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Increasing Digital Out Performance on a USB-6009
pkelley
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07-04-2006 05:21 PM
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I am a little disappointed at the speed when sending digital output
through a USB-6009 in labview. I create a virtual channel which feeds
the task to the digital out 1 channel N samples configuration using
Daqmx VIs. This is all in one VI which gets an array of data (25
elements) passed to it to send. Calling this VI 256 times takes about
10 seconds. I have some questions maybe someone can answer that will
allow me speed things up.
I was under the impression that creating the virtual channel once at a higher level in the application and only calling the read portion would speed things up. It only made about a 1 second improvement. Does that sound right?
I am using a USB-6009. Does the fact that it is USB make a considerable difference? Would a PCI card improve things?
I am using a formula node to create the array of data. Should this be comparable to the speed of regular C programming?
Any suggestions would be appreciated.
I was under the impression that creating the virtual channel once at a higher level in the application and only calling the read portion would speed things up. It only made about a 1 second improvement. Does that sound right?
I am using a USB-6009. Does the fact that it is USB make a considerable difference? Would a PCI card improve things?
I am using a formula node to create the array of data. Should this be comparable to the speed of regular C programming?
Any suggestions would be appreciated.
Evan LV
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07-04-2006 10:33 PM
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Hi Pkelley,
In order to find out root case and solve this problem, could you attach your vi with LV 7.1 here?
Hal_L
NI Employee (retired)
07-05-2006 02:13 PM
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Hi Pkelley,
The digital output of the USB-6009 is going to be software timed. This means that the output rates are going to be completely system dependant. You will see improvement if you switch to a PCI card. If you are looking into getting a new board for your digital i/o application, I would make sure that it supports hardware timed dio. This way, you will be sure exactly which rates the hardware can achieve.
Regards,
Hal L.
