DCS EVOLUTION-WEB CONTROL
APPLICATION
CONTROL SYSTEMS TREND
1) PLC
2) DCS
3) PC - Based Control
.
• PLC
: Introduced in the late 1960 to replace Relays and Hard-wired
DCS
: Introduced in the Mid-1970 to replace
pneumatic controls by using computers.
• PC-Based Control
: Introduced by the early 1980s to avoid the
DCS EVOLUTION
• LOCAL CONTROL : Initially control was performed local to the equipment control. The ADVANTAGE was low wiring costs .DISADVANTAGES were - not much control, monitoring, alarming & history.
• CENTRALISED CONTROL: With the advent of minicomputer, sensors and actuators
were into the Central Control (Computer).
• DISTRIBUTED CONTROL: With the advent of microcomputer, Distributed control
systems were installed in the plants near to the control room via proprietary digital communications lines called as Data Hiway. First DCS was developed by
Honeywell,U.S in 1975.
The ADVANTAGES were greatly reduced wiring costs, much more limited failure and less cost to add more points.
The DISADVANTAGES were that wiring costs were that wiring costs were still significant and there was lack of interoperability among controllers of various
DCS System Installations in RCF
1. Yokogawa - CS 3000 : Ammonia II 2. Yokogawa - CS 3000 : A N P
3. Yokogawa - CS 3000 : N N A P 4. Moore - APACS : Methyl amine 5. Fisher - Rosemant - Delta V field Bus : S T P
6. Honeywell - GUS : Ammonia I Synthesis 7. Yokogawa - Centum Excel : Steam Generation Plant 8. Moore - APACS : Suphala
9. Yokogawa - Micro Excel : Methanol 10. Yokogawa - Micro Excel : S A P/C N A 11. ABB - Freelance 2000 : A B C
12. Honeywell - TDC 3000 : Ammonia I
13. Honeywell - GUS : Ammonia/Urea - Thal 14. Fox boro - I/A series : D M A C - Thal
15. Fisher - Rosemant RS3 : P G R
DCS
• The importance of DCS systems to increase as global competitive dynamics in food and beverage, specialty metals, pulp and paper, pharmaceutical and fire chemical processing.
• The DCS has networking capabilities which are useful for business management.
• The DCS has capacity for processing large number of I/O points.
TYPES OF DCS : 1) Conventional DCS .
2) PLC based DCS. 3) Hybrid DCS.
CONVENTIONAL DCS
This is a pure “Process only” control system. Usually purchased from one vendor. This
DCS arranged into three categories: • Small - Less than $ 100,000.
• Medium - Greater than $100,000 & Less than $500,000. • Large - Greater than $500,000.
PLC Based DCS.
This is a network of PLC’s used to perform the task of conventional DCS and programmable functionality when required.
Hybrid DCS.
Performs both process and sequential control.
Open DCS System.
This is Field-Bus Control. Advantages are lower wiring cost and less failure, smaller expansion costs and multi vendor interoperability DCS and PLC can be more closely and efficiently interconnected.
Honeywell TDC 3000 DCS Architecture
AMC AMC US#1 US#2 HM LCN A B HG A B Data Hiway Field Field EC LinkHiway Gateway (HG)
• LCN Module. Provides a two way communication link between the Local Control Network and data hiway.
• 68020 based high performance intelligence module.
• Converts data and protocol between Local Control Network and data hiway. • Scans the hiway for alarm conditions.
• Synchronize time keeping for hiway-based process connected boxes.
• One HG is required for each data hiway that is connected to the LCN. Up to 20 data hiway pairs can be connected to an LCN.
• Connects following hiway resident boxes to LCN
1. AMCs
2. CPC ( critical process controller ). 3. DHP.
4. Hiway traffic director etc… HG Functions :
1. Data access :- gets box data requested from LCN modules.
2. Event processing :- sends process and box alarm to LCN modules 3. Database configuration :- 3000 points per hg can be configured.
Data Hiway
Data hiway provides communication link between hiway gateway, preferred access devices and process connecting box. Data hiway operates at 250 kbps.
It is redundant pair of 75 ohm coax cable connected to box. It may be 20,000 feet long.
There are 3 kinds of devices on the data hiway,
1. Respond only devices Ex:- A-MC (Advanced Multifunction controller) 2. Polled devices Ex:- PIU’s (Process interface unit)
History Module
• LCN Module. Stores process and system information that can be
displayed.
• Based on microprocessors 68020.
• Winchester disk for data storage.
• Communicates with all Modules on the LCN.
• Stores history and general information.
Universal Station
Universal station (US) communicates with all modules on the LCN, process
connected devices on the hiway via hiway gateway and UCN via network interface module (NIM).
The following are the features of US,
• Intelligent man/machine interface in the TDC 3000 system.
• Stands on the LCN. Communicates with all Modules on LCN, process connected devices on the Hiway via Hiway Gateway.
• Provides comprehensive facilities to the process operator, process engineer and maintenance technician on the Universal Window.
US provides comprehensive facilities to the following people, • Process engineer
• Process operator
AMC
•
TDC 3000 controller
1. Based on Motorola 68000 Microprocessor.
2. Faster execution and control with 500 ms processing rate.
•
Multifunction – Modulating, sequence, logic, I/O monitoring
communication and diagnostic.
•
Faster peer to peer communication over EC link ( 500 kbits/sec ).
•
Proven control techniques
1. Full function algorithms.
2. Process oriented programming.
•
Configured as a box on TDC 3000 Data Hiway. Supported by
HONEYWELL - GUS
HM
NIM
HPM HPM
Local Control Network
US#1 US#2 US#3 US#4
Printer Drive’s Printer
-High Performance Manager History Module
Network Interface Module Universal Station A B C on tr ol N et w or k
Honeywell System Description
• Global User Station
• History Modules
• Network Interface Modules
• Communication Subsystem - Local Control Network & Universal Control
Network
Global User Station
Overview
The TPS system provides an integrated interface between the process and the end user. This interface is named as the Global User Station (GUS).
