12
IC695PNC001-AJ PROFINET Controller Module
GFK-2573K
Operational Notes
Operational Note
Description
Minimum I/O Update Rates for
Bumpless Operation in a Ring
Topology
If your application requires the PROFINET I/O to operate in a bumpless fashion (no
Loss of Device faults and no defaulting of I/O) through a break in the ring, then the
I/O Update Rates of
all
of the devices in that ring must be no smaller than the
Minimum I/O Update Rate described below.
When
no third party items
participate in the ring:
PNC’s Ring
Ports
I/O-Devices in
the Ring
Minimum
I/O Update
Rate
Additional Media
Redundancy Manager
requirements
Ports 1 and 2
both operating
at 100Mbps
No RX3i
PROFINET
Scanners
1ms
None
An RX3i
PROFINET
Scanner using
Ports 1 and 2 for
the ring
2ms
None
An RX3i
PROFINET
Scanner using
Port 3 or 4 for
the ring
16ms
Set Default Test Interval
to 10ms.
Set Test Monitoring
Count to 2.
Ports 1 or 2
operating at
1000Mbps
16ms
Set Default Test Interval
to 10ms.
Set Test Monitoring
Count to 2.
Ports 3 or 4
(any speed)
If
any third party items
participate in the ring, the minimum I/O Update Rate is the
larger
of the following two options, regardless of which PNC ports are used for the
ring:
▪
The smallest I/O Update Rate selectable within PME that is more than 1/3 of
the largest worst-case ring recovery time among the third party items. For
example, if the manufacturer states that the worst-case ring recovery time is
96ms, the rate needs to be more than 96ms divided by 3 which is 32ms. The
next available rate after 32ms is 64ms.
▪
16ms.
When using an I/O Update Rate of 16ms, you must set the Media Redundancy
Manager’s Default Test Interval to 10ms and its Test Monitoring Count to 2.
Storing updated media redundancy
protocol (MRP) configurations to large
operating MRP ring networks with
fast IO update rates configured can
result in PROFINET I/O device
Loss/Add faults
When storing Media Redundancy Protocol (MRP) configuration updates to an
operating MRP ring network, users may infrequently observe one or more pairs of
“Loss of Device” and subsequent ”Addition of Device” faults regarding PROFINET I/O
Device faults on the network. This is expected behavior and is more likely to occur
on ring networks with a large number of PROFINET I/O Devices acting as MRCs with
very fast I/O Update Rates configured.
Because changing MRP configuration settings requires each MRC to break and
reconnect its own connections to the ring network, IP packets on the network may
be lost as this flurry of connection breaks/ reconnects occur on the network. Since a
PROFINET I/O Device is considered lost if it misses three consecutive I/O data
transactions, if three consecutive I/O data packets from a particular PROFINET I/O
Device are lost due to network reconfiguration, the device will appear to be lost to
the PNC and a Loss of I/O Device is logged. When the network stabilizes, the PNC
will be able to reestablish connection with the lost IO Device and an Addition of I/O
Device fault will be logged.