Hello Jian, Thank you for contacting National Instruments.
What version of LabVIEW are you using? If you aren't using 7.0 and DAQmx, multithreading is not supported. With DAQmx, different channels can acquire analog inputs from your device simultaneously. If you are using NI-Traditional DAQ, there is no guarantee of the order in which the inputs are acquired. Try using DAQmx to acquire your inputs and see if that solves your problem. Let me know if this does not work. Sean C. Applications Engineer National Instruments
