ABB i-bus KNX Product Manual page 175

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ABB i-bus KNX
Planning and application
Explanations of terms
These variables are only partly available in the Software-Tool for commissioning, see Software-Tool online
help.
Sensor value
Actual value
Control parameter (setpoint)
This value corresponds with the physically measured value on the sensor input, which
results from the room brightness detected by the Light Sensor LF/ 2.1 (luminance of the
area monitored by the sensor). This value is displayed exclusively as an additional
auxiliary value during commissioning using an external commissioning tool (Software
Tool). The sensor value does not correspond to the lighting intensity (Lux value) in the
room, but rather it is an electrical variable that is present on the sensor input of the DLR/S.
The sensor value is used to detect brightness values directly in the detection range of the
light sensor.
The actual value of the control circuit is the fed back of the control path. If the controlling
lighting group is only assigned to a light sensor, the actual value corresponds to the sensor
value.
If several light sensors are allocated to a lighting group, the actual value is determined
from the sensor values of the individual sensors.
In the Parameter window - Gx Light
largest or the average sensor values are used for light control calculations.
For further information see: Constant light
The control parameter corresponds to the setting of the controller if the setpoint brightness
value is set in the room. For this reason, the control parameter can be set equal to the
control setpoint. In the following section, we refer to the setpoint.
The setpoint is the decisive control value in practical applications for constant light control.
The DALI Light Controller calculates the setpoint for the lighting so that the actual value to
be set is as near as possible to the predefined setpoint (control parameter) with all room
lighting conditions.
Due to the differing ambient conditions in rooms (incidence of light, reflections and
absorption conditions), this setpoint cannot be easily specified using the figure value
defined in the ETS, but must rather be set using a daylight and artificial light calibration.
With this calibration, the lighting characteristic and the technical lighting properties of the
room are automatically detected by the DALI Light Controller in order to match the control
parameters to the room.
For further information see: Constant light
Irrespective of this calibration, an overshoot or undershoot of the setpoint brightness value
can occur during phases in ongoing operation of constant light control. These are even
greater with greater differences of the reflection and absorption conditions from the original
ambient conditions during the calibration procedure. A further reason for the deviation is a
direct or indirect incidence of light on the light sensor. A deviation of +/- 10% from the
setpoint is normal.
controller, you can parameterize if the smallest, the
control, page 171
control, page 171
DLR/S 8.16.1M | 2CDC 507 100 D0202 173