Controlling the brightness

Settable brightness range

The settable brightness range of a group or single device can be limited by defining a lower and upper brightness value. The "Minimum brightness" and "Maximum brightness" parameters on the parameter page "DALI system... -> Configuration groups -> [x] Group name" or "DALI system... -> Configuration single devices -> [x] Device name" define the brightness values that are not undercut or exceeded when a brightness value is set or during a dimming process. In this way, the brightness of the controlled lamps of the DALI operating devices can be adapted individually – even to the brightness sensitivity of the human eye. The configured minimum brightness can be undershot only by switching off or when dimming up starting in the "OFF" state.

Furthermore, the brightness value, which is set for the DALI operating devices whenever switching on by means of the object "Switching - Setting" or "Central function... - Switching" is set for the DALI operating devices. The parameter "Switch-on brightness" defines this brightness separately for each group and each single device. The settable value is anywhere between the minimum and maximum brightness.

Example of a brightness range with switch-on brightness

Setting the minimum brightness

The minimum brightness can be set separately for each group and single device.

  1. Set the "Minimum brightness" parameter on the parameter page "DALI system... -> Configuration groups -> [x] Group name" or "DALI system... -> Configuration single devices -> [x] Device name" to the required brightness value.
  • The set brightness is not undershot when predefining a brightness value or during a dimming process in the "ON" state. The configured minimum brightness can be undershot during the dimming process only by switching off.

The configured minimum brightness must be less than the maximum brightness.

If values are received by means of the brightness value object and are less than the configured minimum brightness, the gateway sets the minimum brightness as the new brightness value for the group or single device concerned.

Setting the maximum brightness

The maximum brightness can be set separately for each group and single device.

  1. Set the "Maximum brightness" parameter on the parameter page "DALI system... -> Configuration groups -> [x] Group name" or "DALI system... -> Configuration single devices -> [x] Device name" to the required brightness value.
  • The set brightness is not undershot in any switched-on operating state.

The configured maximum brightness must be greater than the minimum brightness.

If values are received by means of the brightness value object and are greater than the configured maximum brightness, the gateway sets the maximum brightness as the new brightness value for the group or single device concerned.

Setting the switch-on brightness

The switch-on brightness can be set separately for each group and each single device.

  1. Set the "Switch-on brightness" parameter on the parameter page "DALI system... -> Configuration groups -> [x] Group name" or "DALI system... -> Configuration single devices -> [x] Device name" to a brightness value.
  • The set brightness is set after receiving an ON telegram by means of the communication object "Switching - Setting" or after receiving a central telegram with the polarity "activated".
  1. Set the parameter "Switch-on brightness" to "Memory value (brightness before switching off last time)".
  • When switching on, the brightness value is set that was active and internally stored before switching off the last time. This memory value is stored in a non-volatile manner in the gateway so that the value is retained after the bus or mains voltage returns. After an ETS programming operation, the memory value is predefined to "100%". This value is optionally limited by the maximum brightness.

The switch-on brightness can always be configured within a range of 1...100%. If the switch-on brightness is outside the range defined by the minimum or maximum brightness, the gateway limits the switch-on brightness to the set limits.

In the "memory value" setting: A memory value is stored internally by a switch-off telegram also if the bus-controlled switch-off is overridden, for example, by a disabling or forced position function or by a manual operation. In this case, the internally tracked brightness value is saved as memory value.

If no soft ON function is activated, the brightness value is more or less jumped to when switching on (using minimum DALI fading of 0.7 s). Once a soft ON function is activated, the switch-on brightness is dimmed according to the dimming speed for the soft ON function.

Dimming characteristic and dimming speeds

The brightness of operating devices of a group or configured single device can be changed by a dimming process. The limits of the brightness range that can be set by a dimming process are defined by the maximum brightness and minimum brightness predefined in the ETS.

Example of a dimmable brightness range

A DALI group or single device can be dimmed by...

