Complete Overview

In this complete pages my aims was to give reader a complete overview of Instrumentation and Automation and also the basic components of each section.

The followings are my contents as below

1)What is instrumentation
2)What is Automation
3)What are the basic components of a control system.
4)What are different types of control systems?
5)Open Loop control system?
6)Close Loop Control System ?
7)Feedfarward Control system?
8)Difference between SCADA, DCS and PLC Systems.

What is instrumentation ?

Instrumentation is the ability to control the Process; it is also defined as the combination of different components to properly and smoothly control the process. It can also be defined as the precision of the process. It covers the controlling, Indications and trend or data recoding functions. As with the passage of time there is innovation in instrumentation the system are being compact. It can also be defined as “The process from sensation up to display is referred to as Instrumentation “

What is Automation ?

The systematic approach of controlling machines or process using any electronic based components for their implementation, for easy of human and to reduce human interruption, for good quality of any product and accuracy in there process for removal of wastages and losses.

What are the basic components of a control system ?

A control systems consists of many components such as electrical components,Instruments,mechanical, thermal, or hydraulic etc that work with each other for maintaining actual system performance near to a desired set of performance specification of a system. Hence all the elements involved in controlling of close loop are control system components such as Push button, controllers,PLCs and i/p and Positioned ,control valves. 2)

What are different types of control systems?

Control system can be divided into the following three types:

1) Open Loop control system

2) Feed Back control System

3) Feed forward control System

Open Loop control system?

The open loop system consists of manual system in which control is performed with human being.

An open-loop control system is controlled only from an input signal, without considering feedback. Only act against a disturbance for which it is being designed not for extra requirements .It will be stable as long as control objects are stable.

This process takes a lot time as well as is less accurate for any process.

A system in which the output of process not depends upon the process input is referred to as Open Loop Control System.

Close Loop Control System ?

It is a system in which output is affected by the process input for desired output value maintaining purpose are called Close Loop Control System.

It is a system mostly used by user requires quick response with great accuracy for stability of the system. It works on the feedback, its output will not be stable but it will always try to stabilize it response.

The main reason for quicker response and accuracy is its automatic feedback system that informs the input that the desired movement has taken place. Upon this feedback information, the system stops the actuator. (E.g. Temperature controlling, Pressure Controlling loop, controlling, Flow Controlling, the position, the velocity controlling loops.)

Feedfarward Control system?

It is a system in which preventive action is being taken for smooth operation, It is always used along with the feedback, as it require keep monitoring of set point and suppression of unmeasured disturbance in any process.

By using this method performance of system can be improved as compared to simple feedback control system.

In any system where there is major disturbance that can be measured before it affect s the process output, it is ideal for eliminate the affect of disturbance on the process output.

Difference between SCADA, DCS and PLC Systems.

SCADA

A SCADA (or supervisory control and data acquisition) system. It consists of many remote terminals units for collection of data (field),that is being connected with master station through any communication system, having main task of collection of accurate data and controlling of process for smooth operation.

DCS

It stands for distributed Control System, controlling is performed by embedded system (Microcontroller based or Microprocessor based controlling unit for device or instruments from which data is to be collect. It provides very intelligent analog control capability. It is very sensitive for HMI (Human machine Interface) for easy and smooth control of process.

PLC

It stands for Programmable Logic controller, having get this name from the fact that it replace the relay logic at the initial stage then it get the capability for analog channels also for display then it get the ability for close loop control and after some time it has the ability for redundant operation, and also its HMI having the ability for Indicatiion,controlling,data logging ,Alarming and backup data facility. It is also defined as below:

“A digitally operating electronic apparatus which uses a programmable memory for the internal storage of instructions for implementing specific functions, such as logic, sequencing, timing, counting and arithmetic, to control through digital or analog input/output, various types of machines or process.”

National Electrical Manufacturers Association (NEMA), 1978