strange CPU usage

[skfink]

Hi,

I have the multiple Analog Output circuit as you can see in the picture. The strange thing about is that I have around every 2 sec a cpu usage of 99%. The paradoxically thing is that the system thread uses that and not labview. But as soon as I stop the vi the cpu usage is 0%. And that doesn't happen with other VI's running, so it seems to be a problem of my programming.

But what's the problem ??

I also tried other VI's with Analog Output. No problem.

[skfink]

changing the thread priority of LabView to real time solved the problem. But strange anyway.

[Neville D]

Hi,

I have the multiple Analog Output circuit as you can see in the picture. The strange thing about is that I have around every 2 sec a cpu usage of 99%. The paradoxically thing is that the system thread uses that and not labview. But as soon as I stop the vi the cpu usage is 0%. And that doesn't happen with other VI's running, so it seems to be a problem of my programming.

But what's the problem ??

I also tried other VI's with Analog Output. No problem.

5571[/snapback]

I am not sure why you have separate AO VI's. Why don't you combine all the AO's on Device1 and all the AO's of Device2 on a single AO output Multiptle Chans Single Sample?

As far as I remember, writing vals to the AO uses the onboard FIFO of the DAQ card. Using the 2 DAQ chans, but still having only one physical FIFO means some magic has to be performed at the driver level.

You might want to clean up the locals in your while loop as well. They seem unnecessary & might cause race conditions (they also make extra copies of the data). Wire the controls and indicators directly.

Neville.

[Michael Aivaliotis]

Hi,

I have the multiple Analog Output circuit as you can see in the picture. The strange thing about is that I have around every 2 sec a cpu usage of 99%. The paradoxically thing is that the system thread uses that and not labview. But as soon as I stop the vi the cpu usage is 0%. And that doesn't happen with other VI's running, so it seems to be a problem of my programming.

But what's the problem ??

I also tried other VI's with Analog Output. No problem.

5571[/snapback]

I don't really see the connection between the displayed code and the 99% CPU usage every 2 seconds. What else is happening in this VI? I notice you are using Matlab somewhere. Is it in this VI?