Siemens SIPART PS2 Operating Instructions Manual page 186

Parameter assignment
9.4 Description of parameters
Purpose:
Factory setting:
Note
Incorrect interpretation in case of travel times below one second
If the travel times are less than one second, the positioner does not accurately differentiate
between a normal movement of the actuator and a sudden change. Therefore, increase the
travel time if required.
d1.LIMIT - limit for slipstick detection
Adjustment range:
Purpose:
Factory setting:
d2.FACT1 - Factor 1
Adjustment range:
Purpose:
Factory setting:
186
Use this parameter to continuously monitor the current stiction
(slipstick) of the control valve. If the parameter is activated, the
positioner detects the slipstick that may occur. Sudden changes in
the valve position, so-called slip jumps, indicate excessive stiction.
Where slip jumps are detected, the filtered step height is stored as
a slipstick value. If slip jumps no longer exist, the stiction (slipstick)
is reduced slowly. Monitoring is performed in three steps. To acti-
vate monitoring, set the parameter to 'On'. Sub-parameters are
displayed. Appropriately set the sub-parameters.
The current value is displayed in Diagnostic value '17.STIC - Stic-
tion (slipstick)' (Page 216). The positioner triggers a message if the
current value exceeds one of the thresholds.
OFF
0.1 ... 100.0
Use this sub-parameter to set the base limit for slipstick detection
in percent. Set the base limit in a range from '0.1' to '100.0'.
1.0
0.1 ... 100.0
Use this sub-parameter to set the factor for formation of threshold
1. Set the factor in a range from '0.1' to '100.0'. The threshold is
the product of the values entered for 'd1.LIMIT' and 'd2.FACT1'.
The threshold 1 message is displayed when threshold 1 is ex-
ceeded. The process to activate and display this message is de-
scribed in the 'XDIAG' parameter.
2.0
SIPART PS2 with and without HART
Operating Instructions, 02/2016, A5E00074631-AB