OWON CMS101 Clamp Meter/Oscilloscope Review/Teardown

[@johng4527]

you forgot that you could have easily measured higher current readings with your 10amp power supply by wrapping the cable through the clamp multiple times.

[@fx622b]

Hotswappable 18650 cell, I wish that was a more common sight. I'm a bit surprised though about the lack of ceramic fuses. Maybe there's some on the other side of the PCB?

[@ssalient]

Update on this device; I found a very concerning flaw that was repeatable over and over again (until I removed the battery, now it seems to work fine all the time). Here is what happened: 1) I switched on the meter and put it into VAC to measure the line voltage 2) Connected the probes, measured around 240VAC (Netherlands), no issues 3) Switched it to oscilloscope mode, measured nothing because it always defaults to current 4) Switched it to Voltage measurement and saw the graph overranged (is to be expected) 5) Pressed the A (auto acquire) button and now the problem started. After a while it read 1.4kV RMS, while the waveform still overranged (because it can only go to 1000V of course). 6) Switching back from the oscilloscope mode to the normal digit reading it showed 0,000VAC! 7) Pulling out the probes from the socked and putting them back in still gave 0.000V reading in digit mode and 1.4kV reading in scope mode. This problem went away until the device was restarted, but could be repeated over and over again. When beginning in scope mode and THEN inserting the probes into the socked, all went well. After removing the battery, this behaviour is, so far, not repeatable anymore but I don't think I will ever trust this thing again and I might just return it. I have made a short videoclip of the behaviour for those interested in what it looks like.

[@_droid]

It's good to see manufacturers finally putting standard lithium cells in these type of things. I've converted MANY of my own devices to run this way instead of the awful alkaline and NiMH cells. I use ultra low quiescent current regulators to drop the lithium cell(s) to the 3V or whatever the device uses.

[@sklepa]

could you name some of those regulators you use?

[@_droid]

@@sklepa Mostly I've been using the XC6206. The MCP1700 is alright too.

[@sklepa]

@@_droid thank You.

[@Shiva-ld6bw]

This is great, because it was so cheap I bought the HDS120 along with this, the Multimeter/OSC variant minus Bluetooth capability. I'm glad the update speed is good. I have the 2102S and the update speed is slow. The only thing missing is a filter for measuring current and voltage on VFD's, there's no mention of this on the website, other than that it's really good for the price and is more than capable in most situations. Ok, so I just got the clamp meter and multimeter today, everything works as expected, the only downsides for me is the lack of a high frequency filter and inrush capability when measuring DC current. It's larger than average for a clamp this size but I guess the inclusion of an 18650 cell was a contributing factor. One other thing is the non contact voltage sensitivity is too low, I feel maybe it was implemented for lower frequency of 50hz, I'm not certain but for me it's almost useless, checking with a probe works fine in this mode. Although it's cheaper the build quality is excellent. I think the price is more than justified, it won't replace my Hioki or Fluke but its a good mostly fully featured clamp meter, can't go wrong if on a budget at all, I'm impressed!

[@TheDefpom]

@25:00 looks to be way below the Nyquist from how the waveform is jumping around, analogue bandwidth seemed OK but sampling bandwidth not so much at 1MHz.

[@Thomas_A_H]

The missing single-shot mode is a bummer. Otherwise this looks really nice for its intended usages. Are there any clamp oscilloscopes that support single-shot, at least in amps mode?

[@TheDefpom]

@23:00 that sine wave isn't looking very pure, makes me wonder how good its sampling is, or is your AC line really that distorted ? EDIT: @24:00 it looks better, what's up with your AC line ?

[@KerryWongBlog]

Yep, that's the actual AC waveform. It's not uncommon though (at least here in the US) as I had measured mains waveform in a few different states and they are all distorted to some extend.

[@thepcmaniaccc]

Does imeter app also record the oscilloscope? This would be useful for automotive troubleshooting.

[@KerryWongBlog]

Not in its current version.

[@simontay4851]

In oscilloscope mode can it show the voltage and current waveforms at the same time so you can see the power factor?

[@KerryWongBlog]

Don't believe so. Looks like it's either current or voltage, not both.

[@NiHaoMike64]

@@KerryWongBlog That seems to be a big design oversight. The addition of real power and power factor measurement would make it a far more useful tool.

[@juhaszpeter4796]

This device is a big setback. The HDS120 is still usable and works. The bandwidth depends on whether it is in mV or V setting. In the mV setting, the bandwidth is smaller. I found two big flaws in this clamp meter. 1. The firmware cannot be updated via USB. I don't think it is likely that Owon will release the update for the programming port. 2. It doesn't have and because of the above problem I don't think it is likely that it will ever have Normal and Single trigger functions.😡 3. which is just my personal opinion, is that few people use the 600A measurement range, I think it would have been better if the CM2100E was smarter...

