EB 8389 EN
41
Statistical information
Short-term monitoring
In order to be able to recognize any short-
term changes in set point deviation, the posi-
tioner records the set point deviation accord-
ing to the adjusted 'Scan rate short-term his-
togram' and analyses the last 100 measured
values.
−
The 'Average value e short' contains the
average class assignment for the last
100 measured values.
The positioner saves the set point deviations
in a circular buffer, which holds 100 mea-
sured values at one time.
On changing scan rate in 'Scan rate short-
term histogram', all existing measured values
are deleted from the circular buffer.
Defining parameters
1. Set 'Scan rate short-term histogram'.
2.
Select classification for status messages.
1.
Diagnosis > Statistical information > Set
point deviation histogram e > Short-term
−
Scan rate short-term histogram:
1 to 3600 s, [1 s]
1)
Types 3730-2/-3/-4/-5 (1.5x) and Type 3731-3:
2.
Settings > Positioner > Error control >
Classification report > Extended > ...
Limit working range
−
Down: [ ], , , ( ), ( )
−
Up: [ ], , , ( ), ( )
−
Modification impossible (jammed):
[ ], , , ( ), ( )
Connection positioner - valve
−
No optimum travel transmission (TEST):
[ ], , , ( ), ( )
−
Perhaps loose/(TEST): [ ], , , ( ), ( )
−
Perhaps range limit:
[ ], , , ( ), ( )
Inner (seat) leakage
−
Perhaps existing:
[ ], , , ( ), ( )
Type 3730-5 (1.6x) and Type 3731-5:
2.
Settings > Positioner > Diagnosis
configuration > Classification
−
Limit working range:
[ ], , , ,
−
Connection positioner - valve:
[ ], , , ,
−
Inner (seat) leakage: [ ], , , ,
1)
Type 3730-4: [864 s]
4.4.1 Analysis and monitoring
Analysis of the histogram starts one hour
after the observation period begins.
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 'Limit
working range' message with the selected
status classification.
Set point deviations smaller than 1 % follow
-
ing in quick succession pinpoint to a limita-
tion of the lower working range or to seat
leakage. In this case, the positioner gener-
ates the 'Limit working range' and 'Inner
Note
Summary of Contents for TROVIS 3730-3
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