A look at the Uni-T UT210E

[Tjuurko]

Thsinde 210E, seems an improved version.

Very similar to BSIDE ACM91:
https://lygte-info.dk/review/DMMBSide%20ACM91%20UK.html
https://www.eevblog.com/forum/testgear/new-cheapo-acdc-mini-clamp-meter-bside-acm91/

[Stinger]

.... How modify for adding Frequency...

Mine has a 24C08 in it. So its  1024 Bytes instead of 256Bytes in a 24c02 used in the normal 210E.
There are some additional entries from 0x160  to 0x175 .

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Maybe ... 

Thanks for this precision !

Who try to install 24C08 in non Pro for hack ?

[bayati]

I think it is a new version of UT210e, the layout has been chenged:

[d.bocc]

Hello, today I received my UT210E from amazon (56€), a row of capacitors is unpopulated, it's normal? (I read about other with same "issue", but didn't understand if it's an error or another "revision")
Thanks!!!

[shved]

Some revisions do not have caps populated, never had any problems.

[d.bocc]

Update about missing caps:
According to Tony Zhou <support02@uni-trend.com.cn>
Hello friend,
This unit is normal.
 Best Regards,
UNI-TREND TECHNOLOGY (CHINA) CO., LTD

[ThunderZed]

What's its minimum detectable AC value? I mean the value based on your real experiences, not based on specs, better if in comparison with other more accurate instruments/gauges to see how "effective" is its lowest detected value 

[Neutrion]

Hi folks.

I would like to share a method I discovered to calibrate without need to read and write the flash memory.
Sorry if it is not new fou you, but I searched for it and did not found the procedure explained like this.

1-Simply hold pressed the HOLD+SELECT buttons while you turn on the meter to the ohms/continuity/diode option (second position). Then release the buttons.
I am not sure if this wheel position is really mandatory, but it is described in some places as the correct method.
The meter will show "CAL" and will do some auto tests. You can abort this tests pressing select 2 times. If you let it run over, it will end the auto-tests after some minutes.
(note: after change the count config to reach 6200 counts the aut-test take much more time, then I gave up waiting).

2-Now put in the function/scale you want to calibrate (rotate the wheel and press select until you reach there), can be DCV for example.
I tested only for DCV (all ranges) and DCA (all ranges) but most probably it will work for others, like ohms and capacitance. The ACV seams to share the calibration of DCV. I did not tested ACA.

3- Now comes the main part (apparently undocumented). While you are in whatever function you chose before, you can calibrate the zero point by pressing the ZERO button (once per function/scale calibration procedure) and the gain by pressing the HOLD button (short press to decrease the reading and long press to increase the reading). However, to do so you need to feed the leads with a known integer value, once each press in HOLD will jump the reading to next integer above(long press) or below(short press). So, for example if you feed 12.00Vdc but you read 11.82Vdc, than long press HOLD while you are sure the correct voltage is 12.00Vdc and the meter will adjust the reading to 12.00Vdc (first integer above 11.8V).
-Therefore, each long press will jump the reading to next integer above, while the short press will make jump to the next integer below.
-Depending the scale you are the jump may not be an integer, however you will figure it out while doing the process.
-Pay attention to the scale you are. As DCV is autoscale you need to adjust when you are at 0.000, when you are 00.00 and when you are 000.0. You need to change the scale by changing your voltage source. The point in each range to calibrate is a personal choice. I noticed that the linearity is not so good, than I prefered to calibrate at 17.00Vdc the 60Vdc range once I will be reading values mainly from my battery bank between 12 and 24Vdc.

4-After the procedure for all functions and scales you are interested to calibrate just turn off the meter. In the next turn on the new calibration is used normally.

In the attachment you can see my flash content before(left) and after(right) calibration. Differences are highlighted. I calibrated DCV and DCA only (all ranges).
It seems that some different memory positions were changed compared to the documented positions (devydd post). My meter use the DTM0660 chip.

Did anyone else verify this method? There are some docs and blogs suggesting NOT to do it. Why?

[radiolistener]

What's its minimum detectable AC value? I mean the value based on your real experiences, not based on specs, better if in comparison with other more accurate instruments/gauges to see how "effective" is its lowest detected value 

just tested it at 50 Hz. The test setup is PSG9080 sig gen, BM867S dmm and RF grade 49.85 Ω dummy load (FLORIDA RF 32A1213F C0C).

The first value is measured RMS voltage on dummy load.
The second value is calculated RMS current through dummy load.
The third value is UT210E current reading on 2A range.

