EB 8389-1S EN
41
Valve position x histogram
6
Valve position x histogram
The valve position histogram is a statistical
analysis of the plotted valve positions. The
histogram provides information about where
the valve mainly spends the majority of its
time during its service life and whether it
shows a recent trend concerning changes in
its operating range.
Data are recorded automatically 15 minutes
after initialization (regardless of the operat-
ing mode selected). Data logging does not
need to be activated.
The positioner records the valve position ev-
ery second and assigns the data into pre-
defined valve position classes. The distribu
-
tion showing how often the sound level oc-
curred within a valve position class is shown
in a bar graph.
−
'Mean value': Average class assignment
of valve positions throughout 'Monitoring
duration'.
−
'Number of measurement points': Total
number of values recorded during the
'Monitoring duration'.
−
'Monitoring duration'
The measured data are saved every 24
hours in the positioner.
Short-term monitoring
In order to be able to recognize any short-
term changes in valve position, the position-
er records the valve positions according to
the adjusted 'Sampling time' and analyses
the last 100 measured values.
−
'Mean time': Contains the average class
assignment of valve positions for the last
100 measured values.
−
'Adjusted monitoring duration': 100 x
'Sampling time'
The positioner saves the valve positions in a
circular buffer, which holds 100 measured
values at one time.
Fig. 7:
Diagnostics > Monitoring/tests > Histograms >
Valve position x histogram
