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High Speed Continuous Analog Acquisition

Hello,

I am trying to use a USB-6356 card to acquire some high speed (~1MHz/Ch x 8 Channels) analog input signals.  The signals are coming from blast gauges that will measure the shock coming from a controlled explosion.  The challenge here is that the duration of the explosion is very short (way less than half a second), but the explosion could happen anywhere inside a 10 minute window.  When the explosion does happen, having 2 seconds of pre-explosion data and 2 seconds worth of post-explosion data would be plenty

 

The specs of the USB-6356 say it can read up to 1.25MHz/Channel, and has a 32 million sample buffer.  So as far as I can tell, at 1MHz/Ch x 8 Ch, I should be able to hold 4 seconds worth of data on the card.  My problem though, is that I cant stream the data to my PC fast enough to log everything on the computer.

 

What I would like to do is to have the DAQ start reading data continuously, but have it overwrite itself continuously.  Then when the explosion does happen, I wait 2 seconds, stop the acquisition, and take the data thats written in the buffer at that time.

 

On page 4-45 of the XSeries manual, however, it says that during continuous acquisition, if I dont transfer data out of the bus fast enough, it will fill up and I will get an overflow error.  Is there a way to disable this error and just allow the overwrite since I dont need that data anyway?  Or am I trying to do something thats simply not possible from a hardware perspective?

 

Thanks

Jimmy

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Sorry, double post

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