The Siemens SSD81U 24V, 3 POS NSR PICV Actuator
Pressure Independent Control Series SSD Electronic Valve Actuators require a 24 Vac power supply and receive a floating control signal (SSD81…) or a proportional 0 to 10 Vdc signal (SSD61…) to control a valve. The 0 to 10V SSD61U actuator also accepts a 24 Vdc power supply
These actuators are designed to work with 1/2- to 1-1/4-inch Pressure Independent Control Series Valves with a 1/10-inch (2.5 mm), 1/5-inch (5 mm), or 7/32-inch (5.5 mm) stroke and a threaded valve bonnet that fits the actuator
A 24 Vac control signal to terminal Y1 extends the actuator shaft proportionately to the length of time the signal is applied.
A 24 Vac control signal to terminal Y2 retracts the actuator shaft proportionately to the length of time the signal is applied.
In the event of a power failure with no control voltage, the non-spring return SSD81U will hold its last position.
The SSD81U floating actuator does not self-calibrate.