New clamp meter + oscilloscope - OWON CMS101 - Page 1
Forum section: electronics / testgear

author: LeonR
author_rank: Regular Contributor
timestamp: November 01, 2024, 03:52:29 am
content: Saw this on Aliexpress the other day, but Owon didn't have a page set up on their website with specs. Checked again today and there it was.Features:* AC/DC clamp meter + Recorder Function + Oscilloscope function 3 in 1.* 20,000 count true RMS auto-ranging clamp meter.* Oscilloscope：Capable of measuring both current and voltage waveforms simultaneously.* Recorder Function: View, compare, analyze, and store measurement data via i-meter (app).* Inrush Current Measurement Function.* support for Android/IOS dual systems.* Full touch-key operation enables quick switching with one hand* 2.8-inch IPS LCD display with wide viewing range makes the values and waveforms clearer.* Dual theme display adapts to different light environments* NCV function* 18650 lithium battery meeting the needs of extended operations.Specs:

author: csuhi17
author_rank: Frequent Contributor
timestamp: November 01, 2024, 09:04:20 am
content: In the early description, it is not properly described that in the oscilloscope mode the voltage is 1MHz and the current is only 1kHz.The current is measured at a minimum of 10A/DivVoltage measurement minimum 30mV/DivThere is no base line calibration, more precisely I could not find it.Because of this, there is an approx. -1 Ampere offset that must be taken into account.The noise is also approx. 1 App.I tried the demagnetizer which worked for the CM2100.It didn't work out, the jaw is too big for that in my opinion.It does not have sinlge and normal trigger, only auto.In my opinion, the current measurement can be considered accurate.I measured the DC current with it as much as the Avg offset, and it came out to almost 0, because of the noise there was a fluctuation of about Avg 30mA."Vpp" was around 1 Amp. Even when measuring amperes, peaktopeak is written as Vpp. "Vpp 953mA"You cannot move the wave to the side, if you stop the recording, there is a chance that the part you want to see will be removed from the display and you will not be able to navigate there.The Imeter app does not support the oscilloscope function.The DMM part is fine, you can control it, it works fine, but when I switch it to OSC, it just says "OSC State".And in the Data Chart section, it doesn't write anything meaningful, it doesn't measure anything.The unit of measure says "VA" if the OSC measures Amps or "W" if it measures Volts.It's like the whole device is half baked

author: DaneLaw
author_rank: Frequent Contributor
timestamp: November 02, 2024, 04:32:35 am
content: Quote from: csuhi17 on November 01, 2024, 09:04:20 amThat's a shame. so no 65€ Fluke-345 counterpart from Owon..godammit.https://www.owon.com.hk/products_cms101_1000a_smart_ac%7Cdc_clamp_meter_and_oscilloscopehttps://files.owon.com.cn/specifications/CMS_SPECIFICATIONS.pdf

author: LuizAnghel
author_rank: Newbie
timestamp: November 02, 2024, 03:54:12 pm
content: Last week I ordered this clamp meter from aliexpress but the seller was taking too much time to ship it so I asked him why it was taking too long and he replied that the clamps were returned to factory because of quality problems

author: csuhi17
author_rank: Frequent Contributor
timestamp: November 02, 2024, 07:31:50 pm
content: I hope I misunderstood something.USB is for charging only and not for data connection.so, I can forget the firmware update.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: November 12, 2024, 09:31:45 am
content: Quote from: LuizAnghel on November 02, 2024, 03:54:12 pmAsked some of the sellers that is previously upfront, if there have been any recalls or notices on CMS101.was a blank noQuoteQuite a few Alipress sellers will use "quality problems" if they ain't able or interested in shipping a given order.Would personally love if there was a recall or an update to CMS101, as it is a product that appeals to mecrude waveform and also inrush current + harald blåtand support.I only have one clamp meter with inrush AC/DC ablelity, though it is quite fast, and seems consistent down to the single digit ms...The HT208D, which is a 1kA clamp meter to around 40 bucks from a few years back, though been rebadged amongst a handful of different names.Its also useless for low current, fx below 200mA.

author: LeonR
author_rank: Regular Contributor
timestamp: December 10, 2024, 12:53:55 pm
content: Kerry Wong dropped a review:

author: 1waynger1@gmail.com
author_rank: Newbie
timestamp: December 18, 2024, 07:09:11 am
content: Is it possible the firmware could be updated via Bluetooth?

