AS-Interface Protocol Implementation

How the AS-Interface cycle time depends on the number of connected slaves

The following formula is used to calculate the AS-Interface cycle time depending on the number of activated slaves.

Tcycl = (1 + number of activated slaves) * 156μs

If a pair of slaves using the extended addressing mode (A/B slaves) occupies an address, this pair is counted as a single slave in the formula. Pairs of A and B slaves are addressed in every second AS-Interface cycle; in other words, the calculated cycle time is doubled for these slaves.

The calculated cycle time applies assuming that no frames are repeated, there are no management calls and all slaves are synchronized.

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A-4

SIMATIC NET CP 243-2 AS-i Master

C79000-G8976-C142/02

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Siemens CP 243-2 installation instructions AS-Interface Protocol Implementation