AS-i performance
14
AS-i bus performance
At a Glance
AS-i scanning time
AS-i response time
Example
The AS-i bus is independently managed by the master. This exchanges data on each cycle with each slave device configured on the bus (in ascending order of slave address number).
t scanning time represents the exchange time between the master and n slaves (31 maximum).
Either: l l t = 156 micro seconds x (n+2), if n < 31, t = 156 micro seconds x (n+1), if n = 31.
Thus the scanning time cannot exceed 5 ms.
T response time represents the AS-i cycle time.
l l l
This includes: the bus scanning time, the update of the AS-I module internal memory, the PLC cycle.
The table below shows three examples of T response time for a PLC task lasting 10 ms, 30 ms, and 60 ms.
This T time is for a bus loaded with 31 slaves operating normally with no link faults.
PLC task
10 ms
30 ms
60 ms
Typical response time
35 ms
65 ms
110 ms
Maximum response time
56 ms
96 ms
156 ms
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TLX DS 37 PL7 xxE
AS-i performance
166
TLX DS 37 PL7 xxE
