Continuous Acquisition

[MeganWhite]

Hey Guys,

I was curious to know if it is possible to add header information to a continuous acquiring data write.vi every second without loosing data? I am attaching the case structure where it writes data till the file size is reached and then writes the header. How can I make a loop so that when the file size is not reached still the header keeps updating after every 1 second duration?

Megan

[MeganWhite]

Sorry guys couldn't get the attachment last time

Megan

[hfettig]

Have you considered running two loops in parallel?

The first loop constantly generates/gathers the data and writes it into a write buffer.

The second loop checks the time, if 1s is up, it updates the header, if not, it copies the write buffer to an output buffer and clears the write buffer. Then it writes the output buffer to disk.

This way you decouple the storage part of the task from the gathering part. You just have to avoid the gathering part to write to the buffer while the storage part is clearing it. This will cause a slight delay in you gathering routine, but only for a couple of milliseconds.

I attached a buffer vi. Take a look at it and modify it for your use. In the gathering loop, use the 'add to buffer' action. In the storage loop use the 'read & clear buffer' action. Then you can just loop through the buffer elements to save them. Use the 'Initialise' action before you add the first point.

Download File:post-1022-1100531206.vi

[JackHamilton]

Megan,

A quick way to save the data in segement files without coding it all - is to use the NI "LabVIEW Measurement File". In the configuration - "Save to series of Files" settings you can set the file to be segmented by size, data, time etc.

Regards

Jack

[MeganWhite]

I am already buffering the data with the polymorphic vi AI config and AI read. What I need is when it writes into write.vi the data should be like

header

data

header

data...

in each file that is created. And all the files created should be in the same format continuously. Writing lvm does not help as I need to buffer the continuous data.

Thanks a lot guys

Megan