MOOKAMBIKA TECHNICAL CAMPUS

MUVATTUPUZHA

Submitted by,

Amjad Hussain- S7 ECE

CONTROL INSTRUMENTATION

INTRODUCTION The Kerala state development corporation(KSEDC) was

established 1973 First electronic development corporation in India state

government sector They introduce the state-of-the-art technology in the field of

control and instrumentation There is four self-profit generating strategic business

unit(SBU)and they are supported bye a common service group(CSG’S)

Control and instrumentation Pneumatic products Information technology Strategic service group

This group provides process automation solution for Thermal Power Plants and Process Industries

The group had technical collaborations for Microprocessor Based Distributed Digital Control System (DDCS) with industry leaders in France, United Kingdom, Japan, and Italy.

Most of the Power Plants spread all over in India have C & I Systems supplied by Keltron Controls Aroor.

Control instrumentation is mainly classified in to two

Distributed control system(DCS) Programmable logic controller(PLC)

Figure 3.1 Overview

LCN – local control network,UCN – User Control network,NIM – Network Interface Module

I/O Module The i/o module acts as the interface between the field equipment and

the DCS. Three types of i/o cards are present.

For analog input/output signal For digital input/output signal For pulse input/output signal

The analog input signal may be either low level (mv) signal from devices and high level input signal(1-5 V or 4-20mA)

The analog input card have the capability of accepting both high level and low level

The input is a digital device, all computations are performed digitally

Process Control Unit Process control units are required to function as a closed loop

controllers

Operator station The basic structure of an operator station consists of a video

screen for displays and a two level keyboard for manipulation and system configuration.

The main function of the operators station are manual control, command and setting, display set point of measured variables, display plant alarm conditions, records plant events and print it.

Man Machine Interface The operation interface or man machine interface(switches,pressure/

temperature/ level switches etc) and provide the data necessary for the processor to make it control decision

Output Interface It provides command to software on/off the motor by energizing

breakers,energise solenoids under direction from the processor.

The programming interface takes several forms- such as CRT, keyboard, and register access pannel.

In DCS there is a new approach which replaces large instrument panels with small desk size console employing interactive CRT, displays and keyboard.

PROGRAMMABLE LOGIC CONTROLLER A Programmable Logic Controller is simply a special computer

device used for industrial control systems. They are used in many industries such as oil refineries,

manufacturing lines, conveyor systems. Memory: It is the storage area used to hold the set of instructions to

be executed by the processor. Processor: It is the brain of the system. It interprets the set of

instructions and implements the control of the machine/process Input Interface: It receives signal from field (like limit switch, circuit

breaker contact, and proximity software) Relays: It is electrically operated software. relays have two s/w

positions and they are double throw switches

The components that make a PLC work can be divided into three core areas.

The power supply and rack The central processing unit (CPU) The input/output (I/O) section

The Power Supply And Rack

Figure 3.6 The Power Supply And Rack

The rack is the component that holds everything together.  Depending on the needs of the control system it can be ordered in different sizes to hold more modules

The power supply plugs into the rack as well and supplies a regulated DC power to other modules that plug into the rack

The CPU The brain of the whole PLC is the CPU module The CPU consists of a microprocessor, memory chip and other

integrated circuits to control logic, monitoring and communications. 

In programming mode it accepts the downloaded logic from a PC. 

The CPU is then placed in run mode so that it can execute the program and operate the process. 

Figure 3.7 Central Processing Unit

Figure 3.8 CPU Operating Cycle

I/O System The I/O system provides the physical connection between the

equipment and the PLC.  Opening the doors on an I/O card reveals a terminal strip where

the devices connect.

Figure 3.9 I/O Card

Figure 3.10 Filling Rack With Appropriate Cards

Inputs Input devices can consist of digital or analog devices analog input card converts a voltage or current (e.g. a signal that

can be anywhere from 0 to 20mA) into a digitally equivalent number that can be understood by the CPU. 

Outputs Output devices can also consist of digital or analog types.  A digital output card either turns a device on or off such as lights,

LEDs, small motors, and relays.  An analog output card will convert a digital number sent by the

CPU to it’s real world voltage or current.

The internship was excellently done for two week duration from July 23,2016

I was able to understand about the departments of company

One of the important product of keltron is their towed array which is being manufactured for the defense sector