Author Topic: Multimeters and portable digital oscilloscope from CEM Instruments  (Read 7895 times)

0 Members and 1 Guest are viewing this topic.

Offline pascal_sweden

  • Super Contributor
  • ***
  • Posts: 1512
  • Country: no
How do the multimeters and portable digital oscilloscope from CEM Instruments perform?

They look rather nice!

CEM DT-9987: 50K count Multimeter CAT IV 600V, CAT III 1000V (Waterproof IP-67/Bluetooth)

Website from manufacturer:
http://www.cem-instruments.com/en/pro/pro-825.html
Available on Amazon for 269 EUR:
http://www.amazon.de/CEM-Multimeter-DT-9987-50000-Counts/dp/B00T7WQ5KG

CEM DT-9989: 50K count Multimeter CAT IV 600V, CAT III 1000V and 10MHz/50MS/s digital oscilloscope (Waterproof IP-67/Bluetooth)

Website from manufacturer:
http://www.cem-instruments.com/en/pro/pro-824.html
Available on Amazon for 396 EUR:
http://www.amazon.de/CEM-Digital-Multimeter-Oszilloskop-Bluetooth/dp/B00T6J72QG/ref=pd_sim_sbs_60_1?ie=UTF8&refRID=0ZMVDRCH7W4AQZCXWXAX

CEM DT-990S: 40MHz/200MS/s/125Kpoints mem digital oscilloscope

Website from manufacturer:
http://www.cem-instruments.com/pro/pro-845.html
Available from Chinese distributor. Price unknown.
http://www.diytrade.com/china/pd/10801508/40_MHz_Handheld_Digital_Oscilloscope.html
 

Offline Marco

  • Super Contributor
  • ***
  • Posts: 4862
  • Country: nl
Re: Multimeters and portable digital oscilloscope from CEM Instruments
« Reply #1 on: May 25, 2015, 12:24:21 am »
Colour LCD ... will eat batteries.
 

Offline pascal_sweden

  • Super Contributor
  • ***
  • Posts: 1512
  • Country: no
Re: Multimeters and portable digital oscilloscope from CEM Instruments
« Reply #2 on: May 25, 2015, 03:31:33 pm »
Apparently these multimeters come with a big LiPo battery (2400 mAh)

https://www.youtube.com/watch?list=UUrPuVDBtQIxgzj8_En81r0A&feature=player_detailpage&v=zzfYm2DorWU#t=106

Not exactly the same model of multimeter, but the same manufacturer, and most likely they will use the same type of battery in the higher-end models.

The fuses seem acceptable, and the construction of the connectors inside as well. However I am not impressed at all about the PCB quality. Looks a bit messy! There is also a component sitting on the back that can get loose any moment. This is an older model though, so let's hope they have improved on this in the mean time.
 

Offline ivan747

  • Super Contributor
  • ***
  • Posts: 2022
  • Country: us
Re: Multimeters and portable digital oscilloscope from CEM Instruments
« Reply #3 on: May 25, 2015, 09:57:20 pm »
What's the price for these?
 

Offline pascal_sweden

  • Super Contributor
  • ***
  • Posts: 1512
  • Country: no
Re: Multimeters and portable digital oscilloscope from CEM Instruments
« Reply #4 on: May 29, 2015, 07:19:45 pm »
The prices are available on Amazon. It seems however that the portable scope with 20 MHz is a discontinued product. The combi multimeter and scope only supports 10 MHz, but has a nice form factor.
 

Offline pascal_sweden

  • Super Contributor
  • ***
  • Posts: 1512
  • Country: no
Re: Multimeters and portable digital oscilloscope from CEM Instruments
« Reply #5 on: May 30, 2015, 09:29:26 am »
I have contacted the manufacturer to check if they have a distributor in Europe and if they still deliver the 20 MHz scopemeter. Will post their feedback here when they come back to me.
 

