Operation
Page 23
FA 550 V1.00
12.3.2
Definition of Reference- and System pressure
With the FA 500 the pressure dew point in the pressure line is measured automatically. The
pressure dew point is always related to the pressure in the line.
A pressure input is not necessary, because the measuring principle measures independent of
pressure.
The FA 500 is able simultaneously to the pressure dew point also calculate the atmospheric
dew point or dew point at reduced pressure.
For the calculation of the atmospheric dew point (if the gas would be expanded to ambient
pressure) or the dew point at reduced pressure, it is necessary to define the reference pressure
and the system pressure.
Example:
The sensor is used in a compressed air line after a compressed air refrigeration dryer.
Pressure in the line:
6 bar (overpressure)
Measured pressure dew point:
+ 3 ° Ctd
To calculate the atmospheric dew point, the reference pressure (atmospheric pressure 1013,25
hPa) and the system pressure (overpressure) with 6bar must be entered.
Only after entering the two pressures, a correct calculation of the atmospheric dew point is
possible. (Displayed on screen page 3, here the value 4)
