ABB i-bus
®
KNX
Planning and application
© 2008 ABB STOTZ-KONTAKT GmbH
250
4.6
Valve drives, valves
and controller
4.6.1
Electromotor
valve drives
Electromotor valve drives open and close valves via a small electric motor.
Electromotor valve drives are offered as proportional or as 2 or 3 way valve
drives.
Proportional valve drives are controlled via an analogue signal, e.g. 0-10 V.
They can not be controlled with the Room Master.
2 or 3 point valve drives are controlled via switching of the supply voltage.
2-point valve drives are controlled via the commands OPEN and CLOSE.
The valve can be completely open or completely closed.
2-point valve drives can not be controlled with the Room Master.
The Room Master supports the control of electric motor 3 point valve drives.
These are connected via three connection cables to the Room Master:
Neutral conductor, switched phase to OPEN,
switched phase for CLOSE. Using 3 point control valve drives, the valve can
be opened by any desired percentage and the position can be retained over
an extended period. If the valve does not move, no voltage is applied to the
motor.
The valve is opened wide enough to allow the exact quantity of hot or cold
water to flow that is required to bring the heat exchanger to the required
temperature. Thus the valve is controlled via the valve
opening (0…100 %).
4.6.2
Electro-thermal
valve drives
Electro-thermal drives are adjusted due to heat expansion of a material
caused by a flow of electric current. Electro-thermal valve drives are
controlled by pulse width modulation.
The Room Master supports the control of electro-thermal valve drives via
pulse width modulation.
Electro-thermal valve drives are offered in the
de-energised closed
and
de-
energized opened
variants. Depending on the variant, the valve is opened
when voltage is applied and closed when no voltage is applied, or vice
versa.
Electro-thermal valve drives connected via two connection cables to the
Room Master.