Transmission length

The approximate transmission length can be determined from the bit length and the structure of the data frame. For further (simplified) consideration, a mean settling time of 17.0 ms is used for the forward frames (FF), and a mean settling time of 8 ms for the backward frames (BF). Between the two DALI commands sent within 100 ms (send-twice), a settling time of 14.1 ms is used.

The number of bits results from the number of data bits (8, 16 or 24) plus the start bit. Thus 9, 17 or 25 bits are transmitted with the respective telegrams.

16-bit telegram without backward frame:
17.0 ms + (17 x 0.833 ms) = 31.2 ms.

16-bit telegram with backward frame:
17.0 ms + (17 x 0.833 ms) + 8.0 ms + (9 x 0.833 ms) = 46.7 ms.

16-bit telegram send-twice:
17.0 ms + (17 x 0.833 ms) + 14.1 ms + (17 x 0.833 ms) = 59.4 ms.

24-bit telegram without backward frame:
17.0 ms + (25 x 0.833 ms) = 37.8 ms.

24-bit telegram with backward frame:
17.0 ms + (25 x 0.833 ms) + 8.0 ms + (9 x 0.833 ms) = 53.3 ms.

24-bit telegram send-twice:
17.0 ms + (25 x 0.833 ms) + 14.1 ms + (25 x 0.833 ms) = 72.8 ms.

The following table lists the average transmission lengths of the individual telegrams. This results in a maximum possible number of telegrams per second. The PLC program should be designed in such a way that the number of telegrams always falls below the maximum.