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water vapour concentration around it. If the solid material is hygroscopic, such as
desiccant dust, whenever there is a change in the moisture concentration in the sample
this material must come to equilibrium with the moisture content before the sensor can
respond to the change, which will cause delays in obtaining accurate results.
7.5
Liquid contamination
If the sample gas may contain liquid contamination, such as oil mist, this should be kept
away from the sensor by including a coalescing filter or an appropriate membrane filter
(3) in the sample system.
If the surface of the sensor becomes partly coated with liquid, again it will not affect the
calibration of the sensor. It will restrict the movement of water molecules across the
surface, so increasing the time it takes for the sensor to come to equilibrium with the
water vapour concentration around it. If the liquid is hygroscopic, such as glycol, the
buffering effect described for desiccant dust may be so great that the sensor becomes too
slow to use.
8
SADPminiEx Initial Configuration
Each SADPminiEx is set up prior to despatch to the end users specification. The following
values will be preset: -
The specified sensor type is pre-selected.
The calibration data will be set to values that are applicable to the specified
installed sensor.
The AutoCal value is set to match the installed sensor.
The clock will be set to the correct date and time GMT.
Moisture units set to
o
C Dewpoint.
Pressure units set to barg, pressure value set to 0.
Security codes are set to 1000.
No Single point calibrations.
