I would like to know the parameters to feed to the NI-DAQ function SCAN_to_Disk to sample at 5Ms/s on four channels of a PCI-6110E

[Owen]

I've been trying (unsuccesfully) to get my PCI-6110E card to perform the SCAN_to_Disk function without causing any 'buffer' errors (I don't know what to do to increase the size of the buffer), or processing times that don't seem to correspond to the time the run should have taken, or that increase linearly in time when increasing number of samples. I'm programming in Visual C++ under Windows 2000.

[Erin_B.]

The 6110 is capable of streaming to disk at 5 MS/s. However, that's total throughput, and you will more than likely need an ultrawide SCSI hard drive. Writing to disk on an IDE hard drive is a slow process, and it will severely limit the rates at which you are able to continuously write into memory.

There is an example in the Developer Zone that uses compression to achieve higher stream to disk rates, and I believe that an interface to the C API is also provided.

Another suggestion is to look at what you're really trying to do. Do you really need to write 40 MB/s of data to file? Are you only interested in a particular event, but you are waiting until after the data has been acquired to process the data for that event? There might be a better way to achieve your
goal. This board should have no problem streaming to memory at the rates you want. Perhaps you could use analog triggering to capture the window of time around the information that you are interested in.

Hope this helps.

Regards,
Erin