2-13
2 Nomenclature and Installation
CJ-series PROFINET IO Controller Unit Operation Manual for NJ-series CPU Unit (W511)
2-3 N
etwork In
st
all
ation
2
2-
3-1 MR
P Rin
g Redundan
cy
The ring topology is achieved by extending a line topology back to its starting point. A network redun-
dancy ring protocol such as PROFINET MRP must be supported by all devices that form the ring. This
allows monitoring the state of the network and reconfiguring the communication paths in case of a dis-
turbance.
Advantage of a Ring Topology
•
Malfunction of a single IO Device will not result in disconnection of part of the network as the net-
work redundancy mechanism will automatically maintain the connection with the other devices.
Disadvantage of a Ring Topology
•
Malfunction or power disruption to the MRP manager will result in disconnection of the entire net-
work.
•
High data traffic per connection.
Additional Information
The switch shown above of an industrial ethernet switch type supporting MRP manager function.
Suggested type: Hirschmann Automation and Control GmbH, Series RS20/20/40, Software Ver-
sion 4 or higher.
This protocol, which is part of the PROFINET IO Specification, enables the Unit to be part of a ring-
shaped network structure and adds redundancy to the network. The internal Ethernet Switch of for
instance the Omron GRT1-PNT IO Device Unit supports the Media Redundancy Protocol (MRP).
In case one of the line connections fails, the MRP ensures communication to all IO Devices through
the redundant path. The ring structure can contain up to 50 Units and typically switches to the redun-
dant path within 150ms (max 500ms).
The network requires an MRP manager to facilitate the redundancy. As an MRP client, there are no
specific settings required for the Omron GRT1-PNT IO Device Unit. Please refer to the manual of
the used MRP manager unit for details on how to set up and operate the MRP network.
Ring Network
2-3-1
MRP Ring Redundancy