PAST PRESENT & FUTURE TRENDS PAST PRESENT & FUTURE TRENDS IN INDUSTRIAL AUTOMATIONIN INDUSTRIAL AUTOMATION

Dr. J. PRAKASHDr. J. PRAKASHASSISTANT PROFESSOR IN INSTRUMENTATION ASSISTANT PROFESSOR IN INSTRUMENTATION

ENGINEERINGENGINEERINGMadras Institute of TechnologyMadras Institute of Technology

ANNA UNIVERSITYANNA UNIVERSITY

DATA ACQUISITION SYSTEM (DAS)DATA ACQUISITION SYSTEM (DAS)SUPERVISORY CONTROL SYSTEM (SC)SUPERVISORY CONTROL SYSTEM (SC)SCADASCADADIRECT DIGITAL CONTROL SYSTEM (DDC)DIRECT DIGITAL CONTROL SYSTEM (DDC)DISTRIBUTED CONTROL SYSTEM (DCS)DISTRIBUTED CONTROL SYSTEM (DCS)PROGRAMMABLE LOGIC CONTROLLER (PLC)PROGRAMMABLE LOGIC CONTROLLER (PLC)HARTHARTFIELD BUSFIELD BUS

MOTIVATION MOTIVATION Why is a Control Necessary?Why is a Control Necessary?Control ObjectivesControl Objectives

Personnel SafetyPersonnel SafetyEquipment ProtectionEquipment ProtectionEnvironmental ProtectionEnvironmental ProtectionSmooth operationSmooth operationProduct qualityProduct qualityProfitProfit

Case- I = Fin = FoutCase-II = Fin >FoutCase-III = Fin < Fout

Fin

Fout

Note: Constant Outflow

h1

h1

h2

TT

LT

TS

Controller Controller

PUMP

ON/OFF

Valve

OPEN/CLOSE

Level

HIGH/LOW

Temperature

HIGH/LOW

LS

FIELDCONTROL ROOM

1001

23

4 5 678

9

Gauge

10.0

0.0

2.0

4.0

6.0

8.0

500

Plot 0

Data Values

Power Controller

TT

LT

SP1

FIELD

Electronic Controller

PV1

SP2

PV2

Electronic Controller

CONTROL ROOM

Electronic Indicators & Recorders

I/P

Electronic Transmitter

Thyristor Power

Controller

Computer (DAS)

DAQ

TT

LT

SP1

I/P

DATA ACQUISITION

SYSTEMFIELD

CONTROL ROOM

Analog Controller

PV1

SP2 Analog Controller

PV2

Thyristor Power

Controller

Computer (SC)

AI

TT

LT

SP1

I/P

FIELD

CONTROL ROOM

Analog Controller

PV1

Analog Controller

PV2

SUPERVISORY CONTROL SYSTEM

AO

SP2

Thyristor Power

Controller

Computer (DDC)

AI AO

TT

LT

SP1

SP2

I/P

DIRECT DIGITAL CONTROL

FIELD

CONTROL ROOM

DAQ

DISTRIBUTED CONTROL SYSTEMDISTRIBUTED CONTROL SYSTEM

A system of dividing plant or process A system of dividing plant or process control into several areas of responsibility, control into several areas of responsibility, each managed by its own controller, with each managed by its own controller, with the whole system connected to form a the whole system connected to form a single entity, usually by means of single entity, usually by means of communication buses. communication buses.

Thyristor Power

Controller

MICROPROCESSOR BASED

CONTROLLER

AI AO

TTLT

I/P

MICROPROCESSOR BASED

CONTROLLER

AO AI

NI

NI

DISTRIBUTED CONTROL SYSTEM

OPERATOR STATION

OPERATOR STATION

Thyristor Power

Controller

MICROPROCESSOR BASED

CONTROLLER

AI AO

TT

LT

I/P

MICROPROCESSOR BASED

CONTROLLER

AO AI

NI

NI

DISTRIBUTED CONTROL SYSTEM

OPERATOR STATION

OPERATOR STATION

LOCAL CONTROL ROOM(LCU-I)

LCU-II

Main Control Room

100

0

20

40

60

80

Thermometer10

0

2

4

6

8

Tank

Thyristor Power

Controller

ON/OFF Valve

ON/OFF Valve

BATCH PROCESS

TS

LS

A+B C

A B

C

Programmable Logic Controller

ON/OFF Valve

Digital Inputs

Ladder Logic Programming

HART(Highway Addressable Remote Transducer)HART(Highway Addressable Remote Transducer)

Communication Protocol Communication Protocol –– Industrial Process Measurement Industrial Process Measurement and Control Applications.and Control Applications.

