Siemens SIPART PS2 Series Operating Instructions Manual page 236

Diagnostics and troubleshooting
11.4 Fault and remedy
Fault profile (symptoms)
The pneumatic block does not switch. A
gentle click sound is also not audible
when the or buttons are pressed
in manual mode.
Actuator does not move.
Pneumatic block does not switch (how‐
ever, a gentle clicking sound can be
heard when the or
ed in "Manual" mode.)
A pneumatic block continually switches
in stationary automatic mode (constant
setpoint) and in "Manual" mode.
In stationary automatic mode (constant
setpoint) and in "Manual" mode, the
pneumatic block continually switches
and the actuator oscillates around a
mean value.
Positioner does not move control valve
to the endstop (at 20 mA).
236
Possible cause(s)
● The screw between the cover and
the pneumatic block has not been
tightened firmly or the cover is jam‐
med.
● Dirt (swarf, particles) in the pneumat‐
ic block
● Deposits on the contacts between
the electronic printed circuit board
and the pneumatic block can devel‐
op due to abrasion owing to continu‐
ous loads resulting from strong vi‐
brations.
● Compressed air < 1.4 bar
● Restrictor valve turned off (screw at
the right endstop)
button is press‐
● Dirt in the pneumatic block
● Pneumatic leakage in the positioner
- actuator system; start the leakage
test in "RUN 3" (initialization).
● Dirt in the pneumatic block
● Stiction of the packing gland from
the control valve or actuator too large
● Looseness (play) in the positioner/
actuator/control valve system
● Actuator too fast
● Supply pressure too low. Load on
the feeding controller or system out‐
put is too low.
Remedy
● Tighten the screw firmly; if required,
rectify the deadlock.
● Repair or a new device; built-in fine
screen, can also be replaced and
cleaned.
● Clean all contact surfaces with spirit;
bend the pneumatic block contact
springs slightly if required.
● Set supply pressure PZ to > 1.4 bar.
● Open the restrictor screw by turning
it to the left.
● Repair or a new device; built-in fine
screen, can also be replaced and
cleaned.
● Rectify leakage in the actuator
and/or feed line.
● In case of an intact actuator and tight
feed line: Repair or new device
● Repair or a new device; built-in fine
screen, can also be replaced and
cleaned.
● Reduce stiction or increase dead‐
band of positioner (parameter "dE‐
bA") until the oscillation stops.
● Part-turn actuator: Check for firm
seating of set screw on coupling
wheel.
● Linear actuator: Check for firm seat‐
ing of lever on positioner shaft.
● Correct any other play between the
actuator and the control valve.
● Increase travel times using restrictor
screws.
● If a quick travel time is needed, in‐
crease the deadband (parameter
"dEbA") until the oscillation stops.
● Increase supply pressure, insert bal‐
last converter
● Select 3/4-wire mode.
SIPART PS2 with 4 to 20 mA/HART
Operating Instructions, 11/2019, A5E00074631-AE