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vacon • 132 PROFINET IO
Local contacts: https://www.danfoss.com/en/contact-us/contacts-list/
8.6 System Redundancy
Redundancy is a requirement in process automation systems for high availability and reduced
production downtimes. PROFINET System Redundancy provides a solution to build a system with
redundant PN controllers, devices and communication.
PROFINET System Redundancy fulfills among others the following requirements:
• Highly reliable communication
• Short take over time
• Bumpless IO data during fault recovery
• Monitoring of the backup connection
System redundancy implements two redundant PN controllers, one working as primary and other
as backup. These controllers can be connected via a redundant network to PN devices. This is,
however, not mandatory as system redundancy has different levels which are independent from
each other, meaning that PN controller, Ethernet media and PN device can have different
redundancy configurations.
Figure 45. System Redundancy overview
OPTEA supports "S2" level of System Redundancy as well as Media Redundancy Protocol (MRP) for
redundant connectivity.
S2 uses a single PROFINET interface (NAP = Network Access Point), and two SR-ARs (System
Redundancy Application Relations = connections), one to each PN controller. Redundant PN
controllers have parallel access to a SR PN device, but only one AR acts as a primary (SR-ARa) and
the other is backup (SR-ARb).
Redundant Network
Primary
Device with
redundant
connectivity
Device with
singular
connectivity
Backup
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