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

C4.FACT3 - Factor 3
Adjustment range:
Purpose:
Factory setting:
8.3.3.4

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

d. STIC - Monitoring of stiction (slipstick)
Condition:
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 PROFIBUS PA
Operating Instructions, 05/2019, A5E00127926-AC
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 '50.XDIAG' Activation of extended diagnostics (Page 160) 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 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-parameters are
displayed. Appropriately set the sub-parameters.
The current value is displayed in Diagnostic value '17.STIC - Stic‐
tion (slipstick)' (Page 264). The positioner triggers a message if the
current value exceeds one of the thresholds.
OFF
Parameter assignment
8.3 Description of parameters
173