Using 653x self-test example VI from NI web-site

[blarivee]

Hello-

I am trying to do a self-test on my PCI-6534 by connecting group 1 (ports 0,1:output) to group2 (ports 2,3:Input) and the appropriate control lines. I downloaded an example code from NI which I have attached below. For some reason it is not working properly. The Digital Read VI does not seem to be reading in the data from the buffer, but that could just mean that the buffer control on the input lines is not working properly and there is not actually anything in the buffer. If I don't make the program continuous by inputting a '0' for the Number of updates input on the Buffer Control VI, then the program works fine and the expected inputs are read in by the input group at 20 MHz. How come when I try to
use the program the way it is written and run it continuosly the board doe snot seem to be working properly? Thanks.

[rgharrison]

Hi Blarivee,

I am currently using a DAQCard-6533 board which is very similar to the 6534 (doesn't have the deep memory and uses interrupts instead of DMA for transfer). All I did was change the "Transfer Method" to Pattern I/O, and reduced the clock frequency and buffer size to 1000 (because I am using interrupts and no onboard memory). I then connected REQ1 to REQ2, DIOA[0:7] to DIOC[0:7] and DIOB[0:7] to DIOD[0:7]. Everything ran well at that point.

I've also been able to use this example on a 6534 but I haven't tried it lately. If you are going to perform I/O on all 4 ports, try using a maximum transfer rate of 5MHz. It could be that your system and bus bandwidth are causing errors to occur. Here is a knowledge base that discusses some of the trans
fer rates (one way). I just assumed that performing input or output didn't affect the bandwidth.

Performance Benchmarks For The High-Speed Digital I/O - NI 653x
http://digital.ni.com/public.nsf/websearch/4FCA248D888831C386256D8900563E45?OpenDocument

Anyway, hope that helps. Have a good day.

Ron