author: csuhi17
author_rank: Frequent Contributor
timestamp: December 18, 2024, 02:58:59 pm
content: I think the chance of that is less than 0.01%.I don't see any chance of that, there is no option or function for it in the APP, nor among the functions of the clamp.I already wrote to Owon, but I didn't get any worthwhile answer.They didn't answer when the firmware update can be expected, how to do the update, whether it will have a single trigger, or whether it will have some kind of "base line calibration" function.They also didn't answer my question about whether the Android app will have the option to display the oscilloscope.Now if I switch to oscilloscope mode, the app only says "OSC State" and doesn't do anything else...answer what i got:"Thank you for purchasing OWON product.In the oscilloscope mode, it can't calibrate the baseline to center it.and yes, it has not single and normal trigger, but only auto trigger"

author: DaneLaw
author_rank: Frequent Contributor
timestamp: December 18, 2024, 07:54:03 pm
content: Its not a product that is gonna get any updates.Asked Owon China. before I purchased one, alongside if there have been any recall of this new clamp meter or variations... also asked a couple of sellers on Aliexpress, that are selling as third-party (they are usually are just a customer on your behalf in another shop, when you make a purchase thro8gh their store) if there had been any notice of this product..Nope, no recall or, differences in models..Same with Owon Lilleput China..QuoteIts a very rudimentary scope-function that are in this clamp meter, sadly - but it ain't like there is a lot of self-contained alternatives.Im not familiar with any other, not least in this pricebracket?.. sure a Fluke 345 gonna run rings around the CMS101, but it's another fish.The CMS101 (61€+VAT) is around the same price in Europe as a CM2100B (57€+VAT)

author: csuhi17
author_rank: Frequent Contributor
timestamp: December 18, 2024, 08:33:49 pm
content: That's what I was afraid of.just a clamp meter...In my case the price is a little different, ~50 USD for the CM2100B and over 100 USD for this CMS101. Which is not a good price for it...

author: 1waynger1@gmail.com
author_rank: Newbie
timestamp: December 19, 2024, 01:06:30 am
content: I'm very happy with this unit remote measuring voltage and current both AC and DC have worked well. The app is easy to use and so far very dependable.

author: flr
author_rank: Newbie
timestamp: January 14, 2025, 11:15:13 pm
content: This is my reviewhttps://youtu.be/TEfte1OT-XU?si=P-Kk9a1OhDWEVEcB

author: pso
author_rank: Newbie
timestamp: February 23, 2025, 02:08:00 am
content: I tried it.first impression nice everything in current measurement works fine.then i tried AC Voltage and that device is really dangerous and not reliable.switching between DMM, scope and current results that for AC 0.0 V is displayed and nothing on the scope - but indeed AC 240V are there,or it shows a clipped RMS with 1.4 kV or constantly switching between scales or some other strange behavior.the only way to get it to work is to switch off and on again - but don’t switch between modes …i could reproduce this more than 5-6 times.i returned it and according to the store this problems are well known.forgot: firmware cannot be changed.

author: csuhi17
author_rank: Frequent Contributor
timestamp: February 23, 2025, 02:43:22 pm
content: Yes.Every time it shows something stupid, you have to disconnect the leads and turn it off and on again to measure the correct value.When you turn it on, it is in current measurement.If you switch it to scope mode, it is also in current measurement mode.If you switch it to voltage measurement mode, it starts at 30mV.What you wrote happens to me too.I have been able to prevent this by setting what I want to measure in advance and then connecting the test lead.If I connect it to 230VAC in the 30mV measurement range, it measures it as kV, the top of the wave falls outside the screen.Its abnormal behavior is corrected after restarting the device. So far, I have not managed to ruin it.Unfortunately, every time I turn it on, it sets itself to current measurement.And if I manually change it, and switch back and forth between DMM and scope mode while it's on, it sets the mV measurement range, it doesn't remember what I used before.In DMM mode, it can easily be changed to mV, in which case if I measured a higher voltage, it will behave abnormally afterwards and I have to restart it.It's very inconvenient to use. And in scope mode, both zero line calibration and single trigger are missing. I have to figure out the offset in my head...

author: tonyalbus
author_rank: Super Contributor
timestamp: March 24, 2025, 12:56:05 pm
content: Quote from: pso on February 23, 2025, 02:08:00 amit seems indeed not over USB,but maybe over bluetooth ?

author: arturmariojr
author_rank: Contributor
timestamp: March 31, 2025, 01:56:46 am
content: Although not upgradable directly by usb ou bluetooth, it must have a service screen that shows the software version at least. May be pressing some Keys while turnimg it on... I ask this for keeping record when they release new versions.

