Re: NI DAQCard-6062 command read/write problems

Thanks for the tip Frank. Increasing the FIFO buffer size does help quite
a bit. I can now record for 30-60 seconds at 500 kHz without problems. 

Now, does anyone have any advice regarding my other two problems?

1) Should DAQCard-6062 + comedi be able to do simultaneous command 
    read/write?  I'm attempting the following sequence of events:

    a) issue comedi_command for the AI subdevice
    b) begin continuous reading
    c) issue comedi_command for the AO subdevice
    d) issue command_trigger for the AO device
    e) write to the device

    At this point the program crashes with a segmentation violation error and
    locks up the AO subdevice. I'm working under Labview and the VI's for 
    steps a-b) and c-e) are two separate modules.

2) Is there any way short of rebooting, to correct the "Device or Resource
    Busy" error message I receive when trying to access the AO channel 
    after my program crashes. I can't even remove the comedi modules using
    rmmod. lsmod reports that kernel module ni_mio_cs is being used by 1 
    (process?) but ps -ax shows nothing running that should do so.

Any tips/pointers will help immensly.

Thanks.

Mike Bird


--- Frank Mori Hess <fmhess_at_users.sourceforge.net> wrote:
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> On Friday 19 September 2003 12:37 pm, Michael Bird wrote:
> >
> > 1) When doing command analog I/O (particularly AI but I think I've seen
> > it with AO
> > as well)  at high sampling rates (~500 kHz),  the read/write command
> > fails to return
> > after writing several secons of data. In other words, the I/O operation
> > works fine for
> > short periods of time but then dies after several seconds.
> 
> The ai fifo size for your board was set to 1024 instead of 8192 samples in 
> ni_mio_cs.c.  It should handle high speed input better now.
> 
> - -- 
> Frank
> 
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Received on 2003-09-22Z17:39:17