Ba Goetz Industrial Profile 0509

8/9/2019 Ba Goetz Industrial Profile 0509

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Industrial Profile for IEEE 802.1BA

Status Medienredundanz

Franz-Josef Goetz

Mai 2009

Siemens


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Industry


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Communication Services in Industry

Best Effort Traffic

- Configuration

- Diagnostic

- Web Services

- Events

-

RT-Low Streams

- General Automation to exchange typical anlog an digital values(manufactoring and process industry)

RT-High Streams- Motion Control to exchange typical anlog and digital values

(synchronized processes)

AV Streams

- Vision Systems(inspection, identification, tracking, counting and measurement)

Configuration

DiagnosticWEB Services

EventsGeneral

Automation

Synchr.

Process

Industrial Node

Best Effort TrafficRT-Low

Stream

RT-High

Stream

Ethernet

AV

Stream

Vision


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Streams for Time Sensitive Data in Industry

RT-Streams:

- time sensitive Data

- periodic transmission

Guaranteed QoS for RT-Streams along the end-to-end path:

- guaranteed low latency (low delay variation / jitter)

- guaranteed ressources (no packet loss)

- guaranteed bandwidth (throughput)

- deterministic behaviour in case of high network load


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Industrial Communication

IT-Services

IternetIternet

Factory AutomationEnergy Automation

Power Distribution

Motion Control

Best Effort Traffic

RT-High

Streams

RT-Low

Streams

125s100ms

Process Industry

Typical Application Cycle

or Reaction Time

Communication Services

AV- Streams


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Application Model in Industy (1)

The application model for RT-Streams in industry is differentfrom the application model used for AV-Streams.

Closed Loop application (real procecss, control application and communication)

Dead time shall be kept small to get short reaction time


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Application Model in Industy (2)

Node 1

Node 2

RT-Streams

Data Cycle

Node 3

Application

Data CycleData Cycle

Application

Application

Data Cycle

Application

Application

Application

Application

Application

Application

Application

Application Application

Control applications are synchroniced

Minimized jitter for communication and application

No buffering for RT-Data (just in time)

Consistent process image is required


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Use Cases

RT-Low Streams

Data Length < 300 bytes

Data Cycle < 1ms

32 devices per line

Latency < 1ms

Bay

Controller

Merging

Unit

MergingUnit

PLC

Actor-Sensor

Input /Output

Actor-

SensorActor-Sensor

RT-High-Streams

Data Length < 100 bytes

Data Cycle ~ 125s (typical)

Up to 16 devices in line

Latency < 125s

PLC

Input/Output

Drive

Drive

Drive

Power Distribution(IEC 61850)

Factory AutomationPower Industry

Motion Control


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Typical Topology for Bridged LANs in Industry

LinearTopology (Line, Ring)

Applications mostly feature distributed linear dimension, i.e. production lines

The network is tailored to the application, i.e. line topologies

To reduce total cost, 2-port-bridges are integrated into the end stations

For enhanced availability, lines are closed to rings

Homogeneous segments (100MBit or GBit)

Core

Distribution

+ Access


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Requirements for RT Streams

Low Latency for RT Streams

- RT-Low Streams: Latency < 1ms over 32 hops, data < 300 Bytes- RT-High Streams: Latency < 125s over 16 hops, data < 100 Bytes

(-> avoid interference Best Effort Traffic with RT Traffic)

Transmission Period for RT Streams

- RT-Low Streams: 500s .. 4ms- RT-High Streams: 125s .. 1ms

Synchronization

- End point time synchronization accuracy over 64 hops < 1s


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Requirements for RT Streams

Routing for AV and RT Steams

- No loss of AV and RT Streams caused by RSTP during network reconfiguration

- Shortest Path for RT Streams (low latency)-> do not use learning mechansim for RT Streams

Redundancy

- Alternate path for RT Streams (i.e. in ring topology)

Communication Relation for RT Streams

- Unidirectional RT Streams (Publisher -> Subscriber)

- Bidirectional RT Streams (Client Server ) PLC

Input-

OutputDevice

Input-

OutputDevice

PLC

Output

Device

Input

Device


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Integration of Industrial Communication in network


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Open Issues

AVB and 802.1 includes mechanism to control AV Streams.Simular mechansim may be used for RT-Streams.

Include extensions for stream handling to reduce latency?

Can we describe the extensions in an industrial profile?

How to proceed for industrial profile?


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Thank you !

Documents

Ba Goetz Industrial Profile 0509