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RSTI-EP PROFINET I/O Controller User Manual Section 4
GFK-2571R May 2021
PROFINET System Operation 88
External Switch VLAN Priority Settings
The PROFINET-IO specification indicates the VLAN priorities for each type of Ethernet traffic
that originates from a PROFINET node. VLAN priorities range from 0 to 7, with 7 being the
highest.
The PACSystems PROFINET Controller supports just four traffic classes, giving four levels of
preference. Incoming traffic without a VLAN priority is assigned to the lowest priority traffic
class. The table below lists the VLAN priorities, and their corresponding priorities in the
PROFINET Controller:
VLAN Priority
PROFINET Controller
Priority Ethernet
Traffic
Description
7 Highest priority MRP Media Redundancy
6 Second-highest priority
RT_CLASS_1 Cyclic PROFINET IO
High Priority
RTA_CLASS_1 High-Priority PROFINET
Alarms
5 Third-highest priority
Low Priority
RTA_CLASS_1 Low-Priority PROFINET
Alarms
4, 3, 2, 1
Lowest priority
(reserved) (reserved)
0
IP
DCP
Device Discovery and
Configuration
If a system includes external switches, these switches must be configured to match the
VLAN Priority groupings listed above for the PROFINET Controller.
4.2 Operations of the PROFINET Controller in the
PACSystems System
The PROFINET IO-Controller in the PACSystems controller system performs the following
operations:
• Consumes PROFINET IO-Device configuration from the 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 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 CPU
and the big-endian format used for PROFINET communications.
• Checks for duplicate IP Addresses as described below.