GUS is an important part in the Honeywell Total plant Solutions offerings. It provides access to plant wide process network, plant or organization wide intranet or even Internet.
The following hardware is available to enhance the functionality of the GUS: • Integrated Keyboard for Operators as well as Engineer.
• Matrix printer supported by Windows NT. • 8 * CD-ROM
• 100MB ZIP Drive • 3.5” Floppy Drive
GUS has following functionality's :
• The “Human ” interface allows effective interaction of the Operator through the use of operating displays
• Engineering functions such as data point building, display building and report building are available.
Honey well GUS Hardware:
• Processor : Pentium Pro / 200MHZ • Memory : 64MB RAM ECC
• Cache : 256KB ECC
• Storage : 2 GB hard disk drive, CD ROM, Cartridge Drive • Video : 21” high resolution screen 1280 * 1024 Pixels • Colours : 256 color palette
• Keyboard : Integrated keyboard with mouse • PIN Connection : Built in Ethernet
• Cursor Control : QWERTY & Mouse/Touch Screen
Peripherals supported • Printer • 8 * CD-ROM • 1/4” Steamer Tape • 3.5” Floppy Drive • 100 Mb ZIP Drive
Honeywell GUS software
• Operating System : Windows NT version 4.0
• Base System : Provides real time data exchange between the
network and all GUS functions.
History Modules
The History Modules is the bulk module that can be utilized by all module connected to the Local Control Network. It is as the name implies the mass memory of the TPS System. The memory components of this module are one 1.8 gigabyte Winchester discs. It is controlled by an M68040 microprocessor. This provides the module with significant computing power that this used to structure much of the incoming data and format it
into
a form for easy retrieval.
The history in the model is provided by the History Module. Process variables are available for hourly, shift, daily and monthly average calculation and recording.
All system event history such as process alarms, system status changes, and error messages are stored into the History Modules.
Other modules have access to data in the History Modules for their functions. The History Module provides two functions, storage only and data structuring and
storage. The data structuring and storage function provides much of the historical data of the process to which the system is connected.
HM functions and Historization parameter
HM functions :
It can automatically backup the control databases in the HG, AM, CG. HM can store,
• Continuous process history. • Event journal (history). • Active system files. • Static system files.
• On process analysis program (maintenance aid)
HM Historization parameters :
There can be up to 10 HM’s on the LCN. There can be maximum of 150 groups per HM. Each group can have up to 20 points. All points in the group must be in the same unit.
Network Interface Module (NIM)
The Network Interface Module (NIM) provides the link between the local Control Network and the Universal Control Network. As such it make the transition from the transmission technique and protocol or the Local Control Network to the transmission technique and the protocol of the Universal Control Network. The NIM provides access by LCN modules data from UCN resident devices. The NIM is available in the redundant configuration to provide continued operation in the event of the primary failure. It can also do event processing.
There can be up to 10 redundant NIM pairs per LCN. A NIM can host upto 8000 tag names and supports a data transfer rate of 2400 parameters per second.
Communication Subsystem
Local Control Network (LCN)
The backbone of every TPS system is a communication network, known as Local Control Network. The LCN is a LAN through which TDC 3000 modules
communicate with each other. The LCN is a broadcast type of LAN. It is high speed
redundant communication bus that connect all the control room equipment. All information is transferred on the network at 5 million bits per sec.,serially. It is based on the IEEE 802.4 Token passing and Bus Standard.
Each LCN device that is connected to the Local Control Network is called a module. Up to 64 modules may be connected to the Local Control Network in a TPS system. The Local Control Network is designated as the primary and the other as the back up. Local Control Network provides time synchronization for all modules.
Universal Control Network (UCN)
The Universal Control Network is a high speed, high security process control network based on open system interconnection standards. It features a 5 megabit/second, carrier band, token bus network compatible with IEEE and ISO standards. It is used as the real time redundant Communications backbone for process connected devices such as the High Performance Process Manager (HPM), Advanced Process Manager . The UCN supports peer-to-peer
communication for sharing data and allowing greater co-ordination of control
strategies among network devices. The UCN uses redundant co-axial cables and can support up to 32 redundant devices
UCN supports 2 types of devices - Process manager.
- Logic manager.
High Performance Process Manager (HPM)
The High Performance Process Manager is the latest in the Progression of High Performance control products offered by Honeywell for the application to
Improve controlling of existing and new industrial processes. High Performance Process Manager is a fully integrated member of the TPS family. It is capable of :
• performing data acquisition and control functions
• fully communicating with operators and engineers at the GUSs and universal Work stations.
• Supporting higher-level strategies available on the Local Control Network through the Application Module and Host Computers.
The High Performance Process Manager uses a powerful multi-processor architecture
with separate microprocessors dedicated to perform specific tasks. The HPM consists
of two modules Communication and Control Module (CCM) and the I/O subsystem
the I/O subsystem consist of up to 40 Smart I/O Modules (SIOM). All control
operation are performed within the communication and control module. The process
engineer has complete flexibility of choice within the maximum HPM design limits.
These selections are implemented using the interactive tools provided by both the
GUS and Universal Work Station. The I/O processors, for example, provide such
functions as engineering unit conversion and alarm limit checking independent of the
communication and control modules.
The communication process is optimized to provide high performance network
communications. The control processor is HPM resource dedicated to executing
regulatory,logic and sequence functions, including a powerful user programming
facility. Since communication and I/O processing are provided by separate dedicated
hardware.
