ABB i-bus® KNX
PLANNING AND APPLICATION
9AKK107992A3045
Fig. 35: SAF/A 1.0.1-24
If the SAF/A room temperature and fan coil control unit is used, the following reaction applies to the set-
tings for the fan speed:
• Automatic: The controller takes over the control of the fan speed corresponding to the control value
(fan automatic).
• Fan speed 0: If, in the active operating mode (
Heating
/
Cooling
), the basic stage or additional stage is
used to activate a fan coil unit, the fan is overridden and switched off. All valves assigned to the fan
coil unit are also overridden and control value set to 0 %. The fan and valve override has no effect on
the control value output by the controller to activate the basic stage or additional stage via group ob-
jects. If the controller is in the Building Protection operating mode, there is no override. If the con-
troller changes to the Building Protection operating mode during the override, the override is with-
drawn.
• Fan speed 1 ... 3 (for continuous fans: 33 %, 66 %, 100 %): If, in the active operating mode (
Heating
/
Cooling
), the basic stage or additional stage is used to activate a fan coil unit, the fan is overridden to
suit the speed set. The override has no effect on the control value.
12.2.21.1
Connecting an analog room control unit in actuator mode
An actuator cannot evaluate the values for setpoint adjustment, and therefore a KNX room control unit
with integrated controller must be used in addition to the analog room control unit. The actuator for-
wards the setpoint adjustment of the analog room control unit to the KNX room control unit, which re-
turns the control value and the fan speed.
The value that the actuator sends to the fan can deviate from the values in the analog room control unit.
This deviation is due to the following control panel properties:
• Setpoint adjustments can be made mutually independently in the analog room control unit and in the
KNX room control unit.
• The analog room control unit and the KNX room control unit do not communicate with each other.
Example
Hotel guests can control the fan in their room using an analog room control unit.
Hotel employees can use an additional KNX room control unit per hotel room to control all fans cen-
trally, e.g. to implement nighttime reduction after a certain time.
12.2.22
Forced operation
The function
Forced operation
can be used to set the device outputs to a defined state and block them.
Forced operation is triggered by the switching of a 1- or 2-bit group object.
The controller continues to send the control values on the bus (ABB i-bus® KNX) during forced operation.
Master/slave communication occurs despite active forced operation.
Note
If forced operation is active, operation via group objects, manual operation and i-bus® Tool is blocked.
Higher-priority functions continue to run →
Product manual | EN-US | VC/S 4.x.1 | 2CDC508220D0211 Rev. B
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