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execution time on USB NI-DAQmx (USB-6003 vs. USB6341)

Dear DAQmx experts

 

In my application an USB-6003 is used to control different sensors and actuators. The LabVIEW app is implemented with the actor framework. Each part connected with the USB-6003 has its own actor. Each of these actor has one or multiple tasks that are executed on the DAQ to do the needed job of the connected units. The LV actors ask the USB device for the needed ressources, try later if not free, take it and process the task if free (DAQmx Start Task, Error check -50103, DAQmx Read/Write, DAQmx Stop Task). This concept seems to work.

 

A code snippet USB-DAQmxToDo.png is attached.

 

In 1 to a million I receive an internal software error -224606 caused by the DAQmx Stop Task.vi for DAQmx ConversionTask. A power cycle of the USB port (Hub or PC) is needed to bring the USB-6003 back to life. A replacement by an other USB-6001 showed the same behaviour. Also testing/playing around with implicit stop, inserted delays and the autostart property did not improve the situation. The rate of failure was more or less the same (1 in a couple of hours) for all tests I did. This kind of error is discuded in the NI forims since a decade or longer and pops up every two years again. 

 

I replaced the USB-6003 by an USB-6341 24hours ago without seeing the original failure. During regular operation I noticed some additional delay or increased execution time of the application. Using DETT showed that the execution time of the investigated code on the 6003 takes about 6ms. On the 6341 it takes about 30ms. Code to execude and the configuration of the DAQ task did not change.

 

Does somebody know how to bring the execution time of the 6341 down into the region I see with the 6003 device?

Thanks for your help, hints and possible explanations.

 

 

  

 

 

  

 

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