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PACSystems* RX3i
PROFINET Controller Manual
– December 2011
GFK-2571A
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Operations of the PROFINET Controller in the RX3i System
The RX3i PNC in the RX3i controller system performs the following operations:
Consumes PROFINET IO-Device configuration from the RX3i CPU and transfers it to the
IO-Devices over the PROFINET network.
Consumes input data from each PROFINET IO-Device and makes that data available to the
CPU during the
CPU’s input scan.
Produces the output data that it receives from the RX3i CPU during the
CPU’s output scan
to each PROFINET IO-Device.
Receives PROFINET alarms and diagnostics from PROFINET IO-Devices and converts
them to a PACSystems format.
Maintains a Local Log Table of its own alarms and the diagnostic information it receives. It
also forwards some of the information to the CPU as I/O or Controller Faults.
Automatically converts between the little-endian data format recognized by the RX3i CPU
and the big-endian format used for PROFINET communications.
Checks for duplicate IP addresses as described below.
Duplicate PROFINET Device IP Address
The RX3i PNC will detect an IP address conflict between a device that it is configured to
communicate with and another device in two situations:
First, duplicates are detected when the PNC is trying to initially establish communications with
the configured PROFINET IO Device. During the connection sequence, the PNC queries the
network to see whether any other node has the same IP address as the configured device.
Second, duplicates are detected when a network device announces its presence
1
on the network
and that device’s IP address is identical to that of a PROFINET IO Device that the PNC is
currently communicating with.
In both cases, the RX3i PNC attempts to establish or maintain the connection and logs a Duplicate
IP Address Detected fault for the device. The PNC then periodically queries the network for
resolution of the IP address conflict. If the IP address conflict is resolved, the PNC logs a Duplicate
IP Address Resolved fault for the device.
1
The PROFINET Controller uses the ARP protocol to detect duplicate IP addresses. Devices that issue a gratuitous
ARP to announce their presence on the network are detected.
