PXI-6533, Changing frequency without stopping the card?

[JX5000]

Using PXI-6533 and LabVIEW, is it possible to update the frequency (of a defined pattern) without stopping the output of the card?

[Joshua-B]

Hi JX5000,

You should be able to accomplish this using a DAQmx Timing Property Node to set the sample clock rate.

[JX5000]

Thanks for the reply!  Would you be able to send me an example?  I'm not sure how to apply this.

[Joshua-B]

Hi JX5000,

I don't have an example written for this use case, but you would use the property node in your while loop (perhaps with an event structure).  I've attached a link to the LabVIEW Help file on this property node below.  Hopefully this helps!

DAQmx Timing Property Node (VI)

http://zone.ni.com/reference/en-XX/help/370469AA-01/lvdaqmx/mxtimingpnode/

[JX5000]

Hi Josh,

We've actually attempted to do this for a few days until we hit a wall.  We then received word from another NI Engineer stating:

Unfortunately, the Sample Clock Rate is not a property that can be changed while a 6534 is running.  The device has to be stopped before this property can be changed.

In general though, if this were a DAQmx device that could have this property changed while it was running, you would write to the SampClk.Rate property on a DAQmx Timing property node to accomplish this.

Just so you know.

Thanks,

JX

[Joshua-B]

Hi JX,

I'm actually the engineer that provided the information about the 6534 as well.  I apologize that it didn't register with me on this discussion possible that this wasn't possible with the 6533.  Many DAQmx devices can change this value while running and the property node is how you would accomplish this.  Unfortunately I didn't catch before that the 6533 is one of the devices that cannot do this.