Data Sheet for Product

Pressure Independent Control Technical Instructions
SQD Series Electromotoric Actuators Document Number 155-777
December 22, 2011
Siemens Industry, Inc. Page 3
Operation
SQD85.03U
3-position control signal
Voltage at Y1: Stem extends, valve opens
Voltage at Y2: Stem retracts, valve closes
No voltage at Y1 or Y2: Actuator holds the current position
SQD65U
0 to 10 Vdc or 0 to 1000
Ω control signal
• The valve opens/closes in proportion to the control signal at Y or R.
• At 0 Vdc or 0 Ω the valve is closed (A Æ AB).
• When the power supply is removed, the actuator maintains its current position.
Engineering Notes
The actuators must be electrically connected in accordance with local regulations and the
connection diagrams.
CAUTION:
Safety regulations and restrictions designed to ensure the safety of people and
property must be observed at all times.
For admissible temperatures, see Specifications.
Commissioning
Notes
When commissioning the system, check wiring and the functions.
Manual override
Switch off the positioning signal.
The valve can be fully closed (= 0% stroke) by turning the manual adjuster
counterclockwise. Control is automatically resumed when the positioning signal returns.
Three-position control
Every actuator must be driven by a dedicated controller. (See Wiring Diagrams.)
Troubleshooting
Check Wiring for proper connections.
If the actuator does not provide full flow or full close-off, check that the actuator is
properly attached to the valve.
If not:
1. Turn the power off.
2. Turn the override knob to manually retract the output shaft to the zero position.
3. Tighten the bonnet ring onto the valve completely.
4. Power up.
The actuator must be correctly installed on the valve before commissioning.
Repair
The actuator cannot be repaired. It has to be replaced as a complete unit.