Samson 4740, Mounting And Operating Instructions

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EB 8357 EN 7
Design and principle of operation
3 Design and principle of oper-
ation
The Type 4740 Limit Switch can be mounted
onto the following devices:
−
Type 3353 Angle Seat Valve (see Fig. 1)
−
Type 3354 Globe Valve
− Type 3379 Pneumatic Actuator
The inductive proximity switches or micros -
witches cause signals to be sent to a control
or alarm system when the travel exceeds or
falls below the adjusted limit.
The limit switch can optionally be fitted with
a 3/2-way solenoid valve. When the inte
-
grated solenoid valve is energized, supply
air is applied to the actuator. When the so-
lenoid valve is de-energized, the actuator is
vented and the control valve moves to its fail-
safe position.
The switching points of the limit contacts can
be changed within the travel range after in -
stallation. See section 5.1 on page 20.
3.1 Versions
Two versions of the Type 4740 Limit Switch
are available:
− With inductive proximity switches
− With microswitches
Fig. 1: Type 4740 Limit Switch with optional
solenoid valve on a Type 3353 Angle
Seat Valve