Endress+Hauser Cerabar M PMC51 Operating Instructions Manual page 13

Cerabar M Analog
Endress+Hauser
Vacuum application
For applications under vacuum, Endress+Hauser recommends mounting the pressure transmitter
below the diaphragm seal. This prevents vacuum loading of the diaphragm seal caused by the
presence of filling oil in the capillaries.
When the pressure transmitter is mounted above the diaphragm seal, the maximum height
difference H1 in accordance with the illustration below left must not be exceeded. The maximum
height difference depends on the density of the filling oil and the smallest ever pressure that is
permitted to occur at the diaphragm seal (empty container), see illustration below right.
P01-PMx5xxxx-11-xx-xx-xx-006
Fig. 8: Installation above the diaphragm
seal
Mounting with temperature isolator
Endress+Hauser recommends the use of temperature isolators in the event of constant extreme
medium temperatures which lead to the maximum permissible electronics temperature of +85°C
(+185°F) being exceeded. To minimize the influence of rising heat, Endress+Hauser recommends
the device be mounted horizontally or with the housing pointing downwards.
The additional installation height also brings about a zero point shift of approx. 21 mbar (0.315 psi)
due to the hydrostatic column in the temperature isolator. You can correct this zero point shift.
 ä 25 "Function of the operating elements".
12.0
10.0
8.0
6.0
H1
4.0
2.0
0.0
50 100 200 300
Fig. 9: Diagram of maximum installation height above the
diaphragm seal for vacuum applications, depending on
the pressure at the diaphragm seal
max. 115
Installation
Low temperature oil
Vegetable oil
Silicone oil
High temperature
oil
Inert oil
400 500 600 700 800 900 1000
Pressure at diaphragm seal [mbar abs ]
P01-PMP75xxx-05-xx-xx-en-011
P01-PMx5xxxx-11-xx-xx-xx-008
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