GEM 687 Installation, Operating And Maintenance Instructions page 35

10.2 Control functions
The following control functions are available:
Control function 1
Normally closed (NC):
Valve resting position: closed by
spring force. Activation of the actuator
(connector 2) opens the valve. When the
actuator is vented, the valve is closed by
spring force.
Control function 2
Normally open (NO):
Valve resting position: opened by
spring force. Activation of the actuator
(connector 4) closes the valve. When the
actuator is vented, the valve is opened by
spring force.
Control function 3
Double acting (DA):
Valve resting position: no defined normal
position. The valve is opened and closed
by activating the respective control
medium connectors (connector 2: open /
connector 4: close).
Connector 2
Control function 1
Connector 4
Connector 2
Control function
2 + 3
Control function
1 (NC)
2 (NO)
3 (DA)
+ = available / - = not available
(for connectors 2 / 4 see pictures on the left)
10.3 Connecting the
control medium
Important:
Connect the control medium
lines tension-free and without any
bends or knots! Use appropriate
connectors according to the
application.
Thread size of the control medium
connectors: G1/4
Control function
1 Normally closed (NC)
2 Normally open (NO)
3 Double acting (DA)
For connectors 2 / 4 see pictures on the left
10.4 Optical position indicator
Control function 1: standard
Control functions 2 + 3: optional accessories
Valve open
35 / 48
Connectors
2 4
+ -
- +
+ +
Connectors
2: Control medium (open)
4: Control medium (close)
2: Control medium (open)
4: Control medium (close)
Valve closed
687