ABB i-bus
®
KNX
Planning and application
© 2008 ABB STOTZ-KONTAKT GmbH
235
4.4.2
Fan operation
In fan operation a single phase fan, blower or convector can be controlled.
In combination with a valve control 2, 3 or 4 pipe system can be
implemented.
The fans are controlled via a 3 stage speed controller. For this purpose
three windings are tapped off of the fan motor. The speed which results
is dependent on the tap-off. It must be ensured that two contacts are not
switched on simultaneously with a changeover control. For control purposes
at least one three stage changeover switch with zero position is usually
used. This switch is mapped with a group of outputs in the Room Master.
The control of the RM/S is implemented in accordance with the following
schematic principle:
With three
Fan speed x switch
(x = 1, 2, or 3) communication objects that
are independent of each other, the fan stages are controlled via the outputs
of the Room Master.
Alternatively, the fan control can be implemented via a 1 byte
communication object
Switch speed
or via the communication object
Fan speed UP/DOWN
.
Some ventilation controls require an additional central switch on mechanism
(main switch) in addition to the stage switch. This can be implemented with a
further output of the Room Master.
The output must be linked to the
communication object Status Fan ON/OFF
.
Hereby, the main switch is switched on if at least one fan speed is set. If the
fan is OFF (
Status Fan ON/OFF
= 0), the main switch is also switched off.