Applications of PLC in Automation

 

Abstract

              The use of Programmable logic controllers [PLC] in automation processes increases reliability, flexibility and reduction in production cost. Flexible and can be reapplied for fast and simple operation of certain programs. Practical application of PLC technology in automation control, Industrial automation systems (Manufacturing Automation System, Process Plant Automation). Industrial applications (Continuous bottle filling system, Batch mixing system, Control of Planar machine, Water and wastewater management control)

Introduction and Research Objectives

          Programmable logic controllers [PLC] are single processor computer-based machines that mimic the actions of an electrical ladder diagram and can regulate several forms of manufacturing machinery and whole controlled systems. In manufacturing, PLCs are typically a large part of integrated systems. They are very effective and consistent in automotive, chemical and process industries applications requiring sequential monitoring and the coordination of processes and auxiliary components. Besides getting the technical benefits of utilizing PLC, costs in the specialized stage and the complicated control structure are often that. Nowadays, the PLCs also replaced much of the control elements used to implement the device logic. The word logic is used as the programming relies on applying logic and transferring operations. Entry devices like switches, and output devices like motors, The controller is connected to the PLC, and then the inputs and outputs are monitored by machine or process. Originally PLCs is designed to substitute hard-wired relay and logic control systems with timer. (Hard cabling indicates all the components is attached manually by wires).

Content

          The use of Programmable Logic Controllers with power electronics in electrical machines has been implemented in the production of automation systems with the emerging developments and the provision of motion control of electric drives. PLC usage in automated systems improves efficiency, versatility and output cost reduction. Using power converters, personal computers and other electrical equipment interfaced with PLC allows industrial electrical drive systems more reliable and effective. PLCs have achieved prominence on the manufacturing floor and are expected to stay preponderant in years to come. Much of this is because of the advantages they provide, such as

     · Efficient expense to control complex systems.

     · Flexible and can be reapplied for fast and simple operation of certain programs.

     · Computational skills allow for more complex regulation.

     · Shooting difficulty makes planning simpler and it reduces downtime.

     · Reliable components make these likely to operate for years before failure.

Practical application of PLC technology in automation control:

          As PLC technology first emerged, it did not completely display its roles and principles in support of electrical engineering automation. Standard automation management of the electrical engineering has specific tasks. With the increasing growth of the field of industrial production and electrical engineering, higher demand has been pursued for electrical engineering automation regulation. In this situation, PLC technology performed its maximum role in support of electrical engineering automation, the functional implementation of which was primarily expressed in support of sequential control and control of the switching interest.

 

INDUSTRIAL AUTOMATION SYSTEMS:

           Industrial automation involves the use of devices aided by machines and equipment to perform the different industrial processes in a well regulated manner. Industrial automation systems are generally classified into two groups according to the operations involved; (a) Manufacturing automation and (b) Process plant automation systems.

·       Manufacturing Automation System

         The manufacturing industries utilize robots / computers to produce the commodity from raw materials. Some of these industries include paper making, glass and ceramics, textiles and clothing, food and beverages, and so on. Throughout any point emerging developments in industrial processes using automated systems such as material processing, machining, assembling, testing and packaging. The factory automation is very scalable and effective with machine assisted control and industrial robotic systems.

·       Process Plant Automation

           In process industry, the output is the consequence of several chemical processes dependent on other raw materials, some of the industry are cement, pharmaceutical, pulp, petrochemical, etc. Thus the whole production plant is optimized to provide the better quality, more efficient and highly consistent regulation of the physical process variables.

Industrial applications:

1.    Continuous bottle filling system:

        It is one of the essential uses of PLC in the bottle filling industry where we want our bottles passing on the conveyor belt to be automatically sensed at the right location and filled with the required liquid as well as making the queued bottle filled in. If this whole process is carried out manually it will really take a long time and also the quantities will be quite lesser. Thus PLC is the controller needed for these kinds of industry. There, too, only a limited example of the procedure was conducted with the aid of PLC where a ladder diagram was generated to guide the method and the ladder diagram was implemented to show its logic by the PLC trainer package.

