Siemens SIPART PS2 Betriebsanleitung Seite 61

Fault description (symptoms)
The two piezo valve constantly
•
switch alternately in stationary au-
tomatic mode (constant setpoint),
actuator oscillates around a
middle point
Table 4
Fault description (symptoms)
Zero point shifts sporadically
•
(> 3 %)
Device function breaks down Device function breaks down
•
totally: no display
Table 5
SIPART PS2 EEx d FF
A5E00351419--01
Possible cause(s)
Static friction on the packing glands
•
of the fittings or actuator too high
Play in the positioner, actuator,
•
fittings system
Actuator too fast
•
Possible cause(s)
Such high accelerations have oc-
•
curred through impact or shock that
the friction clutch has shifted (e.g.
through steam jets in the steam pipe-
lines)
Insufficient electrical supply
•
With very high continuous stresses by
vibrations, the following can occur:
Screws of the electrical terminals can
•
loosen
The electrical terminals and/or elec-
•
tronic modules can be shaken loose
Operating instruction
Corrective actions
Reduce static friction or increase
•
dead zone of SIPART PS2
(parameter dEbA) until the
oscillating movements stop.
Part-turn actuator:
•
Check seating of the lever on the
positioner shaft
Linear actuator:
•
Check seating of the stub screw of
the coupling wheel
Correct any other play between the
•
actuator and fittings
Increase positioning times by
•
means of restrictor screws
If fast positioning times are
•
required, increase dead zone
(parameter dEbA) until the
oscillating movements stop.
Corrective actions
Shut off the cause of the shocks
•
Reinitialize the positioner
•
Check electrical supply
•
Tighten screws and secure with seal-
•
ing varnish
Repair, see page 60
•
Prevention: Mount the SIPART PS2
•
on rubber metal
59