UT210E  Problem measuring AMPS!!! :( - Page 1
Forum section: electronics / testgear

author: marce002
author_rank: Regular Contributor
timestamp: May 07, 2020, 04:33:05 pm
content: Hello allI have an UT210E clamp meter that went wrong doing amps measurements, it shows an offset of around 5A, in cont. amps 10A set,,,,,, and also does not allow me to (zero button) , and it is even worse in the 2A !! setting which do nothing and shows "0L"What can be wrong?

author: Fungus
author_rank: Super Contributor
timestamp: May 07, 2020, 05:12:39 pm
content: If it's been exposed to a strong magnetic field or a current far in excess of its rating then it might need degaussing.https://www.google.com/search?q=degauss+current+clamp

author: marce002
author_rank: Regular Contributor
timestamp: May 09, 2020, 02:46:30 pm
content: Thanks .. sorry Im a normal user for this clamp and take advantage of its DC measurements.. i do not remember using in over exposed currents and wonder if it might be a common problem and what to do if you cant make a diy degauss tool.... the vendor cant repair and maybe an easier solution exist like leaving the tool close to something or using a more detailed tutorial explaining how to build a tool with this purpose.

author: cdev
author_rank: Super Contributor
timestamp: May 09, 2020, 03:07:17 pm
content: Have you tried removing the batteries for some time and putting them back in? Maybe it simply needs to reboot/reset.

author: marce002
author_rank: Regular Contributor
timestamp: May 09, 2020, 07:45:04 pm
content: yes i have tried but needs degaussing because it is in an 5A DC offset.. i have taken apart an hdd hard drive to remove the magnets and made them turn in the same hdd motor to no avail... it is the "drill" method but with another turning way... what is wrong? Location of radial magnet?

author: Chris Roubis
author_rank: Contributor
timestamp: May 10, 2020, 04:53:33 am
content: Quote from: Fungus on May 07, 2020, 05:12:39 pmNever thought of that.

author: joeqsmith
author_rank: Super Contributor
timestamp: May 10, 2020, 05:36:11 pm
content: Quote from: marce002 on May 07, 2020, 04:33:05 pmI see you the person who is asking me on the YT channel. So you are spinning the platter with the magnet stuck to it to try and make an alternating field. Beyond just buying a new meter, you could try cutting up an old E core transformer so you are left with the exposed E. Still, seems like a lot of work. An old tape eraser would be safer to use if you could find one.I've been able by hand to wave a magnet near the head and get it close enough to allow it to zero. I think I show that in the video when I was using the magnet to magnetize the head to then demagnetizing it with my degauss coil.With you may not have used it to read high currents, as Fungus suggests, placing it near a magnetic field like what you have with your RC toy motors can cause problems. Similar to using a magnet to magnetize a bit of steel during our grade school science class. To demagnetize the steel, you could whack it with a hammer but I don't think you want to hit the UNI-T with a hammer. Or maybe you do??!!

author: marce002
author_rank: Regular Contributor
timestamp: May 10, 2020, 06:09:27 pm
content: Thanks very much for your answers... of course when you buy a thing like an e210e you think in several uses innfact.. i have not used it just for my rc drone motors but a whole other dc current measures like my ebike consumption ... house appliances ... and several other that cant recall.. so i assume my knowlesge is far from yours but enough to understand a clamp use .. although not it way of work .. i do not care the hall effect theorics im a computer programmer so just :use it" like abstracting its fundamentals...so i only wanted of a simple way to "de bias " it without touchinh the trimpots ..(is a last resource) because it has 5A offset in 20A and obviously has a OL lecture under 2A (unusable).... im not the kind of person who goes and buy another just for that with out knowing what did i wrong ... even inna covid19 situation and even i did a normal use of the clamp not doing anything stupid with it.Sorry my english is 2nd lang.

author: Fungus
author_rank: Super Contributor
timestamp: May 10, 2020, 06:26:40 pm
content: Quote from: marce002 on May 10, 2020, 06:09:27 pmSwitch it to 5A and wave a strong magnet near it to see if if goes down towards zero (try both poles of the magnet).When it's near zero, switch to 2A and repeat.Quote from: joeqsmith on May 10, 2020, 05:36:11 pmJust like joe does...