Observation:-

 The green light (L1) switches ON until the start button is pushed and stays ON before the stop button is pushed. When light turns Off the feed motor(M2) begins to work. After M2 runs and if any maximum switch(LS) has not indicated or the state of the filled bottle has been met, the motor(M1) begins. Once T1 sends the signal and the photoeye detector (PE) is activated, the solenoid valve comes into operation. When PE signals the solenoid stops and buzzer(B1) sounds during which the timer is triggered, T2 is allowed to interrupt the cycle for 0.7 seconds. If the state of the full bottle is triggered the process again begins. In the PLC simulator, the ladder diagram was successfully tested, and all the specified conditions were thoroughly observed.

2.    Batch mixing system:-

       This is another widely used PLC application where two liquids are combined in the necessary proportion to create a flow rate collection. We just regulate flow period. The level sensor changes senses the volume of the liquids in the tank

Observation:-

           The water is pumped up to L2 as the start button is pushed and it stops when L2 is lifted. First of all, the O:0/15 output is pressed as a start and remains ON until the tank is emptied. Rung 2 usually shuts open drain valve, before triggering the T:4 timer. Rung 3 energizes the solenoid before L2 does not indicate as it signals that the solenoid is de-energized. Likewise, up to L3 acid is filled by solenoid b.as amount is sensed by L3 solenoid b de-energizes. And then mixer begins and operates for 3 minutes. With a period of 3 minutes of solenoid c opens and the blend gets drained out. When the blend is out fully, the restarts of the phase loop. In the PLC simulator, the ladder diagram was successfully tested, and all the specified conditions were thoroughly observed.

3.    Control of Planar machine:-

 Within this unit, the piece of work or the job put on the table travels by rack and pinion system fixed on the squirrel cage motor shaft to and fro. Here the cutting device is set while table movement operates on the job put on the surface. Table movement is regulated by switches 1LS and 2LS between two ranges, left and right. When the table moves from left to right, the tool works on the job while it remains ideal during table move from right to left. Tool gets feed for next cut on the job at the end of right to left move. The following are complex control criteria for the job:- (1) The motor can be operated manually by pushing the push-button to operate. When the motor begins it is immediately changed by maximum switches2LSand1LS at the end of right or left movement. (2) Jogging the motor by jog-push button should be given. (3) If the system table lies between the severe location, then the system does not operate. The initial path of travel should be selected through right and left push button, PBR and PBL. (4) In order to allow the tool to get the feed for the fresh cut on the job, there should be delay in starting the motor in left to right stroke. (5) The computer will avoid pressing the avoid push – button or tripping the motor over load. (6) Interlocking of the motor (running) of the coolant pump should be given as a precondition for system initialization.

Working of the circuit :-

·       The input terminal 1 of AND1 is strong as the start-push button is pushed, its performance always goes up when its input terminal2 is also high due to near touch with the stop-push button. To keep production high, production is fed back to terminal1.

·        Output of AND1 appears at OR1 Terminal 1 making the OR1high output that appears at AND2 Terminal I. If the engine overload relay link is CLOSED and the engine of the coolant pump is working so AND2 terminals 2 and 3 still provide a strong signal. And all AND2 's three input terminals are small, and their performance is high.

·        Output of AND2 occurs at Terminal 1 of AND3 and AND4 Depending on the memory entity state whether it is in fixed mode or in reset mode, either AND3 or AND4 output will go high and the corresponding R or L contactor will be energized. However, you can pick the appropriate direction of travel by pressing the right or left push buttonsPB3 or PB4 before pressing the button START-shift.

·       In order to explain the reversing operation of the device, it is presumed that the system table is originally in an severe left location such that the ILS limit transfer is in actuated condition and its usually accessible communication (NO) is locked. And a strong signal occurs from closed ILS communication at terminal A of the retentive brain. The memory factor gets set and its terminal performance X goes big.

