analog input

i have pir sensor it gives some output voltage with respect to sottunding

if i activate my internal pull down resistor of my analog input pin i am getting correct digital values
if i activate my internal pull up resistor of my analog input pin i am getting no values values(digital value as 0)

Which pir sensor do you use?

What is your question?

Elektrix

thanks for forwarding
i thought that there internal pulldown resistor in arduino but my guess is wrong.now i am clear thanks