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Circular Buffer on cRIO USB drive

Hello,

I'm wondering if it is possible streaming of data to a memory connected to cRIO 9063 USB connector.

My application currently streams data to a circular buffer implemented in Pc Host, using Network Streams. I need data of 24 channels sampled at 250 Hz for half an hour. This because sometimes the trigger condition is given from a web service which is updated every 20 minutes giving the timestamp of the event. So I use the timestamp to search data in the buffer and extract it from there. 

This cannot be carried out by 9063. I would remove Pc Host from my application and use USB memory. Is it possibile? I'm looking for an example but it seems there are no examples on the web.

KR

Davide

 

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Hi Davide,

 

Yes, It is possible. Look at this simple example:

http://digital.ni.com/public.nsf/allkb/65C685BD7EC10D6B86257D07004A9825

 

As you see, there is an internal drive letter called U or V, if you have more than a USB port. (cRIO -9063 has only one)

 

Maybe this is also interesting for you, http://digital.ni.com/public.nsf/allkb/B098CEBF7864135C862577AF005CA979

 

Have a nice day!

 

 

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Hi Daragor, thank you very much.

 

Unfortunately, at this point, I don't know how can I apply your suggestion because it is not clear to me how to develop a circular buffer based on data logging. Maybe I should explain better the application.

I want at each time a buffer containing acceleration measurements sampled at 1 kHz and the indication of the timestamp of the first value. For example just now I have an array of 24(channels) columns and 30(minutes)x60(seconds per minute)x1000 (samples per second) and a timestamp. Thei will change in the next loop interation.

The trigger is from Twitter. It gives the timestamp of the event, I can find the measurements of interest having the data array and knowing the timestamp of the first event in the array and the sampling rate. This is trivial using a shift register.

 

But how can be done with a txt file?

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