[@wtmayhew]

Something which would be useful would be ability to measure amplitude of the harmonics contained in the current waveform. I have an Amprobe digital clamp meter which can measure harmonics. Doing an FFT to measure line frequency harmonics should be within reach of the processing power of the ARM CPU in this meter. Some software tools to help determine phase rotation order, power consumption, etc. would be handy for people working with 3-phase power distribution. This Owon meter still looks like a well thought out and handy tool even though there is room for improvement.

[@ssalient]

I got this clamp meter myself too. For the price (75 euros in the Netherlands) it’s a really nice meter. Of course for this money you can’t expect it to be a mini Fluke 345PQ but would be nice though :)

[@vbc2059]

Still waiting for the electric screwdriver / oscilloscope combo!

[@HoangLam]

There is soldering iron/DMM combo already. We will get there soon 😄

[@G-P_H-T]

Thanks to Kerry for this review. Sincerely from Russian radio amateurs!

[@legobuildingsrewiew7538]

Let's hope it's not like the FNIRSI products.

[@Peter_S_]

I've had an OWON HDS310S scope/meter for a couple years and I'm quite happy with it. I don't think I would buy a FNIRSI item unless there are no other options.

[@fresheFresse]

The HDS2102s handheld scope I have from Owon is much better than any of the Fnirsi stuff. Works great and the specs are real. The only downside is the mediocre (little input protection, no integration into the rest of the device like graphing time series etc.) multimeter that is included.

[@legobuildingsrewiew7538]

thanks for the input guys

[@wtmayhew]

Owon products leave FNIRSI in the dust. I have the 100 MHz snd 200 MHz HDS200 series two-channel scope meters. There are only slightly more expensive than say, Zotek ZT-703S which I also have. The Owon are actually useable for quantitative scope measurements. I’ll give the nod to Zotek for the navigation buttons being a little easier to use, but it is very outclassed in scope performance by the Owon scopes. Where the Zotek gets some mojo back is that its multimeter function is surprisingly good. The Owon multimeter is still perfectly fine though and beats its promised performance. I’ve got the Owon CM-2100, not the B (Bluetooth) version. It is a very handy meter that and it was very affordable. The AC and DC current clamp readings easily meet or exceed the published specifications. The Cm-2100 internal construction is pretty decent. I believe the CM-2100 is probably safe to use at its published category ratings. I’ve taken the Zotek ZT-703S apart and there are some traces in the multimeter section which are very close to one of the screws holding down then PCB. The multimeter is opto isolated, but I don’t know how much I’d trust it at the limits of its high voltage rating. Of course I wouldn’t use the included probes wirh any of the meters for serious work. I have a nice set of Fluke probes with show white if the insulation is damaged.

[@juhaszpeter4796]

Unfortunately, they are heading in that direction with this current clamp. It is not possible to update it and it has been stripped of one of its most important features. single trigger...

[@stoptheirlies]

Hi Kerry, on the Capacitance ranges, does it show anything like ESR or Q on the sub scales?

[@KerryWongBlog]

No, it does not. It's just displays capacitance.

[@stoptheirlies]

@@KerryWongBlog Thank you

[@Electronic4U-david]

Thanks ❤❤

[@szekerespista3758]

It is possible to measure current at high frequency 14Mhz, pulsed DC ?

[@KerryWongBlog]

No, the maximum frequency for current measurement is only 1kHz.

[@szekerespista3758]

@KerryWongBlog thank you for your response!

[@harasti]

How we can support you, personaly I want to pay for this video review ? Also can get UNI-T new product directly from factory for you to review.

[@KerryWongBlog]

Thanks @harasti for subscribing to my channel! Being a subscriber is the best way to show your support. I do have a paypal link you can find on my channel home page www.youtube.com/@kerrywongblog If you have any future video suggestions/leads please PM me.

[@LawpickingLocksmith]

Now you need the Dave Jones EEV television power supply capacitor discharge via its built in Ohms range and see if you get a winner winner chicken dinner.

[@KerryWongBlog]

IMO, just because you can doesn't mean you should as the protection mechanism is not meant for repeated usage. My preferred way is to use a 10K to 100k resistor to discharge the capacitors, it really isn't that incontinent.

[@LawpickingLocksmith]

@@KerryWongBlog But Dave posted his video twice! After all he must be stuck with excess stock of them home branded Brymens he keeps bragging about.

[@andr27]

finally, mf chinese used pleasant to eyes fonts on display, overall its nice piece of hardware