author: cdev
author_rank: Super Contributor
timestamp: May 10, 2020, 06:43:17 pm
content: Do you have a tape head demagnetizer from the cassette era? What I used to do with tape decks is simply turn it on at least say 20 cm away, then bring it to the tape head, move it around it a few times and then slowly move away, then turn it off.Quote from: marce002 on May 10, 2020, 06:09:27 pm

author: joeqsmith
author_rank: Super Contributor
timestamp: May 10, 2020, 06:44:07 pm
content: When I show the degauss coil, it is clearly a decaying AC magnetic field. You ask about placing it next to a large magnet overnight and suggest the auto power down is part of the problem. Knowing that you didn't understand that magnetic fields can alternate gave me some idea on how to try and answer in terms I thought you may understand. After seeing the disk drive, it seems you now understand this part. Trying to make the field mechanically could be done but it's just easier to use the 50/60Hz line to create it. Again, you could decay the field by slowly moving the clamp out of it, or electronically as I have shown. If you used an old tape eraser, you would do this by hand, waving the eraser while moving it away from the clamp.I suggest never trying to take the meter apart and certainly not adjust the pots. These are a pain to get set right. The one pot is really sensitive.Using this clamp with an RC toy using brushless motors may not work, depending where you are trying to measure.Personally, I would just invest in a real degauss coil instead of messing around with these disk drive magnets. Then you will have it for the next time. My old Tektronix clamp has the coil built in. It's a nice feature.

author: marce002
author_rank: Regular Contributor
timestamp: May 11, 2020, 01:57:30 pm
content: ok, i dont have a tape bulk eraser but might get a microwave transformer easily... i can modify removing the secondary but i thing will be closed in shape (Not an E right?) the HDD was just an experiment but did not work for the clamp, worked fine for screwdrivers though (magnet and demagnet them). So Joe, can ido something useful out of a microwave transformer?FUNGUSyou said Switch it to 5A and wave a strong magnet near it to see if if goes down towards zero (try both poles of the magnet).When it's near zero, switch to 2A and repeat.i did, i get a perfect 0.000, then I switch to 2A and it is close to 0 too, but doing it forever I think wont solve the offset at all.thanks for more ideas

author: joeqsmith
author_rank: Super Contributor
timestamp: May 11, 2020, 02:12:24 pm
content: If its a laminated core, you could take it apart. Unwind the secondary, separate the laminates and modify them to form an "E"It may be less work to make one from scratch.

author: marce002
author_rank: Regular Contributor
timestamp: May 11, 2020, 02:17:23 pm
content: thanks Joe, i will be doing this procedure becasuse the microwave is almost here, and saw videos to make an E removing de secondary yes... I will be placing the clamp by hand a few cm from the center of the E , and then moving apart from the field in upwards direction.... sound reasonable?

author: joeqsmith
author_rank: Super Contributor
timestamp: May 11, 2020, 02:26:32 pm
content: You will have to play around with your technique once you have it built.That's going to be a lot of work. I would make sure the meter is at least working before you spend too much time on it. Again, you should be able to get it close enough with a magnet to at least zero it out.

author: Fungus
author_rank: Super Contributor
timestamp: May 11, 2020, 03:22:00 pm
content: Quote from: marce002 on May 11, 2020, 01:57:30 pmAt least you confirmed what the problem is.

author: cdev
author_rank: Super Contributor
timestamp: May 11, 2020, 11:39:32 pm
content: If I were you I would just make a coil with a bunch of nails and a long piece of thin wire. You can energize it with a transformer, dont use mains voltage. You dont need a super lot of power and indeed, less is more in this situation. You'll likely not need a degausser that often.You dont want to damage the UT210e

author: joeqsmith
author_rank: Super Contributor
timestamp: May 12, 2020, 01:15:32 am
content: Quote from: cdev on May 11, 2020, 11:39:32 pmObviously no want wants to damaged any of their equipment. I suspect you meant damage it from something to do with magnetizing the head or degaussing it. Care to explain?As far as what's required, I was using about 600 gauss peak with a half second decay.

author: Electro Detective
author_rank: Super Contributor
timestamp: May 12, 2020, 09:22:51 am
content: Would an old school hand held tape head demagnetizer do the same trick ?I would assume to switch it on first from a distance,gradually approach the clamp area,give it a slow magic wand job pass or twoand back off slowly, then switch it off when far far away,say 2 or 3 meters ?

author: Fungus
author_rank: Super Contributor
timestamp: May 12, 2020, 09:30:03 am
content: Quote from: Electro Detective on May 12, 2020, 09:22:51 amVery likely.

author: CDaniel
author_rank: Frequent Contributor
timestamp: May 12, 2020, 09:39:07 am
content: If you find an old CRT tv or monitor you can use the degaussing coil ... you can google easily for details , far more common than a tape eraser . And pretty powerful .

