Go to the block diagram of the VI you posted. Use the mouse to drag the AI function. You will see another AI function underneath. Drag that one and you will see another AI function underneath. Drag that one. You will see another one underneath that. Delete the extras. You should have only one - the one connected to the channel control.sample rate, etc. The AI function you are using is not the most effecient either. It configures the DAQ board each time you call it and to have 4 of them just makes it worse. Inside a while loop, you should really be using lower level functions. Open this VI and you will see that AI Waveform Scan is called. This is the VI that you should in the while loop. You can wire the iteration input to the iteration terminal of the while loop and avoid configuring the DAQ card each time.
