I have a futaba BLS551 brushless motor digital servo (3 wires-+,-, signal). i also have a CRIO+real-time+fpga and 9477 digital out module. how can i generate servo signals using this module
In order to control your servo motor with the FPGA and or DIO module you will have to write drivers to control your motor and drive. While this is possible is an extremely complicated and time consuming process. I would highly recommend you consider using the NI 9514 with soft motion as it will provide full servo functionality and is relatively easy to use.
