Basic function principles

Coupling to price-sensitive actuators in a controller system is a challenge for a universal gateway. A building's illumination is typically implemented through a large number of devices. The price of a lamp, and therefore of the connection to a control system, is thus of great significance.


The Digital Addressable Lighting Interface (DALI) is a simple bus system for building automation that transmits the signals for the digital operation of lighting devices. The lamp, sensor, button and switching elements are wired in parallel, and are linked through the controller. Other actuators, such as heating control valves or the motors for operating blinds are increasingly being put under digital control.

DALI offers the following advantages:

The KL6811 DALI Master Terminal from Beckhoff closes the gap between lighting controller and lamp and enables the connection of up to 64 DALI devices (DALI devices). The KL6811 is integrated into the BECKHOFF Bus Terminal system as a normal Bus Terminal and is therefore fieldbus independent. The higher-level Bus Coupler transfers the data from the DALI master terminal to the controller. The DALI power supply unit integrated in the KL6811 supplies the DALI bus. No further components are required for the operation of the DALI line.

During the start-up phase, the KL6811 searches for connected DALI devices and supports the user during commissioning of the system. The KS2000 configuration software can be used to parameterize the DALI master terminal from a PC. The parameterization takes place via the fieldbus or via a RS232 interface, which are connected to the configuration interface of the higher-level Bus Coupler.


The KL6811 can also be operated as a DSI master. The Digital Serial interface (DSI) is an even simpler bus system for lighting control. The DSI master sends digital light intensity values serially to the DSI devices. The brightness of the devices can be set between 1% and 100%. The assignment of the brightness to the control values is logarithmic, so that a human observer sees a uniform increase in brightness when the control values are increased linearly. The devices can be switched to dark by setting the control value to 0, without having to switch off the mains voltage.