The
Dynamic stress factor
parameter is spec-
ified as a percentage reflecting the stress of
the packing. An alarm is issued if the dy-
namic stress factor exceeds 90 %.
The
Dynamic stress factor
is determined from
the cycle span and how often the cycle spans
occurred (frequency) depending on which
packing has been selected (see section 1.4)
self-adjusting, adjustable or bellows seal.
To ensure this factor is correctly determined,
make sure the correct packing is selected in
the
Stuffing box
parameter in the
Identifica-
tion
folder (>
Positioner
>
Valve
).
The cycle counter records the number of cy-
cles and the cycle spans which are assigned
to cycle classes.
The calculated percentages on how often a
cycle occurs within a class are shown as a
bar graph.
The
Cycle counter histogram
folder contains
long-term data, i.e. measured data points
are updated cyclically over the entire
positioner service life and stored every 24
hours in the positioner’s non-volatile mem-
ory for long-term monitoring.
The
Average value z long
parameter con-
tains the cycle class in which the average
cycle spans were found.
The
Counter of all measured values
parame-
ter contains the total of classified measured
data points previously recorded.
In order to obtain a summary of recent cy-
cles, the last 100 cycles measured are
stored in an FIFO memory.
The
Short
folder contains this additional cy-
cle counter histogram.
The
Average value z short
parameter con-
tains the average cycle class for the last 100
measured data points stored in the FIFO
memory.
Data can be reset in the
Status messages
folder.
14
EB 8388 EN
Statistical information AUTO
Fig. 6 · Cycle counter histogram
