Types Of Profinet Communications; External Switch Vlan Priority Settings - GE PACSystems RXi User Manual

10.1.3 Types of PROFINET Communications

The PNC uses two types of PROFINET communication transfers: real-time and non-real-
time. The illustration below shows real-time communications as solid lines and non-real-time
communications as dashed lines.
Real-time data:
Inputs, Outputs,
■
Real-Time (RT) communication: PROFINET real-time communication is used for time-
sensitive data. A PROFINET IO-Controller and PROFINET IO-Device use two types of
real-time communications to exchange data: cyclic communication and acyclic
communication:
-
-
■
Non-Real-Time (NRT) communication: PROFINET non-real-time communication is
used for less time-sensitive data such as configuration, parameterization, diagnostics,
and identification data.

10.1.4 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 switch on the PNC 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 PNC:
VLAN
Priority
7
6
5
4, 3, 2, 1
0
If a system includes external switches, these switches must be configured to match the VLAN
Priority groupings listed above for the PNC.
GFK-2816F
Alarms
PROFINET
IO-Device
Real-time Cyclic communication is used to periodically transfer the application's input
and output data. Cyclic communication occurs each PROFINET IO production cycle.
Real-time Acyclic communication is used to transfer non-periodic data such as
alarms. Acyclic communication occurs only when needed.
PNC Priority
Highest priority MRP
Second-highest RT_CLASS_1
priority
High Priority RTA_CLASS_1
Third-highest Low Priority RTA_CLASS_1
priority
Lowest priority (reserved)
IP
DCP
Chapter 10. PROFINET IO-Controller Operation
RXi Controller
RXi
Controller
PROFINET
IO-Device
Ethernet Traffic
August 2015
with PNC
Non-real-time data:
parameters, configuration, etc
Description
Media Redundancy
Cyclic PROFINET IO
High-Priority PROFINET Alarms
Low-Priority PROFINET Alarms
(reserved)
Device Discovery and
Configuration
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