YOKOGAWA CENTUM EXCEL
ARCHITECTURE
EOPS /1 EOPS /2 ENGG. STATION EFGW EFMS EFCD Closed loop control signal Through I/O NESTHF BUS : High frequency Bus: no. of station on HF Bus are 32
EOPS : Extended Operator station: Hard disk capacity of EOPS is 80 MB EFCD : Extended field control
station : 80 laps per controller EFMS : Extended field mauture Monitoring signals
Through I/O NEST Third party system with PLC,Gas Analyser etc. thr RS 232C port At the rate of 9600 bps HF BUS (1 Mbps) A B I/O #1 ncst I/O #2 ncst I/O #3 I/O #4 I/O #5 ncst Micro-XL
HIS HIS PRT
PRT HIS
Windows NT Based Centum CS Configuration
NIU NIU
Ethernet Connectivity (optional)
Inkjet Printer DM Printer FCS RIO BUS OPERATOR/ENGINEERING STATION
OPERATOR STATION SUB-SYSTEM
INTERPLANT NETWORK PC (OPTIONAL)
DUAL “V NET” 10 Mbps
HIS – Human Interface Station. FCS – Field Control Station. NIU – Node Interface Unit. RIO Bus – Remote I/O Bus.
Centum CS 3000 System Overview
Centum CS 3000 is an integrated production control system for medium and large control applications. This system is a synthesis of the latest technology with Yokogawa’s experience and specialist know-how.
Centum CS 3000 system features :
• Synthesis of DCS with Personal computers. • Online Documentation.
• Powerful Operation and Monitoring Functions. • Two Types of Control Station.
• Compact I/O Modules.
• Powerful Control and Communication Functions. • Efficient Engineering.
• Virtual Test functions don’t require Control Station hardware. • Full-Featured Batch Package.
Centum CS 3000 System Overview
Centum CS 3000 is an integrated production control system for medium and large control applications. This system is a synthesis of the latest technology with Yokogawa’s experience and specialist know-how.
Centum CS 3000 system features :
•Synthesis of DCS with Personal computers.
•Truly open system for integrating multi-vendor solutions.
•High Reliability of computed process data by the unique fault tolerant control processor. •Powerful built in “RISC PROCESSOR” with high speed and dynamic error correcting code. •Remote I/O concept enables geographically distribution of I/O Modules thereby reducing cabling cost.
•1:1 Redundancy at almost all the system levels except for control processor which employs a special Redundancy with 4 identical CPU’s.
•Powerful Control Tools and Communication Functions.
•Virtual Test functions don’t require Control Station hardware. •Full-Featured Batch Package.
•Built in security features to prevent mal-operations. •CENTUM CS micro-XL Integration ( to be released ).
HIS HIS PRT
PRT HIS
CS3000 – System Configuration
NIU NIU
Ethernet Connectivity (optional)
Inkjet Printer DM Printer FCS RIO BUS OPERATOR/ENGINEERING STATION
OPERATOR STATION SUB-SYSTEM
INTERPLANT NETWORK PC (OPTIONAL)
V NET 10 Mbps
HIS – Human Interface Station. FCS – Field Control Station. NIU – Node Interface Unit.
Remote Domain System
CS, CS 1000
Centum – XL, -V, -MXL
CGW
CENTUM CS 3000 NETWORK
FCS FCS FCS
HIS
HIS HIS
CENTUM CS3000 SYSTEM SPECIFICATION
• NO. OF TAGS MONITORED
1,00,000
• TOTAL NO. OF STATION
256
• NO. OF DOMAINS
16
• NO. OF STATIONS IN A DOMAIN
64
CENTUM CS3000 SYSTEM SPECIFICATION
• Max. no. of stations : 256 / system
• Max. no. of Domains
: 16 / system
• Numbering of Domains
: 1 to 64
• Domain No. CS3000 Domain
(V net Domain)
: 1 to 16
• Max. no. of stations/Domain : 64
• Domain No.Virtual Domain
(Non V net Domain)
: 17 to 64
• Station NO. HIS : 1 to 64 in descending order
• Station NO. FCS
: 1 to 64 in ascending order
• Max. No. of ICS / Domain
: 16
• Max. No. of NIU / FCS : 8
• Max. No. of IOU / FCS : 40 ( Max. 5/ IOU)
• Max. length of Vnet
: 20 Km
Centum CS-3000 Communication
V net
V net is 10 mbps real time control bus which links station such as FCS , HIS , BCV and CGW. It can be dual redundant. It can be up to 500m using coaxial cable alone, or up to 20 Km when repeater are used or optical fiber is used.
• 10BASE2 cable
used by HIS, maximum segment length = 185 m • 10BASE5 cable
used by stations other than HIS(FCS,CGW etc.) maximum segment length = 500 m
V net Communication
FCS FCS HIS V net HIS Protocol : IEEE802.4 Access Control : Token Passing Trans. Speed : 10 MbpsTrans. Distance: 500m to 20Km
V net specification
ITEM
SPECIFICATION
Transmission route
Coaxial or fiber optical cable
Type
Bus type or Multi-drop type
Communication rate
10 Mbps
Transmission Distance
500M –20Km Max
Redundancy
Dual-redundant
Proto type
Token passing
V- net Features
• Real time control bus. ( Dual redundant possible )
• Cable : 50 ohm coax. cable with BNC connector ( 10Base2 comp. )
• Communication speed : 10 Mbps.
• High reliable token passing communication
( performance guaranteed )
• Std. max. length : 185 m.
