Siemens SIPART PS2 6DR50xx Manual page 24

Design and Functional Principle
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Figure 2-9 Method of operation five-point switch
24
Figure 2-10, page 25 shows the block diagrams for single- and double-
acting actuators with the linear actuator as an example.
NOTE
The exhaust air valve is always open when there is no current.
SIPART PS2 Manual
A5E00074631--06