event script e os.sleep

[Frank68]

Hello
I am trying with an event-based script when the value of a byte changes, to send mail, the byte can have value 0,1,2 my problem ache inside the script I should delay sending the mail for a time and re-read the value, as it takes time to pass between the various values, I tried with os.sleep () and to read the value after the time but it doesn't work, is there another way to do this function?

thanks a lot