Industrial Automation
Automation Industrielle
Industrielle Automation
1.5
Control System Architecture
Arquitectura de control
Architecture de Contrôle - Commande
Leittechnik-Architektur
1.5 Control System Architecture
1 Introduction
1.1
Automation and its importance
1.2
Applications of automation
1.3
Plants and controls
1.3.1
Open loop and closed loop control
1.3.2
Continuous process
1.3.3
Discrete process
1.3.3
Dual plants
1.4
Automation hierarchy
1.5
Control System Architecture
Industrial Automation
Control system hierarchy 1.5 - 2
Principle
The control system is a communication system consisting of
controllers and links.
The structure of the control system should reflect the
structure of the plant
Ideally, each unit of the plant should have its own controller,
interacting with the controllers of the other, related units,
mirroring their physical interaction.
Example: Airbus: a wing is delivered with its own computers.
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Control system hierarchy 1.5 - 3
System Architecture
Conceptual model presenting
• Structure
• Relationships
• Behavior
Including
• Description of most important elements of system
• Mapping of functionality onto hardware and software components
• Description of top-level human interaction with components
Goal:
• support reasoning about elements, structure and behavior
• guide for implementation
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Control system hierarchy 1.5 - 4
Example: Power plant control - 1980 (!)
Control systems still look similar
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Control system hierarchy 1.5 - 5
Buses and processors in industrial plants
instrument bus
(mimic board)
disk
Process pictures
open network, WAN
Operator panel
Mimic board
Process Data Base
workstation bus
station
station
Logging
plant network (500m .. 3 km) – includes control network
processor pool
P
P
P
C
P
PLC nodes
(multi-processors)
P
C
P
node bus
I/O MEM I/O
MEM BC
directly coupled
input/
output
fieldbus (30m..2 km)
control
stations
backplane bus
sensor bus
sensor bus (0,5.. 30 m)
transducers
plant (Werk, usine)
M
valve
thermo-couple
Industrial Automation
position
motor
Control system hierarchy 1.5 - 6
Example: Production management system
production
planning
enterprise network
scheduling
maintenance
quality control
plant network
transportation
cell control
cell
manufacturing
cell control
floor network
robot
controller
milling
machine
rail-guided
vehicle
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Control system hierarchy 1.5 - 7
Plant with process (e.g. chemical) and electrical (substation) parts
Engineering
Workplaces
plant network
vertical
communication
IEC 61850
connectivity server
CN Connectivity
Server (and router)
Aspect Servers
process network
substation network
horizontal communication
interface
controller
CI871
PB
PI
PN
PI
PB
PI
PN
PI
PB
PI
Engineering
PN
PI
PB
PI
PN
PI
PB
PI
PN
PI
Profibus
horizontal communication
Profinet RSTP
Industrial Automation
Engineering
LANs are
separate:
there is no
IP routing
between
them
SAN IEDs
PI
PI
PI
PI = Process Interface
MU = Merging Unit
MU
PI
MU
PI
bay bus
Control system hierarchy 1.5 - 8
Example: Newspaper Printing Architecture
MPS =
Managed
Print Services
Each level has its own bus !
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Control system hierarchy 1.5 - 9
Example: ABB Industrial IT (redundant system)
Workplaces
(clients)
Plant Network / Intranet
Enterprise
Optimization
(clients)
3rd party
application
server
Firewall
Mobile
Operator
Plant Network (Ethernet)
connectivity
server
aspect
server
application
server
engineering
workplace
Control Network (Ethernet)
Serial or
fieldbus
Field Bus
Programmable
Logic Controller
AC 800C
Redundant
AC 800M
3rd party
controllers,
servers etc
touch-screen
Field Bus
sensor network
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Control system hierarchy 1.5 - 10
Centralized (Hierarchical) Control Architecture
Central Computer
(Mainframe)
Group
Group
Group
Control
Control
Control
Sensors, Actors
PLCs
plant
Classical, hierarchical, centralized architecture.
The central computer only monitors and forwards commands to the PLCs
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Control system hierarchy 1.5 - 14
Decentralized Control System (DCS)
hierarchical
(vertical communication)
engineering
workstation
operator
workstation
data logger
peer-to-peer (horizontal communication)
plant bus
controller
controller
controller
controller
field bus
plant
all controllers can communicate as peers (without going through a central master),
restricted only by throughput and modularity considerations.
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Hierarchies are simple and traditional
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Control system hierarchy 1.5 - 16
but Distributed Control Systems reflect a more complex world....
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Control system hierarchy 1.5 - 17
Assessment
1. What is a bus and why do we have more than one kind of
them in a plant?
2. Name the parts of a typical hierarchical control system its
busses and controllers
3. How does the network hierarchy relate to the plant control
hierarchy?
4. What is the difference between a centralized and a
decentralized control system ?
What are the (dis)advantages of the two approaches?
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Control system hierarchy 1.5 - 18