Siemens SIPART Series Operating Instructions Manual page 231

10.4.5 Remedial measures table 4
Symptoms
In stationary automatic mode
•
(constant setpoint) and in manual
mode, both piezo valves continually
switch alternately, and the actuator
oscillates around a mean value.
Positioner doesn't move control
•
valve to the stop (at 20 mA).
Error table 4
See also
Cleaning of the screens (Page 232)
SIPART PS2 with and without HART
Operating Instructions, 10/2013, A5E00074631-11
Possible cause(s)
Sticking friction 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
output is too low.
Alarm, error, and system messages
10.4 Fault correction
Remedial measures
Reduce friction or increase dead
•
zone of positioner (parameter
"dEbA") until the oscillation stops.
Part-turn actuator: Check for firm
•
seating of set screw on coupling
wheel.
Linear actuator: Check for firm
•
seating of lever on positioner shaft.
Correct any other play between the
•
actuator and the control valve.
Increase actuating times using
•
throttle screws.
If a quick actuating time is needed,
•
increase the dead zone (parameter
"dEbA") until the oscillation stops.
Increase supply pressure, insert
•
ballast converter
Select 3/4-wire mode
•
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