ABB i-bus
®
KNX
Planning and application
© 2008 ABB STOTZ-KONTAKT GmbH
247
4.5.2
Direct operation
With direct fan control via the ABB i-bus
®
, a fan drive is connected directly to
the Room Master and switched via three floating contacts. A single speed,
two speed or three speed fan can be connected.
The Room Master sets the fan speed in accordance with the value received
via the ABB i-bus
®
. The value is received as a 1 byte value. The conversion
of the received 1 byte value to the fan speed occurs as with the automatic
fan control via the parameterised threshold values.
1 byte value
Fan
speed
0… 9 %
0 (fan off)
10… 39 %
1
40… 69 %
2
70…100
%
3
4.5.3
Switchover between
automatic and
direct operation
In the Room Master you can switch between automatic operation and direct
operation. The changeover to manual fan control is implemented via a 1 bit
value. The fan stage is switched in accordance with the received 1 byte
value.
The fan control is changed back to automatic operation if a 1 is received in
the respective communication object.
The current status of automatic operation is fed-back via a 1 bit value.