UNI-T UT-61E

[ModemHead]

Some follow-up information:

I decided to have a go at calibrating my unit's DC voltage range.  I used 2.10V and 21.0V sources monitored with a bench meter, and adjusted for best results between the two.  The trimmer pot was very finicky, but after exercising it a bit I got reasonable results.  The meter seems to drift less than it did before, my theory is the trimmer pot may have been a little shaky from the beginning.

The last digit will never be particularly meaningful in terms of absolute accuracy, but as long as the meter is stable, the LSD can be useful for observing short-term trends.  My unit was not that stable at first, but it seems a little better now.

During the DIY calibration exercise, I found that if the meter is in ACV range with auto-ranging on, probing a DC voltage of more than about 10V will cause the meter's auto-ranging algorithm to fail with lots of beeping and flashing.

I decided to check the unit's AC performance a little further, since measuring AC in the presence of a DC offset is not exactly an uncommon scenario in electronics.  DC power supply ripple, an audio signal in an amplifier, etc.

My test signal was a 200mV rms sine on top of a 10V DC offset, provided by a function generator.  On DCV I got a correct display of 10V.  On ACV with auto-ranging, I got the crazy display.  With manual ranging, I eventually got a correct reading of 0.2V after a long settling time.  On the ACmV range, I got unstable readings in the area of 25 mV.  It would only produce the correct value of 200mV if I reduced the DC offset to less than 2V.

[DaveXRQ]

Oh yeah, don't forget the multipurpose socket as they are so called. It's a meter world first 

[HVAC Guy]

And ... this is the first meter i had that smells VERY nice, the plastic's smell if both of mine do fade away, i am tempted to buy another one ... just for the smell

 

Mmmm.

[Kiriakos GR]

It would only produce the correct value of 200mV if I reduced the DC offset to less than 2V.

Your story motivated me to test under the same conditions the Agilent U1273A.
I did the test at 200Hz sinusoid 600mV / and tested it with +5 & -5 DC offset, no problem.
When I did try to lower down the output to 200mV by inserting attenuation filters,  my function generator was capable to output 200mV but only +/- 1,5V DC offset. 
 
http://www.ittsb.eu/my%20bench.html#PHILIPS

[ModemHead]

Your story motivated me to test under the same conditions the Agilent U1273A.
I did the test at 200Hz sinusoid 600mV / and tested it with +5 & -5 DC offset, no problem.
When I did try to lower down the output to 200mV by inserting attenuation filters,  my function generator was capable to output 200mV but only +/- 1,5V DC offset. 

Interesting, thanks.  I would fully expect Agilent to get it right.  I tested many Fluke meters here, and all of them were able to read the 10VDC and 200mVAC components of the signal without problems.

I forgot to mention my test signal was 200Hz as well.  I chose 200mV just so that I could test the 220mV range of the UT61E.

You can insert more DC offset if you wish, by putting a battery in series with the FG output. But you probably knew that already, it just makes a mess with the cables.

Along with a basic ACV bandwidth check, I think an 'ACV with DC bias' test might make a good addition to multimeter performance tests.

BTW, nice function generator!

[Kiriakos GR]

Along with a basic ACV bandwidth check, I think an 'ACV with DC bias' test might make a good addition to multimeter performance tests.

In my review about the Agilent U1272A I did wrote that if I detect DC volts mixed with AC in one AC Mains plug I would feel strange,  like to had see a Ghost. 
I did wrote that mostly, so to point out, that electricians favor (or better said) .. appreciate differently its feature found on a multimeter.   
I would expect from the people who claim to be more experts to electronics, to do such tests.

BTW, nice function generator!

Thanks mate.

[TimothyS]

Martin demonstrated on Youtube that the UT-61E showed some nasty overshoots in the measured value that was also sent to the PC logging. Is there any explanation found, and/or a remedy for this? Does the same phenomina also show in the UT-61D?
 

[Monkeh]

Martin demonstrated on Youtube that the UT-61E showed some nasty overshoots in the measured value that was also sent to the PC logging. Is there any explanation found, and/or a remedy for this? Does the same phenomina also show in the UT-61D?

It's an autoranging glitch. The 61D most likely does not show the same behaviour, not only is it deathly slow but it's electrically entirely unrelated to the 61E.

[NevDickens]

Hello Gents,
First post so please be gentle.  I purchased a UT61E a while back (thanks Franky). My new computer does not have a serial port, only usb’s. Ok, need a serial to usb adapter. While checking on Ebay I found this  http://www.ebay.com.au/itm/UNI-T-Multimeter-USB-Data-interface-cable-UT-D08-replace-UT-D04-for-Windows-7-XP-/130743143940?pt=AU_B_I_Electrical_Test_Equipment&hash=item1e70e60e04 . You beauty, won’t have to mess around joining up leads to adapters. The unit is the same as a Silicon Labs CP2104 USB to UART Bridge controller and as such you will also need : Leadtek_GPS_Driver.zip  so your computer will recognise the lead hook-up. And yes I know it’s a gps driver, but it works. Apparently some GPS units use the same technology.
Hope this info helps someone.
Cheers Neville
 

[NevDickens]

Forgot this. Where I downloaded the software from.

[Majes]

Thanks for this, amazing what ya can get working just by trying a few things ain't it ?

[NevDickens]

Thanks for this, amazing what ya can get working just by trying a few things ain't it ?

G'day Majes,
Glad to help. It took quite a bit of searching and hair pulling to find something that actually worked and as you said trying a few things and vwalla, it worked

cheers Neville
 

[Cpx]

I found a new sensitivity issue with ut61E.
A reverse bias in capacitance range (>3 volts) even with  small current (<1mA) will make the processor freeze and display all segments and will increase current draw from its internal battery. This doesn't happen with normal bias and the meter displays a "discharge cap" message. So be extra careful with this function when measuring caps  that may have even a small voltage on them.


True rms accuracy with square wave at low voltage:

1.64v (high on range):
20 hz    1.634
40 hz    1.641
400hz   1.645
4khz     1.644
20khz   1.653
40khz   1.664
75khz   1.679
120khz 1.667
150khz 1.593

2.4v square wave(low on range):
20hz     2.400
40hz     2.412
400hz   2.415
4 khz    2.385
10khz   2.344
20khz   2.295
40khz   2.188
62khz   2.100

[ENW]

an amazing device! is unique at this price! 

[ENW]

and how much will be accurate if the measured resistance is less than 1 ohm?