saving data?

[Pells]

Hi! I have some problems with saving some data. I read small voltages with DAQ-assistant and now I want to save the data in a file. I guess the problem is veery basic but I'm totally new to this stuff. I tried to use "write to measurement file" to do the job but I can't seem to get files (LVM) bigger than 114kB and then the program creates backupfiles instead of adding more numbers to the same file...is this a built in limitation or can I get bigger files? (I use the saving to only one file option)

My real question is if this is the best way to store a lot of values or is there another VI that I should use?

I want to use 10kHz sampling rate and save data for about 10 minutes....if anyone have the time to help me out a little I would be very grateful!!

[devchander]

For the data of size that you mention( 10Ks/sec for 10 min), The best would be to save data as a binary file

In examples shipped with LabVIEW, you will find a vi called 'Cont Acq&Graph Voltage-To File(Binary).vi'

It can be found at:  Find examples>>Hardware input output>>DQAmx>>Analog measurements>>Voltage folder

You can use 'Graph Acquired Binary Data.VI'  found in the same folder, to read and plot the scaled data on a Waveform Graph.

Hope this helps

Regards,

Dev

Message Edited by devchander on 03-30-2007 04:38 AM

[Pells]

great exampel! but I have a couple of more questions...when I run the program I get some kind of disturbance on the signal..is this something that is added by purpose by the program?

And my other question- how do I actuallu get the values from a binary file? 😃

[Pells]

also I get this error when I increase the sample rate..I use 6025E and it should be able to sample with 200kHz if I'm not mistaken and this error occurs with much smaller sampling rates

Error -200279 occurred at DAQmx Read (Analog 2D I32 NChan NSamp).vi:1

Possible reason(s):

Attempted to read samples that are no longer available. The requested sample was previously available, but has since been overwritten.

Increasing the buffer size, reading the data more frequently, or specifying a fixed number of samples to read instead of reading all available samples might correct the problem.

[eesen]

Hello,

This knowledgebase perheps can help you

http://digital.ni.com/public.nsf/allkb/7AD4854943BF344186256D6500807935

Message Edited by eesen on 03-30-2007 06:55 AM

[devchander]

No noise/dithering is added to the values you read.

Also take a look at this High speed data logger vi found here

This data can be read using the VI 'High Speed Data Reader.vi'

you can find it in examples shipped with LabVIEW