EB 8389-1S EN 45
Set point deviation e histogram
Note:
Changing 'Sampling time' causes all
existing measured values to be delet-
ed from the circular buffer.
Dening parameters
1. Set the 'Sampling time' for the short-term
monitoring.
2. Select classication for status messages.
See u Section 7.1.
1.
Diagnostics > Monitoring/tests > Histograms
> Set point deviation e histogram > Short-
term monitoring
− Sampling time: Adjustable as required,
[00:14:24 d.h:min:s]
2.
Device settings > Alarm settings > Status
classication > Valve
Seat leakage
− May exist: [
], , ,
Device settings > Alarm settings > Status
classication > Valve position
Manipulated variable range limitation
− Lower: [
], , ,
− Upper: [ ], , ,
− No change possible: [ ], , ,
Positioner-valve linkage
− Travel transmission not optimal:
[ ], , ,
7.1 Analysis and monitoring
Ideally, the set point deviation should be
nearly 0%.
Set point deviations greater than 1% follow-
ing in quick succession pinpoint to a limita-
tion of the upper operating range. In this
case, the positioner generates the 'Manipu-
lated variable range limitation' and 'Posi-
tioner-valve linkage' messages with the se-
lected status classications.
Set point deviations smaller than 1% follow-
ing in quick succession pinpoint to a limita-
tion of the lower operating range or to seat
leakage. The positioner generates the 'Ma-
nipulated variable range limitation', 'Posi-
tioner-valve linkage' and 'Seat leakage'
messages with the selected status classica-
tions.
If almost all set point deviations during the
short-term monitoring are greater than 1%
or smaller than –1%, this may indicated that
the actuator or valve stem is jammed. The
positioner generates the 'Manipulated vari-
able range limitation' and 'Positioner-valve
linkage' messages with the selected status
classications.
Diagnostics > Monitoring > Valve
− Seat leakage:
, , ,
Diagnostics > Monitoring > Valve position
− Manipulated variable range limitation:
,
, ,
− Positioner-valve linkage: , , ,