I am not familiar with you device, but I can give recommendations about acquisition you described.
In your VI there are two tasks within one while loop and the loop time is determined by the Simulate Signal express VI (you can see it, if you would take an indicator to output of the interation variable).
The iteration time is processed from Number of Samples / Samples per second. In your case it is 100 / 1000 Hz =0.1s.
It would be better to use separate, parallel loops for each task.