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SI-PROFINET RT User Guide
Issue Number: 2
Table 4-3 SI-PROFINET RT Ethernet connections
4.6
Module grounding
SI-PROFINET RT is supplied with a grounding tag on the module that should be
connected to the closest possible grounding point using the minimum length of cable.
This will greatly improve the noise immunity of the module.
For information on the drive grounding arrangement refer to the relevant drive
documentation.
4.7
Network topology
The SI-PROFINET RT module has two PROFINET ports with integrated switches to
allow the use of line networks (see Figure
For the device replacement feature to work,
). However, when using line networks, a break
in the connection (for example when replacing a device) will cause all devices
downstream from the failure to also stop communicating with the controller.
Other Ethernet network topologies can be used but care must be taken to ensure that
the system still operates within the constraints specified by the designer.
Generally a star or tree network structure using separate switches gives improved
availability in the event of device failure or replacement. Also, managed switches have a
web page interface which can be used to configure the switch to monitor the data traffic
on specific ports using any appropriate protocol analyzer.
Although the PROFINET protocol does support all major topologies, line topology
networks are normally used for practical and financial reasons, other Ethernet
topologies (e.g. star) may not be suitable for real time communications due to their
inherent use of switches or other network equipment.
Any network devices used, such as switches, must be capable of RT communications
and ideally, also IRT (Isochronous Real Time) communications, although SI-PROFINET
RT does not currently support this protocol. Standard office equipment is not normally
suitable and should not be used.
For the device replacement feature to work, the physical network topology must be
configured in the PLC, for further information please refer to the PLC documentation.
Port A / B
Pin
Function
1
Tr
2
Transmit -
3
Receive +
4
Not used
5
Not used
6
Receive -
7
Not used
8
Not used
8 7 6 5 4 3 2 1
NOTE
NOTE
