Siemens SCALANCE X-200 사용자 설명서

Network topologies / media redundancy 

 

2.3 Media redundancy in ring topologies 

 

SCALANCE X-200 

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Operating Instructions, 12/2011, A5E00349864-19 

An interruption of the ring can be caused by loss of the connection between two devices or 

by failure of a device in the ring. 
If the test frames of the redundancy manager no longer arrive at the other ring port, the 

redundancy manager connects its two ring ports. This substitute path once again restores a 

functioning connection between all remaining devices in the form of a linear bus topology. 
The time between the ring interruption and restoration of a functional linear topology is 

known as the reconfiguration time. 
As soon as the interruption is eliminated, the original transmission paths are established 

again, the two ring ports of the redundancy manager are disconnected and the redundancy 

clients informed of the change. The redundancy clients then use the new paths to the other 

devices. 
If the redundancy manager fails, the ring becomes a functional linear bus. 

Media redundancy methods 

The following media redundancy methods are supported by SIMATIC NET products for ring 

topologies:   
●  HSR (High Speed Redundancy) 

Reconfiguration time: 0.3 seconds 

●  MRP (Media Redundancy Protocol) 

Reconfiguration time: 0.2 seconds 
Automatic configuration of the ring 

The mechanisms of these methods are similar. With both methods, up to 50 devices can 

participate in the ring. HSR and MRP cannot be used in the ring at the same time. 
If you configure your plant using STEP 7, you can only select MRP as the media redundancy 

method. 
If you configure your devices with Web Based Management, CLI or SNMP, you can choose 

either HSR or MRP. 

Media redundancy with IRT   

For ring topologies in which MRP is activated, the "MRPD" function is activated automatically 

for IRT devices capable of IRT, if this is supported by the device. 
●  MRPD (Media Redundancy with Path Duplication) 

For use only with SCALANCE X-200IRT 
This procedure allows redundancy with IRT. You will find details in the section MRPD