15
4 Mounting
WIKA Operating Instructions - Process pressure transmitter IPT-2x
4.2 Ventilation and pressure compensation
The filter element in the electronics housing has the following func-
tions:
•
Ventilation of the electronics housing
•
Atmospheric pressure compensation (with relative pressure meas-
uring ranges)
Caution:
The filter element causes a time-delayed pressure compensation.
When quickly opening/closing the housing cover, the measured value
can change for approx. 5 s by up to 15 mbar.
For an effective ventilation, the filter element must be always free from
buildup. In case of horizontal mounting, turn the housing so that the
filter element points downward after the instrument is installed. This
provides better protection against buildup.
Caution:
Do not use a high-pressure cleaner. The filter element could be dam-
aged, which would allow moisture into the housing.
The following paragraphs describe how the filter element is arranged
in the different instrument versions.
1
2
3
4
4
4
Fig. 7: Position of the filter element - non-Ex, Ex-ia version
1 Plastic, stainless steel housing (precision casting)
2 Aluminium housing
3 Stainless steel housing (electropolished)
4 Filter element
With the following instruments a blind plug is installed instead of the
filter element:
•
Instruments in protection IP66/IP68 (1 bar) - ventilation via capillar-
ies in non-detachable cable
•
Instruments with absolute pressure
→
Turn the metal ring in such a way that the filter element points
downward after installation of the instrument. This provides better
protection against buildup.
Filter element - Function
Filter element - Position
Filter element - Position
Ex-d version