VEGA VEGABAR 81 4 … 20 mA - Operating Instructions - Manual (Page 15)

15
4 Mounting
VEGABAR 81 • 4 … 20 mA
45025-EN-131010
•
Ventilation electronics housing
•
Atmospheric pressure compensation (with relative pressure meas-
uring ranges)
The process assembly of instruments with Second Line of Defense
(gastight leadthrough) is completely encapsulated. An absolute pres-
sure measuring cell is used so that no ventilation is required.
1
1
Fig. 7: Position of the filter element - gastight leadthrough
1 Filter element
With relative pressure measuring ranges, the ambient pressure is
detected and compensated by a reference sensor in the electronics.
The filter element is mounted into the electronics housing. It has the
following functions:
•
Ventilation electronics housing
•
Atmospheric pressure compensation (with relative pressure meas-
uring ranges)
1
Fig. 8: Position of the filter element - IP 69K version
1 Filter element
Instruments with absolute pressure have a blind plug mounted
instead of the filter element.
4.3 Process pressure measurement
Keep the following in mind when setting up the measuring system:
•
Mount the instrument above the measuring point
Possible condensation can then drain off into the process line.
Instruments in IP 69K
version
Measurement setup in
gases