0.100 Vrms / 0.0020 Amps  => 0.000 Amps
0.200 Vrms / 0.0040 Amps => 0.000 Amps
0.242 Vrms / 0.0049 Amps => flashing 0.000/0.001 Amps
0.250 Vrms / 0.0050 Amps => 0.001 Amps
0.300 Vrms / 0.0060 Amps => 0.003 Amps
0.405 Vrms / 0.0081 Amps => 0.005 Amps
0.502 Vrms / 0.0101 Amps => 0.008 Amps
0.600 Vrms / 0.0120 Amps => 0.010 Amps
0.702 Vrms / 0.0141 Amps => 0.012 Amps
0.802 Vrms / 0.0161 Amps => 0.014 Amps
0.900 Vrms / 0.0181 Amps => 0.016 Amps
1.001 Vrms / 0.0201 Amps => 0.018 Amps
2.002 Vrms / 0.0402 Amps => 0.037 Amps
3.004 Vrms / 0.0603 Amps => 0.057 Amps
4.004 Vrms / 0.0803 Amps => 0.076 Amps

So, the minimum detectable current which shows 0.001 value on the display is about 4.9 mA.

PS: I was used two 1 meters wires and 1 meter coax with alligator clips, so there is possible a little measurement errors due to cable resistance, capacitance and non reliable contact on alligator clips.

[ThunderZed]

Thanks but I just forgot to say I'm evaluating this clamp as a cheap tool to measure domestic low currents, I mean "leakages", so we know the conditions: 50-60Hz, 220-230V AC (here in Italy) and a 1.5mm (= 0,059 in) diameter ground wire "many" meters (don't know) long. So could you please test this clamp on 2A scale in these conditions and tell me what's its minimum and "reliable enough" detectable AC value? I mean it'd be fantastic if you could compare its minimum value with a more reliable tool (eg. fluke) so we can answer the question: can this clamp measure down to 8-10mA in those domestic conditions with enough reliability?

[Kean]

As

so we can answer the question: can this clamp measure down to 8-10mA in those domestic conditions with enough reliability?

As shown by the results of radiolistener's tests the readout of the UT210E at low AC currents is pretty ordinary (i.e. useless).  If you want to properly measure AC leakage currents then the UT251A Precision Leakage Clamp Meter is a much better option, as it has 1uA resolution on the lowest range.  It is pretty much only usable for low frequency AC leakage measurements though.

Another option which I quite like is the SE-07 AC/DC Clamp Meter which has a 0.1mA resolution on its 400mA scale, and I've confirmed this can measure 1mA at 50Hz reasonably accurately.  It is available on AliExpress, and I've had one for many years and prefer it to my UT210E's.

Attached are some comparison measurements I just took using a test jig I made for testing RF current probes.  I measured the output voltage of the PSG9080 output (50Hz sine) with a Keithley 34465A, and measured the current at each setting with two different UT210E's, a UT251A, and a SE-07.


(I just noticed the third spreadsheet column is labelled "Irms (mA)" but is actually in amps.  )

The fact you are measuring leakage currents at 220-230V AC (vs our small voltages) doesn't change the way the current meters work.

Also note that radiolistener did his calculations based on his measured 50 ohm load, but for my measurerments the current will actually be the PSG9080 output voltage into 100 ohms (50 ohm generator output impedance plus 50 ohm load) and the 34465A measurement was just a sanity check.  I then doubled that measurement to simplify comparison.  The PSG9080 only allows the output set in Vpp, which is why I have that column in the spreadsheet.  My load resistor measured about 50.8 ohm DC, and the PSG9080 output measured about 49.6 ohm when off, but the numbers are just meant as a ballpark to show why the UT210E is not suitable.

Forgot to mention: I checked at what point my two UT210E's switch from reading 0mA to 1mA, and it was at 1.58Vp and 1.48Vpp, so 790mV RMS (7.9mA) and 740mV RMS (7.4mA) 523mV RMS (5.2mA) and 559mV RMS (5.6mA).

[radiolistener]

we know the conditions: 50-60Hz, 220-230V AC (here in Italy) and a 1.5mm (= 0,059 in) diameter ground wire "many" meters (don't know) long. So could you please test this clamp on 2A scale in these conditions and tell me what's its minimum and "reliable enough" detectable AC value?

Voltage doesn't matter here, because UT210E measure current. The results for 220V mains will be exactly the same as shown on my measurement results.