author: marce002
author_rank: Regular Contributor
timestamp: May 12, 2020, 12:28:58 pm
content: Hi cdev ... sounds smart solution... but can you give more details? Nails? what transformer to use i have for eg a 220v 12v from battery charger.... what cable and how many turns would you use...after that is clear.. would you pass them close trough the clamp or meant wrap the jaws or do turns like if you were measuring current.. im talking about DC measurementes.Yes the device my UT210E works perfect in all other functions that is why im so interested in its rescue.Yes im not gonna opem to touch trimpots nor update firmware wich would be great though.Joe yo know too much and showed your knowledge.. but from point of view of myself as an user i wanted just my device working at least on +- 100mah error and would be more than happy i bet with your device could be achieved.

author: NoisyBoy
author_rank: Frequent Contributor
timestamp: May 12, 2020, 04:57:28 pm
content: This is a clamp meter with a 2.5% +/-5 digits spec, so you will only achieve +/- 0.1A accuracy at low amperage (like below 4A). So temper your expectation on what this meter can really deliver in terms of accuracy. Due to its design, it is hard to achieve the 0.1A accuracy in clamp meters throughout its measurement range even for expensive meters, let alone a $10 Uni-T.

author: 2N3055
author_rank: Super Contributor
timestamp: May 12, 2020, 07:22:06 pm
content: Quote from: NoisyBoy on May 12, 2020, 04:57:28 pmIt has 2A range.. 2.5% +/-5 is +/-5mA+/-5d max error..EDIT: It has 2A range.. 2.5% +/-5 is +/-50mA+/-5d max error.. stupid me, it's been a long day.....

author: joeqsmith
author_rank: Super Contributor
timestamp: May 12, 2020, 07:44:44 pm
content: Quote from: 2N3055 on May 12, 2020, 07:22:06 pmI'm going to say It has 2A range.. 2.5% +/-5 is +/-50mA +/-5d or +/-55mA. Maybe we can vote on it and see who's right.

author: 2N3055
author_rank: Super Contributor
timestamp: May 12, 2020, 07:53:21 pm
content: Quote from: joeqsmith on May 12, 2020, 07:44:44 pmYou are, had a brain fart...

author: AVGresponding
author_rank: Super Contributor
timestamp: May 12, 2020, 07:56:55 pm
content: Don't be too quick to write off cheap clamp meters, unless you've checked the thing first.I have a cheap Mastech 2108A, icr what it cost, but was certainly less than 30USD.The low dc range is 40A, with 10mA resolution.Obviously I was curious about the accuracy, so I gave it some on the job testing.I was helping out a fellow sparky who was commissioning a small fire alarm panel; he'd found the current draw was so small that putting his DMM in series on mA setting (Fluke 77 iirc) the panel just wouldn't power up.The reason you need to do this is for fire regs, you have to measure the quiescent current and the full alarm current as part of the battery capacity formula.So I used the Mastech, and we were looking at around 30mA quiescent, and 50mA with all the sounders running.Since that's effectively in the noise as far as this meter goes, I was rather sceptical, and went for a rummage around in my van, and dug out a precision shunt I'd made.Using this we measured the currents again... and found them the same, though with the shunt we got an order of magnitude better precision.Nevertheless I was pretty surprised, and even impressed, with the performance of the cheap clamp meter.

author: NoisyBoy
author_rank: Frequent Contributor
timestamp: May 12, 2020, 08:14:48 pm
content: Good point, I have seen similar scenarios before.However, I have also observed cheap meters often are nonlinear in reading. The error may be low at some point, but huge at others, and likely you can even find a point where it is dead-on if you run it through a calibrator, but I would be careful to rate any overall accuracy from limited data points.Meters with good linear results are those with multiple cal points across each function and on each range selected, unfortunately, most low cost meters do not offer it.So, while at some amperage range, the Uni-T may offer <.1A accuracy. My point is it is very unlikely that it will deliver this accuracy across a wide current range.

author: AVGresponding
author_rank: Super Contributor
timestamp: May 12, 2020, 08:19:08 pm
content: That's a fair point, and tbh I've not checked it at the other end of the range.The aforementioned shunt will measure up to 70A or so before it becomes too hot to handle, so now I just need to fathom a 39A or so load to check them against each other...

author: cdev
author_rank: Super Contributor
timestamp: May 13, 2020, 02:48:20 am
content: My UT2010E meets the specs - it can measure a low current to 1 ma accuracy, which for the price was a great deal. Also the non contact meter is very useful. And it has a decent voltmeter, ohmmeter, so I think it was a great purchase. I wish it could connect to a USB port, but you cant have everything. I paid around $30.00 for it. Totally happy with it.

