I am using a PCI 6534 for pattern output. I only seem to be able to trigger a pattern many times if I rewrite the buffer each time.However I want to write to the buffer once and then output a pattern whenever I trigger the card.

[Geneva L.]

The 653x digital boards do not support retriggerable pattern generation. However, there is a trick you can do to accomplish that behavior. It involves using a 660x counter/timer board set to retriggerable finite pulse train generation. You apply your trigger to the counter/timer board to trigger a pulse train. This pulse train can be wired to the 653x REQ line as an external clock. The pulse train contains the number of pulses as the size of your output pattern. In pattern generation, each time an edge occurs on the REQ line, data is latched out. Your 653x program is a pattern generation with external clock example. The 660x program is a finite pulse train example with the trigger set to retriggerable. Thus, your digital pattern will appear on the output bas
ed on that retriggered pulse train.

Regards,

Geneva L.
Applications Engineering
National Instruments
http://www.ni.com/support

[sarosh]

I have a similar problem. 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. Now 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.... hpw to resolve this issue?