ACS712 5A

good morning.
i have assignment to read current use ACS712 with ARM. but, i have troble because output value of sensor is not constant and always change in every time. can yo give me solution to finish my assignment?
thank you.

You have not told us enough information.
I have used the ACS712 with a ARM.

What ARM?
Please send the schematic of how the ACS712 is connected to the ARM???
What are you measuring? Current AC or DC?
"output value" Please send data???