Monitoring Deadband; Partial Stroke Test; Monitoring Of Dynamic Control Valve Behavior - Siemens SIPART PS2 Series Operating Instructions Manual

Monitoring is always carried out whenever the process valve is in the "tight closing/fast closing
Down" position. The current position is compared with the position that was determined as the
lower endstop at the time of initialization. Requirement: '39.YCLS' Tight closing/fast closing
with manipulated variable (Page 153) parameter is set to one of the following values: 'do',
'uP do', 'Fd', 'Fu Fd'.
Example: A value of 3% is set. The position is normally adopted for "tight closing/fast closing
Down". A fault is reported if a value > 3% or < -3% is determined instead.
The fault message remains activated until either subsequent monitoring remains within the
tolerance or a re-initialization process is executed. Even the deactivation of monitoring ("F.
ZERO"=OFF) may trigger an error message.
This monitoring function does not deliver any utilizable results if the endstops were not
determined automatically at the time of initialization, but the limits were set manually (manual
initialization, "5.INITM").
Similar diagnostics is carried out for the upper endstop. The "G. OPEN" parameter is used to
set the limit for this. Requirement: '39.YCLS' Tight closing/fast closing with manipulated
variable (Page 153) parameter is set to one of the following values: 'uP', 'uP do', 'Fu', 'Fu Fd',
'uP Fd', 'Fu do'.
11.3.4.7

8 Monitoring deadband

If the deadband increases disproportionately when adjusting it automatically ("DEBA"=Auto
parameter), it indicates an error in the system (e.g. severely increased packing gland friction,
play in the position displacement sensor, leakage). A limit can therefore be entered for this
value ("E1.LEVL3", threshold for deadband monitoring). An error message output is activated
when this value is exceeded.
11.3.4.8

9 Partial stroke test

On the one hand, this fault message appears when a manual or cyclic partial stroke test is
initiated and the test cannot be started since the process valve is not within the starting
tolerance. On the other hand, the fault message appears when one of the three thresholds of
the partial stroke test that are determined from the 'A9.PSTIN' reference stroke time multiplied
by factors 'AA.FACT1', 'Ab.FACT2' and 'AC.FACT3' is violated. The severity of the fault
message is shown by the number of bars on the display. The severity of the fault message is
simultaneously displayed using the fault message output or digital outputs A1 and A2
depending on the mode of extended diagnostics.
11.3.4.9

10 Monitoring of dynamic control valve behavior

The monitoring of the operational behavior responds when the actual process valve position
shifts from a narrow corridor between the setpoint and the expected position course. In this
case, the deviation between the expected and actual position course is output filtered. The
deviation is compared with the configured thresholds that are determined from the "b2.LIMIT"
limit multiplied by the factors "b3.FACT1" to "b5.FACT3".
SIPART PS2 with 4 to 20 mA/HART
Operating Instructions, 11/2019, A5E00074631-AE
Diagnostics and troubleshooting
11.3 Online diagnostics
233