Hybrid Protocol Hybrid Protocol –– Analog +Digital Communication.Analog +Digital Communication.

HART Analog Communications HART Analog Communications --use industry standard 4use industry standard 4--20 20 mA signal only mA signal only ––only one parameter (Process Variable or only one parameter (Process Variable or Controller Output) Controller Output) ––communicated to the host system.communicated to the host system.

HART Digital Communications HART Digital Communications ––Added information (Device Added information (Device Status and Diagnostic Alerts;Process Variables and Status and Diagnostic Alerts;Process Variables and Units;Loop Current and % Range, Basic Configuration Units;Loop Current and % Range, Basic Configuration Parameters, Manufacturer and Device Tag etc.,) Parameters, Manufacturer and Device Tag etc.,) –– 3535-- 40 40 information itemsinformation items. .

HART Digital Communications HART Digital Communications –– Low level modulation Low level modulation superimposed on the standard 4superimposed on the standard 4--20 mA current loop 20 mA current loop ––BELL 202 MODEMBELL 202 MODEM-- Frequency Shift Keying (FSK) Frequency Shift Keying (FSK) ––Logic 1 Logic 1 –– 1200 Hz and Logic 0 1200 Hz and Logic 0 ––2200 Hz (with an 2200 Hz (with an amplitude of amplitude of ––0.5mA to +0.5mA) 0.5mA to +0.5mA) –– Device Device configuration, nonconfiguration, non--realreal--time diagnostics, and status time diagnostics, and status monitoring.monitoring.TwoTwo--way communication.way communication.Master/Slave Protocol (Message Rate Master/Slave Protocol (Message Rate ––2)2)HART burst mode communications (Message RateHART burst mode communications (Message Rate-- 3)3)Multivariable Instruments.Multivariable Instruments.HART Multidrop Mode.HART Multidrop Mode.Interoperability.Interoperability.

HART CommandsHART CommandsUniversal Commands ( Primary Variable and Units; Universal Commands ( Primary Variable and Units; Current output and % of Range; Manufacturer and Current output and % of Range; Manufacturer and device type) device type)

Common Practice Commands (Device range values; Common Practice Commands (Device range values; filter time constant; set fixed output current; filter time constant; set fixed output current; transfer function (square root/linear)transfer function (square root/linear)-- perform self perform self test test ––remote calibrationremote calibration

Device Specific Commands (PID enable; PID Device Specific Commands (PID enable; PID setpoint; start, stop or clear totalizer; user units, setpoint; start, stop or clear totalizer; user units, local display information; travel limits; valve local display information; travel limits; valve setpoint)setpoint)

Benefits of HART CommunicationBenefits of HART CommunicationImproved Plant operationImproved Plant operation

Commissioning and InstallationCommissioning and InstallationPlant operation and improved qualityPlant operation and improved qualityMaintenanceMaintenance

Operational FlexibilityOperational FlexibilityInstrument Investment ProtectionInstrument Investment ProtectionDigital CommunicationDigital Communication

Control in Field DevicesControl in Field DevicesHandHand--Held CommunicatorHeld Communicator

