SI-Ethernet User Guide 147
Issue: 3
Safety
information
Introduction
Mechanical
installation
Electrical
installation
Getting started Parameters
Key features
and Protocols
PC Tools
Applications
Security Diagnostics
Glossary of
terms
Index
By choosing the most appropriate transmission type an efficient and reliable network can be
designed.
For example:
• Three drives must use an ELS (Electronic Line Shaft) to follow a Smart Drive. In this case
a multicast message should be used to transmit the reference position from the Smart
Drive.
• Three drives need to return general status information to the Smart Drive. In this case,
each drive should send a unicast message to the Smart Drive.
• The Smart Drive needs to command all other drives to stop/start. The Smart Drive should
use a broadcast message to transmit the command to all the other drives.
Unicast
A unicast link will only be processed by the specified destination address, the transmitting device
specifies the destination address in S.10.015, S.10.025 or S.10.035 (Tx1, Tx2 or Tx3 respectively)
and the receiving link in the relevant device must be set to “Direct” in S.10.044, S.10.054 or
S.10.064 (Rx1, Rx2 or Rx3 respectively).
Multicast
A multicast link can be processed by more than one destination address, the transmitting device
configures the multicast address group (Multicast1, Multicast2, Multicast3 or Multicast4) in
S.10.014, S.10.024 or S.10.034 (Tx1, Tx2 or Tx3 respectively), the appropriate multicast
destination address is automatically set in S.10.015, S.10.025 or S.10.035 (Tx1, Tx2 or Tx3
respectively), a receiving link on the same network must be configured to use the same multicast
address group as specified in S.10.014, S.10.024 or S.10.034 (Tx1, Tx2 or Tx3 respectively) in
S.10.044, S.10.054 or S.10.064 (Rx1, Rx2 or Rx3 respectively).
Any device on the same network as the transmitting device may be configured to receive a
multicast message.
Each cyclic link can be configured for one of four multicast addresses, this means that on any given
network, there may be up to four groups of multicast addresses.
The multicast addresses used are in the local scope addresses ranging from 239.255.0.1 to
239.255.0.4.
Broadcast
A broadcast link can be processed by any device on the network, the transmitting device sets the
message type as “Broadcast” in S.10.014, S.10.024 or S.10.034 (Tx1, Tx2 or Tx3 respectively), the
broadcast IP address (255.255.255.255) will be automatically set in S.10.015, S.10.025 or
S.10.035 (Tx1, Tx2 or Tx3 respectively), a receiving link on the same network must be configured
to “Direct” in S.10.044
, S.10.054 or S.10.064 (Rx1, Rx2 or Rx3 respectively).
Any device on the same network as the transmitting device may be configured to receive a
broadcast message.
Broadcast messages should be used with care, bottlenecks in the network can be
easily created by using broadcast messages, this will reduce the performance of the
network and, in extreme situations, seriously impair the system operation.
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