Siemens Acvatix SAS31.03 - Fail Safe Function

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Siemens Actuators SAS.., SAT.. for valves CE1P4041en
Building Technologies Functions and control 2015-05-19
4.3.3 Fail safe function
The fail safe function works mechanically with a return spring and ensures the
protection of the plant. It guarantees the safe operation in uncontrolled operating
states.
In the event of a power failure, the actuator will return to its 0 % stroke position with
the help of the return spring, closing the valve. The Y positioning signal is not
valued.
Fail safe
function
Actuator Valve
Spring return
time
At positioning
time
Active
Actuator’s stem
retracts
Spring in valve
closes
Valve closes
<8 s
1)
<14 s
1)
<28 s
1)
15 s
30 s
120 s
1)
Spring return time increased slightly at low temperatures