How to control the data rate of a digital write to a port on a PCI-6509

[hawkeye978]

I am using a PCI-6509 to write digital words to a custom digital board. I can generate the proper patterns with the 6509 but the resulting pulse rates are very high (150+ khz) which is very noisy. I know the board cannot have its clock controlled. Is there a simple way to adjust the output rate? I am generating a 1D array and writing this to the device with the NI-DAQmx commands. About all I could come up with is interleaving this array multiple times to stretch the resulting pulse. Anything more elegant, as this seems pretty brute force?

Thanks,

Tom

[Andy F.]

Tom,

An easy way to control the output rate for digital generation is to use the DAQmx Timing.vi. Place this VI anywhere between the configure and start VIs to apply a sample clock, for which you can define the rate. A good example of this is the "Write Dig Chan-Int Clk-Dig Start.vi". If you launch the NI Example finder (Help >> Find Examples), that example is located under Hardware Input and Output >> DAQmx >> Digital Generation. This example uses a digital trigger, which is probably not necessary for your application, but also shows the DAQmx Timing.vi in action.

Andy F.
Applications Engineer
National Instruments