparky

author: Kibabalu
author_rank: Regular Contributor
timestamp: March 05, 2020, 07:12:32 am
content: Just received my 121GW with firmware version 2.04. No issues discovered so far during first day of use.

author: pppopol
author_rank: Newbie
timestamp: March 05, 2020, 06:32:17 pm
content: Are you sure it's V2.04? On the website is V2.02?

author: Brumby
author_rank: Unknown
timestamp: March 05, 2020, 09:13:42 pm
content: Dave provided v2.04 a few weeks ago:HERE

author: ceut
author_rank: Regular Contributor
timestamp: March 06, 2020, 02:25:20 pm
content: Quote from: Kibabalu on March 05, 2020, 07:12:32 amHello,How fast is it in voltage mesurement with this new firmware for example with a lab power supply ?Is there some lag when changing range ?Thanks !

author: dougg
author_rank: Regular Contributor
timestamp: March 06, 2020, 04:02:29 pm
content: These results were obtained with a recently delivered 121GW running upgraded 2.04 firmware** and an Agilent U8001A power supply. I was pressing the "Output On/Off" button with the voltage set to 20 Volts (1 Amp current limit). When pressing "On" the meter's digital readout blanks in most cases and just after 1 second displays 19.992 volts. The indicator bar goes fully to the right then drops back to the correct position in probably 1/3 second. Once in a while a voltage in the 8 to 9 volt range pops up momentarily before showing the correct voltage. Pretty well the same thing happens in reverse when I press the "Off" button, but it is more likely to show a lower voltage momentarily and the bar indicator drops to zero more or less immediately. The ambient temperature was around 17C .** Somewhat worryingly the meter was delivered with 2.01 firmware which is listed in the manual as "do no use".

author: dougg
author_rank: Regular Contributor
timestamp: March 06, 2020, 04:09:03 pm
content: Plus I would guesstimate a similar 1 second delay while the digital readout was blank when pressing the Range button on the 121GW. One range indicated overflow (the press after showing "20.0"). The bar indication moved promptly.

author: ceut
author_rank: Regular Contributor
timestamp: March 06, 2020, 04:54:00 pm
content: Quote from: dougg on March 06, 2020, 04:02:29 pmQuote from: dougg on March 06, 2020, 04:09:03 pmThank you !!So as I have seen in many youtube reviews(I think I saw all) , the meter is really slow to change its ranges, even in DC Volt mode.So I will check for future FW update before buying it, and I may buy the U1272A which I find really fantastic but very expensive (I have one which not mine for testing purpose).I have a good BM257 too, very good but too low in diode&capacitance mode.

author: pppopol
author_rank: Newbie
timestamp: April 29, 2020, 06:41:42 pm
content: Hi,I ask myself this question, why the firmware version 2.04 is not included on Dave's EEVBlog site?The latest firmware on EEVBlog being 2.02?Regards

author: Brumby
author_rank: Unknown
timestamp: April 30, 2020, 01:56:01 am
content: It's on his "To Do" list.Has been for a while ....

author: EEVblog
author_rank: Unknown
timestamp: May 04, 2020, 01:22:28 am
content: Quote from: pppopol on April 29, 2020, 06:41:42 pmI'm a slack arse.It's now updated.

author: n3mmr
author_rank: Regular Contributor
timestamp: May 04, 2020, 02:37:34 pm
content: Quote from: EEVblog on May 04, 2020, 01:22:28 amGreat self-esteem!

author: ralphrmartin
author_rank: Frequent Contributor
timestamp: August 05, 2020, 07:32:12 pm
content: The manual on the site doesn't seem to mention 2.04. Has it been updated (if only to tell us what's new in 2.04), and if so can it be made available please?

author: jancumps
author_rank: Unknown
timestamp: August 05, 2020, 08:02:11 pm
content: ow, c'mon

author: ve2mrx
author_rank: Regular Contributor
timestamp: August 05, 2020, 09:21:12 pm
content: Quote from: EEVblog on May 04, 2020, 01:22:28 amQuote from: ralphrmartin on August 05, 2020, 07:32:12 pmQuote from: jancumps on August 05, 2020, 08:02:11 pmWell, I can confirm that onhttps://www.eevblog.com/product/121gw/, the documentation is NOT updated. The firmware 2.04 is there, however.In addition, the "Report an issue" link is bad. Dave @EEVblog should look at this when he has a chance!Martin

author: dzenbo
author_rank: Newbie
timestamp: June 06, 2021, 05:51:12 pm
content: The message above is still actual. And now 2.05 firmware is not presented on the site.Also, can someone present actual stage of further firmware features development? Because I little bit frustrated with my new device and waiting for a new firmware revision which makes this multimeter truly the best one!

author: Kijo
author_rank: Newbie
timestamp: July 05, 2021, 10:11:21 am
content: Just got a new 121GW and it is displaying 2.05 - not sure if its a beta release?

author: bateau020
author_rank: Frequent Contributor
timestamp: July 05, 2021, 10:31:02 am
content: Quote from: Kijo on July 05, 2021, 10:11:21 amSee here:https://www.eevblog.com/forum/testgear/eevblog-121gw-discussion-thread/msg3554407/#msg3554407You can say many things about Dave, but he certainly provides a certain sense of continuity:Quote from: EEVblog on May 04, 2020, 01:22:28 am

author: Sharp
author_rank: Contributor
timestamp: November 14, 2021, 07:26:55 pm
content: Hi guysI have three 121GW Multimeters and have updated them regularly, but the 2.05 is not working – it is rejected…Any idea why ?

author: Sharp
author_rank: Contributor
timestamp: November 14, 2021, 08:02:01 pm
content: I gave the file another go and it worked

author: npelov
author_rank: Frequent Contributor
timestamp: March 23, 2022, 11:05:47 pm
content: Why is the firmware changelog in the manual instead in the zip file with the firmware. There is no need to update the manual every time the firmware is updated. I'm curious what was fixed in 2.05...

author: urbite
author_rank: Newbie
timestamp: July 03, 2022, 02:07:46 pm
content: How does one check which firmware version is in the meter. I assume the firmware version is displayed briefly at power on, which in my case displays "U - 1.18".Does this indicate version 1.18? Asking because there is no v1.18 athttps://www.eevblog.com/product/121gw/. The versions go from 1.17 to 1.21It would be nice if the user manual mentioned how to check which firmware version is installed after an update. Also, it would be helpful if the beginning of the manual would mention that the firmware version is displayed briefly when powered on (if, indeed, this is correct).UPDATE: Just upgraded to 2.05 and confirmed that powerup message is version number. Would still be nice to have this info in user manual.

author: Electrohacker
author_rank: Newbie
timestamp: October 30, 2022, 08:09:37 pm
content: First Time caller long time listenerI noticed what I call a bug. in setup the beep mode reverts to off when I turn the meter off and on again. This is firmware 2.05

author: J-R
author_rank: Super Contributor
timestamp: October 30, 2022, 08:54:13 pm
content: After setting b-OFF or b-On, hold the Setup button down until it stops flashing. That will save the setting permanently.

author: Electrohacker
author_rank: Newbie
timestamp: October 30, 2022, 09:56:57 pm
content: good catch, I must have forgot to confirm by a long press. Thanks.