• Max. length : 20 Km ( with optical fiber )
1.6 Km ( with coax. Repeater )
BNC Connector
VL net I/F card ( PCI ) VL net
Ethernet
HIS and ENG, HIS and supervisory systems can be connected by an
Ethernet LAN; supervisory computers and personal computers on the Ethernet
LAN can access messages and trend data in the CS 3000 system. The Ethernet
can also be used for sending trend data files from the HIS to supervisory
computers, or for equalizing the data in the two HIS station ( rather than using
the V net control bus to do this ). A system with only one HIS with engineering
functions installed, does not need Ethernet – but in general Ethernet ( and
Ethernet Specification
ITEM
SPECIFICATION
Transmission Route
Coaxial or Fiber optical cable
Type
Bus type or Multi–drop type
Communication Rate
10 Mbps
Transmission Distance
500m – 2.5 Km max.
Redundancy
Not available
TYPES OF HIS
• Console type HIS
• Desk top type HIS
HIS Hardware
• CPU
Pentium 166
• Main memory
96MB or larger(for op & monitoring only)
• Hard disk
1 GB or larger
• Display
256Colors min. resolution 800*600
1024*768 recommend(1280*1024 best)
• Serial port
RS232C*1 or more (for operation keyboard)
• Parallel port
1 port for printer or more
• OS
Windows NT 4.0 Workstation
Field Control Station Configuration
HIS Sub system Sub system I/O Unit I/O Unit HIS HIS V net Ethernet Node Interface Unit RIO Bus NodeConnection to Centum CS 3000 System
FCS FCS
Exapilot communication data Process data read/write
V-net
HIS ENG Exaopc
Exapilot client (engineering, operation) Exapilot server (engineering, operation) Exapilot client (engineering, operation) Ethernet
Features of Exapilot
• Standardize and Automate Manual Procedures • Improve Plant Operating Efficiency
• Improve safety of Plant Operation
Features of Event Analysis Package
• Analysis DCS Event History to Help You Enhance Efficiency.• Enhance Process Stability: Balance Process Events and Operator Actions. • When, Where, What (3W) Filters Help You Narrow Focus of Analysis.
OPEN DCS SYSTEM
Safety Barrier Pressure TX. Control Valve Terminator H M I Ethernet
Field bus
It is a standardized digital communication protocol between a process Control field devices
and the Control room. It is a simple pair of wires to power and carry the communication signal between the field devices and the Control room.
FEATURES :
• Drastic reduction in cable, conduits cable trays, marshallive racks, and connectors etc. • Drastic reduction in installation cost.
• Fewer non field devices.
• More reliability due to the smaller number of devices.
• More efficient operation due to better accuracy (no A/D and D/A conversion). • Easy integration into plant management system.
• Flexibility for different suppliers are interoperable and interchangeable. • Major reduction in maintenance cost.
Field-bus Benefits
Wiring Wire (pair) Screw Terms I/OCards ISBarriers
Traditional Field bus 3500’ 168 2 2 640’ 64 1 1 Savings Savings % Savings $ 2860’ 104 1 1 82% 63% 50% 50% $ 3000 Material $ 2000 Labor $ 5000 Total
Typically comments from a plant personal :
•Easy to identify what’s out there. •Consistent calibration procedure.
Function
Block(s)
Function
Block(s)
Transducer
Transducer
(Servo)
(Servo)
Block
Block
F
OUNDATION™fieldbus
Basic Components
Resource
Resource
Block
Block
Resource
Resource
Block
Block
Valve
FOUNDATION™ fieldbus Vocabulary
Blocks
Function
Block(s)
Function
Block(s)
Transducer
Transducer
Block
Block
Resource
Resource
Block
Block
Resource
Resource
Block
Block
F
OUNDATION™fieldbus
Temperature
Transmitter
FOUNDATION™ fieldbus Vocabulary
Blocks
FOUNDATION™ fieldbus Vocabulary
H1 and H2
• H1 Segment
– Moderate speed
– Use existing wiring
– Bus powered
– Can be intrinsically
safe
– Low power 2 wire
devices
– 4 wire devices
– Replace analog &
proprietary digital
• H2 Segment
– High speed
– Link multiple H1
Segments
– I/O subsystem bus
– Replace proprietary
networks
– New wiring
FOUNDATION™ fieldbus Vocabulary
New Approach for H2
• 100 Meg Ethernet technology with extensions
– Improve time to market
– High speed
– Mandatory redundancy
– Widely available technology and silicon
– Widely available tools
– Limited incremental development
– Many suppliers
– High volume for low cost
– Works with installed equipment
– Evergreen technology
H2 Segment 100 Meg Ethernet PLC H1/H2 Bridge Control Module H1/H2 Bridge Replaces Traditional I/O H1/H2 Bridge Replaces Traditional I/O Server H1 Segment H1 Segment H1 Segment
FOUNDATION™ fieldbus Vocabulary
H1/H2 Bridges
FOUNDATION™ fieldbus Standards
Organizations
• IEC
– International Electro-technical Commission
• ISA
– International Society for Measurement and Control
(formerly: Instrument Society of America)
• SP50
• CENELEC
– European standards body
FewerTerminations FewerTerminations Marshaling Junction Box IS (Ex i) Barriers H1 I/O Terminations H1 Fieldbus all-digital H1 Fieldbus all-digital H1 I/O Interface Controller
Similar I/O Cards
Similar I/O Cards
Cost savings: • wiring
• I/O cards & cables • terminations • IS barriers • marshaling Cost savings: • wiring
• I/O cards &
cables • terminations • IS barriers • marshaling Fewer Terminations Fewer Terminations Reduced Wiring Reduced Wiring
FOUNDATION™ fieldbus Topography
H1 Fieldbus Installations
Barriers
FOUNDATION™ fieldbus Topography
Intrinsic Safety
DeltaV System Architecture
Printer Printer 8 port Hub primary 8 port Hub Redundant Se ria l P S D I D O D I A O A I A I C on tr. C on tr. P S B la nk B la nk HI B la nk B la nk B la nk D O B la nk PLC For 8 DI & 8 DO H1 Connector 1 Operator station Engineering station8 wide carrier for I/O subsystem 2 wide carrier for
Power/Controller
Power supply Controller
Pressure Transmitter
I/O extension cable RS232 Modbus
DCS communication system Hierarchy
MIS
SCHED.
