Test/review of DMM/Clamp UNI-T UT210E

EDC Gear for Flashlight Carriers
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DMM UNI-T UT210E







This is a cheap clamp meter with DMM function.







It included the DMM, a pair of probes, a pouch and a manual (Both a English and a Chinese version).









The probes has removable tip covers.







The probes are rated for 10A, but it is not important for a clamp meter.

























Display







The above picture shows all the segments on the display.

The circle with the arrow indicates auto power off, holding down the SELECT button during power on will disable that.







Typical display during usage, it will show the number and what measurement is selected.







When using the NCV function the display will show a number of -, depending on the electric field. This can usual be used to see if a mains outlet or cable is powered or trace a cable that is just under the wall. This function is always a guideline and not a 100% confirmation of voltage or no voltage.







Functions







Buttons:

  • Select/VFC (Blue): Will select secondary functions, holding down the button will enable a low pass filter for AC measurement (VFC).

  • Zero: Save the current measurement and show the following measurements relative to that value (Very important for DC clamps).

  • Hold (Yellow): Freeze the display, hold down to turn background light on.


Rotary switch:

  • Off: Meter is turned off

  • V: Show voltage, use the blue button to select between AC and DC

  • Ohm: Resistance, continuity, diode and capacitance

  • 2A: Measure current with the clamp, use the blue button to select between AC and DC. Zero must be used on DC range

  • 20A: Measure current with the clamp, use the blue button to select between AC and DC. Zero must be used on DC range

  • 100A: Measure current with the clamp, use the blue button to select between AC and DC. Zero must be used on DC range

  • NCV: Non contact voltage. Any AC field near the clamp will be indicated.



Input



The two socket is used for V, Resistance, continuity, diode and capacitance



The clamp is used for all current measurements and for NCV. There is a red led at the bottom of the clamp to show when voltage is detected with the NCV function (Buzzer will also sound).



Measurements

  • Volt and frequency

    • AC volt can measure up to about 2kHz (RMS will not work at the frequency).

    • AC volt with VFC reduces bandwidth to 400Hz and limits range to 200.0V & 600V

    • All ranges starts on AC

    • Input impedance is 10Mohm to 11Mohm on AC and DC

    • Buzzer sounds on over voltage (600V)

  • Current

    • Buzzer sounds on over current (100A).

    • All ranges starts on AC

    • As usual clamp meters are not very precise and at 0.5A and 5A it was about 2% out.

  • Ohm, Continuity, diode and capacity

    • Ohm is 1V open and 0.33mA shorted

    • Continuity is fast (Below 4ms).

    • Continuity beeps when resistance is below 50ohm.

    • Continuity is 1V open and 0.33mA shorted

    • Diode range uses 3.3V, max. display is 2.2V at 0.5mA, max. current is 1.4mA shorted

    • 11000uF takes about 9 seconds to measure.

  • Miscellaneous

    • Current consumption of meter is 7.2mA (13.2mA with backlight) in current mode

    • Current consumption of meter is about 1.7mA (7.7mA with backlight) in other modes.

    • Meter works down to 2.2V where it turns off, battery symbol show at 2.5V.

    • Backlight only works down to about 2.6V where it is fairly dim.

    • Both current and voltage readings are stable with changing battery voltage.

    • The meter usual need a couple of display update to reach the final value.

    • Viewing angle is good.

    • Display updates around 3 times/sec

    • Backlight will automatic turn off in about 15 seconds.

    • Will automatic turn power off in about 15 minutes.

    • Weight is 174g without accessories, but with batteries.

    • Size is 174 x 62 x 32mm

  • Probes & clamp

    • Probe resistance 37mOhm for one.

    • Probe wire is 90cm long.

    • Clamp can handle up to ø17mm




A look at the capacity measurement waveform.






Tear down



I had to remove two screws to open the meter.



The circuit board is carefully made to fit inside the meter and use all aviable space.



I assume the green wire is the NCV sensor



The circuit board has some input protection with two PTC’s and 3 MOV’s. The input resistors (R37A, R37B, R37C, R37D: 4x2.5Mohm) is split into 4 resistors, between these resistors and the input is a PTC.
Close to the MOV’s is a EEPROM (IC2: 24C02A) for parameter storage and some calibration, there is also trimpots for calibration.
There is a voltage clamp made with two transistors (Q4, Q9), it is not directly connected to input or output resistors but is probably switched in depending on range.
The big IC (DM1106EN) is the main multimeter chip and the frontend for the clamp is mounted close to it (U4:OPA4330 Quad OpAmp).




One this side is another string of resistors (R27A, R27B, R27C: 3x300kohm), but strange enough they are connected directly to the input terminal without any protection. The NCV voltage led (LED3) and the transistor to drive it (Q2) is also placed here.



There is also space for unused protection (Q6 & Q8). The backlight led is a side emitting led (LED2) mounted at the border of the LCD display.





The pink zebra stripe that connects the display to the circuit board can be seen here.






Some backlight on the circuit board makes it easier to see the traces.



Conclusion

This meter is nice for measuring 100’s of mA or more without any voltage drop, using it for lower DC currents requires careful use of the zero button.
It has basic DMM functions, but it missing frequency and low currents.
It looks like it has real input protection and the CAT rating may be correct.



