Monitoring The Number Of Total Strokes; Monitoring The Number Of Changes In Direction; Monitoring The Lower Endstop / 7 Monitoring The Upper Endstop; Monitoring Deadband - Siemens SIPART PS2 Operating Instructions Manual

10.3.4.4

4 Monitoring the number of total strokes

The diagnostics value "1 STRKS" is constantly compared with the thresholds that are
determined from the "L1.LIMIT" to "L4.FACT3" parameters. If the thresholds are exceeded,
the fault message output or the alarm outputs respond depending on the mode of the
extended diagnostics. These two functions can be deactivated using the parameter setting
"OFF" for "L. STRK".
10.3.4.5

5 Monitoring the number of changes in direction

The diagnostics value "2 CHDIR" is constantly compared with the thresholds that are
determined from the "O1.LIMIT" to "O4.FACT3" parameters. If the thresholds are exceeded,
the fault message output or the alarm outputs respond depending on the mode of the
extended diagnostics. These two functions can be deactivated using the parameter setting
"OFF" for "O. DCHG".
10.3.4.6

6 Monitoring the lower endstop / 7 Monitoring the upper endstop

If the parameter "F. ZERO" is set to "ON", monitoring of the lower endstop is activated. This
function can be used to detect the errors in the valve seat. An overshot limit indicates the
possibility of deposits or foreign bodies in the valve seat. An undershot limit indicates
probable wear and tear of the valve seat or flow restrictor. Even a mechanical misalignment
of the position feedback can trigger this fault message.
Monitoring is always carried out whenever the valve is in the "down tight closing" position.
The current position is compared with the position that was determined as the lower endstop
at the time of initialization. The activation of "down tight closing" ("YCLS" parameter) is
therefore the condition.
Example: A value of 3% is set. The position is normally adopted for "down tight closing". A
fault is reported if a value > 3% or < -3% is determined instead.
The fault message remains activated until either a 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 end stops 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. The activation of "up tight closing" ("YCLS" parameter) is therefore the
condition.
10.3.4.7

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.
SIPART PS2 with and without HART
Operating Instructions, 02/2016, A5E00074631-AB
Alarm, error, and system messages
10.3 Online diagnostics
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