Hallo Oliver
the pxi 5112 is a high speed 100MHz, 100MS/s, 14-Bit Digitizer board with two input channels. Each of the two analog input channels has its own 100MS/s, 8-bit analog-digital converter, so you can simultaneously acquire data on each channel sampled at rates from 100MS/s to 1S/s.
What sample rate would you have? What do you mean by a ForLoop counter with three values?