Rockwell Automation 20-750-PNET2P Profinet Dual Port Option Module - Manual (Page 23)

Rockwell Automation Publication 750COM-UM007A-EN-P - January 2013 23
Installing the Option Module Chapter 2
Using MRP (Media
Redundancy Protocol) for
Ring Topology A Ring network is a single-fault tolerant network intended for interconnection of
automation devices. MRP (Media Redundancy Protocol), a simple and
deterministic protocol, when enabled in a PROFINET network connected in
Ring Topology achieves re-configuration time of 200 ms. A maximum of 50
devices can be connected in a ring network by using MRP.
When enabled in ring topology, MRP offers the following advantages:
• Media redundancy
• Higher communication availability
• Reduced number of network components
• Fast network fault detection and re-configuration
• Resiliency of a single-fault tolerant network
• Easy implementation without any additional hardware requirements
The 20-750-PNET2P option module can only be connected as MRC (Media
Redundancy Client) and will not work as MRM (Media Redundancy Manager).
An MRM capable device needs to be present in the network to achieve the media
redundancy. See
Figure 3 for typical connection having MRM and MRC in a ring
network.
Figure 3 - Network Connection for an MRP Switch/PLC in Ring Network
The following settings need to be considered for an MRP capable switch/PLC
connected in a ring network:
• Cycle Time: 128 ms
• MRM functionality: Enabled
• Ring ports to be defined
PowerFlex 750-Series Drives
(with 20-750-PNET2P Option Modules)
Computer with
Ethernet Connection
MRP Capable
Switch
MRP Capable
Switch
Controller
To Other Profinet
Networks