author: arturmariojr
author_rank: Contributor
timestamp: March 31, 2025, 01:59:38 am
content: May be someone could discover a service screen that shows software version, at least.This could help to track New versions.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: March 31, 2025, 05:47:35 am
content: I reckon all CMS101 are running on the same fw.Tried to look into a while back, also some of the other naming schemes in Owon Lilliput CMS-clamp meter line, and if there were aspects that differed but didnt compare the specs in details and the actual reason for CMSxxx model naming variables, and if its regional or solely bluetooth vs non-bluetooth ver. that differed between models like CMS101 & CMS061.Specsheet between CMS061 & CMS101https://files.owon.com.cn/specifications/CMS_SPECIFICATIONS.pdfCMS101 Quick Guidehttps://files.owon.com.cn/probook/CMS_quick_guide.pdfCMS101 User Manualhttps://files.owon.com.cn/probook/CMS_User_Manual.pdfCMS061 Quick Quidehttps://files.owon.com.cn/probook/CMS061_quick_guide.pdfCMS061 User manualhttps://files.owon.com.cn/probook/CMS061_User_Manual.pdfAs far as I can tell, after a brief glance on the above links, it looks to be the max current-aspect that specifies the naming-variable.. CMS101 [=1000A] & CMS061 [=600A].

author: DaneLaw
author_rank: Frequent Contributor
timestamp: April 01, 2025, 06:48:07 pm
content: Been testing some more with CMS101 and its a shame if it can't be firmware optimised, as there are some aspects that I would guess are bugs, as it makes very little sense that its only visible while in "HOLD" mode.Not least if you activate your numerical top display, and what I reckon is an electric field read-out value [V/m] for your NCV sensor..Exampled with 150 below (minor display in the topbar, that seems to reflect a given V/m NCV value)Seems to be in the ballpark of what other V/m reports.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: April 15, 2025, 10:57:08 pm
content: A rebrand, though the lesser 600A variant. [Hanmatek CO601]https://video.aliexpress-media.com/play/u/ae_sg_item/2212876366178/p/1/e/6/t/10301/5000233504748.mp4https://www.aliexpress.com/item/1005008497882590.html?

author: DaneLaw
author_rank: Frequent Contributor
timestamp: May 03, 2025, 06:11:59 pm
content: Tested the inrush current on the CMS101, and it seems to be in the same ballpark as the other way cheaer 1K Amp AC/DC clamp meter I got .As a crude current source (as in easy to ms-adjust and can deliver hundreds of amps) I rely on an older handheld-spotwelder from China with a max of 2 pulses (preheat 0-10ms & main 0-80ms)Its a battery-spotwelder that does leave some to be desired, as it tends to drain the inner LIPO while in storage (annoying as) though at 20 bucks with EUVAT delivered, it's difficult to expect a lot more.I'm left with the impression that the inrush reading on CMS101 can go quite a bit lower than what I see on the HT208D, which works from around +7A before it takes inrush AC/DC notice and display a value, while CMS101 at times would pick up at xxx mA values.Both seem willing to pick up very fast pulses on their inrush-feature, down in the single-digit of ms, but dont have a picture of what effect such fast pulses have on the accuracy..1ms preheat & 2ms main pulse, and 10ms + 45ms on second pic, but since the CMS101 doesn't have a single shot, you need to "HOLD" and catch the waveform the moment it visualizes to represent it like below.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: August 20, 2025, 07:25:51 pm
content: Noticed a DC offset up around 0.5A, same with the HT208D was around 0.42A... both can obviously be zero'edTried to give this cheap degausser a chance that I purchased from Aliexpress some time back.This watch degausser was 4 USD incl. EUVAT, for some reason the US-plug model was significantly cheaper than the EU model, almost half price, and these degausser seems to be multivoltage, so likely only the plug that differs.Overall seems to work okay for this task and got it down around 0 to a few tens of mA, while the degausser peaks around 35W in use from 230V Danish AC socket..Worth noting that the DC-offset/bias on the CMS101 in numerical mode seems to be locked & tied with the DC waveform range, so the bias on that wf-display-range did increase, after centering & aligning the numerical.But it should also be emphasized, in practice it makes relative little purpose to degauss-align a clampmeter in DC range to these out-of-the-gate centered values, as the moment you're using it.. you're gonna field it with a certain bias again.

author: DaneLaw
author_rank: Frequent Contributor
timestamp: August 23, 2025, 05:17:24 pm
content: CMS101 Ω