·       At terminal 2 of AND3, high performance from terminal X occurs after a certain delay provided by the timer T, whereas at terminal 2 of AND4 a low signal appears because the NO T gate is in series with the performance from X.

·       As all AND3 terminals I and 2 are now high, the output of the arc is small, energizing the R motor contactor through the amplifier. Consequently the machine table moves in the right direction.

·       After entering the extreme right location, limit switch 2LS is enabled. Is usually Accessible (NO) touch removes the memory dimension and resets it. Terminal X performance is small and thus Terminal 2 and AND3 are weak as well. Therefore, the performance of AND3 goes small and contactor R is de-energized. At the same time when memory element gets reset, terminal 2 of AND4 goes high due to a NOT gate inverting the low output from X

·       Therefore, the 2LS Terminal 2 and AND4 limit transition is small while its Terminal 1 is weak. A strong performance that energizes the motor contactor L via the amplifier occurs thus. Now the motor works in the opposite direction, shifting the monitor from right to left.

·        When the table reaches the extreme left position limit, the ILS switches are activated and the memory element is set so that the AND4 terminal 2 is low and the output is low. Therefore Contactor l is de-energised. Again Contactor R is energized as performance of AND3 is fast after a delay set to timer.The to and fro motion, due to setting and resetting of memory elements by actuation of limit switches. Continues till the stop push Button is pressed or overloads trips to make the terminal1 of AND3 and AND4 low.

·       When you need to push the computer table gradually in steps to change the device to the job location, then click the button

 

4.    Water and wastewater management control:-

                Bayindir & Cetinceviz defines a water pumping control device, planned for manufacturing plants and applied in a laboratory experimental configuration, Fig. 19. Such facilities involve hazardous conditions where there are liquids, noises or shifting pieces that may actually harm the cabling or wires that are components of the control device. Additionally , the data must be transmitted across freely available routes. The control devices it uses are software for PLC and urban local area wireless (IWLAN) networks. A PLC, a contact processor (CP), two IWLAN devices, and a distributed input / output ( I / O) panel, as well as the water pump and sensors are used to execute it The contact device is based on an Industrial Router which utilizes the regular Traffic Control Protocol / Internet Protocol for parameterization, setup which diagnosis. The PLC 's key role is to give a electrical signal to the water pump to transform it on or off, depending on the depth of the reservoir, using a pressure transmitter and inputs from the maximum switches showing the water level of the tank.

 

 

 

 

 

 

References

[1].                    Alphonsus, E. R., & Abdullah, M. O. (2016). A review on the applications of programmable logic controllers (PLCs). Renewable and Sustainable Energy Reviews, 60, 1185–1205. doi:10.1016/j.rser.2016.01.025 

 

[2].                   Rahul Pawar, Dr. N. R. Bhasme, “Application of PLC’s for Automation of Processes in Industries”, ISSN: 2248-9622, Vol. 6, Issue 6, (Part - 3) June 2016, pp.53-59

[3].                   Luxian Fang, “Application of PLC technology in electrical engineering and automation control”, February 2017, https://doi.org/10.2991/meita-16.2017.56

[4].                   Bayindir R, Cetinceviz Y. A water pumping control system with a programmable logic controller (PLC) and industrial wireless modules for industrial plants-An experimental setup. ISA Trans 2011;50:321–8.

 

[5].                    Fernández-Ramos J, Narvarte-Fernández L, Poza-Saura F. Improvement of photovoltaic pumping systems based on standard frequency converters by means of programmable logic controllers. Solar Energy 2010;84(1):101–9.

 

[6].                    http://ethesis.nitrkl.ac.in/2654/1/final.pdf

 

[7].                    Weng Guoqing, Chen Mingjun, Zhang Youbing. Optimization of “modern electrical control and PLC technology” course practical procedures. Proceedings of the sixth national college electrical engineering and automation specialty teaching reform seminar, 2014:617-621.