Data Sheet for Product

Technical Instructions SKD Electronic Valve Actuator 3-Position (Floating) Control
Document No. 155-181P25
September 25, 2018
Page 6 Siemens Industry, Inc.
Start-Up, Continued
Normally Open Valve
Actuator pressure cylinder moves outward (0 to 1): Valve closes.
Actuator pressure cylinder moves inward (1 to 0): Valve opens.
Three-Way Valve
Actuator pressure cylinder moves outward (0 to 1): Valve opens between ports NC
and C.
Actuator pressure cylinder moves inward (1 to 0): Valve opens between ports
NO and C.
Manual Operation
Figure 10. The Manual Setting Knob in Manual and Automatic Position.
Turn the manual setting knob clockwise for manual override. As you begin to turn, a red
indicator becomes visible. Each complete revolution (360°) is equal to 3/32-inch
(2.5 mm) stroke.
If a signal is sent to the actuator while it is in manual operation, the actuator will move
but the control will not be accurate. The valve cannot be commanded to its 0% position
while in manual operation.
Automatic Operation
For automatic operation the manual setting knob must be in the fully-closed position.
Turn the manual setting knob counterclockwise until the red indicator disappears.
Wiring
Do not use auto transformers. Use earth ground isolating step-down Class 2
transformers.
Determine supply transformer rating by summing total VA of all actuators used. The
maximum rating for a Class 2 step-down transformer is 100 VA.
Actuator
Power
Consumption
Actuators per
Class 2 Supply Circuit*
(80% of Transformer VA)
SKD82.50U
10 VA
8
SKD82.51U
15 VA
5
* Operating more actuators requires additional transformers
or separate 100 VA power supplies.