extract portion of signal to send to main vi

[Intern Liz]

I have a main vi where I am sending to subvis that acquire data and then analyze it. My problem is with my acquire subvi. I continuously take data for however long the user wants and then save it on a button click. The data that I want to send back to the main vi is only the portion of the signal that was saved to file. I am having a lot of trouble figuring out how to correctly do this. My first try was to just send whatever is in the case structure with the write to file express vi to the main vi but the data is different data. I also tried getting the time stamps where I am trying to save the data and using that to get a subset of the data. The subset just didnt happen when I tried to test it. Are these ways I am trying good attempts or am I just in the complete wrong direction here?

[shb]

Hi Intern Liz,

the signal you return out of the loop are just the values that "Analog read.vi" read in the last cycle, the last 1000 values.

The simplest approach is to read back the data from the file. If you do not want to do this (because it is to slowly), you must store the data in your program.

Greetings,

shb

[Intern Liz]

How do I store the data in my program?

[shb]

A shift register is a good idea for storing data.

How to do it exactly? This is to complicated to explain by words. See the attached VI which shows an implementation for a waveform array (your data type).

Greetings,

shb

Message Edited by shb on 04-03-2008 07:10 PM

[Intern Liz]

That works perfectly. Thank you.