Greetings,
You can setup the SCXI-1520 for parallel mode operation within Measurement and Automation Explorer (MAX).
Right-click on the PXI-1010 (SCXI) chassis within NI-DAQmx devices folder of MAX and select properties. Left-click the details button to the right of the SCXI-1520. Go to the cabling tab, and select parallel mode. This is all you need to do to set the SCXI-1520 to parallel mode.
I hope this helps. Let me know if you have any additional questions. Have a great day.
Regards,
Todd D.
NI Applications Engineer