Emerson PACSystems RX3i, Руководство пользователя

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RSTI-EP PROFINET I/O Controller User Manual Section 1
GFK-2571R May 2021
Introduction 21
1.6.8 Systems that use PROFINET System Redundancy
(PNSR)
PACSystems support S2 type PNSR, as diagrammed in Figure 13 . The ‘S’ denotes that the IO
Device has single network support. PROFINET defines an ‘R’ option in which the IO Device
may have redundant network interfaces which could be on different network s. The ‘2’
denotes that the network supports two connections as a set.
Note that in each case the firmware installed in the PROFINET Controller and in the
PROFINET Device must themselves support PNSR. PNSR allows a set of Hot standby CPU
controllers to have an active and hot backup connection to an IO device, so that if something
fails in one CPU controller, the other CPU controller can continue IO operations without
disruption.
PNSR relies entirely on PROFINET features to support this configuration. PACSystems only
supports PNSR in Dual HWC Hot Standby systems. Within a PNSR system, simplex IO devices
may be controlled by one CPU Controller in addition to redundant IO devices which are
controlled by the Active CPU of the Hot Standby system. When the CPU controller which is
controlling a simplex IO Device is stopped, that IO Device is lost.
The PROFINET PNSR Network may be either Ring or Star formation. Using a Ring formation
with the Media Redundancy Protocol (refer to Section 6:), is often useful with PNSR systems
since a single cable failure is handled by MRP allowing both IO Controllers to maintain
connection with the IO devices.
Figure 13: PROFINET System Redundancy S2
1.6.9 Systems that use Hot Standby CPU Redundancy
Figure 14 shows a Hot Standby CPU Redundancy system that uses a PROFINET I/O network
with MRP ring topology. Use of MRP ring topology is recommended because it eliminates
the I/O network as a single point of failure. If elimination of a single point of failure is not
required, a star topology can be used.