Summary

Even though the test program is only representative, it can be clearly seen that the cycle time of the background communication has a decisive influence on the data throughput. If a maximum data transfer rate is required on the DALI bus, the following points must be observed:

• K-bus and fieldbus should be arranged so that the cycle time for the PLC task accessing the DALI terminal (background communication) does not exceed 6 ms.
• The number of events of the DALI sensors (input devices) should be as low as possible. The more events are sent, the higher the probability of collisions on the DALI bus. The DALI sensors should be configured so that the number of events is minimal.
• To reduce the number of collisions on the DALI bus, the DALI priorities should be used. Recommendations for this can be found in the chapter DALI priorities.
• A large number of DALI control devices also increases the probability of collisions on the DALI bus. If necessary, the DALI control devices must be divided among different DALI lines. DALI control devices are DALI controllers and DALI sensors (see chapter Communication).