how often the valve travel remains within a
class is shown in per cent. The result is pre-
sented as a bar graph.
The
Travel histogram
folder contains
long-term data, i.e. measured data are up-
dated cyclically (scan rate 1 s) over the en-
tire positioner service life and stored every
24 hours in the positioner’s non-volatile
memory for long-term monitoring.
The
Number of measurement values
param-
eter shows the total amount of classified
measured data points previously recorded.
The
Average value x long
parameter con-
tains the class in which the travel remained
on average the most.
In order to be able to recognize any
short-term changes in valve travel properly,
the last 100 measured data points are
stored at a scan rate (default: 1 s) in a
non-volatile memory. The scan rate can be
changed in the
Scan rate short time
param-
eter. On changing the scan rate, old data in
the short-term histogram are deleted.
The
Average values x short
parameter con-
tains the average class assignment for the
last 100 measured data points stored in the
non-volatile memory.
Data can be reset in the
Status messages
folder.
2.3
Setpoint deviation histogram
The setpoint deviation histogram contains a
statistical analysis of any setpoint deviations
recorded. This provides a summary of how
often and to which level a setpoint deviation
has occurred during the positioner service
life and whether it shows a recent trend con-
cerning the setpoint deviation.
The setpoint deviation is recorded and as-
signed to predetermined level classes. The
percentages showing how often the setpoint
deviation remains within a class is presented
12
EB 8388 EN
Statistical information AUTO
Fig. 4 · Travel histogram