I mean it'd be fantastic if you could compare its minimum value with a more reliable tool (eg. fluke)

BM867S pefromance is the same as Fluke, this is very precise and reliable DMM.
It has 0.03% for DC and 0.3% for AC RMS.

The PSG9080 only allows the output set in Vpp

The voltage on my measurement is RMS voltage measured with DMM (BM867S). This is not what on PSG9080 display. I just tune PSG9080 output to get required voltage on a dummy load by checking it with DMM and didn't bother what voltage is shown on PSG9080 display

It is possible that resistance of dummy load was a little bit higher during my experiment, because it was connected through alligator clips. It may add a little resistance. I was used low resistance probes to measure dummy load, so 49.85 Ω don't include alligator clips resistance.

Also, different UT210E may have a little bit different results, because they have different calibration.

[ThunderZed]

Ok, I know I can't go on my personal "domestic" trouble here because it'd be OT, I just wanted to know from you if I could consider this "famous" tool for my goal but the answer is no if I'm not wrong despite I don't need "so much accuracy" (see my personal thread if you wish)

[radiolistener]

I don't see why no. It is very useful for testing or research mains distribution box. And it detects current down to 5-7 mA. Also it is very useful for testing DC current consumption, especially if you're needs to measure more than 10 Amps.

[ThunderZed]

Sorry, I've misunderstood this

As shown by the results of radiolistener's tests the readout of the UT210E at low AC currents is pretty ordinary (i.e. useless)

I've heard quite different opinions about this ut210e: someone says it's able to measure down to 10mA, someone else says it's not. Look at the pic in my attachment taken from another forum and posted by a final ut210e user. The forumers say: 1) this clamp is not reliable enough measuring only one lead on 2A scale; 2) if looping the wire 10 times this clamp measures 20 times the real value. Consider that I asked them if this clamp will be good enough for my specific goal in my scenario. Maybe that user/forumer/buyer was just unlucky and got a "defective" ut210e?

[RoGeorge]

I've just tested mine on AC current and it is completely off the scale.  Another series DMM measures 137mA  AC, while the UT210E shows zero A on AC.  If I pass the wire 4 times through the clamp it still shows 0.000 AC, on 2A scale and on 20A scale it shows 0.3A AC instead of 0.548A

Also, when it is set on DC current 2A scale it shows "0L", which I assume it means overload, so the clamp became magnetized since the last time I used it.

I should demagnetize the clamp, then try to measure again, but I have nothing to demagnetize it right now.   

I'll say it's unusable when the clamp became magnetized, and it self magnetizes either by simply sitting there, or by coming nearby strong magnets or nearby very strong currents.  Even measuring a big DC current with the clamp can magnetize it.  So it kind of works, but only when demagnetized and when no magnets or ferromagnetic materials are in the vicinity of the clamp.  When well demagnetized, it can even sense the Earth magnetic field on 2A DC current.

What does your UT210E shows on 2A but DC (not AC) current when nothing is connected?

[radiolistener]

1) this clamp is not reliable enough measuring only one lead on 2A scale; 2) if looping the wire 10 times this clamp measures 20 times the real value. Consider that I asked them if this clamp will be good enough for my specific goal in my scenario. Maybe that user/forumer/buyer was just unlucky and got a "defective" ut210e?

if you look at my measurements results, it well corresponds with your photo:

0.0060 Amps => 0.003 Amps

That's ok, just because this current is too weak and close to the sensitivity limit level of UT210E, so the result on it's display may be a little distorted due to calibration and ADC non-linearity.

What is your goal?
If you want to  detect 5 mA, UT210E can do it.
If you want to measure 5 mA very precisely, UT210E can't do it (with one wire turn).
But as said above, you can add 10 turns instead one and get more precise result for a weak current.

[ThunderZed]

Sorry again, maybe I'm too noob to understand these:

I've just tested mine on AC current and it is completely off the scale.  Another series DMM measures 137mA  AC, while the UT210E shows zero A on AC.

If you want to  detect 5 mA, UT210E can do it.

Aren't these statements in contradiction? Can you explain me please?

PS - I can't loop any wire due to my domestic outsets.

[radiolistener]

Aren't these statements in contradiction? Can you explain me please?

I don't know what means RoGeorge when he said that his UT210E shows zero.
But UT210E can measure 137 mA AC or DC with no issue.

If it shows zero for 137 mA, then it is broken and you're needs to ask seller for replacement.

Most of all there was an actual zero current and this is why UT210E shows zero.
And his "other DMM" just is not intended to measure low current, so it shows 137 mA for zero current. 


