Problems about the Cross correlation function VI

[在那菊花盛开的地方]

Hi everyone!

I'm a student from China ,and i have studied labview just for one month.I want to make a Vi that can calculate the Cross correlation coefficient of  two waveform data which is known in a txt .I have also build a graph that shows these two waveforms,which is correct and with good Cross correlation,however the Cross correlation function can not give the correct results of the data,and even when I input '1',which can give the normalization in theory,some results are larger than 1!I really have no idea about that ,Could anyone do me a favour ?Thanks!