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