SUP.
DDC
SUP.
DDC
DDC
DDC
S A A S A S S S A S S A Level 5 Management Low data ratesSuperior responsibility
Level 1 Sensors (S) & Actuators (A) High data rates Low responsibility Level 2 Direct digital Control (DDC) Level 3 Supervisory control Level 4 Scheduling High Low
History of Process Control Signal
Around 50 years ago, most plant used 3-15psi pneumatic signal to control their process.
The last change change in signal standard was the open protocol HART digital communications format. The HART protocol provides simultaneous digital communications with the 4-20 mA output.
The next protocol change will be fieldbus. Fieldbus is entirely digital-there is no analog
Signal. Fieldbus also allows migration of control functions to field devices. Process control Timeline – The Evolution of Signal Standard
Signal standards have evolved over the years, starting with the 3-15 psi standard.
There are also other communication methods, but they have not gained widespread acceptance. With many standard there is typically a slow transition period as plant engineers and managers test period does gain widespread acceptance. However, once the benefits of the Fieldbus become tested and proven, more plant will install Fieldbus because of its benefit and economic cost. Digital plus Analog: HART with 4-20mA
Digital: Fieldbus
I/O Bus Network Protocol
I/O Bus Network
Discrete
Byte-wide
Data
Bit-wide
data
Several Hundred
Data Bytes
Analog
Device bus network Process bus networkProtocol Standard
Device bus network
Process bus network
Field Bus Foundation (Field Bus std.)
Profibus Trade Organization (Profibus std.) Byte-Wide Data Bit-Wide Data CAN Bus Inter Bus-S Device net SDS Seriplex ASI
Fieldbus Architecture
Fieldbus is more than just a new signal communications protocol, but a whole new way to control the process. With the release of the low fieldbus (H1), the entire fieldbus will be defined. Most of the recent published literature has focused on the intricate details of the fieldbus architecture, especially those layers that have not been released. However, except physical layer and the user layer, these layer are transparent to the engineers and the manager.
Physical Layer Data Layer Application Layer User Layer Sy st em m an ag em en t N et w or k M an ag em Maintenance information system Workstation st ac k Pump Level Transmitter Valve Multivariable Transmitter
Open System Interconnected Reference Model
Application
Presentation
Session
Transport
Network
Data link
Physical
MBAP, SMB, FTP, SMTP, FMS, IEC 61158, ANSI/ISA S50.2,IEEE 1451TCP, SPX, UDP
IP, IPX, NetBeui
HDLC, ETHERNET, ANSI/ISA S50.02
EIA-485, ETHERNET,ANSI/ISA S50.02
Physical – Provides the standard for transmitting raw electrical signals over the communication channels.
Data link – Contains the rule for interpreting electrical signals as data, error checking and physical addressing
Network – Describes the rule for routing messages through a complex network and deals with congestion.
Transport – Establishes a dependable end-to-end connection between two host.
Session – provides Management and Synchronization of complex data transaction.
Presentation – Establishes protocol for data format conversion, encryption and security.
Application – Contains protocol that accomplish task
such as e-mail, file transfer or reading a set of registers from a PLC.
Field Bus
Field Bus is a bi-directional digital communication that interconnects smart field devices to control system or to instrument located in the control room.
Field Bus is based on the OSI (Open System Interconnect), which was developed by the ISO (International Standard Organization) to represent the various functions required in any
Communication network.
Layer Function
7 Application Provides formatted data 6 Presentation Converts data
5 Session Handles the dialogue 4 Transport Secures the transport
connection
3 Network Establishes network connections
2 Link Establishes the data link connection
Field Bus
The OSI model consists of seven layers. However for real time application layers 3 to 6 are not considered since they deal with transference of data among networks. For such
application following layers are used: • LAYER 1 - PHYSICAL LAYER
Defines the type of signal, transmitting medium, data transmission speed, etc. • LAYER 2 – DATALINK LAYER
Define the interface between the physical layer and the application layer. It establishes how the messages shall be structured and normalizes the use of multiple masters.
• LAYER 3 – APPLICATION LAYER
PHYSICAL LAYER
The Physical layer defines the medium that transport the messages frames, the signal shape and amplitude limits, data transfer rate, and power distribution.
Technical Characteristics:
Physical Medium
Three types are defined: wires, optic fiber, and radio signals. The specification for wire has been already approved.
Bit rate for wire media 31.25 Kbps (H1)
1 megabits and 2.5 megabits (H2).
H1 and H2 are classification of the two hanks of Field Bus target applications. H1 has low speed and utilizes existing wires. H2 has high speed and may require independent wires to power up field devices.
Number of devices per link (31.25Kbps)
2 to 32 devices, without power and no IS (intrinsic safety). 2 to 6 with power and IS.
Maximum distance
Up to 1900 meters for 31.25Kbps, without repeaters. Up to 750 meters for 1 megabits. Up to 500 meter for 2.5 megabits.
PHYSICAL LAYER
Signal Modulation
Manchester bi phase L synchronous.
Physical layer preamble
on transmissions, the physical layer will add to the data sent by the layer above a preamble and one start delimiter in the beginning of the frame and one end delimiter at the end delimiter at the end of the of the frame.
DATA LINK LAYER
The Data Link Layer will assure the integrity of the message by using the frame check sequence: Two bytes added to the frames and a polynomial calculation of all frame data.
