Lenze E84DGFCA User Manual download pdf (Page 31)

Lenze · Decentralised frequency inverter 8400 motec (AS-Interface option) · EDS84DMOTASI EN 4.0 - 09/2013 31

Data transfer

AS-i cycle

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7.2 AS-i cycle

The complete AS-i cycle consists of:

• AS-i messages

Max. 31 messages (sum of the standard slaves connected to the network or the maximum of A

and B slaves)

• 1 management call

Consists of a parameter exchange or a command to a slave and an optional response.

• 1 call from the recording phase

Search for new slave addresses and optional response

• 1 reserve message (if required)

Cycle time

• The cycle time results from the following formula:

• When the maximum cycle time is determined, 33 messages are maximally estimated. Hence:

• Thus, approx. 200 cycles are passed per second.

• Thus, a standard slave can be provided 200 times per second with new output data and can

transmit its input data to the master.

Medium response time

• The medium response time results from the following formula:

•The jitter, which is the fluctuation around the medium response time, amounts to ...

• ± 2.5 ms for standard slaves;

•±5.0 ms for A/B slaves.

Cycle time = messages per cycle x max. message duration

Max. cycle time = 33 messages x 154 μs = 5.08 ms

 Note!

Wherever A and B slaves are operated on one address, the cycle time is twice as long.

Medium response time = 0.5 x max. cycle time + max. message duration

Medium response time = 0.5 x 5.08 ms + 154 μs= 2.7ms

 Note!

Wherever A and B slaves are operated on one address, the medium response time is

twice as long (5.4 ms).

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Lenze E84DGFCA User Manual Page 31