I am using MPXH6400A pressure sensor for measuring pressure inside a closed chamber. Clean air is being passed through the closed chamber. The readings were taken after allowing system to stabilize for 15 minutes. Day 1 reading for output voltage was 1.22 V (corresponding pressure value = 102.2865 KPa), and day 2 reading for output voltage was 1.18 V (corresponding pressure value = 99.0469 KPa), although all the system parameters were maintained.
Kindly explain the reason for the difference.