Introduction To Industrial Automation

AUTOMATION:-
The term 'Automation' stands for 'Automatic'. Automation is nothing but a Delegation of human efforts to technical equipment for increasing Productivity, Reduced Cost, Better Quality & Increase In Safety Working Conditions.
AUTOMATIC CONTROL SYSYTEM:
A control in which regulating and switching operations can be performed automatically with respect to the predetermined conditions is called as automatic control system. The control systems are classified into two types

1)FEEDBACK CONTROL: In feedback control the variable being controlled is measured and compared with a target value. The difference between the desired and reference value is called Error. Feedback control manipulates an Input to the system to minimize the error. Feedback control mainly consists of five basic components 1)Input 2)Controller 3) Process to be Controlled 4)Output 5) Sensing Elements

In the figure,We are seeing that an feedback signal is going from the output to an comparator. Where, The desired value from feedback parameters and referrence input is get compared. The differrence between desired value(b) and referrence(r) is known as error.
For example, We want to maintain a Liquid level of 75% in the tank But, The level is exceeded upto 80% this level is detected by the Level transmitter and it send an feedback signal to the Controller to correct the error. Such type of control system is called as feedback control system.

ADVANTAGES:
1)An advantage of the closed-loop control system is the fact that the use of feedback makes the
system response relatively insensitive to external disturbances (e.g. temperature and pressure) and
internal variations in system parameters (e.g. component tolerances) which are not known or
predicted
2)They are more accurate.
3)They are composed of feedback mechanism, So they clear out the errors between input and output signals.

DISADVANTAGES:
1)They are relatively more complex in construction.
2)Costlier as compared to feedforward control system.
3)Since it consists of feedback loop, It may create oscillatory responses of the system and it also reduces the overall gain of the system.

2)FEEDFORWARD CONTROL:
Feedforward control system doesn't give any feedback to the controller

In the above figure we can see,That there is no feedback from the output likewise we see in feedback control system.
Let us assume we have a mechanical arm which lifts boxes from a conveyor belt to fill a container. The arm have been instructed to repeat its action for 10 times, after which the container will be full. This works well so long as the supply of boxes on conveyor belt is Uninterrupted. If there is an interruption, the arm keeps on repeating its action even though there are no boxes to move. The result is that the cycle of 10 movements had been completed. But, the container had not received 10 boxes.
A control system of this type is called as Feedforward control system because it has no feedback to tell the control that some of the movements have failed to move boxes.

ADVANTAGES:
1)They are simpler in their layout.
2)They are easier to construct.

DISADVANTAGES:
These systems do not having a feedback mechanism, So they are very inaccurate and Unable to remove the disturbances occuring from external sources.

DIFFERENT VARIABLES IN CONTROL SYSTEM:
1)PROCESS VARIABLE(PV): This variable values comes from the sensing elements as a Feedback signal to the controller.
2)SETPOINT VARIABLE(SV):This is a desired input variable value which is given by the operator to the controller.
3)MANIPULATED VARIABLE(MV):This is an action taken by the controller to control the error or deviation between PV & SV.

COMPONENTS USED IN INDUSTRIAL CONTROL SYSTEMS:
Major Components Which Plays A Major Role In Industrial Automation Are,
1)DCS(Distributed Control Systems)
2)SCADA(Supervisory Control & Data Acquisition)
3)PLC(Programmable Logic Controllers)
4)FIELD INSTRUMENTS
5)COMMUNICATION PROTOCOLS



In My Next Post I Wll Go Through DCS In Detail.

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