Functional safety for SIPART PS2 FF
34 A5E00489774-02, 10/2013
Remedial measures table 4
● In stationary automatic mode
(constant setpoint) and in manual
mode, both piezo valves continually
switch alternately, and the actuator
oscillates around a mean value.
●
Sticking friction of the packing gland
from the control valve or actuator
● Reduce friction or increase dead
zone of positioner (parameter
"dEbA") until the oscillation stops.
● Looseness (play) in the
positioner/actuator/control valve
system
● 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.
● Actuator too fast ● Increase actuating times using
throttle screws.
● If a quick actuating time is needed,
increase the dead zone (parameter
"dEbA") until the oscillation stops.
● Positioner doesn't move control
valve to the stop (at 20 mA).
● Supply pressure too low. Load on
the feeding controller or system
output is too low.
● Increase supply pressure, insert
ballast converter
Remedial measures table 5
Zero point displaces sporadically
Impact or shock loads result in
accelerations so high that the
friction clutch moves, e.g. due to
"vapor shocks" in vapor lines.
Rectify the causes for shock loads.
● Re-initialize the position controller.
● The device function has completely
failed: No representation on the
display either.
● Electrical auxiliary power supply is
● Check the electrical auxiliary power
● In case of very high continuous
loads due to vibrations
(oscillations):
● Screws of the electrical connecting
terminals may be loosened.
● Electrical connecting terminals
and/or electronic components may
● Tighten the screws firmly and
secure using sealing wax.
● Repair
● For prevention: Install the positioner
on the damping pads.
The certificates can be found on the enclosed CD and on the Internet under:
Certificates (http://www.siemens.com/processinstrumentation/certificates)