Simply connect the two wire sensor lead to the computer and for accurate calibration set 20 m/A that’s it! The new Shaw sensor connects directly to a factory computer line to measure the amount of moisture in dry air or gas without the need for a separate power supply or hygrometer. With the sensor in room air, Shaw Automatic Calibration has entered the range of -80 deg c. which is less than 1 part per million of water vapour, to 0 deg c.