EB 8389-1S EN
57
Leakage sensor
9.1.2
Process reference
The process reference test (Fig. 11) measures
the response of the leakage sensor to pro-
cess conditions. Process medium, inlet and
outlet pressures as well as the process envi-
ronment can have an effect on the sensor's
response. The alarm limits are determined
from the measured data.
The process reference test is performed and
analyzed in the same manner as the manu-
facturer reference test described in
9.1.1. This test must be performed after the
valve has been installed and the plant has
been commissioned.
If it is not possible to perform the process ref-
erence test, the user-defined alarm limits can
be entered. See
While the process reference test is running,
the parameters listed below are automatical-
ly deactivated:
−
Activate CLOSED end position
−
Activate ramp function
Phase 1:
The valve moves to eleven defined
set points one after the other. After reaching
a set point and after the 'Settling time before
sound level measurement' has elapsed, the
leakage sensor measures the sound pressure
level.
If the difference between two neighboring set
points is larger or equal to the adjusted 'Sen
-
sitivity sound level', the valve does not move
to the next set points. Instead, Phase 2 starts.
Alarm limit 3
Alarm limit 1
Alarm limit 2
Fig. 11:
Start-up > Reference graphs > Leakage sensor >
Process reference