how can i use a ring buffer to do digital input at 0.5 MB/sec

[fady]

Hello,
I am supposed to capture input coming at ~ 0.5 MB/sec. I have 6533 DI card to do so. I was trying to set up a ring buffer (like the buffer in IMAQ) to use with this high data rate but it is not coming along. I get the first 300 samples (16-bit/samples) only and the rest is not filled up. I get this by making library calls using the C functions to do the acquisition since using the high level LabVIEW vi's would not acquire anything. So I was wondering if somebody has tried this before and would tell me the steps or if there is an example in LabVIEW that does something similar (I tried the Pattern I/O, Handshaking etc that use double buffering but I dont seem to get them to work). Any hints would be appreciated. Thanks

[TylerS]

Hello fady,
What kind of errors are you getting? Have you tried any of the LabVIEW shipping examples for this card with your application? Are you using a C example that downloads with DAQ? There is no on-board memory with the 6533 and the transfer rate is system dependent. Could this be a factor? I'm including a link to a document on NI's website that might have some useful information for you:

http://zone.ni.com/devzone/conceptd.nsf/webmain/E5A26C86E0C32E4886256BE20050E9E3?opendocument#1