UNI-T UT71D review

[WackyGerman]

Ok  for the new fuses but still  for the crappy input jacks . Why don t they fit them like in the EU version of the 61 series ? 

[Wytnucls]

What do you mean? They look the same to me.

[Shock]

Wytnucls do you know a decent source of suitable replacement 500mA HRC fuses that would fit the 71D?

[Wytnucls]

If by decent you mean cheap, I don't.
Otherwise, Jaycar has a SIBA fuse that should fit (in the 1000V model at least):
https://www.jaycar.com.au/fuse-for-cat-iv-dmm-1kv-500ma/p/SF2278

I don't think there are any 1000V HRC fuses that would fit the original glass fuse holders, unless they are moved further apart (not recommended).

[Wytnucls]

There is now a Bluetooth adapter for the 71 series:
UT-D07A with software for iPhone and Android.

[spikey1973]

@abraxa and Wytnucls (well the rest too ofcourse)

i just recieved my ut71c (from china, production 01-2017)
i just got sigrok installed on my 17.04 ubuntu.

am not really how to get the data from the meter to pulseview, and or which drivers to use.  Unfortunately i do not have the time at the moment to dive into the subject. so if anyone is willing to give me some hints i would truely appreciate it!

secondly, i took the time to open the meter up as i was curious about the fuses.. specially as i read some about newer models having the better fuses?
anyway, that didn't count for mine.. shouldn't have expected it either, as the price was really low.
I made some picture as mine is a 71c instead of the 71d, thought maybe it could be helpfull, although i don't see much difference from the D model myself.



(doesn't seem to work well :/, but when i click the broken image links, i can still see them here.)

anyway, there is the space to upgrade the fuses so i would like to do that at one time in the future.
have googled for the fuses.. but really didn't find any. also it is really difficult to if it is a surface mount pcb fuse or a massive fusebox fuse when just looking at picture.

So as Wytnucls lives in belgium, just as i do. can i ask where you got yours? for your b upgrade?

additionally something else the three empty spots onm the left on the pcb are for varistors? would there be any use in trying to find out what varistors where "intended there", whould that help (a little) as security upgrade? (keep i'm mind i'm reallly not sure what i'm asking here)

additionally, if anyone has the bluetooth adaptor Wytnucls talked about.. maybe some inside pictures? see if we can build one with a mini / micro arduino board with bluetooth board?
Anyway, thanks for this tutorial, made me even more happy with my meter then i already was.

kind greats. Matt

ps: about measuring higher voltages.. i guess a quick check of voltage and frequency on a 230V 50hz european mains should still be oke! not? 

[spikey1973]

Ps: to anyone Interested, I ordered the ut-d07 today so once it arrives I will let people know.. and post some pictures of a small review (maybe it would be better to lend it to someone local who would be more knowledged )

Anyway . I will keep informed.

[picitup]

@Breizh13 did you ever make any progress on sending the internal data to the PC?  I have exactly the same problem on a meter I bought this week.

I know the setup is all OK, because if I press and hold SEND, the program logs data to the pc in real time as expected, however when I press RECALL -> the data runs through on the meter quickly, but the software doesn't capture it.

I tried the supplied version of the software (3.0) and the version from this thread (1.1) on Windows 7 and 8 but no joy.

Cheers

Steve

[picitup]

I had another play with this, and looked at the IR led on the back of the meter through my phone camera.  Funnily enough, I couldn't see it through my main camera, but the reverse camera worked well. When I press SEND, the led blips every second or so and when I press RECALL ->, the led seems lit pretty much continuously, so it looks like the meter is working as expected, pointing to a bug in the software.

I also tried my UT61E serial adaptor until I realised that the LED positions are swapped from the UT61E to the UT71D.  Bummer.

[myf]

Hello,

I use ut-61 and the uni-t usb link works fine with sigrok, but you must send a reset from the laptop just before tracking data to sigrok.

I use this short python program : about 10 lines at the end of this page.

https://www.cnx-software.com/2015/03/07/sigrok-and-pulseview-in-ubuntu-14-04-with-uni-t-ut61e-digital-multimeter/

Have a nice day!

F. (from France)

[picitup]

Hi @myf Thanks for your reply.  I've not used Linux for decades so am looking for a windows solution.  I see there is a windows version of sigrok - is the main method of obtaining data by Python scripts?

Cheers

Steve

[myf]

Hello, (again)

I suppose you use windows, I read that uni-t cdrom runs out-of-the-box on windows. Maybe you dislike the interface and you prefer a ascii-raw data.

I do not understand if you have a rs-232 cable or a usb-cable. I use my ut61with usb-cable I must reset it before every use, but I get a rs-232 cable in the new box.

