Data aqucition on matlab

hi everybody,

first of all i am a mechanical engineer, and i have no choice but to deal with programming using matlab, the problem now that i need to get data through the sound card into the computer,

the signals are DC voltage (analogue) from a load cell, varying from 1.8 volts to 4.2 volts, these values were taken by AVOMETER and they were very stable.

when using matlab , i use [GETDATA] order , but the output is totally nonlogic, some values having a cyclic pattern, i use 8000 samples per sec.

all what i want is graph with certain values corresponding to the load cell output.

i dont know if everything is clear, but i can tell any other details you want

thnx in advance.