Lenze E84Dxxxx - Manual (Page 15)

Lenze · Decentralised frequency inverter 8400 protec (EtherNet/IP™ option) · Communication Manual · DMS 3.0 EN · 07/2014 · TD17
15
4 Technical data
4.4 Internal switch latency
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4.4 Internal switch latency
The integrated 2-port switch causes runtime delays. For "store-and-forward" and 100 Mbps, these
runtime delays can be calculated as follows.
Runtime delay for an output data packet of the scanners incl. 32-bit "run/idle header" with 16-bit
sequence counter:
Runtime delay for an output data packet of an adapter without 32/bit "run/idle header":
Example
Delay of an output data packet of the scanners with 8 output data words (16 bytes):
• ((66 permanent bytes + 16 bytes) x 8 x 10 nsec) + 4 μsec
• (82 bytes x 8 x 10 nsec) + 4 μsec
• 6.56 μsec + 4 μsec = 10.56 μsec
Runtime delay = ((66 permanent bytes + I/O data in bytes) x 8 x 10 nsec) + 4 μsec
Runtime delay = ((62 permanent bytes + I/O data in bytes) x 8 x 10 nsec) + 4 μsec

Note!
The use of external switches can also lead to runtime delays. Depending on the system
constellation, it may be useful to create a star topology or a line/mix topology.
 Network topology ( 16)