History of industrial Automation

What is Automation? Sensors for sensing the input parameters (RTD, Thermocouple, Pressure, Flow, Level, etc) Transmitters for transmitting the raw signal in electrical form Control system which includes PLC, DCS, PID & PC based controllers Output devices / actuators like drives, control valves. Automation is delegation of human control functions to technical equipment for increasing productivity, better quality, reduced cost & increase safety in working conditions

INDUSTRIAL PROCESS INFORMATION FLOW ENERGY FLOW MATERIAL FLOW Objective of plant automation is to identify information flow and control material and energy flow as desired optimum way.

Evolution of Automation It is not a discovery of recent past but its rather as old as industry itself. Designers has attempted to make industry run as autonomous as possible based on available instrumental tools. With advances in theoretical and technical innovations, Full Scale Automation is commonplace for industries Flexible Manufacturing: merging of high technology instruments with most advanced method. It emerges a concept of CIM (Computer Integrated Manufacturing) Found several applications in space, surface, air and water transport

Factors contributed to development of automation Advances in microprocessor, memory and VLSI design Development in intelligent semiconductor and fiber optic sensors Implementation of programmable controllers Standardizations of modular hardware and software Advancement in computer technology Emergence of powerful interactive graphics for human interface Standardization of data communication links and networks Development in artificial intelligence and methods of knowledge engineering

AIMS OF PLANT AUTOMATION Production volume enhancement Production cost reduction Productivity increases Production quality improvement Optimal production flexibility Optimal production scheduling Optimal use of available facilities Market competition Humanization of work place Environmental pollution control Production reliability Plant safety

Process of Automation What are the Aims of Automations How they can be realized in given conditions Affecting factors: Investment cost Cost of possible production disturbances during automation process Approaches: Partial plant Automation Complete plant Automation Recent trend in automation is Integrated Plant Automation

Plant automation Modern Classical methods methods Manual control On-off control Close loop control PLC , PID control SCADA DCS

Classical approach to plant Automation Direct manual process control

Development up to 50s Controller ( Electrical , Pneumatic ,hydraulic ) PID controller Controller ( Electrical , Pneumatic ,hydraulic ) Sensor ( Temperature , pressure ,Level , Flow)

Modular presentation of a Control loop

Need of Process Computers Plant size and parameter increase No of operators increase on floor Sequential process Self regulation and re-adjusting of set point of controller required , example – chemical plant Data logging and material balance sheet Optimal process control

Computer based plant automation concept Digital computer has long been real alternative of analog control Initially they were unreliable, slow, bulky and too expensive First RW-300 computer based plant controlled online polymerization unit in Texas on March 12, 1959 Centralized computer era :- 1965-1970 Minicomputer era:- 1971- 1975 Distributed computer era :- Since 1975 Being unreliable, they had to be used in Operator Guidance Mode and Set-point Control Mode

Operator guidance mode

Set-Point Control mode

Direct Digital control

Advantage of DDC Easy configuration, reconfiguration and parameterization of process loop Self tuning of controller parameter Simple introduction of new control loop Possible to go for few advance control algorithm Model based calculation Comprehensive data acquisition and presentation

Disadvantage of DDC Low fail safety : failure of all digital loop Higher investment Higher Maintenance cost High Programming cost Overload of CPU Not possible for High level process control

Dual computer system for DDC

Back up concept of DDC

Distributed control system Relay based control system can’t control Continuous process DCS designed for Continuous process control To fill the gape of Discrete and batch process PLC introduced by General Motor High speed microcomputer introduced in 1972 using semiconductor technology In 1975 Honeywell introduced first DCS with PLC and DDC control facilities.

What is PLC? Hardware interface for input sensors and final output control element of the field. The field I/p include element like limit switches, sensors, push button and the final control elements like actuator, solenoid/control valves, drives, hooters etc. PLC Senses the input through I/P modules, Processes the logic through CPU and memory and gives output through output module

Leading PLC providers The leading PLC providers include Rockwell Automation : Allen Bradley (Micrologix, SLC, PLC, Control Logix) Siemens ( S7 200, S7 300 , S7 400) Grouppe Schneider : Modicon ( Nano, Micro, Premium, Quantum) GE Fanuc : Versa, Series 90-30, 90-70 OMRON

DCS DCS is powerful and flexible integrated control system that supply data acquisition , advance process control and monitoring , batch control capacities. Plant operator monitor and manipulates set point of process from central control room Operator views the process information on CRT screen and Control through keypad BASIC function of DCS Data collection ( analog and digital ) Generate output signal to actuator Plant GUI Remote location control

Advantages of the DCS The computer can record and store a very large amount of data The data can be displayed in any way the user requires Thousands of sensors over a wide area can be connected to the system The operator can incorporate real data simulations into the system Many types of data can be collected from the RTUs The data can be viewed from anywhere, not just on site

Disadvantages The system is more complicated than the sensor to panel type Different operating skills are required, such as system analysts and programmer With thousands of sensors there is still a lot of wire to deal with The operator can see only as far as the PLC

Leading DCS providers The leading DCS providers include Yokogawa : CS 3000 , CS 5000 (Earlier Centum Excel, Micro Excel) Honeywell : TDC 3000 Fisher - Rosemant - Delta V ABB - Freelance 2000 Moore - APACS Fox boro - I/A series

References Reference : Distributed computer control for industrial automation by Popovic & Bhatkar.