Process Loop Components

IE 311 PROCESS LOOP COMPONENTS

Objectives:

After completion of this course students will be able to:

A) Understand the principle of operation, and selection of different components in order to integrate the process control system.

B) Work upon logic development, testing of various process control components.

Unit I

Fundamentals of process control
Elements of process control loop, concept of process variables, set point, controlled variable, manipulated variable, load variable.
Representation of process loop components using standard symbols(basic with reference to control loop), and Examples of process loops like temperature, flow, level, pressure etc.
Process characteristics: Process load, Plant lags: Measurement lag, control lag, process lag, Distance/ velocity, lag(dead time), transfer lag, Regulation, Capacity
[08 Hrs]

Unit II

Transmitters: Need of transmitter (concept of field area & control room area), Need for standardization of signals, current, voltage and pneumatic signal standards, concept of live & dead zero, Signal conditioning (analog & digital) for RTD, T/C, magnetic flow meter, DPT, span & zero adjustment, Two wire transmitter, Electronic and pneumatic transmitters Electronic Differential Pressure Transmitter: Types, mounting (Installation), manifolds, calibration setup, Application of DPT for level measurement, Zero elevation, Suppression.
SMART transmitter: Comparison with conventional transmitter, Block schematic.
Converters: Difference between converter & transmitter, Pneumatic to current converter, Current to pneumatic converter

[08 Hrs]

Unit III

Types of control actions: Discontinuous: ON/OFF, Time proportional
Continuous: Proportional, integral, derivative, proportional-Integral, Proportional- Derivative, Proportional-Derivative-Integral, Anti-reset windup, Rate before reset
Concept of bump less transfers in PID controller, Effect of process Characteristics on PID combination, control actions for various processes.
Digital PID controllers: concept of velocity & position algorithm, block schematic of series and parallel combinations.
Tuning of controller: Quarter Amplitude Decay, controller performance criterion, Tuning methods: Process Reaction curve(open loop), Ziegler Nichols (closed loop), set point tuning Vs load disturbance tuning.

[08 Hrs]

Unit IV

Programmable Logic Controller (PLC)
Continuous versus Discrete Process Control, ladder diagram using standard symbols, Architecture of PLC, Types of Input & Output modules (AI, DI, AO, DO), wiring diagram, Interfacing pneumatic & Hydraulic systems, Fixed & Modular PLC (Rack, Slot, Grouping), Specifications, manufacturers, PLC ladder diagram and instructions, PLC Programming for process applications.

[08 Hrs]

Unit V

Control valve: Necessity, comparison with other final control elements, Classification of control valves based on: Valve body. Construction, type of actuation, application etc. Construction, Advantages, Disadvantages & applications of Globe: single, double, 3way, angle, Gate, Needle, Diaphragm, Rotary valves, Ball, Butterfly.
Types of actuators: Construction, Advantages, Disadvantages & applications: Spring Diaphragm, Piston cylinder(power cylinder), Pneumatic, Hydraulic, Electro-hydraulic, Electric, and smart actuators.
Control valve terminology: Range ability, turndown, valve capacity, Air to open, Air to close, valve gain etc
Control valve characteristics: Inherent & installed Control valve accessories
Positioners: Application/Need, Types, Effect on performance of control valves. Volume boosters, Pressure Boosters, Reversing relay, Solenoid valves, Air lock, position indicating switches, Electro pneumatic converter, Hand wheel.
Cv sizing concept & basic equations

[08 Hrs]

Unit VI

Auxiliary components: Construction, working & applications of: Feeders, Dampers, Alarm annunciator, square root extractor, High/Low selectors, Flow tantalizer, Computing relays, Seals, Snubber. Hazardous area classification & intrinsic safety, Concept of safety cycle, HAZOP, fault tolerance and safety integrity level.

[08 Hrs]

Text Books:

ﾂ｡ Process control and instrument technology, C. D. Johnson, TMH

ﾂ｡ Instrumentation for process measurement and control, N. A. Anderson

ﾂ｡ Process Control, Instrument Engineering Hand book, B. G. Liptak

ﾂ｡ Introduction to programmable Logic Controller, Gary Dunning

ﾂ｡ Programmable Logic Controller, Webb

Reference Books:

ﾂ｡ Instrument Technology, E. B. Jones, vol. III

ﾂ｡ Tuning of industrial control systems, ISA

ﾂ｡ Applied Instrumentation volume 2, William Andrews

ﾂ｡ Control valve handbook, ISA