EEVBlog 121GW Discussion thread - Page 1
Forum section: electronics / testgear

author: plexus
author_rank: Contributor
timestamp: January 09, 2018, 12:16:53 am
content: I searched the forum and coulnd't find an appropriate general purpose 121GW thread. So here it is!Question: what are the various straps in the case to be used for? I can't figure them out.Here is an unboxing video I made today when mine arrived:I'll be RTFM now that I have played around with it a bit. It's a very nice meter so far. Feels well built!

author: Mr.B
author_rank: Unknown
timestamp: January 09, 2018, 01:56:33 am
content: I don't have mine yet.I will be in wave 2 of the shipping (March?).My question:The manual specifically says: Battery Type: 4 x 1.5 V AA alkaline battery (ANSI/NEDA 15 A or IEC LR6)Can anyone (Dave) confirm if it is safe to use the slightly higher voltage Energizer L91 Ultimate Lithiumhttp://data.energizer.com/pdfs/l91.pdfMany thanks

author: beanflying
author_rank: Super Contributor
timestamp: January 09, 2018, 02:46:50 am
content: Quick Capacitance check on mine against my HP box. Does that very close 😎

author: beanflying
author_rank: Super Contributor
timestamp: January 09, 2018, 03:48:27 am
content: Quick resistance check against my 0.02% (1ohm 0.03%) Resistance box. Temp is 25-26 degrees btw.It does ok below 1 ohm but that territory isn't fair on two wire so just 1 ohm and up was all I have included.Also tested against some Vishay 0.005% (some pairs) I have 'laying' around10k 9.999k10k 10.000k500R 0.5000k500R 0.5000k100R 100.055k 5.000k

author: knapik
author_rank: Regular Contributor
timestamp: January 09, 2018, 04:43:23 am
content: I just got mine earlier today. I'm pretty happy with it so far, but I haven't really gave it any purposeful use yet.In regards to the question about the straps, I'm pretty sure they're for securing the multimeter and leads like this. I also see that there's another strap on the back, Dave must have liked that multimeter strap patent so much, that he wanted one too

author: beanflying
author_rank: Super Contributor
timestamp: January 09, 2018, 04:54:29 am
content: Quick DC low Voltage DC tests against an AD584M (closest Reference to hand) as per my Agilent 34401A % deviation to the 34401A of 0.02% or better.2.49905 2.49895.00021 5.00007.49955 7.49810.00028 9.999AC Voltage and Frequency Referenced to Agilent 34401a.Mains TestingAgilent 121GW248.07 49.98 249.90 49.95 HzFeeltech Sig Gen (don't mention the war)5V P-P (indicated) SINE used (1.7677 V rms)5V P-P (indicated) Square wave used which is fairly clean and sharp under 1MHz121GW 'Frequency Range' is shown not the dual scale value!Rough test on Triangle showed reliable Frequency to 1Mhz and consistent Voltage to 100KhZ.Indicated Agilent SINE 121GW SINE 121GW Square50Hz 1.7992 50.002 1.8040 49.997 2.5513 49.997100Hz 1.7996 100.004 1.8054 99.995 2.5518 99.995500Hz 1.7998 500.022 1.8049 499.98 2.5461 499.981KHz 1.7994 1.0000 1.8109 999.96 2.5521 999.9510KHz 1.7953 10.0005 1.8408 9.9996 2.6186 9.999550KHz 1.7920 50.0022 1.8394 49.998 2.6634 49.998100Khz 1.7914 100.005 1.8590 99.996 2.6617 99.995500Khz 1.7745 500.023 .6801 499.98 0.8457 499.981MHz 1.8453 1.00005 0.0000 999.95 0.0000 999.96These tests are really done for me so I have an idea when to break out the Agilent over the 121GW.First impressions are good, Auto Range is a little slower than I would like butso far.

author: beanflying
author_rank: Super Contributor
timestamp: January 09, 2018, 07:13:52 am
content: Doing some 'advanced' testing of my reference cabinet. Seems to much 'testing' happening and insufficient drinking the beer is nearly at pommie tempReference 4 wire RTD against the supplied K thermocouple is within spec at this sort of temp.

author: fanOfeeDIY
author_rank: Unknown
timestamp: January 09, 2018, 12:07:41 pm
content: I also made unboxing video.First time to upload a video on youtube.EEVblog Multimeter Unboxing, Continuity Voltage reviewhttps://youtu.be/tqFaSVsl-R4

author: lowimpedance
author_rank: Super Contributor
timestamp: January 10, 2018, 04:13:23 am
content: Gotta say the weight of it was a bit of a surprise! but it gives that solid built feel. Nice addition to my already to large a collection of DMMs.Pic of my 'Blog' related tools(yes I have taken its blue jacket of for a closer inspection!)

