Reading data from differential pressure sensor

pylon:
The formula for the pressure is simple: p = vout / vs * 5 - 0.5

No, it is p = 5*[(Vout/Vs)-0.5] or p = 5*Vout/Vs - 2.5

Examples: if Vout = 2.5V, p = 0 kPa. If Vout = 3.5V, p = 1 kPa. Both with Vs=5V.