Offline firehopper

  • Frequent Contributor
  • **
  • Posts: 387
  • Country: us
Re: Multimeters and portable digital oscilloscope from CEM Instruments
« Reply #6 on: May 30, 2015, 10:01:34 am »
the first one looks almost exactly like a fluke 289
 

Offline Neverther

  • Regular Contributor
  • *
  • Posts: 129
Re: Multimeters and portable digital oscilloscope from CEM Instruments
« Reply #7 on: May 31, 2015, 05:51:35 am »
I got:
DT-9918T as generic meter.
DT-9985 for testing ground faults on heaters/motors (tripping RCDs started to annoy after attempted repairs, got it at half price on sale) good voltage measurement and other stuff, continuity is slow.
DT-3351 for testing alternators and starters (also got it for half the price on same sale).
DT-3218 in car incase I need it (replaced Kaise SK-6590, would have preferred the newest SK-6592 but I could not get it anywhere,  the CEM meter is huge when compared to the small Kaise).

Yellow bodies as they were made before the Fluke thing.
They are pretty good for the price.

Inside the 9918t, look into the old 100$ multimeter shootout and you might see something.
I have looked inside the 3351, but no idea where the pictures are.
 

Offline pascal_sweden

  • Super Contributor
  • ***
  • Posts: 1512
  • Country: no
Re: Multimeters and portable digital oscilloscope from CEM Instruments
« Reply #8 on: May 31, 2015, 11:52:02 am »
It seems they have fairly good protection with 5 MOVs: 2 on one side of the board, 3 on other side.
The connectors are connected pretty well with a screw.
 

Offline Lightages

  • Supporter
  • ****
  • Posts: 4302
  • Country: ca
  • Canadian po
Re: Multimeters and portable digital oscilloscope from CEM Instruments
« Reply #9 on: May 31, 2015, 01:03:58 pm »
CEM makes some pretty good designs with good features and for reasonable prices some times. They are also the OEM for some other companies too. For example Extech re-brands some of the models for the EX series. CEM and Extech have a mixed history with quality control. Dave received a meter with a broken circuit board that was fixed with a bodge wire. Others have had problems with very bad solder joints, loose screws, control dials falling off, etc. The opinions and reviews with these problems are easy to find with a few searches. There are also many happy people with CEM products.
 
The following users thanked this post: Bobson

Offline pascal_sweden

  • Super Contributor
  • ***
  • Posts: 1512
  • Country: no
Re: Multimeters and portable digital oscilloscope from CEM Instruments
« Reply #10 on: May 31, 2015, 01:45:28 pm »
Apparently some people tried to get a sample in 2012 without success:
http://www.ittsb.eu/forum/index.php?topic=330.0
 

Offline pascal_sweden

  • Super Contributor
  • ***
  • Posts: 1512
  • Country: no
Re: Multimeters and portable digital oscilloscope from CEM Instruments
« Reply #11 on: June 03, 2015, 02:08:51 pm »
No feedback from CEM yet, but I will keep this posting updated.
 

Offline ozcal

  • Newbie
  • Posts: 1
  • Country: au
Re: Multimeters and portable digital oscilloscope from CEM Instruments
« Reply #12 on: July 07, 2016, 04:33:49 am »
We bought 10 of the DT-9989 meters nearly 2 years ago. Would not recommend. We've had endless quality issues with them.
Missing screws, battery not charging, readings out of spec (new OOTB), intermittent dropouts, incorrect units displayed (mA when uA selected). Yesterday, I even had one flip its display (mirrored).
 

Offline Bobson

  • Contributor
  • Posts: 14
  • Country: ru
Re: Multimeters and portable digital oscilloscope from CEM Instruments
« Reply #13 on: July 08, 2016, 06:39:12 pm »
I have DT-9979. Assembly quality is good, precision is up to specs. 

Cons: there is no known possibility to upgrade the firmware, and some of the features described in the built-in help are unavailable. Also, there are some Chinglish grammar errors. Trends could not be zoomed and traced. Clock precision is bad - upto several minutes per month. BT logging speed could not be changed.

Pros: it is easy to calibrate, bluetooth interface is working. Price is rather low. Display is so-so without backlight, but very good with it. Battery life upto 200 hours in logging mode. IP67 waterproof. Manual says 7 hours battery life, but my experience show 4 times better without backlight.

Summary: poor man's version of Fluke 289 with better display and BT.
 