Network System: HARTNetwork System: HARTTechnology Developer: RosemountTechnology Developer: RosemountYear Introduced :1989Year Introduced :1989Openness: Open standard,600+ products, Openness: Open standard,600+ products, 130+suppliers130+suppliersNetwork Topology: pointNetwork Topology: point--toto--point; digital Multidroppoint; digital MultidropPhysical media: Twisted pairPhysical media: Twisted pairMaximum devices(2 masters,1slave); 17 multidrop(2 Maximum devices(2 masters,1slave); 17 multidrop(2 masters,15 slaves)masters,15 slaves)Maximum Distance:3,000mMaximum Distance:3,000mCommunication methods: Master/Slave; broadcastCommunication methods: Master/Slave; broadcastTransmission properties:2Transmission properties:2--4 updates/sec continuous 44 updates/sec continuous 4--20mA current loop20mA current loopData Transfer size :Data byte Structure : 11 bits, 15Data Transfer size :Data byte Structure : 11 bits, 15--50bytes50bytes

FOUNDATION FIELDBUSFOUNDATION FIELDBUS

All digital serial twoAll digital serial two--way communication system way communication system ––interconnects field equipments (sensors, actuators interconnects field equipments (sensors, actuators and controllers) and controllers) –– architecture for building architecture for building interoperable distributed real time control systems.interoperable distributed real time control systems.

Controller

FF- Level Transmitter

FF-Valve Positioner

FOUNDATION FIELD BUS TECHNOLOGY

FF Card

FF-Temp Transmitter

NI

Operator station

100.0

0.0

20.0

40.0

60.0

80.0

50.00tank [cm]

60.0

0.0

10.0

20.0

30.0

40.0

50.0

99.90.0h(t)0.00time [sec]

Operator Station

Multidrop wiring ( 32 devices on a single pair Multidrop wiring ( 32 devices on a single pair of wires (called a segment)of wires (called a segment)

Multivariable Instruments (Multiple variables Multivariable Instruments (Multiple variables from one field device )from one field device )

TwoTwo--way communication way communication

New types of informationNew types of information

Control in the fieldControl in the field

Interoperability :Device from different suppliers can Interoperability :Device from different suppliers can be communicate with each other and perform their be communicate with each other and perform their function in multifunction in multi--vendor environments. (standardize vendor environments. (standardize communication protocol from Physical layer through communication protocol from Physical layer through Application Layer)Application Layer)Interchangeability: Device from different suppliers Interchangeability: Device from different suppliers can be functionally interchanged by providing the can be functionally interchanged by providing the same functionality for the same type of devices. same functionality for the same type of devices. (Standardize various function blocks)(Standardize various function blocks)What user wants is to provide interoperability and the What user wants is to provide interoperability and the same basic functionality for the same type of devices same basic functionality for the same type of devices and room for innovation by suppliers for additional and room for innovation by suppliers for additional unique functionality (Provide a common way to unique functionality (Provide a common way to describe/understand suppliers specific features describe/understand suppliers specific features (DDL).(DDL).

Foundation fieldbus communications modelFoundation fieldbus communications modelThe Physical LayerThe Physical LayerData Link Layer and Application LayersData Link Layer and Application LayersThe User LayerThe User Layer

Physical Layer: Translating messages into Physical Physical Layer: Translating messages into Physical signals on the wire signals on the wire ––and vice versaand vice versaPhysical Layer: Provides the common Electrical Physical Layer: Provides the common Electrical Interface for all foundation fieldbus devices. (H1 Interface for all foundation fieldbus devices. (H1 segments segments --Power supply 9Power supply 9--32 Volts DC Power and 32 Volts DC Power and 1515--20 mA of current per device 20 mA of current per device –– communication rate communication rate ––31.25 31.25 kbaudkbaud ––32 devices per segment; 32 devices per segment; uptoupto 240 240 devices total with repeaters.devices total with repeaters.

Data link and Application layers: Control Data link and Application layers: Control transmission of data on the fieldbus.transmission of data on the fieldbus.Standard way of packaging the data as well as Standard way of packaging the data as well as managing the schedule for communication and managing the schedule for communication and functionfunction--block execution.block execution.User Layer: contains transducer block, resource block User Layer: contains transducer block, resource block and function blocks that describe and execute and function blocks that describe and execute ––device capabilities such as control and diagnostics. device capabilities such as control and diagnostics. Device descriptions enable the host system to Device descriptions enable the host system to interact with and understand these blocks without interact with and understand these blocks without custom programming.custom programming.

