Read from text file and plot in real time

[DaniloP]

Hello to everybody,
I recently started using labview and so I know very few features, I apologize for any crap I'm about to write.
My problem is as follows:
_ A wireless node is sampling, with a known frequency, the voltage and the current of an electronic device
_ These data are sent to a coordinator connected to the PC
_ Each packet sent includes a single column with: Letter V followed by voltage samples, Letter I followed by current samples (all in a single column as in the attached example)
_ The coordinator saves it in a .txt file

I want to do a labview application that:
_ Reads that file (continuosly update by the coordinator)
_ Plots on two different graphs the values (over the time) of current and voltage

Thanks for your help

Danilo

[mikeporter]

There are File IO examples that ship with LV which show you how to write to red from a file . A more fundamental question though is why have the file at all? Is it serving strictly as a data communication channel, or will it be used for something else?

The "coordinator" that you mention, can it be accessed directly? Serial IO? TCP/IP? Telnet? ActiveX? .NET? Anything?

If so, that would be the preferred way to handle this situation.

Mike...

PS: Sorry for the next bit, but I used to be a magazine editor and my grandmother was a school teacher so I am just a tiny bit anal retentive about word usage: In English "data" is a funny word in that while it is a singular form, it is (depending upon context) often understood to referring to multiple things and so can be sort of plural. Consequently, it is proper to say: "This data is sent.. " or "The data indicates...", but not, "The data are showing..". Likewise it is always incorrect to try to make it plural by saying "datas".

PPS: The same goes for the word "code" when used as a noun. It can also be a verb, but that's a whole different rant...

PPPS: Also be aware that many of the people who know me well would object to the "tiny bit" part...