We have easily been able to achieve analog outptut using the NI4551. However there is a problem in achieving analog input using NIDSA_read_scan_channel which gives an output of a buffer having all zeroes if timeout is given as 0.0 secs and hangs for any other(including default) timeout values.
I do not see a function called NIDSA_read_scan_channel in the NI-DSA Help for C Programmers. It also does not come up in a search of NI's support site. Where did you find a reference to this function?
It came on the CD with the card. The library of APIs for C programming are listed in the DSA manual. You are right about not finding anything on NIs(non)support site.