I saw 2 versions of this ut-d04 usb-cable with 2 hardware / firmware / signature, and in both cases I must reset it.

I do not know if this is interface is the same as yours. Are interfaces the same fom ut-61 and ut-71?

I do not know, but I feel that Python3 sources run the same way under linux and windows. Might you want I run some tests about reading DMM data from Python? I'm not sure I can do it, but  I can try.

[picitup]

Hi :-)

Yes I use Windows and the software does run, but doesn't seem to work properly.  It only supports com1-4 and my first com port is 6.  Also the data dump function from internal memory doesn't seem to work.

The physical interfaces of the UT61E and UT71D are identical apart from the former is RS232 and the latter is USB.  This is the opposite of what I said earlier.  I checked the transmit led using the rear camera of my phone, which I've just found out mirrors the image. 

Armed with that knowledge and remembering you have to have DTR high to power the serial adaptor, I've just got the UT61E RS232 cable working with the UT71E using Termite.  With Termite you can click on the DTR led and it will set that output high and it works well.

Here's some raw data for a taster:

000051101
000061101
000051101
000061101
000051101
000051101
000051101
000051101
000051101
000051101
000061101
000061101
000051101
000051101
000051101

I think i can paste this into a spreadsheet and parse it quite easily so job done.

I'll do some more over the weekend and post it up.

Thank you for your kind offer to try Python under Windows.

Cheers

Steve

[myf]

Thank you, !

So your ut-61 is right, your interface is rs-232, and is awake as claim the kermit-telnet interface.

You are looking for translating ut-protocol to ascii data.

For the ut61 there are a lot of program which do this translate.
Do you have a Python2 on your laptop ? With python2 (not Python3) this program may be right.

https://github.com/pklaus/ut61e_python/blob/master/ut61e/es51922.py

There are others programs which translate this protocol. One day, I compile one in C language.
Maybe you can download if you prefer C-language.

https://sourceforge.net/projects/ut61/files/ut61-1.0-beta2.tar.bz2/download

But I read on sigrok page that getting inside data memory will be impossible. Can you read this inner memory with the uni-t-cd ?

https://sigrok.org/wiki/UNI-T_UT71x_series#Protocol

I feel there are 2 steps for this program : first read data, second translate data.

I hope theses information help you.

Have a nice day !

F.

[picitup]

Hi again @myf and I appreciate all the links you sent me.  The most useful one for my UT71D was the last  one:

https://sigrok.org/wiki/UNI-T_UT71x_series#Protocol

Which offers some brief information on the protocol and the VC960 link at the bottom takes you through to a page which described the protocol in more detail.  This page isn't completely correct as testing showed that some of the range characters were different on my UT71D.

So to review from the start here's what I did:

1) Log data internally in the 71D on the DCV range and connected a small solar panel to the meter and pointed it towards the window for a bit less than a day.
2) Transferred the data to Termite with at UT61E serial cable ($10 from Aliexpress) with 2400,7,O,1 settings.  Don't forget to click the DTR led which makes it high and supplies power to the serial lead electronics.
3) Copied the serial data from Termit and pasted it into an Openoffice spreadsheet
4) Wrote a parser for the data using spreadsheet functions such As LEFT, MID and VLOOKUP.

Piccies of the sheet are below and the columns contain the following:

A - The raw data
B - The data with leading zeroes to make it fixed length
C - The raw multimeter data (no decimal point)
D - The function selected EG DCV looked up from the tables
E - The range EG 4V looked up from the tables
F - Time - F4 = F1 then F5 =F4+$H$1/24/3600 etc.....
G - Measured Value complete with decimal point with divisor looked up in the tables.

I tested pretty much all functions, but not all ranges so there may be some errors.  My AC volts test is max. 10v, DC is max 60v and frequency is max 25MHz.

All frequency measurements are normalised to Hz so they can be plotted on a graph if/when the range changes.

The data format is (mostly!)

213492501
213562501
213512501

Where digits 1-5 are the measured value, digit 6 is the range code and 7 is the function code.

I've attached some piccies of the main spreadsheet and lookup table and also the spreadsheet in .xls format if it's any use to anybody.

It's been quite a bit of work but it was fun and you will see from the graph on the piccy that it does, indeed, get dark of a night time and light in the morning in the UK.  I think the little square bump is our security light turning on and off followed by a couple of car headlights.

[myf]

Hi Picitup,

Thanks a lot for your detailed answer !

Might you explain a bit, my english is too poor. I don't understand if ut-71 is designed by (A) or (B)

(A)
Can you get "inner stored data" in ut-71, with a time-stamp ?
Do you send a character code to ask it from the PC to the ut-71 ?
Do you get all this previous data when you connect the rs-232 link ?
Can you get them twice or more ?

