Samson 3730-3 Operating Instructions Manual page 100

Leakage sensor
7.1.2.1 Analysis
While the repetition test is running, the posi-
tioner determines three alarm limits from
which alarm limits 2 and 3 can be used for
the alarm setting. The relation between Valve
position x [%] and Sound level [dB] is shown
in TROVIS-VIEW:
− Relation 1: Valve position and sound
level at 0 % position
− Relation 2: Valve position and sound
level at the point where the curve in the
'Leakage detection repetition' graph
starts to rise monotonously
− Relation 3: Valve position and sound
level at the last measurement
x [%]
1
0
Fig. 18: Tight-closing process and calculated mean values for analysis of the repetition test
100
2 3
7.1.2.2 Alarm settings
After connecting the leakage sensor and
performing the reference and repetition tests,
the positioner is able to pinpoint any seat
leakage. To do this, it records the sound level
in closed-loop operation while the valve is
tightly shut. The seat leakage monitoring is
performed automatically while the process is
running.
The alarm limits detected in the reference
test, repetition test or user-defined settings
can be selected. When user-defined limits
are entered, the alarm limits must rise contin-
uously from 'Alarm limit 1' to 'Alarm limit 3'.
During closed-loop operation, the mean
sound levels while the valve is tightly shut are
4 ... 29 30
[dB]
G H
D
F
A B
E
C
31
t [s]
I
EB 8389 EN
t [s]