Unfortunately the 1500 samples/s will only be reached by using the FPGA interface for controlling the WF 3132 module.
As seen in the WF 3132 User's manual there are two different software drivers for the module; cRIO Software (FPGA) and cDAQ Software. The cDAQ driver is unfortunately so slow that 1500 samples/s will not be achieved using that driver.
The switching speed achieved with the cDAQ driver is highly dependent on the PC software that is calling the cDAQ driver. Benchmarking have showed that a switching speed of about 100 Hz can be achieved with the cDAQ driver.