Notes

How do I review a DMM
2

Thanks for the review & testing.

A lot of people here bought these a little while back in a group buy.

3

Nice review, thanks! :smiley:

4

Thanks for your review. I’ve bought one in the GB. It seems to me that the tailcap-current is gradually sinking. Also with lights that I hardly use. I top up the battery and use the outcome just to compare it with that of the newer lights.
In the good old days I had music-cassettes (MC) and had to degauss the heads of the recording machine once or twice a year. Need I to perform a simular operation on this clamp-meter, and how? Or is it sufficient that I reverse the current I’m measuring. Because (thinking of it) I always hold the end of the loop against the bottom of the battery in my left hand and the other end against the tube in my right hand. So the current in the loop always has the same direction.

5

It can be magnetized, especially if you measure high currents. If the display shows a fairly high value without any current running you may be able to improve it by a degauss.

6

I know.
My idea it to test some more DMM’s (I do not have any more clamps in queue), then it will be easy to compare the schema and see what the differences between the DMM’s are.
I have also made a review of a 34461A 6½ digit DMM (not published yet), not because I believe any here will buy one, but simply to show the differences between a cheap DMM and one that cost about 100 times as much.

7

Thanks , i having been using it for over a year and it’s great :slight_smile:

Oh… I think right model name is U T 210E .

8

Thanks HJK for the “official” confirmation that this is a decent meter. :slight_smile:

I bought one a while back basically only for the DC clamp current measurement to measure tailcap and LED currents, but I have found that it has been a good little meter for the occasional other basic uses as well.

9

Second DMM review and second DMM where I get the name wrong, I am obvious not good at the letter combinations.

And thanks, I have fixed it.

10

There are other variants of the 210. They have different ending letter such as “C” “D” etc.

Anyone knows the differences? maybe different ranges of measurements?

11

Check UNI-T website, there can be huge difference between the models.
There is a comparison between D & E on the website:
http://www.uni-trend.com/productsdetail.aspx?ProductsID=712&ProductsCateId=773&CateId=773

The main difference is that D has temperature, but lowest current range is 20A

12

A little late, great review!

Does a lot of Uni-t DMM that you tested has a high burden voltage, and is this normal?

Which of the DMM you tested so far has the most accurate reading?

Can you see yourself using a budget DMM after testing them? Even though you have expensive DMM.

I’m not sure if you can get it easy but can you add the Klein Tools MM600 DMM to your list? There a Klein Tools in Europe. Asia.

13

Just about any DMM has high burden voltage on the high mA range, the fuse is one of the reasons, it about double the burden voltage.
The only one where you sort of avoid it is the AN8008, because it do not have a mA range, but uses the A range for mA (You can, of course, do that on other meters too, to get much lower burden voltage).

You have to look at the tolerances and all of them is in the 0.5-1% range. Just because the meter I tests is more or less precise do not mean the next meter of the same type will be the same. It is only bad if they are outside the tolerances.
I will get around to more precise DMM’s later.

Not on my main work bench, I have a Keysight U1252B next to me and four (soon 5) 6½/7½ digit bench DMMs.
When moving away from my bench some of the mid-range may be used (That is 17B+, UT139C, AM-510 and I like a small Southwire, review will be published later).
The UT210E do also get used, it can fit in where my better clamp meters cannot and it is great at small currents.

Yes, I could get it from Ebay.

14

Thanks for testing, HKJ.
The UT210E was (still is) a great addition to my UT61E (which had been HKJ-approved as well).

Got my UT210E for about 9 months or so, the clamp at 2A-range is really really good in the low Ampere range. I immediately tested it against the voltage drop over a shunt and even at 10mA-100mA the difference between the 2 measurements was only up to 3mA - when carefully zeroed, of course.

Other useful purposes are for the high currents like 15A in an SRK or simply as a nice portable DMM due to its handy size.
I had missed the groupbuy and paid a bit more locally, but worth every penny.

15

Thanks for the replies HKJ!

With your more expensive Fluke (189,289) and the Keysight DMM. Do they have a high burden voltage in mA range?

16

I do not remember the exact values, but it is probably about the same.
Typically you have a 1 ohm resistor and about 1 ohm in the fuse, this means about 0.2V at 100mA and 1.2V at 600mA (For DMM’s with 6000 reading).
The solution is to use a A range (That is one digit less in resolution), if the meter has one (Some meters only have the 10A range and that means you loose one digit more). Then the burden voltage is very low.

Most of the time when I need to measure current I can use a power supply with a good current display or a electronic load.
With my bench meters it is also fine to use the A range, they have enough resolution :slight_smile:

17

A test:
Fluke 289 400mA range with 100mA: 183mV
Keysight U1252B 400mA range with 100mA: 246mV
Keysight U1281A 400mA range with 100mA: 190mV
Metrahit Energy auto range with 100mA: 39mV
Fluke 179 400mA range with 100mA: 170mV
Keysight U1461A 600mA range with 100mA: 250mV

Except the Metrahit all the other follows the general 1+1ohm pattern.