Siemens SIPART Series Operating Instructions Manual page 20

Connecting
4.4 Pneumatic connection
The difference between a failure of auxiliary pneumatic power and a failure of electrical auxiliary
power:
● Failure of electrical auxiliary power means the failure of the signal source at the analog
input 4 to 20 mA.
● Failure of auxiliary pneumatic power means the supply air PZ is interrupted.
Actuator type
Single-acting
Double-acting
20
Response to failure of auxiliary power: The actuator moves into safety position
Failure of electrical auxiliary power
Y1 = vented
Y1 = pressurized
Y2 = vented
Failure of pneumatic auxiliary power
Y1 = vented
Y1 = closed
Y2 = closed
Operating Instructions, 10/2018, A5E45863537.-AA
SIPART PS100