author: cdev
author_rank: Super Contributor
timestamp: May 13, 2020, 02:59:18 am
content: Looking good! Your degausser is designed for this use. Mine are for my old cassette deck and for erasing old VHS tapes.Yes, that is exactly what I meant. its basically the same thing. Maybe its unnecessary but I always turn it on and only then bring the item to be degaussed into the field, leave it there a bit, maybe move it around a bit to make sure its gotten a good degaussing and then remove it from the magnetic field, while its still energized. I am trying to not remagnetize it by breaking the circuit in the middle of a cycle while the object to be degaussed is still in the field.Quote from: joeqsmith on May 12, 2020, 01:15:32 amThat is definitely the way to go.

author: joeqsmith
author_rank: Super Contributor
timestamp: May 13, 2020, 03:09:58 am
content: That is pretty much what I do. Turn it on near the thing I am trying to clear, and never turn it off until I am far away. Depending on what it is, I will rotate the eraser in the field. The homemade one was designed for this probe. You can find my build here:https://www.eevblog.com/forum/testgear/a-look-at-the-uni-t-ut210e/msg1040540/#msg1040540

author: cdev
author_rank: Super Contributor
timestamp: May 13, 2020, 03:25:08 am
content: Joes's coil where you put the clamp into the magnetic field is clearly the way to go. It puts the meter right into the magnetic field. make sure you use enameled (insulated) wire and not bare copper wire which would defeat the whole purpose and likely start a fire! (joke)You can use any electromagnet, any kind at all, as long as you run it on AC, and not DC. 50 Hz, 60Hz, whatever. I being an old school kind of guy who used to dote on my audio hobby, have a tape head degausser and also a large tape eraser. Either one would do. The most important thing is safety. mains voltage of 115 v is high enough to hurt or perhaps kill somebody, 220 volts or more is at least twice as dangerous. So make sure whatever coil you use has enough length to not present a short, any demagnetizer will get warm, thats okay, but especially make sure its well insulated. When I said big coil I meant big enough to not blow fuses or melt at a bare minimum, but it shouldnt get too hot either. Dont use wire thats so thick it cant be long enough. Measure its DC resistance to make sure its high enough to not be a heater instead of an electromagnet. A good degausser will hum when you energize it a bit.Quote from: marce002 on May 12, 2020, 12:28:58 pm

author: marce002
author_rank: Regular Contributor
timestamp: May 13, 2020, 09:48:31 pm
content: ok thanks again, i think i will end up doing it with a microwave transformer with an "E" reformed core, because will be the most easy to get materials here around..... the truth is that I do knowvery well what to do once it is energized to 220v in the primary and an "open sky sight" to let the magnetic field scape from the core upwards.... a mean,,, should i manually get the clamp to the middle part of the core and then fast very fast rise it until the efects are far and turn it off? that in 20A scale where the offset is 5A, not in the 2A scale where i can only see 0L (out of scale)

author: cdev
author_rank: Super Contributor
timestamp: May 14, 2020, 08:37:18 pm
content: I'd use something like Joe's degaussing coil with it's added switch. Its good to mess with mains voltage as little as possible. That why I got my UT-210E to tell you the truth.

author: gyrex
author_rank: Newbie
timestamp: September 01, 2024, 10:32:22 pm
content: I've got a similar issue with my UT210E where my DC Amps is reading 0L. Regarding degaussing, would a degausser like this work?https://www.aliexpress.com/item/1005007458615469.htmlDo I need to be able to pass the entire meter through the hole or like the degaussing video, can I just put the clamp opening in the hole? Apologies if these are stupid questions but I'm not sure how to fix my meter.

author: ledtester
author_rank: Super Contributor
timestamp: September 01, 2024, 11:32:50 pm
content: Quote from: gyrex on September 01, 2024, 10:32:22 pmHere's a good video on those Aliexpress degaussers - including teardown, theory of operation and a way to improve it.Adding a PTC to a Chinese Demagnetiser making it easier and safer to use - TheHWCavehttps://youtu.be/AhTYBPdJG7A

author: Kean
author_rank: Unknown
timestamp: September 02, 2024, 03:55:29 am
content: Quote from: ledtester on September 01, 2024, 11:32:50 pmThanks for this reminder. I have one of these watch degaussers that I've used on my UT210E's (with some success) and I've been meaning to do a similar mod.

author: Mrnt
author_rank: Contributor
timestamp: March 11, 2025, 05:40:33 pm
content: In the case of my UT210E reading "OL" for DC current (and 0A for AC current), the issue was a failed opamp - seehere