writing to file continuously

[Brian123]

Hi,

I'm working on aquiring image data from the NI DAQ card. to increase efficiency, user could choose to not to do the calculation and displaying of images or to only aquiring data for postprocessing. The image diaplaying and data saving functions are in a while loop, so the program saves the data in a new file upon each iteration of the while loop. For aquiring data, I want to make it such that the data is stored in the memory continuously and the data collected from all iterations would be saved in a single file once the while loop stops. I know how many sample points are for each image, therefore for postprocessing, I could simply divide the entire data set and reconstruct the images. could someone suggest me what's best way in doing this?

Thanks

Brian

[Real_McCoy]

"Brian123" <x@no.email> wrote in message
news:1132868443726-292603@exchange.ni.com...
> Hi,
>
> I'm working on aquiring image data from the NI DAQ card. to increase
> efficiency, user could choose to not to do the calculation and
> displaying of images or to only aquiring data for postprocessing. The
> image diaplaying and data saving functions are in a while loop, so the
> program saves the data in a new file upon each iteration of the while
> loop. For aquiring data, I want to make it such that the data is stored
> in the memory continuously and the data collected from all iterations
> would be saved in a single file once the while loop stops. I know how
> many sample points are for each image, therefore for postprocessing, I
> could simply divide the entire data set and reconstruct the images.
> could someone suggest me what's best way in doing this?
>
> Thanks
>
> Brian

You can do this with registers and a while-loop switch.

McC

[devchander]

Hi,

What you want to do is pretty risky, bcoz once this shift register starts getting loaded, your program will hang an you might lose all the data.

is there any reason as to why you do not want to save immediatly after acquiring in each iteration?

[Brian123]

I'd like to append the data into one file at the end (there's appending option on the save function, but I do not know how to use it). I would like not to save the data after each iteration because I am trying to aquire data as fast as the hardwares can to achieve higher frame rates. I think as long as I set the data aquisition to not past the memory limits of the DAQ card and PC RAM, it's ok.

thanks

[DFGray]

Check out Managing Large Data Sets in LabVIEW.  You should be able to slightly modify one of the examples there to get what you need.  Note: it is a fairly advanced tutorial.