Emerson PACSystems RX3i, User Manual

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RSTI-EP PROFINET I/O Controller User Manual Section 6
GFK-2571R May 2021
Redundant Media 135
Test Packet Interval × (Test Packet Count + 1) < I/O Update Rate × 2
6.1.4 MRP Operation at I/O Update Rates Less Than 16ms
The PACSystems implementation of MRP supports fast LinkUp/LinkDown detection on
devices, an optional part of the MRP standard. This allows an MRC experiencing a network
link failure or recovery to send LinkUp/LinkDown messages to the MRM immediately. The
MRM can heal the network without needing to wait for multiple test-packet timeouts to
detect the failure. This feature allows the network recovery time to be significantly shorter
than the test packet timeout interval because the break is detected immediately.
6.1.5 Minimum I/O Rate When Configured in an MRP Ring
The minimum I/O rate that is possible for bumpless operation depends on the speed and
the type of physical connection being used for the MRP ring ports. PACSystems PROFINET
I/O Controllers support a specified number of PACSystems PROFINET I/O devices running at
or above the minimum I/O Update Rate listed in the table below.
6.1.6 Minimum I/O Update Rates for Bumpless Operation
in an MRP Ring Topology
If your application requires the PROFINET IO to operate in a bumpless fashion (i.e.,
experience no Loss of Device faults and no defaulting of IO) whenever a break in the ring
occurs, then the IO Update Rates of all the devices in that ring must be no smaller than the
Minimum IO Update Rate described in this table.