The Data Link Layer also checks to see that the data reaches the devices correctly.
Technical characteristics
Medium Access: There are three forms to access the network: • Token passing:
Token is the right to initiate a transaction on the bus. A device must have the token to initiate a conversation. As soon it finishes it will return the token to the LAS (Link Active Scheduler). The LAS send the token to the unit that requested in either in a pre-configured way or via scheduling.
• Immediate response:
A master station will give an opportunity to the station to reply with one frame. • Requested token:
a device request a token by using a code in any of the response sent to the bus. The LAS will hear this request and will then send a token to the device when there is time
APPLICATION LAYER AND MANAGEMENT
The Application Layer provides a simple interface to the end user’s application. Basically , it defines how to read, write , interpret and execute a message or command. A big part of this job is to define the message syntax. The contents include the requested message, action taken, and the response message.
The management defines how to initialize the network : tag assignment, address assignment, clock assignment, clock synchronization, distributed application scheduling across the network or association of the input and output parameters of the function blocks. It also controls the operation of the network with statistic of faults and detection of the addition of the new element or the absence of a station. The system always look for the new stations on the bus by polling the possible station addresses.
Digital Communication Protocol
ISO - International Standard Organization. Responsible for developing the model that the communication specification are based upon as well as standards for each layer of communication specification.
IEEE - Institute of Electrical and Electronics Engineers. Formed the IEEE 802 project for defining standards for network media and access methods.
SP72 - Institute Society of America, Standards and Practice committee Number 72 Developing EIA1393 companion standard for process control messaging.
SP50 - Institute Society of America, Standards and Practice committee Number 50 Developing standards for digital communication between field devices.
F.I.P - Factory Information Protocol, approved French National Standard.
Profibus - Process Fieldbus, approved German National Standard.
WorldFIP - A U.S./French conglomerate of instrument manufacturers.
ISP - Interoperable Systems Project, a multinational group of some 80 manufacturers spanning U.S/Europe and Japan.
HART COMMUNICATION PROTOCOL
Why HART protocol ?
4-20 ma is tried, tested and widely used standard but only limited amount of information is sent by a 4-20 ma signal.
HART (Hiway Addressable Remote Transducer) protocol enhances these operations by transmitting digital data along with the 4-20 ma signal – without interfering with it ! HART permits two-way communications. It also has all digital mode that allows instrument to be connected to a single cable, cutting installation costs dramatically.
Features :
1. Field proven concept that is easy to understand and use. 2. Compatible with existing 4-20 ma systems.
3. Simultaneous point-to-point 4-20 ma and digital communication. 4. Alternative multi-drop mode.
5. Measured variables, tag no. , range and span settings, device information, diagnostics and simple messages transmitted.
6. Digital response time of 500 msec; burst mode response of 300 msec. 7. Open architecture; freely available to any vendor and every user.
Method of Operation :
The Hart protocol operates using the FSK principal. The digital data is made up from two frequencies –1200 Hz and 2200 Hz representing bits 1 and 0 respectively. Sinusoidal waves of these frequencies are superimposed on the DC analog signal cables to give simultaneous analog and digital communications
HART Protocol Structure :
HART follows the basic Open Systems Interconnection (OSI) reference model, developed by the International Organization for Standard (ISO). The HART protocol uses a reduced OSI model, implementing only layers 1,2 and 7
OSI reference model
Open Systems InterconnectionsHART COMMUNICATION PROTOCOL
LAYER
FUNCTIONS
HART
7 Application Provides formatted
data HART instructions 6 Presentation Converts data
5 Session Handles the dialogue
4 Transport Secures the transport connection
3 Network Establishes network connections
2 Link Establishes the data
Layer 1, the physical layer, operates on the FSK principle Data transfer rate: 1200 bit/s
Logic “0” frequency: 2200 Hz Logic “1” frequency: 1200 Hz
the vast majority of existing wiring is used for this type of digital communication.
Layer 2, the link layer establishes the format for a hart message. HART is a master/slave protocol.
the structure of these messages is given below:
SD – start character. AD – display terminal and field addresses. CD – HART instruction. BC – Byte count.
Status – Field device and communication status (only from field device to master)
The individual characters are : 1 start bit, 8 data bits, 1 bit for odd parity and 1 stop bit.
HART PROTOCOL LAYERS
Layer 7, the application layer, brings the HART instruction into play. The master sends messages with requests for specified values, actual values and any other data or
parameters
available from the device. The field device interprets these instruction as defined in the HART protocol. The response message provides the master with the status information and data from the slave.
For slave devices, logical uniform communication is provided by the following command sets:
Universal commands – understood by all field devices.
Common practice commands – provide functions which can be carried out by many, though not all, field devices.
Drive-specific commands – provide functions which are restricted to an individual device.
DATA TRANSMISSION
Types of data transmission : Frequency shift keying (FSK) Transfer rate : 1200 bit/s.
‘0’ bit information frequency : 2200 Hz ‘1’ bit information frequency : 1200 Hz
Signal structure : 1 start bit, 8 data bits, 1 bit for odd parity, 1 stop bit. Transfer rate for simple variables : Approximately 2/s (poll/response)
DATA INTEGRITY
Physical layer : Error rate destination circuit : 1/(10^5)
Link layer : Recognizes : all groups up to 3 corrupt bits and practically all longer and multiple groups.
Application layer : Communication status terminated in a response message.
MODBUS
The MODBUS protocol describes an industrial communication and distributed control system developed by Gould-Modicon. MODBUS is a Master/Slave
communications protocol, whereby one device (Master), controls all serial activities by selectively polling one or more slave devices. The protocol provides for one master device and up to 247 slave devices on a common line. Each device is assigned an address to
distinguish it from all other connected device.
