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read values from multimeter


v_pan

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hello ...

i have bought a multimeter and i tried to upload values to Labview

this multimeter has own software to read and represent values

But i did an effort to build my own software to take and show values.

actually , i made the simpliest communicate on RS232 without result.

do you think that data have a codification or something?

is there anyone who did that before?

if you want i can upload manual of multimeter.

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hello ...

i have bought a multimeter and i tried to upload values to Labview

this multimeter has own software to read and represent values

But i did an effort to build my own software to take and show values.

actually , i made the simpliest communicate on RS232 without result.

do you think that data have a codification or something?

is there anyone who did that before?

if you want i can upload manual of multimeter.

Don't upload the manual just yet... But maybe some word about the multimeter model and an upload of your code would be a good start. ;)

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i didn't make any specific code on LABVIEW.

i open the example basic serial read and write.vi

and just try to communicate

i also try on hyperterminal without result.

model of multimeter (UNI-T UT70D)

i did as operating manual said:

Baud rate 9600

start bit 1 (always 0)

stop bit 1 (always 1)

data bits 8

parity none

................................

is there anything else to check?

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i didn't make any specific code on LABVIEW.

i open the example basic serial read and write.vi

and just try to communicate

is there anything else to check?

What do you mean you "just try to communicate". What command did you send to the unit?

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i don't send any command. actually , when i press some "letter" my PC stucks.<br>that i'm a doing is to connect them and wait receive data.<br>normally, multimeter sends all time data over 232.

thus, if i connect multi with PC i will can see data.

either hyperterminal or VI can not see anything.

multi and software dont have problems.

Edited by v_pan
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i don't send any command. actually , when i press some "letter" my PC stucks.<br>that i'm a doing is to connect them and wait receive data.<br>normally, multimeter sends all time data over 232.

thus, if i connect multi with PC i will can see data.

either hyperterminal or VI can not see anything.

multi and software dont have problems.

With RS-232, you have to send a query to receive data. You might not see it, but that's what the manufacturer's software does. The same is true from Hyperterminal or LabVIEW. Now, I'm not used to HyperTerminal so I don't know why it bugs you, but with LabVIEW, make sure you check these things:

  • To which COM port is your DMM connected?
  • What is the command (query) to fetch data? (the manual is 55MB and takes forever to download, so I don't think I'll have the patience to finish the download)
  • Have you installed VISA drivers from NI? You should get an error message like this if you didn't:

Error -1073807202 occurred at Property Node (arg 1) in VISA Configure Serial Port (Instr).vi-&gt;Basic Serial Write and Read.vi  Possible reason(s): LabVIEW:  (Hex 0xBFFF009E) VISA or a code library required by VISA could not be located or loaded.     This is usually due to a required driver not being installed on the system.

Using the "Basic Serial Write and Read.vi" example you got from NI examples is exactly where you should start. To query the DMM, you've got to have both "write" and "read" switches to ON position. In the "string to write", put the query command. Then press the start Arrow and you should get the data in "read string". Make sure you have the right COM port selected in "VISA resource name".

  • Like 2
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I finished downloading the manual... guess what, they don't list the commands. From the looks of it, it's not SCPI compliant, so good luck figuring it out unless you can read the bytes sent on the Tx wire.

I think you should call Uni-trend and ask directly the commands to one of their engineers...

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Just took a look on the NI Instrument driver site and there is a driver for a

Uni-Trend UT804

So I'd take a look at that and see how they have implemented the protocol, I suspect it would be similar.

Also go to the Uni-Trend site for your model there is some software which you can interface to your multimeter which will allow you to read values etc, its not a driver but the useful thing is that it will give you a reality check, also if you build a serial proxy or sniffer you can then look at the packets going back and forth which will give you some insight into what you need to implement in your own driver.

But in the mean time definitely do as Francois has suggested and contact the manufacturer and ask for the protocol.

  • Like 1
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Your remark that the "multimeter sends data continuously" is a red flag. Some of the older stuff had the idea that computer compatibility consisted of just "hosing" data up the line in RS-232. No dialog, no trigger, just hose the data up the channel continuously. That is an entirely different I/O situation than a more civilized exchange of requests and acknowledgments.

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problems never ends!!

well, i download a program-spy-watch-serial data.

i have done a communication multi and software and i wanted to saw

what data sends-recieves.

now, software doesn't let me communicate with multi!!!

says , (check COM1 or the unit)

:(

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problems never ends!!

well, i download a program-spy-watch-serial data.

i have done a communication multi and software and i wanted to saw

what data sends-recieves.

now, software doesn't let me communicate with multi!!!

says , (check COM1 or the unit)

:(

Did you have any success with the software from Uni-Trend?

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