Solution
To communicate between the FPGA VI running on NI-9149 and the real-time VI running on the cRIO controller you can use the same communication techniques that you can use to exchange data between the cRIO controller and the local cRIO FPGA:
In the Real-Time VI, you will need to call
Open FPGA Reference VI to be able to communicate between the host VI (running on the cRIO processor) and the FPGA VI (running on the FPGA of 9149): when you
configure this function, ensure to point to the proper FPGA target in your LabVIEW project.