Synchronised AIO causes system freeze

[ContemporaryInsanity]

Using a PXI 1042 with 6115 IO.

I need to simultaneously generate and sample a waveform.  The attached VI works to a certain extent, however depending on the waveform it can generate an error or freeze the entire system requiring a power cycle and I have no idea why.

Running the vi with the defaults results in error 10864 @ AI Buffer Read.

Running the vi with the frequency set to 100k and cycles to 10 freezes the system with the waveform being continually generated on the output (I can hear it, it's driving a piezo).

Running the vi with the frequency set to 200k and cycles to 100 works fine.

Any advice whatsoever would be gratefully received, this is driving me to my wits end...

[hannahW]

Hi,

What version of LabVIEW are you using? Also what version of the NI-DAQ driver?

I've found the following knowledge base article which may help to explain why you are seeing these overwrite errors.

http://digital.ni.com/public.nsf/websearch/75BF35EB4AFB834F862566210065FA61?OpenDocument

You say in your post that if you increase the number of 'cycles' then the system seems to improve. If this is correct, then as the knowledge base explains, increasing the buffer size can help this - your 'cycles' value is directly linked to the buffer size that you are creating.

I would check these values out, and see if you get an improvement.

If you are using LabVIEW 7.x or above, the I would recommend looking into using NI-DAQmx instead of Traditional NI-DAQ. This supports the device you have, and may be more efficient. There are in built examples with LabVIEW 7.x that show how to perform these multifunction operations using NI-DAQmx.

Let me know how you get on with modifying the figures to see if this helps, if not then let me know more about the versions of software you have, and I'll give you more help with getting a working piece of code.

Regards

Hannah
NIUK & Ireland