How can I store the previous data elements in labview

[kasula]

Hello,

    I am using PXI1042Q chassis with 8106 microcontroller and PXI 6289 DAQ cards. I am implementing a real time system where we acquire data point-by-point.  I would like to know if there is any way that I can store previous 500 sample points. I know that shift registers can be used to store values from previous cycles. It seems impractical to insert 500 shift registers in to system. Is there any way to store the previous 500 samples?

Thanks,

kartik 

[altenbach]

Well, you would use an array in a shift register and append your data using "built array".

For better memory performance, you would use a fixed size=500 array and replace the oldest element with the newest at each iteration. Keep track of the current element index with another shift regsiter.

Or wrap it all into an action engine. 😄

[Coq_Rouge]

A shift register may contain all labview datatypes. Not just numeric. So you can have a 1 shif tregister containing 500 data points.

[altenbach]

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altenbach wrote:

For better memory performance, you would use a fixed size=500 array and replace the oldest element with the newest at each iteration. Keep track of the current element index with another shift regsiter.

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Here is an old example tha keeps the last 10 values in a size=10 shift register and calculates the mean.

Modify as needed.

Information about action engines can be found here.

There is also the "collector express VI". Since it uses dynamic data, it's probably more demanding on resources.