Only a master initiates a transaction. Transactions are either a query/response type, or a broadcast/no-response type. A transaction comprises a single query and single
response frame or a single broadcast frame.
Certain characteristic of a MODBUS protocol are fixed such as frame format, frame
sequences, handling of communication errors and exception conditions, and the functions performed.
Other characteristics are user selectable. These include a choice of transmission media, baud rate, character parity, no. of stop bits and the transmission modes. The user selected parameter are set at each station. These parameter cannot be changed while the
RS-232 Communication
RS-232 is an asynchronous communication network. Normally, a binary system is used to transmit data in ASCII (American Standard Code for Information Interchange)
format. This code translates human readable code (letter/numbers) into “computer readable” code(1’s and 0’s).
There are 2 types of RS-232 devices. The first is called a DTE (Data Terminal Equipment) device and a common example is a computer. The other type of device is called DCE (Data Communication Equipment) device and a common example is a modem.
In RS-232 the first thing a terminal send is start bit. This start bit is a synchronizing bit added just before each character being send. The last thing send is a stop bit. This stop bit informs to the receiving terminal that the last character has just being send.
RS-232 communication is done through Serial port which usually has a 9-pin configuration. The pin and their purposes are shown below.
RS-232 Communication
9-PIN
PURPOSE
1
Frame ground
2
Receive data (RD)
3
Transmit data (TD)
4
Data terminal ready (DTR)
5
Signal ground (GND)
6
Data set ready (DSR)
7
Request to send (RTS)
8
Clear to Send (CTS)
PC-to-PC Communication through Serial Port
CD 10 RXD 20 TXD 30 DTR 40 GND 50 DSR 60 RTS 70 CTS 80 RI 90 01 CD 02 RXD 03 TXD 04 DTR 05 GND 06 DSR 07 RTS 08 CTS 09 RIPC-to-PC Communication through LPT1 Port
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22Flavours of Internet Telephony
The Internet The Internet The Internet PC PC PC Phone Phone PhoneLocal ISP Local ISP
Local ISP Local ISP Voice Gateway Local ISP PC-to-PC PC-to-Phone Phone-to-Phone Dial-up or Leased Line Access Code
APACS - Operation Platform
Database Ownership
Operator Console Engineer Console Operator Console
Controller Module
Transmitter Interlock I/P Valve
I/O Modules
I/O Level•TAGS •Range •Engineering Unit •Diagnostics Console Level Controller Level
TODAYS INDUSTRIAL SYSTEMS
H M I
Planning
H M I
1 2 3
4 5 6
Application Drivers Devices PLC DCS I/O---PC Based Industrial Systems
H M I
Planning
H M I
1 2 3
Devices PLC DCS I/O OPC Client Application OPC Server---Enterprise Automation Schemes
Windows NT Windows NT Embedded Real System Control network Corporate IT Network ServerWindows NT (“New technology”)
FEATURES:
• A true 32 bit processing.
• A very reliable operating system.
• Real operating system.
TECHNICAL ASPECT:
• Multiprocessing, Multithreading and partitioned memory space.
• Security - C2 compliance.
• In-built networking.
• Internationalization .
• Human interface as Windows 95.
• Object - based : DCOM/OLE - ActiveX.
• for special need of the process industries. DCOM and OLE are not robust,
deterministic and secure.
Transparent inter-connectivity to typical business systems in plants: 1) ODBC : It provides access to most SQL databases.
2) ActiveX/OLE : Supports data access between application and embedding of one applications function within another.
3) DDE : Dynamic Data Exchange supports simple data exchange between applications such as plant data populating an Excel spread sheets.
Windows NT features
Windows NT is gaining ground in open control because of the following advantages : • User acceptance.
• Corporate interoperability • Ease of use.
• Connectivity.
• Scalability for small and large application.
However, Windows NT has the following disadvantages : • Needs a lot memory and processing power.
• Optimized for office, not control, requirements. • Requires a disk drive which may fail.
• Depends on single vendor. • Reboots at unexpected times • Unstable operating system.
Embedded control Operating System - QNX
QNX real-time operating system, has evolved from the first-ever micro-kernel operating system for PCs into one of the best selling and most trusted operating systems for mission critical application. Today, QNX is the real time operating system in industrial automation, hand held devices, controllers and soft PLCs
QNX is recognized as :
• The fastest and most dependable real time operating system. • The most proven high speed, deterministic real time kernel. • Having a hard real time engine that gives PLC-style control. • Enabling data acquisition with milliseconds resolution.
• Providing a fault-tolerant architecture on which you can run control, events, alarms in a virtually crash-proof environment.
Windows NT - for Process control
Windows NT features :
• A true 32 bit processing.
• A very reliable operating system. • Real operating system.
• Multiprocessing, Multithreading and partitioned memory space. • Security - C2 compliance.
• In-built networking. • Internationalization. • Human interface.
• Object-based DCOM/OLE :
The sending object is shown as client and receiving object is known as server. The MS technology allows any developer to produce small, self contain objects that have “packaged” visual component and specific action. These components are called
“ActiveX” objects. NT’s OLE technology is part of Microsoft’s Distributed
Component Object Model (DCOM) operating across networks. Anyone can develop ActiveX Object using VC++ or even VB on a PC. For special needs of the process control industries DCOM and OLE are not secure, deterministic and robust enough. OPC is a process industry consortium that is working to make extension to
Ethernet
Ethernet was originally designed by Digital, Intel and Xerox (DIX) in the early 1970’s and has been designed as a broadcast system. The original format for Ethernet was developed in Xerox Palo Alto Research center (PARC), California in 1972. The two inventors were Robert Metcalf and David Boggs.
