PCI6520 - how many samples can I acquire?

[Rafi2003]

Hi,

I'm going to use the PCI 6520 (M-Series) card for signal Analysis.

Since the sampling rate is 1Mhz, I was wondering If I can use this card/DAQ software to acquire 1 sec worth of samples (1 million samples)?

What are the limits/considerations I need to take into account in order to find out the maximum  number of samples I can acquire?

Thanks

Rafi

[Stefo]

Rafi,

in number of samples you can acquire at once you are limited by computer memory. You can configure the board to acquire data continuously while using the 1MS/s sample reate. If you need to acquire big amount of data, you can either programmatically increase buffer size, or you can read data in smaller portions and use them just at the end.

I suggest you to check examples for continuous acquisition.

regads,

stefo

[Rafi2003]

HI,

I would like to describe my application further...

My input contains pulses (500us spikes) at a frequency of 4hz. (4 spikes in a second).  In addition, it will appear at different voltages.

What I would like to do is sense this input, waiting for a certain voltage and only then, acquire a 1 sec worth of data.

An alternative (tell me if it's possible to do...) is to acquire data for 4 seconds (4 million samples).  The 4 seconds is a complete loop that include all my data.

As a matter of fact, I don't need to acquire the full 1 second but just the pulses (every 250ms).  

1.  Can you give me some guidelines as to how to approach this task?

2.. Is it possible to tell the DAC to acquire for some time, stop,  start again, stop and so forth?

3.  Is is possible to acquire 4 seconds worth of data?  How much memory is required?  is it certain that I won't loose any data?

Thanks

RK

[JustinP]

Hello,

I am attaching a link to an example that I think addresses your application pretty well.

http://zone.ni.com/devzone/cda/epd/p/id/5228

Justin

[Rafi2003]

Hi

Thank you very much for the example.  However, we don't work with LabView, only with CVI.  Is this example available also in LabWindows//CVI?  Otherwise, it it's not, can you describe the general approach taken in this example?

Thanks

RK

[JustinP]

Hello,

This example is not currently available for CVI but I am attaching a screenshot of the LabVIEW code with the steps listed and the functions used.  CVI code is structured in much the same manner and order.  One thing to beware of is for LabVIEW continuous acquisition is done in a while loop where in CVI it is an event based structure.  You can find analog measurement examples in CVI under Help»Find Examples. The functions are DAQmx functions and work for both LabVIEW and CVI. 

Regards,

Justin