author: beanflying
author_rank: Super Contributor
timestamp: January 11, 2018, 12:30:56 am
content: Temperature logging commenced. 10s intervals. Nearly time to head to the beach or crack a beer while it logsedit - topped 30 before midday Beach time (sorry Northerners)

author: Terry01
author_rank: Frequent Contributor
timestamp: January 11, 2018, 12:59:31 am
content: Quote from: fanOfeeDIY on January 09, 2018, 12:07:41 pmNice 1st video buddy.The EEV meter looked very slow auto ranging? It was quick showing continuity and never missed a beat. You made a very good point too though that not 1 meter does everything the best. Having a couple (3 or 4) is a good idea as you cover all bases.Look forward to your next video.I hope you enjoy your new meter and it's all you hope for. Thanks for sharing

author: beanflying
author_rank: Super Contributor
timestamp: January 11, 2018, 04:33:18 am
content: Dropped onto David's Droid software app while the meter was logging Temperature to the card. Hooked up fine and displayed the data in graph form and mirrored the displayHit the save button and it allowed me to save the raw captured data from the start of the sync period till then. Would be nice to have maybe a screen capture option as well.Raw data captured via bluetooth below. Full log to follow off the SD card which is about 1500 records at 10 seconds.The Time Stamp I haven't tried to figure out? Perhaps David might chime in?time (s), Temp (°C)1.734916, 363.002225, 365.636383, 368.999986, 35.99.731009, 3610.41355, 3610.6082, 35.912.41178, 35.813.72841, 35.814.41105, 36

author: beanflying
author_rank: Super Contributor
timestamp: January 11, 2018, 06:09:00 am
content: SD card logs follows. Over 1500 records without a glitch (except record 1 being way low?). It is CSV formatted and as the site doesn't allow that format included as Libre Calc and Excel below if anyone is interested.Couple of observations on the logged data and the format. After the very last record the maximum and the minimum values are stored and will need to be either excluded from the list or moved elsewhere in the data for any post processing. I gather the meter appends them both after each write to the log file? If not can they be moved to the top of the log file with the other headers? If not just something to be aware of.For a meter that has an internal RTC and Calendar not having an actual time against the recorded data is a PITA.Basics of it however is it logs data easily and reliably. As you will see from the data there is plenty of other unused columns already.The sample logs below are a Small log of a VRef last night. Big log of the Temps today (over 36C)

author: BravoV
author_rank: Super Contributor
timestamp: January 11, 2018, 06:12:05 am
content: Quote from: beanflying on January 11, 2018, 06:09:00 amCompressed file ZIP is allowed, also usually CSV has high compression rate.

author: Seppy
author_rank: Unknown
timestamp: January 12, 2018, 01:55:07 am
content: Quote from: beanflying on January 11, 2018, 04:33:18 amYeah, so SD card records the samples in a sort of indexed form.As Bluetooth LE is sensitive to interference and the packet sent doesn't contain the sample index the app records the time that the packet was received successfully.

author: flano
author_rank: Contributor
timestamp: January 12, 2018, 08:55:24 am
content: Is there a link for the firmware download?I have 1.01, however I see some videos show 1.02?Thanks Mike

author: FrankBuss
author_rank: Unknown
timestamp: January 12, 2018, 03:55:10 pm
content: I thought about buying one, because I really like the low burden voltage, logging, and bluetooth connectivity. Butthis threadsuggests that it might be better to wait for the next revision, especially the reported contact problems of the rotary switch worries me. Can someone confirm this? The other problems, like unusable 7 seconds for ohms autorange, hopefully can be fixed by firmware updates.

author: Iagash
author_rank: Regular Contributor
timestamp: January 12, 2018, 08:18:53 pm
content: Quote from: FrankBuss on January 12, 2018, 03:55:10 pmWell I had two days fun with the meter and tried a lot of things. I think the switch is fine. Over the time I had a lot "malfunctions" of the switch and think it is firmware related.One time when I switched the meter on from the right side off-position to the mA range it dropped me into LowZ mode, which is on the other side of the switch next to the left off-Position.This clearly makes it look like firmware problems.The build quality of the meter is great and I like the size and I don't care about the slow autoranging, it's still faster than me twiddling the range switch on my manual meter.The 15V diode test is great and the low burden voltage is also very nice.But the firmware seems to stem from the shadiest corners of the shenzhen market. No matter in which of the "advanced" software features of the meter I look, it's broken or messed up.So the future will tell if this becomes a good meter or not. The hardware seems great but until there is a firmware that deserves the name it's hard to tell.If you want something to play with, get one. If you want a "tool" you can trust I'd rather recommend you wait if UEI will either publish enough of the firmware sources that someone who can writes one or they cobble up a firmware that works. Adding up the issues I found, my guess would be that it rather needs to get rewritten than fixed, since some of the bugs point more in the direction of software design errors (look at the bluetooth protocol thread) than just bugs, but I might be totally wrong on that since I have way too little background information.At the moment it's not an advanced meter but a well built prototype with basic features and hardware working.That doesn't mean I regretted it one second to get one. It's just to adjust the expectations on a meter that received very limited testing upto now.If you want something working, you never buy the first revision.