Offline Hydrawerk

  • Super Contributor
  • ***
  • Posts: 2393
  • Country: 00
Re: Multimeters and portable digital oscilloscope from CEM Instruments
« Reply #14 on: July 08, 2016, 08:26:05 pm »
As a poor man I would buy a decent Brymen for the price of DT-9979. I think I would hardly need a graphic DMM.
Amazing machines. https://www.youtube.com/user/denha (It is not me...)
 

Offline Bobson

  • Contributor
  • Posts: 14
  • Country: ru
Re: Multimeters and portable digital oscilloscope from CEM Instruments
« Reply #15 on: July 08, 2016, 08:46:08 pm »
Graphing is usable on DT-9987 and DT-989, but not of much help on DT-9979 due to restrictions (one static graph w/o marks, trace and zoom).

But I don't know any Brymen model which has BT connectivity, easy calibration, events and clock. They are in the completely different league, IMO.
 

Offline Hydrawerk

  • Super Contributor
  • ***
  • Posts: 2393
  • Country: 00
Re: Multimeters and portable digital oscilloscope from CEM Instruments
« Reply #16 on: July 08, 2016, 09:40:09 pm »
OK, for some time-correlated datalogging stuff the CEM might be good.
Amazing machines. https://www.youtube.com/user/denha (It is not me...)
 

Offline Bobson

  • Contributor
  • Posts: 14
  • Country: ru
Re: Multimeters and portable digital oscilloscope from CEM Instruments
« Reply #17 on: July 08, 2016, 10:47:17 pm »
Not only datalogging. Top CEM models have good resolution, better  uV, pF and MHz ranges than any Brymen. I've read  bad CEM quality reports, but no statistics. Brymen has better QC, supposedly. CEM products have rather high prices (higher than UNI-T) and are hard to obtain. Definitely, good software could improve functionality very much, but CEM lacks resources as I can see.

Would add some more details to Fluke 289/CEM DT-9979 comparison:

Compared to Fluke 289, CEM DT-9979 is not much cheaper (I can get second-hand Fluke 289 for $350, DT-9979 new for $350 and second-hand for $200), and have lower quality.

CEM has much better display, faster boot time, BT and  software is free. It uses built-in lithium battery. There is no known available calibration manual, but using Fluke's one can help.

Fluke has much better trend capture analysis built-in (however, using BT logging and PC/Android program with CEM you can do better), you can buy BT adaptor for $$. Also, Fluke has LowZ, conductivity, AC smoothing. It uses AA cells (sometimes it is better than built-in lithium, sometimes not). It has higher diode test voltage - 7 Volts compared to 3.2 and signals on wrong input jacks used. FLUKE HAS AN UPGRADEABLE FIRMWARE!! It has problematic built-in backup battery, thou.

If you have money and can cope with display problems, Fluke is much better.
« Last Edit: July 08, 2016, 10:51:48 pm by Bobson »
 

Offline Hydrawerk

  • Super Contributor
  • ***
  • Posts: 2393
  • Country: 00
Re: Multimeters and portable digital oscilloscope from CEM Instruments
« Reply #18 on: July 09, 2016, 12:00:47 am »
Yes, all the Brymen multimeters can measure max 1MHz frequency or less. It is probably because of the internal high voltage protection that has little impedance for high frequencies. My Unit UT70A (2009) can measure 10MHz and my Metex M-3650D can measure 20MHz. These two DMMs are rather basic, they have no autorange and no True RMS.
Quote
Fluke has LowZ, conductivity, AC smoothing. It uses AA cells (sometimes it is better than built-in lithium, sometimes not)
I prefer it. You can always use some accumulators like Eneloop advanced NiMh.
Amazing machines. https://www.youtube.com/user/denha (It is not me...)
 

Offline skander36

  • Regular Contributor
  • *
  • Posts: 236
  • Country: ro
Re: Multimeters and portable digital oscilloscope from CEM Instruments
« Reply #19 on: March 03, 2020, 08:56:09 pm »
Hi,
This days CEM DT 9979  is 225 E on Amazon .
Consider this , it is an option to Fluke 289 ? . Fluke is simply too expensive .
UNI-T DT181A is suddenly over 400 E almost as much as Fluke . They think that color display is make it worth ...

Thank you .
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf