I have a PXI-5622 that needs to record bandwidths up to and including 20MHz. The onboard-memory for this module is 256MB and data is stored in a circular fashion: when the 256MB is filled, the sampler begins to overwrite from the beginning. Data is fetched and written to the hard drive in blocks. Block sizes are currently defined as: BlockSize = 2^(floor(log2(IQR) - 2)), where IQR is the sample rate.
My problem is that when the sample rate is too high (recording bandwidth too wide) the memory being overwritten "catches up" with the data being written to the hard drive. This causes the operation to halt with the error, "Requested data has been overwritten in memory so it is no longer available for fetching." This makes sense and I would expect it, but I'm wondering if anyone could help in figuring a way to avoid memory being overwritten before it has a chance to be stored on the hard drive.