author: beanflying
author_rank: Super Contributor
timestamp: January 13, 2018, 09:32:30 am
content: Without knowing the actual code used for the autoranging I would suspect bloated and lazy code may be part of the issue. It is also possible looking at the bar graph that it is running a loop more than necessary to set a range. I think Dave needs a bit of time to get back from his break and do some to and fro with UEI and nothing really can be gained until that happens.Apart from the bluetooth data issue above I haven't found an issue but I will set up some more logging tests over the next couple of days as my schedule is a bit lighter.On the rotary switch I like the general feel of it and it works on the stand with two fingers to turn it. Once again no issues with it.Very unlikely UEI will publish their firmware and I think that has been made more than clear. The original kickstarter without checking only talked about open source on the bluetooth communications protocol? My meter is still on 1.01 btw but perhaps when future updates are made Dave can put up a changelog along with them?

author: dcac
author_rank: Frequent Contributor
timestamp: January 13, 2018, 03:48:15 pm
content: Quote from: beanflying on January 13, 2018, 09:32:30 amDecent speed on Auto-ranging is such a basic function that you’d think Dave made sure of this during the early stages developing the 121GW. And I can’t really see a reason they needed to change anything, and possibly introduce bugs, in those routines. But I agree that the display behaviour during auto-range seems to do some (weird) extra steps or delays, but still I’m not too optimistic an easy fix is going to speed things up enough.And also the eevblog “VIP" members who had more insight in the early development doesn’t seem a least bit surprised over this issue - even though it’s been established that the 121GW is twice as slow as the U1282A - a DMM Dave even have >warned< about having “Very slow” auto-ranging.

author: FrankBuss
author_rank: Unknown
timestamp: January 13, 2018, 03:59:17 pm
content: Quote from: dcac on January 13, 2018, 03:48:15 pmRight, that's odd. Usually Dave is not biased and says that some aspect sucks if it sucks, even if he gets money from something. Maybe it is difficult with the high precision? But I guess they could show a few most significant digits fast, then the final result after some seconds if you need it.

author: 1anX
author_rank: Regular Contributor
timestamp: January 13, 2018, 10:05:59 pm
content: Quote from: Iagash on January 12, 2018, 08:18:53 pmFrom what I've been reading, Iagash has it summed up with his above quote!The meter I bought from Dave's kickstarter campaign is in the second production run, so I have my fingers crossed the early firmware bugs are sorted. Buying a version 1.0 is always an act of blind faith but I'm sure Dave will get it sorted out once he is back from his break.I'm tipping it has not been a relaxing time for Dave with a fake campaign running his product and reading of the teething problems with the nicely made and manufactured EEVBlog 121 GW meter. He could not have picked a worse time to be on "holiday" than with the release of a best selling new product. Hurry home Dave we miss you, and your ability to fix complex electronic things, and to make us smile while you do it!One of the reasons I waited for this meter to become available was that I believed Dave had some great ideas put into its design. Also Dave's character came into play as he comes across a straight talking no BS engineer. The hardware looks good, lets see if the bugs can be fixed quickly as more owners test the meters and more insights become known.

author: mattselectronics
author_rank: Contributor
timestamp: January 14, 2018, 01:02:21 am
content: I made a short video about it:https://youtu.be/Ao2Is4LeQIYI like it, but the slow auto rangeing is a bit annoying. I hope they can do something about that in software.

author: 1anX
author_rank: Regular Contributor
timestamp: January 14, 2018, 01:48:12 am
content: Matt, I liked the video you made!You commented on the hassle of getting the SD card out from the meter to have access to the csv file for processing. Maybe Seppy, (Dave 2) can comment, but cant you have access to the csv file from the BLE app? I'm assuming the app on android can use dropbox, etc, or maybe the app is also available for your PC?I would like to know if this is possible with the app?The accuracy of the meter looks really good from what I have seen so far, just the slow autoranging holding back its full potential.

author: beanflying
author_rank: Super Contributor
timestamp: January 14, 2018, 05:12:36 am
content: Dropping the card out is a bit of a PITA. In general use for me I may only log data with this meter occasionally. Even then being able to check Min/Max figures would do me a lot of the time.On the other hand my two Victor 86B's are strapped to my coffee roaster and get used 10-30 times a week every week. I also have a couple of Agilent DAQ units I am playing with. Plus a heap of independent Temperature logging gear.Below is some sample data from the shack on why I have a UPS arriving on Monday. On AC the 121GW logs Voltage and Frequency btw. Approximately 40m cable run from the main switchboard over 1kW of commercial refrigeration, 3.3kW of coffee machine or 3.6kW of Roaster plus the electronics gear.The Voltage troughs in the graph are the elements of the Coffee machine kicking in and out. 10 Seconds per log point.