(B)
Do you only get the 20-hours long measures as soon as they are made? and the inner memory can't be read by the rs-232 link.
So you must link the pc and the dmm at the very beginning of the measures.

Have a nice day !

[picitup]

Hi @myf I hope you are well :-)

Your English is fine!

I like to share this information, because someone else can correct my mistakes!

To answer your questions:

a) The UT71D has no time stamp, so you must note the time and date when you start recording on a piece of paper.  I guess this helps save memory.  If you look at the Termite data in the picture above, that is exactly what you get out of the UT71D so I have fields in the spreadsheet for time and interval to produce the time column.

There is no communication from the PC to the UT71D.  The multimeter only has a TX LED and the interface cable only has an RX sensor, so data is sent by the 71D 'blind'.  If you send data from the 71D, it just spits it out with no handshaking, even if the cable is not connected.

Yes it works fine with the UT61E RS232 link.  That is what I have been using.  I can't use the USB interface as it doesn't work with the UNI-T software!

Yes you can send the data to the PC, and it is still stored in the 71D so you can send it as many times as you like.  When you record some more data, you can choose to overwrite existing data, or append data to the existing storage.

b) No.  If you connect to the PC and long press SEND, it logs data to the PC in real time.  However, if you choose to store to internal memory, you can store 9,999 records internally without a PC.  So you can start it recording on site, then come back the next day, pick up your meter, take it back to the office and dump the data there.  This is one of the features that made me buy the 71D.

The data I showed in the pictures (solar panel out the window) was logged without a PC.  The next day I pressed EXIT to finish the logging and connected it to a PC and dumped the data into Termite.

I hope that answers everything.

Kind Regards

Steve

[picitup]

Oh, I forgot to mention.  The internal log data is stored in some kind of flash memory.  My meter was turned off overnight and in the morning the log data was still present.  Then I removed the battery and switched the meter on for an hour and when I replaced the battery, the data was once again, still present.  Very handy :-)

It would be nice if you could set the logging frequency to more than 255 seconds - maybe 255 minutes?  And if you could also set the log count so if you cannot attend quickly, the meter could, say log 1,000 entries and then auto power off.

We live in hope....

[hkmk23]

I just wanted to say thank you on the forum for the terrific help WYTNUCLS gave me in pm's. He was a terrific help and this sort of guy s what makes being a member of a forum worthwhile. Thanks W. Just found out you live in Belgium, I live in SW France, so anytime you are passing near Tarn and Garonne give me a call.

[Wytnucls]

Glad I could help. Been in your neck of the woods before. Thanks for the invite.

[cosmin1]

Hello.
Did anybody observe some constrast issues on this UT71D?
Mine has not that good contrast when i watch from above.
Maybe with some dump mod...

[cosmin1]

Anybody?

[cosmin1]

Found the EEPROM. Can somebody help me with dump editing?

[andrew.heard]

Can anyone confirm graph zooming with the UNI-Trend Windows interface program works? The only reference I can find (by Wytnucls) is to left+click mouse drag, but versions 1.3? and 3.0 ignore any attempt to zoom. The graph Y-axis is scaled +/-40,000.

[andrew.heard]

Exactly, i can't transfer it to the offical uni-t software.
The DMM is running through the entries and sending them but the software only gets the first entry, doesn't matter which version i use.
Normal logging is possible, in "live" mode but stored values aren't transfered.
Maybe it's because of this:
"The communication parameters are 2400 baud, 7o1. However, the vendor software opens the serial port with 8n1 settings, so the vendor protocol descriptions are slightly off. "

Sadly I have exactly the same issue with the UT71D I have just bought. Logging in "live" mode (hold MAXMIN) works fine, UT71C_D_E.exe displays each value, but hold RECALL > press HOLD > shows all entries on the DMM screen but nothing in UT71C_D_E.exe. Unfortunately though sigrok-cli is not saving anything although I followed the instructions for USBDeview, zadig & sigrok-cli. Can anyone help? The whole point of buying this meter was for its offline logging ability.

The original poster was not 100% clear on the settings for zadig. I performed: main menu > Options > List All Devices > select USB to Serial > click Replace Driver. When I next run USBDeview there is a red dot on the LHS of USB to Serial. This is the only issue I can think that may be wrong. And of course, now UT71C_D_E.exe doesn't work because its driver has been replaced.

PS (2 hours later) - solved - in zadig I have used the libusb-win32 driver, and possibly more importantly sigrok-cli had an output file option of -o test,txt but the directory C:\Program Files (x86)\sigrok\sigrok-cli (possibly) didn't have write access. When I used this command line, all finally worked:

sigrok-cli --driver uni-t-ut71d:conn=1a86.e008 --continuous -o c:\temp\test.txt -O analog

Note the logging option -l 5 was useful in tracking down the issue.