how to do continuous pattern output from buffer

[sarosh]

I am using a PCI6534 with Labview 5.0 & NI DAQ 6.9. I am trying to continuously output a pattern (read in from a file). I am using burst output triggered on an external clock (connected to pckl). I load the buffer with data using "buffer write" and than use "buffer control" to start output operation. If i set # of scan in buffer control to -1, i get the required pattern only once. Setting it to "0" outputs data more than once. BUT there is lot of unwanted data being generated.... How do i make it to loop on my data continously reading it from the buffer and outputting it?

[Ryan_M]

Setting the "Number of scans/updates" control to a "-1" tells the driver to leave the input alone. That is, use the last value. Setting it to "0" specifies that LabVIEW acquires or generates data continuously or until you clear the operation. There is a decent explanation of how the 6534 is used in Burst mode in the manual available at http://www.ni.com/pdf/manuals/321464c.pdf.

Also, there is a buffered pattern output shipped with LabVIEW to which you can apply your specification (external clock, etc). I might recommend running this example to see if you have better luck with it.

In response to your unwated data, to what degree is it unwanted? Is it corrupt, flipped, negated, etc?

[sarosh]

I am using a double buffered continuous output with external trigger. The data output is fine till 32M samples after that the data becomes misaligned, causing erroneous outputs on my device under test...
i have even tried making the data size an exact multiple of 256 but it does not help...