Detection Of Foreign Bodies; Calibration - Siemens Acvatix SAS Series Basic Documentation

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50%. The error message disappears as soon as the actuator moves. The actuator
moves 35% in the direction of "Retract actuator stem" and reaches the valve seat.
The internal stroke position is set to 0%.
The actuator now follows the changed valve stroke position effective immediately.
4.3.2

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
As "Upper limit of valve clogging", if the clogging was detected
when traveling in the direction of "Actuator's stem extending".
Now, the status LED blinks red and the actuator only follows the positioning signal
between the positions "Actuator's stem retracted" and "High 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 LED continues to
blink red (see "Indicators", page 43).
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).
4.3.3

Calibration

To match the actuator to production-related mechanical tolerances of the individual
valves and to guarantee accurate positioning and position feedback, a calibration
should be performed when the plant is commissioned (page 21). During
commissioning, the actuator detects the valve's end positions and files the exact
stroke in its internal memory.
Calibration takes place in the following phases:
· Actuator drives to the upper end position (1),
valve closes. Detection of upper end position.
· Actuator drives to the lower end position (2),
valve opens. Detection of lower end position.
· The detected values are stored (3). Then the
actuator follows the positioning signal.
The internal position feedback is set to 0% during calibration. For a setpoint > 0%,
the actuator detects calibration based on the deviation between setpoint and stroke
position and reports this in Register 769 with the warning "Mechanical error, device
blocked, manual intervention or calibration". The LED on the actuator cover blinks
green, the LED on the cable adapter is red.
Actuators SAS.., SAT.. for valves
Functions and control
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CE1P4041en
2019-04-09