"Scan from string" function issue

[ukbaisdumb]

Hi all,

I have a beginner's question. I am collecting some data from a micromanometer through labview. The input is through a serial RS232 port in ASCII format. Using one of the example VI viz, "Basic serial read and wirte" I see the data coming in the following way:

DP -0.123mmH2O

What I would like to do is now sort out the above string into just its numeric part and save it as a text file or table for post processing. I tried using the scan from string function but the final output i get is mmH2O if i scan it twice. Can please anyone help me find a solution.

Thanks for reading the post!

[Vsh]

Have you tried the functions match pattern or match regular expression?

Check in context help and LV help about these functions.

These will help you to solve your problem. 

[jcarmody]

Regular expressions are difficult (but not too difficult to make their value worth the effort); here's a reference I always use.

\- searches for the negative sign

{0,1} says to take it if you find it, but don't worry if it's not there (find zero or one of them)

[0-9] is a character class that will return a number

* says to take all that you find

\. looks for the decimal point

[shrekt]

Hi ukbaisdumb

If the format of the string will be same  DP -0.123mmH2O then you can use the following method

regards,

shrek

[ukbaisdumb]

Thanks guys! I should have mentioned I am using labview 7.1 and I do not have the regular expression function, so what do I do? I have the "match pattern" function and "scan from string" function.

[GerdW]

Hi ukbaisdumb,

use ScanFromString this way:

It's as simple as it looks like... Search the context help for the different format codes!

In case the "DP" in front of the number can change: split the string at the " " (space) and scan for "%f"...

Message Edited by GerdW on 11-12-2009 09:56 AM

[Vsh]

Incase if you need the units too...

[ukbaisdumb]

Further to the problem, now I am reading the string from a VISA read block gathering input from a serial port, which is connected to a pressure measuring instrument. I have used the idea given in the example file of "basic serial read and write.vi" to read the input. Any suggestions as to how I should be doing this?

Thanks.