PID

#2

BKCAL_IN BKCAL_OUT

CAS_IN

FF_VAL

IN

TRK_IN_D

TRK_VAL

OUT

Analog Output

#3

BKCAL_OUT

CAS_IN OUT

Analog Input

#1

OUT

FOUNDATION FIELD BUS BENEFITSFOUNDATION FIELD BUS BENEFITS

Application clock (Real time clock)Application clock (Real time clock)Process Control is time dependentProcess Control is time dependentSystem management function System management function ––periodically periodically broadcast the time to all devices. Each device broadcast the time to all devices. Each device uses an internal clock to keep time between uses an internal clock to keep time between these synchronization broadcastthese synchronization broadcast-- all devices all devices have the same realhave the same real--time, enabling deterministic time, enabling deterministic communications and control executioncommunications and control executionAlarms and events are time stamped at the Alarms and events are time stamped at the device where they occur.device where they occur.

Parameter statusParameter statusStatus associated with every parameter (quality Status associated with every parameter (quality of the data)of the data)

Good, bad or uncertainGood, bad or uncertain

Scheduled CommunicationsScheduled CommunicationsAll devices and function blocks on a FF segment execute and All devices and function blocks on a FF segment execute and communicate communicate --process control information process control information --on a regular, repeating on a regular, repeating cycle.cycle.TimingTiming--master schedule in a link active scheduler master schedule in a link active scheduler ––residing in the residing in the host system or one of the devices on the segment. (link active host system or one of the devices on the segment. (link active scheduler function maintains the central, deterministic schedulescheduler function maintains the central, deterministic schedule for for the communication between devices on a segment. Communication the communication between devices on a segment. Communication reliabilityreliability--by compelling each device to transmit cyclic data when it by compelling each device to transmit cyclic data when it is schedules to do so. (if the LAS fails, then backup LAS in anois schedules to do so. (if the LAS fails, then backup LAS in another ther device or host system component takes over as master scheduler)device or host system component takes over as master scheduler)Cyclic communications use publisher/subscriber methodCyclic communications use publisher/subscriber methodCyclic communications are Deterministic Cyclic communications are Deterministic

Unscheduled Communication (or) acyclic communication Unscheduled Communication (or) acyclic communication (flexible timing(flexible timing--lower priority on the segment than scheduled lower priority on the segment than scheduled control loop related communication)control loop related communication)

Configuration informationConfiguration informationAlarm and trend dataAlarm and trend dataDiagnostic and status informationDiagnostic and status information

Benefits of FieldbusBenefits of FieldbusSystem can be built from devices manufactured by System can be built from devices manufactured by different vendorsdifferent vendorsNo single company controls the evolution of the No single company controls the evolution of the standardstandardInteroperabilityInteroperabilityReduced CostReduced Cost

Less wiring installation and maintenance cost because of Less wiring installation and maintenance cost because of multimulti--dropdropBetter diagnostics through softwareBetter diagnostics through softwareControl distributed in the fieldControl distributed in the field

More data available from the devicesMore data available from the devicesDiagnostic DataDiagnostic DataMultiple variablesMultiple variables

Network System: FIELDBUSNetwork System: FIELDBUSTechnology Developer: Fieldbus Foundation(H1/HSE)Technology Developer: Fieldbus Foundation(H1/HSE)Year Introduced :1995/2000Year Introduced :1995/2000Openness: Multiple vendorsOpenness: Multiple vendorsNetwork Topology: star, busNetwork Topology: star, busPhysical media: Twisted pair, fiberPhysical media: Twisted pair, fiberMaximum devices:32 devices/ segmentMaximum devices:32 devices/ segmentMaximum Distance:1,900 at 31.25 KbpsMaximum Distance:1,900 at 31.25 KbpsCommunication methods: PeerCommunication methods: Peer--toto-- peerpeerTransmission properties:31.25KbpsTransmission properties:31.25KbpsData Transfer size : 128 bytesData Transfer size : 128 bytes