Monitoring Of Stiction (Slipstick) 'D.\\Stic - Siemens SIPART PS2 Series Operating Instructions Manual

C4.FACT3 - Factor 3
Adjustment range:
Purpose:
Factory setting:
See also
11 Monitoring/compensation of pneumatic leakage (Page 234)
8.4.3.4

Monitoring of stiction (slipstick) 'd.\\STIC'

d. STIC - Monitoring of stiction (slipstick)
Requirement:
Possible settings:
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.
SIPART PS2 with 4 to 20 mA/HART
Operating Instructions, 11/2019, A5E00074631-AE
0.1 ... 100.0
Use this sub-parameter to set the factor for formation of threshold 3.
Set the factor in a range from '0.1' to '100.0'. The threshold is the
product of 'C1.LIMIT' and 'C4.FACT3'.
A leakage was detected when threshold 3 is exceeded. The control
quality is strongly affected. Maintenance is necessary. The thresh‐
old 3 message is shown.
The process to activate and display this message is described in the
'XDIAG' parameter.
2.0
The '52.XDIAG' Activating for extended diagnostics (Page 162) pa‐
rameter is set to 'On1', 'On2' or 'On3'.
● OFF
● On
Use this parameter to continuously monitor the current stiction (slip‐
stick effect) of the control valve. If the parameter is activated, the
positioner detects the slipstick that can occur. Sudden changes in
the process 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 effect) is reduced slowly. Monitoring is performed in three
steps. To activate monitoring, set the parameter to 'On'. Sub-pa‐
rameters are displayed. Appropriately set the sub-parameters.
The current value is displayed in Diagnostic value '17.STIC - Stic‐
tion (slipstick)' (Page 220). The positioner triggers a message if the
current value exceeds one of the thresholds.
OFF
Parameter assignment
8.4 Description of parameters
173