The communication with the NI 9144 will always rely on the Scan Engine. Therefore, the only method available to communicate with the FPGA of the NI 9144 to your Real-Time controller will be through User-Defined I/O Variables. You will not be able to use other methods like DMA FIFOs or Read/Write Controls. User Defined I/O Variables will also be updated at the same rate of the Scan Engine.
Please consider the documentation below for more information on setting up the NI 9144 and User Defined I/O Variables.
Note: In versions of LabVIEW older than LabVIEW 2009, the NI 9144 can only be used with the CompactRIO Scan Interface and the FPGA cannot be programmed.