I am interested in the advantages and disadvantages of the use of Programmable Logical Controllers in industrial automation. Does the industrial automation depend on them and are any other solutions possible?
A PLC is a programmable controller like an Arduino that is mainly used for industrial automation. However the main difference between a PLC and an Arduino is their price, as the PLC usually has 100 times the price of an Αrduino. The PLC has a better processor power & memory, can handle more current in the I/O ports, the ports are optocoupled, it is more robust, it is closed architecture, it comes with industrial certificates, safety features etc.
If you are dealing with an industrial application, PLC is the way to go. If you are looking for a hobby project or small research project you can use an arduino controller that costs as low as 15$.
...do not forget the communication as well as integration aspects in large scale control problems! PLC and DCS are the hearth of industrial automation and control!
Regards,
Ljubomir Jacic
A PLC is programmed with ladder logic (mostly). Other (micro) controllers require the use of a programming language (like C).
@Fotios Dimeas, I do not agree for ladder diagrams. Today, the most of PLC's have been programmed by functional blocks (FBD). See GRAFCET and GRAFCHART...
Regards,
Ljubomir
@Vijaykumar S,
the following link is a brief explanation of PLC programming standard IEC 61131 : Programming languages for industrial automation http://www05.abb.com/global/scot/scot267.nsf/veritydisplay/95c0dd2588fe299b852575060077296b/$file/2101127.pdf
Hope it will be helpful. Of course @Fotios Dimeas, it considers ladder diagrames also, but for any complex automation problem, Sequential Function Charts (SFC) are much effective!
Good luck,
Ljubomir Jacic
Better than what?
The aim of project is also important - if you worked out a new industrial system for only one instalation, it is simplier, faster, genneraly more effective to based it on PLC or similar components. But if that system will be implemented mamy times in the same form (eg. control in CNC ,other machines), it is more effective, costless, etc. to design an embeded system, which is unique, but usualy better fited.
PLC electronics are more robust and can withstand harsh environmental conditions, the reason why we chose Siemens PLC in solra tracking automation for example
https://www.researchgate.net/publication/260795547_Carbon_footprint_optimization_as_PLC_control_strategy_in_solar_power_system_automation
Article Carbon Footprint Optimization as PLC Control Strategy in Sol...
It is depend on process where you will use the PLC.
If your process is big , it is better to choice PLC.
But in any case if you can design a good and robust microprocessor based system , it is also good.
The first reason is cycle time. Second is robust.Third is protocols for communication.
Communication is important , because several protocols are being used in industry for communication between PLC and instrument field euipments. If you solve the protocols , it will be great.
Let me bring to your attention the following interview with father of plc Dick Morley! He discuss the difference between the PLC and PC-based control!
http://www.controldesign.com/articles/2015/the-father-of-the-plc-explains-the-difference-between-the-plc-and-pc-based-control/?utm_content=buffer93c72&utm_medium=social&utm_source=facebook.com&utm_campaign=buffer
Arduino is generally used for small projects such as college projects which work on C language etc. On a large scale, PLC is the best. It is very convenient to work under environmental conditions such as temperature, moisture and also high voltage level as well as for several different logic at a time. second thing is that Arduino is cheap compared to PLC.
Dear Vijaykumar S , please do find attached article about selection of PLC.
Dear Vijaykumar S,
A PLC is a ruggedized, digital industrial computer control system that is preprogrammed to carry out automatic operations in industrial processes. PLCs are used in industrial automation to increase reliability, system stability and performance, minimizing the need for human operators and the chances of human error.
How PLC is better than a simple computer-
The PLC has a better processor power & memory, can handle more current in the I/O ports, the ports are opto coupled, it is more robust, it is closed architecture, it comes with industrial certificates, safety features etc. PLCs are the preferred method of controlling, measuring, and carrying out tasks in complex manufacturing and industrial applications because they play nicely with other systems. PLCs work well with PCs, PACs (programmable automation controllers), motion control devices, and HMIs.
Advantages
What Advantages of PLC are made; they are very fast, easy to change logic i.e. flexibility., reliable due to absence of moving parts, Low power consumption, easy maintenance due to modular assembly, facilities in fault finding and diagnostic and moreover capable of handling of very complicated logic operation.
Ashish
Ashish Thakur , do always bring the source which were used. (copy/paste) Otherwise, it is pure plagiarism. It is very bad academic practice. You have combined at least 4 sources. I will show one copy/paste example! Links follow:
https://www.unitronicsplc.com/what-is-industrial-automation/
https://forumautomation.com/t/applications-and-advantages-of-plc-programmable-logic-controllers/467
https://iamsanjoy.wordpress.com/industrial-controlling/
https://www.telstarinc.com/blog/what-is-plc-and-why-use-it/
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