DALI parameters and initialisation
Besides assignment of individual and group addresses and status scanning, the DALI interface facilitates the transmission of many DALI parameters and DALI commands from the control device to the control gear units.
The most important DALI parameter used in all DALI applications is the dimming value. It is transmitted in 8-bit resolution (255 steps from 0% to 100% and “unmodified”).
Further DALI parameters can be used on an application-specific basis. They are frequently transmitted to the control gear units in the context of initialisation during commissioning or at every switching-on of the power supply of a control device. They serve to optimise the overall system’s operation. The range of utilised parameters as well as their pre-settings can vary vastly between control devices. It is therefore advisable to perform a reset of all DALI parameters in an existing lighting installation when exchanging the DALI control device to prevent possible interference effects by parameter settings established by the preceding device.
To ensure that a DALI application implemented using a DALI control device is fully functional, it is generally advisable to utilise universal-use control gear units. This means devices intended to support all DALI commands and DALI parameters defined for their device type by the DALI standard. Only if this condition is fulfilled, control gear units and their documentation may have the DALI logo printed on them.
Other commercially available, less complex control gear units are frequently only serviceable for narrowly specified applications and only comply with parts of the DALI definition. They often feature the term “DALI” on their label, but do not bear the logo.
For DALI-2 components, there is a separate logo which can only be issued through the process of independent certification by the DiiA (Digital Illumination Interface Alliance).
The complete description of all DALI parameters and DALI commands can be found in standard IEC 62386. Further information can be found at www.dali-ag.org/discover-dali/dali-standard.html.