SI-Ethernet User Guide 137
Issue: 1
Safety
information
Introduction
Mechanical
installation
Electrical
installation
Getting started Parameters
Key features
and Protocols
PC Applications Security Diagnostics
Glossary of
terms
Index
7.3.9 VLANs
To guarantee the timing of synchronous links VLANs must be enabled using VLAN
Enable (S.02.030). VLANs include a priority field that is applied to all messages. This
field is used to apply a higher priority to synchronous cyclic data than other non-
deterministic traffic.
7.3.10 Virtual Master
It is possible to send cyclic data to devices on the network and use the same data on
the transmitting device. The cyclic links must be synchronous to include timing
information. On the transmitting device a receive link must also be configured with a
matching link number to the transmit link. For this link you must set Rx1 Source Type
(S.10.044) to be Local. The Ethernet interface will delay the usage of the data
transmitted until the same point in time that all receiving slaves will use the data.
7.3.11 Parameter Update Rate
Parameters are exchanged over the network. The value exchanged over the network
must be exchanged with the drive or option parameter. The rate of data exchange
differs for synchronous and non-synchronous cyclic links as well as for drive and option
destinations.
The diagram below depicts the update cycles used within the Ethernet interface. Cyclic
link mappings being exchanged with the drive will be updated at the background task
rate. This rate (Background cycles per second (S.09.008)) varies with the load on the
Ethernet interface; EtherNet/IP data exchange also takes place in the background task.
Synchronous
Cyclic Links
Cyclic Links
Background
Task
500 µs
O
P
T
I
O
N
S
D
R
I
V
E
>=500 µs
Network
>=1 ms
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