Basic Documentation

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Siemens Actuators SAX.., SAY.., SAV.., SAL.. for valves CE1P4040en
Smart Infrastructure Functions and control 2020-01-30
After a power failure, valve seat identification is not active – the actuators without
fail safe function define their stroke position upon return of power at 50% and
automatically set their internal setpoint in register 1 to the startup setpoint (register
516). The actuator closes at this setting. There is a short-term deviation between
the setpoint and the internal stroke position.
When the valve plug reaches each seat for the first time, the actuator readjusts its
stroke mode.
Setpoint prior to power outage 35%, no manual adjustment during the power
outage. Internal stroke position value after return of power 50%. Internal setpoint
after return of power equal to startup setpoint (register 516, here 0%). The actuator
moves 35% in the direction of "Retract actuator stem" and reaches the valve seat
(if the setpoint has not been changed in the meantime). The internal stroke position
is set to 0%.
The actuator now follows the changed valve stroke position effective immediately.
4.13.2 Detection of foreign bodies
The actuator detects when the valve is clogged and adjusts its operational
behavior accordingly to prevent damage to itself or the valve.
If the actuator hits an obstacle within the calibrated stroke and is not able to
overcome it with its nominal positioning force, it stores the position at which the
obstacle was hit. Depending on the direction of travel, as …
· "Lower limit of valve clogging", if the clogging was detected when
traveling in the direction of "Actuator’s stem retracting".
· "Upper limit of valve clogging", if the clogging was detected when
traveling in the direction of "Actuator’s stem extending".
Now, the actuator status LED blinks green and the actuator only follows the
positioning signal between the positions "Actuator’s stem retracted" and "Upper
limit of valve clogging" or "Actuator’s stem extended" and "Lower limit of valve
clogging".
After detection of clogging, 3 attempts are made to overcome clogging by traveling
about 15% in the opposite direction and then trying again to overcome the position
of clogging. If the attempts made are unsuccessful, the actuator continues to follow
the positioning signal within the restricted range only and the actuator LED
continues to blink green (refer to "Indicators" on page 70).
As long as the external setpoint is greater than the position of the high limit valve
clogging, the deviation between the setpoint and position feedback in register 769
is displayed with the warning “Mechanical error, device blocked, manual
intervention or calibration.” The LED on the cable adapter is red. The warning is
reset if the external setpoint drops below the high limit valve clogging, since the
setpoint and stroke position are once again the same. The LED on the cable
adapter switches to green blinking (=communication).
4.13.3 Calibration
To match the actuator to production-related mechanical tolerances of the individual
valves, accurate positioning and position feedback must be ensured, if calibration
is performed when the plant is commissioned (page 43). During commissioning,
the actuator detects the valve’s end positions and files the exact stroke in its
internal memory.
Example