30
EB 8389-1S EN
Valve signature
2. Set the limit for zero monitoring in con-
trol valves with closed position ATC (air
to close).
3.
Select classification for status messages.
See
2.
Device settings > Alarm settings
−
Zero limit (Code 48 - d5):
0.0 to 100.0 %, [5.0 %]
−
Lag time: 1 to 9999 s, [30 s]
3.
Device settings > Alarm settings > Status
classification > Positioner
−
Zero (Code 58): , [ ], ,
Device settings > Alarm settings > Status
classification > Actuator
Defective actuator springs
−
Reduced spring pre-loading: [ ], , ,
4.2.1
Analysis and monitoring
If the monitoring line has a smaller gradient
than the reference line, this pinpoints to a re-
duced compression of the actuator springs.
Diagnostics > Monitoring > Actuator
−
Defective actuator springs: , , ,
Valves with ATC (air to close) closed posi
-
tion
In valves with ATC closed position, the posi-
tioner generates a zero error when the valve
position in the tight-closing position is larger
than the sum of the initialization zero points
and 'Zero limit' or smaller than the negative
'Zero limit' after the adjusted 'Lag time' has
elapsed.
Diagnostics > Monitoring > Positioner
−
Zero (Code 58): , , ,
Fig. 3:
Diagnostics > Monitoring/tests > Valve signature >
Valve signature, signal pressure(x)
