Regarding to my project I have implemented a LabVIEW program which is doing data acquisition. We have LabVIEW 6i Installed in PXI-8170. The DAQ Card that we use is NI6030E DAQ Card Multifunction I/O.
I have implemented a VI to acquire and plot and record multiple analog input channels. By using AI Acquire Waveforms VI to acquire waveforms from 4 channels in a single run and using Index Array function to extracts the data for each channel.
For plotting waveforms, I use waveform chart for each channel. I put all this functions in a While Loop and use a stop push button to stop the acquisition. I also put another push button named Save to disk in the loop that by pressing it we can save data to a File by using Write to Spreadsheet File. VI, located in a case structure out of the while loop. I save data as a 2D array by connecting the waveforms output connector of AI Acquire Waveforms VI to the input connector of Write to Spreadsheet File VI.
But I have some problem that I can not solve it yet which are listed below:
1- I want to record all the data that I acquire for a specific time, but I can not. I only can save the specific part of the waveforms which I think it is specified by the number of samples/ch and Scan rate controls.
For example I do the acquisition for about 1:30 minute and save it, but when I plot the data which is saved in the spreadsheet file; it is only the last 20 seconds. So I can not save all the data that I try to acquire.
2- I want to record data for a specific time automatically. I mean when I run the VI after press the Save to disk push button the VI automatically start saving data for a specified period of time and then automatically stop. (How to define a timer to control the VI?)
3- I want to start acquisition each time from zero base time. I mean when I do the acquisition for the first time and then I want to do it for second time, the pervious acquisition reset or clear and the time axes of each chart again start from zero not continue the pervious time. It means that I need to clear the chart.
Regarding to this problem I try to use the AI Clear VI, but it didn�t work. May be I don�t know how to use it.