I tested my UT210E with Brymen BM867S (which is very precise DMM with 0.03% for DC and 0.3% for AC) and UT210E shows very precise measurements. The difference from 500000 count BM867S was about 1 in the last digit

Here is comparison for DC current measurement on my UT210E:

[RoGeorge]

Aren't these statements in contradiction? Can you explain me please?

It can detect 5mA when its clamp is de-magnetized.

However, it can get magnetized, or even self-magnetized, very easily.  Mine was magnetized.  Probably yours is magnetized, too.

So to be sure it measures correctly, you need to demagnetize it first.

Magnetized -> unusable and unreliable clamp.
Demagnetized -> great sensitive clamp, that on DC can even sense the Earth magnetic field.



LATER EDIT:
You need to do this before measuring:  https://www.eevblog.com/forum/chat/demagnetizing-a-tweezer/
https://www.eevblog.com/forum/testgear/a-look-at-the-uni-t-ut210e/msg1409125/#msg1409125

In the past I've demagnetized mine with this:

[radiolistener]

It can detect 5mA when its clamp is de-magnetized.

I didn't tested how magnetization affects AC current measurement, but I didn't notice any visible effect from magnetization for AC measurement.

Magnetization is a problem for DC current measurement, because it add offset.


For my AC measurement above I didn't performed demagnetization, the DC offset due to magnetization was about -0.060 Amps on 2A range.

Usually I'm trying to keep my clamp in demagnetized state, so I perform demagnetization after high current pulses through clamp (50-100 Amps). But if you don't apply high current pulse to the clamp, there is almost no magnetization and no needs for demagnetization.

Demagnetized -> great sensitive clamp, that on DC can even sense the Earth magnetic field.

Yes, you can easily use UT210E as a magnetic compass to find where is Earth's magnetic pole. It is very sensitive, so you can see effect from Earth magnetic field as a current offset change (for about ±20 mA) when you rotate UT210E in the space.

[RoGeorge]

Apparently it self-magnetizes by itself.  I left mine demagnetized (I'm very sure about that), but it stayed in the bag with other car tools.  Maybe at some point there were some screwdrivers with magnetic heads in that bag, don't know for sure, it's been many months since I demagnetized the clamp and didn't used it since then.

Now, on 2A scale DC Amps with no wire it shows "0L", which means it is very magnetized.
Apparently this does influence the AC measurements, too, not only the DC.

Or maybe mine got defective since the last time I used it, or maybe I have a different version (the plastic on the clamp is red on mine, yours seems to be black plastic in the photo).

[radiolistener]

maybe I have a different version (the plastic on the clamp is red on mine, yours seems to be black plastic in the photo).

My one is UT210E PRO

The difference between UT210E and UT210E PRO is that PRO version has frequency measurement mode and black color clamp. But you can enable frequency mode for usual UT210E in EEPROM settings.

Here is what inside of my UT210E PRO:

[RoGeorge]

I thing mine got some problem since I used it last time.   

I demagnetized it and it still doesn't work properly.  When powered on while blue and yellow buttons are kept pressed simultaneously, it displays CAL, then after about a minutes it displays "Error 0".

- When on DC current it displays about -12 ... -13A DC with nothing connected, thought I just degauss it.
- If I get a button cell size Neodinium magnet touching the clamp's jaws I can get it to show close to zero Amps or even positive DC, thought something seems very wrong, and no matter how much I try to magnetize it to compensate the -12.59 A DC bias, it doesn't magnetize enough
- so far I guess the cause is something else, and not the remnant magnetization

The EEPROM is original, never modified anything and never really used it, the DMM was just sitting in the bag with car tools, and mostly indoors.

Meanwhile, found out there is a schematic for UT210E on elektrotanya!   
https://elektrotanya.com/uni-t_ut210e_schematic.pdf/download.html

There is a bridge of 2 hall sensors and 2 trimpots, apparently for balancing and biasing the two Hall sensors, but before messing with them I would like to know what happened since the last time I used it.



Can you tell what offset (in DC Amps) your UT210E Pro displays before pressing zero on the DC 2A current range, and no wires, please?

[radiolistener]

Apparently it self-magnetizes by itself.

I think this is not self magnetization, but Earth magnetic field change over time...

Can you tell what offset (in DC Amps) your UT210E Pro displays before pressing zero on the DC 2A current range, and no wires, please?

-0.014 ... -0.070 Amps depends on orientation in the space

I demagnetized it last time about 2 or 3 months ago