Ethernet version 1.0 and 2.0 followed until the IEEE 802.3 committee re-jigged the Ethernet II packet to form the Ethernet 802.3 packet. Nowadays you will see either
Ethernet II (DIX) format or Ethernet 802.3 format being used.
The ‘Ether’ part of Ethernet denotes that the system is not meant to be restricted only to one medium type, copper cables, fiber cables and even radio waves can be used.
Briefly, stated Ethernet what is referred to as the Physical layer and the Data-link layers protocols. The physical layer defines the cable types, connectors and electrical
characteristics.
The Data link layer defines the format an Ethernet frames, the error checking method and the physical addressing method. As Ethernet is only a Physical/Data link layer other protocols need to be added on top of it to address the issues of routing, end-to-end data integrity and house specific network task are carried out.
10Base5
Traditionally, Ethernet is used over ‘thick’ coaxial cable called 10Base5 ( the 10
denotes 10 Mbps, base means that the signal is baseband i.e, takes the whole bandwidth of the cable, 5 denotes 500m maximum length ). The minimum length between stations is 2.5m.
The cable is run in one long length forming a ‘Bus Topology’. The segments are terminated by 50 ohm resistor and the shield should be grounded at one end only.
10Base2
Thin Ethernet (Thinnet) uses RG-58 cable and is called 10Base2 (the 2 denotes
200 mtr maximum length cable). Each station connects to the Thinnet by way of
Network Interface Card (NIC). At each station the Thinnet terminates at a T-piece and at each end of the Thinnet run a 50 ohm terminator is required to absorb stray signals thereby preventing signal bounce.
10BaseT
Nowadays, it is becoming increasingly important to use Ethernet across Unshielded Twisted Pair (UTP) or Shielded Twisted Pair (STP), this being called 10BaseT (the T
denotes twisted pair). UTP is installed in star wire format and Ethernet Hubs with UTP ports (RJ45) centrally located. Also there should be no more than a 11.5db signal loss and the
minimum distance between devices is 2.5 meters.
The advantages of the UTP/STP technology are gained from the flexibility of the system, with respect to moves, changes, fault finding, reliability and security.
10BaseF
10BaseF standard developed by IEEE 802.3 committee defines the use of Fiber for
Ethernet. 10BaseFB allows up to 2 Km per segment and is defined for Backbone application such as cascading repeaters. 10BaseFL describes the standards for the Fiber optic links
between stations and repeaters allowing up to 2 Km per segment on multimode Fiber.
The following table shows the RJ45 pin outs for 10BaseT :
RJ45 Pin
Function
Colour
1
Transmit
White/Orange
2
Transmit
Orange/White
3
Receive
White/Green
4
Blue/White
5
White/Blue
6
Receive
Green/White
7
White/Brown
8
Brown/White
Ethernet
PC-to-PC Communication through Ethernet
RJ45
RJ45
1 1 2 2 3 3 4 4 5 5 6 6 7 7 8 8Controller
Controller
Workstation Workstation Workstation Workstation
Switched Hub
Segmented (star) topology Bus topology
Wireless LAN
Wireless LAN is based on standard IEEE 802.11b which throughput of up to 11Mbps in the 2.4 Ghz band. Similar Wireless Personal Area Network (WPAN) are Bluetooth and Infrared. Ethernet works on the CSMA/CD technology but wireless LAN has difficulty of detecting collision in Radio frequency. Therefore they are using CSMA/CA (Collision Sense Multiple Access / Collision Avoidance) technology to transmit data. Physical Layer is either Photonic or Radio frequency.
Process control Software characteristics
The most important feature of process control system is that it needs to be reliable. The
process control system used has to be completely crash-proof and any changes in the system need to be made on-line.
The process control needs to be made real time, which means that it can update the I/O data table and process the control program in the time required by the process.
A process control system that is deterministic refers to whether the operating system allows the highest priority task to work without interruption from task with lower priority. Software offerings in the automation and the process control fields must be versatile and open enough to address the needs of different applications.
Finally the chosen solution must deliver tangible, quantifiable values such as : 1. Reducing project implementation time and cost.
2. Improving time-to-market.
3. Achieving higher production and quality. 4. Cutting maintenance and training cost. 5. Increasing profits.
PC-based control system features
Unlike the other systems, PCs provide a more open architecture making them ideal for improving, optimizing and integrating the overall automation process, as well as conducting control task.
In addition PCs offer the following features : • Lower cost.
• Ease of use.
• Graphical user interface.
• Easy integration of logic, motion and process control. • Simplified application development.
• Software portability
• Independence from proprietary control system. Using PCs enable the following functions,
• Millisecond time stamping which is essential to utilities. • Real time control.
• Sequence of events. • Alarming.
PLC conceptual overview
Process Graphics History & Trend Alarm & Events SCADA configuration editor Other Aspect systemopc
Modbuscomli
Protocol
xx
Protocol
yy
SCADA server OPC serverOP Client SCADA Control Aspect
Real-time database
PLC Programming Standards
The open, manufacturer-independent programming standard for automation is IEC 61131-3. You can thus choose what configuration interface you wish to use when writing your application :
• Ladder Diagram
• Instruction List
• Function Block Diagram
• Sequential Function Chart
• Structured Text
All users, be they plant electrician or computer scientists, thus have a configuration interface in which they can feel at home.
Industrial IT Trends
The availability of information is becoming increasingly crucial in the view of growing global competition. In future, a decisive competitive edge can only be achieved by providing the right information at the right time, in the right place and in the right form for the right person. these leading- edge application are continuously optimized and repositioned.
Industrial IT consists of five components:
1. Engineering IT 2. Operation IT 3. Production IT 4. Optimization IT
ASSET OPTIMIZATION
