HygroMatik DDS20, Manual

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Page 13
7.2 Actuator
The actu ator contro ls the va lve cone position ing against the
valve face. Through continuous actuation a spe cific control sig-
nal can be assigned to every position of the valve cone.
To prevent air-duct over-saturation all actuators, even pneumati-
cally opera ted ones, sho uld be equip ped with a fail-safe. This
fail-safe closes th e contro l valve immedia tely in the case of
power failure or pressure loss.
Electrical Actuator
The spinde and valve co ne are set in motion by the ele ctrical
actuator by means of a motor.
Electrical Actuators typically requ ire a 24 V AC su pply voltage
and a control signal of 0-10 V.
Actuators with a 3 position control for modulated control voltages
are also available.
In order to comply with DIN 32 730* an electrical actuator must
have a fail-safe function so that in the case of a power failure the
control valve is reset into a safe position (fully closed).
Pneumatic Actuator
Pneumatic Actuators are controlled using compressed air (e.g.
0,2-1bar).
Compressed air is su pplied over a compressed air supply (3)
to a diaphragm (2) . As soo n as th e supply pressure e xceeds
the spring (1) strength the d iaphram is p ushed upwards. T his
pulls the two a ctuator spindles (4) and control valve (5)
upwards and the actuator opens.
If control pressure drops the spring lowers the spindle again. In
the case of a total pressure loss the spring immediately causes
the control valve to close.
Control valve signal options
pneumatic 0,2 - 1,0 bar
electrical
3-Position 24V AC
(230V on request)
electrical
0 (2) - 10 V, continuous
Supply voltage 24V AC
electrical
0 (4) - 20 mA, continuous
Supply voltage 24V AC
The 500Ohm (or 2x1KOhm parallel) resisi-
tor is connected to over connectors 1 and 3.
The resistor is attached under the cover.
Type Hygromatik E-4111680
Type Spirax Sarco PN9000