Absolutely yes, NI-VISA and NI-VXI can coexist, and in general, you
can use both of them in your same application.
Note that there is a difference between multiple VXI systems and
multiple VXI chassis. A single VXI system is made of 1 or more
chassis. NI-VXI can access only one VXI system number due to its
legacy API. NI-VISA, on the other hand, can access multiple systems
because the system number is part of the resource name.
So if you have multiple VXI systems, you can use the VISA API to
access devices in all systems. You can optionally use NI-VXI to
access devices in only one of the systems. But you can still use VISA
to access other devices in the same system as the one that NI-VXI is
using.
Dan Mondrik
National Instruments