PLC (Programmable Logic Controller)
PLC (programmable logic controller) is a digital electronic device used in industrial automation. PLC is used in manufacturing control systems where cost of maintaining and developing automation systems is high, assembly lines, safety control and where you require automation in factories. Physically if we see it is the interface between input and output devices.
Dick Morley was the fastest of PLC who invented first Modicon plc .Before invention of PLC hardwired connections were done and there were lots of wiring connections which were difficult to troubleshoot.
Initially PLC worked like smart relays and one by one evolution took place and nowadays from a days from small process to a very complicated process we can use plc for simple automation to very complicated factory automation nowadays use PLC controllers for automation. Siemens, ABB, AB, Delta, Mitsubishi, Omron these are leading brands of PLC. IPCS Global Pune provides the training on these all PLC modules with maximum hands-on knowledge .
Types of PLC
Depending on I/O handling capacity they are classified as small ,large and very large plc. Plc are again classified as compact plc and modular plc.
Compact PLC – Inbuilt fix number of input mostly binary, power supply , processor. It can be expanded.
Modular PLC: Separate power supply, processor, I/O. It has a large number of i/o choices.
Programming languages of PLC
PLC programming is done in ladder language ,function block diagram , instruction list, structure text, sequential flow chart.
Manufacturers of PLC
Allen Bradely, Siemens, ABB, Honeywell, Delta, Hitachi. Schneider Electric
Different PLC modules in Siemens and AB PLC ?
Siemens PLC family there are Logo plc – Logo soft software ,S7-200 – Microwin , s7-300/ s7-400 – Siematic manager , s7-1200 and 1500 series – TIA portal. Initially different software with different controllers were used, But nowadays TIA portal totally integrated automation is for the whole package where we can find plc, scada , him, drives.
Similar AB plc there are Pico plc – Pico soft, Micro 800 CCW(connected component workbench), Micrologix/ SLC -RSlogic 500, PLC – RSlogic , compact logic/ control logic/ Flex logic – RSlogic 5000 . Another advanced software is Studio 5000.
Hardware parts of PLC includes Power supply, Bus system, CPU, Input module , Output module, Rack and Rail, communication port, Display unit.
CPU: It is a microcontroller based circuit. It consists of ALU, memory, internal timer and counter , flags, and process image memory. CPU performs the function like scanning, i/o bus traffic control, self diagnostics and communication. The brain of the whole PLC is CPU module .Manufacturers offer different modules of plc as per need of the system.
Input module: it acts as a link between input devices and CPU. There is a digital input module and analog input module.
Example of input devices:- Relay contact, motor starter contact, thumbwheel switches, Photoelectric sensor.
Examples of digital inputs are pushbutton ,limit switches, proximity sensors, selector switches etc. When input condition is true it passes 24 vdc or 230/110v ac supply to the controller and when it is false or off ,it will pass 0 v supply. Analog inputs continuously provide the field condition to the controller for e.g. temp is 37.8 f.
Output module: it is the link between output devices and CPU.Input devices connected with plc can be digital as well as analog.
Example of output devices :- Alarms, Lights, Horns , Valve, Fans ,Solenoid.
Bus system – There is control ,address, data bus system.
Address of input file ,output file and other files like timer/counter/control register is given by the address bus system. Data bus system all data to plc modules from different modules connect to it. Control bus system mainly synchronised all data at one speed for uploading and downloading.
Rack(rail) It is the platform on which all modules are mounted. Again the rack is of 4 ,7,10,13 slots .
Uploading and downloading of PLC
Downloading means you have developed a program and then it is given to the controller.
Uploading means you are taking data or a program from the plc controller to your system .
Protocols uses in PLC
Protocols are the set of instructions used for communication purposes when placed in a network RS232, DH485, Ethernet, profibus, MPI, Profinet, Control net, Device net, USB there are some examples.
Applications of PLC in different sectors
1) PLC in coal mining :-
In coal mines there are many hazardous gases, gas poisonings. Mine are mostly recognized hazardous areas where accidents take place due to roof fall, gas and dust explosion. By using the PLC system, underground miners’ lives can be saved.
The safety system is driven by plc and with its features like alarm system, gas monitoring system it takes real time decisions to overcome the problems.
2) Food industry:-
It is used in food processing, packaging ,and labelling systems. Hygiene is most impotent in the food system for this plc is used. Dairy products, Beverages, ready to use products, edible oil industry plc are used.
3) Water treatment:-
The process like sedimentation, chlorination, oxidation, grit removal are done with the help of plc.
4) Wind turbine monitoring system:-
To reduce the maintained cost and improve turbine performance.
5) Building management system :–
Internal and external light control, fire detection, alarm system, security system, water level monitoring, protection of devices after power failure,car parking.
Future scope of PLC
To fulfil customer requirements day to day new technology is invented and new technology changes are done in plc hardware and software. Higher level of automation on the factory floor. IPCS Global Pune provides PLC training based on Industrial requirement along with Python course in Pune, Data science course in pune, Data analytics courses pune, Machine learning courses in pune, Full stack developer course in Pune. So get trained from IPCS Global Pune and make your career in Industrial automation domain as application engineer, service engineer, PLC programmer.
For more details visit our website – https://ipcsglobal.com/ipcs-global-pune/