  • Relative dimming:
    Relative dimming can be triggered either by the 4-bit communication object "Dimming - Setting" available for each group or single device, additionally - in the event of colour temperature control - by the 3-byte combination object "Relative dimming (brightness and colour temperature) - Setting" or by pressing and holding a button of the manual control. The data format of the 4-bit object complies - as is normal with KNX dimming actuators - with the KNX DPT 3.007, which means that the dimming direction and relative dimming increments can be specified in the dimming telegram or dimming operations can also be stopped. The data format of the 3-byte object corresponds to KNX DPT 250.600, which enables combined relative dimming of brightness and colour temperature by means of separate dimming increments and dimming directions.
  • With relative dimming by local manual operation at the gateway, a dimming process is executed while the corresponding button is pressed. The dimming process ends when the button is released or when the maximum brightness or minimum brightness is reached. A relative dimming process allows a brightness value to be changed constantly and always starts from the brightness that is set at the time of the dimming command.
  • In the ETS, the dimming speed for relative dimming can be configured separately for each group or single device.
  • Absolute dimming:
    Absolute dimming is triggered by specifying a brightness value. This value can be triggered by the 1-byte communication object "Brightness value - Setting" present in each group or single device according to KNX DPT 5.001 or - in the case of colour temperature control - additionally by the 6-byte combination object "Absolute dimming (brightness and colour temperature) - Setting" according to KNX DPT 249.600. In addition, brightness values can also be set by a disabling or forced position function or by the scene function. Absolute dimming can also be activated, even in case of bus voltage failure, after the bus or mains voltage returns or after programming with the ETS, by specifying brightness values.
  • When specifying a brightness value by means of the objects or by a scene recall in the ETS, it can be configured whether the value is jumped to directly or alternatively dimmed to over a dimming time or fading is carried out. When dimming by means of the 6-byte combination object, it is possible to specify an individual dimming time in the KNX telegram. If a valid time is specified there, the gateway executes the dimming time transmitted in the KNX telegram and not the one specified in the ETS. The brightness specified in the telegram value is then dimmed within the transmitted dimming time (fading). If the time is defined as "invalid" in the telegram, the gateway always executes the dimming behaviour defined in the ETS parameters during absolute dimming.

The setting of a dimming time for relative or absolute dimming (with dimming to the brightness values) is carried out within the range of minimum to maximum brightness at the gateway. The dimming times are derived directly from the configured times between two dimming steps.

Even if brightness values are instantly jumped to, the dimming procedure on DALI operating devices always takes a very short time as well as when switching without soft ON or soft OFF. This dimming procedure is dependent on the system. The brightness value jumped to is dimmed to within 0.7 s (short fading). This time cannot be altered.

Setting dimming behaviour for absolute dimming

In the ETS, the dimming behaviour for absolute dimming can be set separately for each group and single device. The parameter "When receiving a brightness value" on the parameter page "DALI system... -> Configuration groups -> [x] Group name" or "DALI system... -> Configuration single devices -> [x] Device name" defines the behaviour.

  1. Set the parameter to "jumping to".
  • As soon as a new brightness value is specified, it is instantly jumped to.
  1. Set the "dimming to" parameter.
  • Once a new brightness value is specified, it is set by means of the configured dimming increment time for absolute dimming.
  1. Set the "fading" parameter. Configure the duration of the dimming process for the parameter "Time for brightness value via fading".
  • As soon as a new brightness value is specified, it is set by means of the configured fading time for absolute dimming. The dimming process then always takes exactly the set time, regardless of the initial value of the dimming process.

During a scene recall, the dimming behaviour can be configured separately.

Setting dimming time for relative dimming

In the ETS, the dimming time for relative dimming can be set separately for each group or single device.

  1. Set the parameter "Time between two dimming steps for relative dimming" on the parameter page "DALI system... -> Configuration groups -> [x] Group name" or "DALI system... -> Configuration single devices -> [x] Device name" to the required dimming step time.

The entire brightness range of 0...100% is divided into 255 dimming steps. The duration of a complete relative dimming process within this brightness range is calculated according to the formula: t = 255 x time between two dimming steps [ms]. The actual dimmable range is limited by the configured minimum and maximum brightness.

Setting dimming time for absolute dimming

In the ETS, the dimming time for absolute dimming can be set separately for each group and single device.

  • The dimming behaviour must be configured as "dimming to".
  1. Set the "Time between two dimming steps for absolute dimming" parameter on the parameter page "DALI system... -> Configuration groups -> [x] Group name" or "DALI system... -> Configuration single devices -> [x] Device name" to the required dimming time.

The entire brightness range of 0...100% is divided into 255 dimming steps. The duration of a complete absolute dimming process within this brightness range is calculated with the formula: t = 255 x time between two dimming steps [ms]. The actual dimmable range is limited by the configured minimum and maximum brightness.

Setting dimming behaviour in OFF state for relative dimming

A relative dimming telegram for controlling the brightness can also switch on a group or single device in the "OFF" state. In the ETS, the behaviour in the "OFF" state when receiving a relative dimming telegram can be set separately for each group and each single device by the parameter "With relative dimming up in the switched-off state".

  1. Set the parameter to "Switch-on".
  • The group or single device is switched on in the "OFF" state by a relative brightness dimming telegram and carries out the dimming process. After reaching the intended brightness, the dimming process stops.
  1. Set the parameter to "No reaction".
  • The group or single device in the "OFF" state is not switched on by the relative dimming telegram. The group or single device remains switched off.
Additional information