Introduction: The PLC – logic controllers or programmable – Is an electronic device used in automation in industrial systems Kaltgm mechanism of action of the production lines at the plant what , and unlike systems traditional computer has been designed to suit the conditions more difficult in terms of the areas of bearing temperatures and dust and resistance to the conditions of jamming electromagnetic and other conditions of compression and mechanical vibration .
These controllers work control programs stored in read-only memories . And the PLC is an important example of the systems real-time Real Time Systems , where the output is a direct response to certain income during a specific time thoughtful , and if it is not this response That will lead to errors in the process control entrusted to him , and therefore, designed the structure of the governors digital serial .
We have invented the PLC to meet the needs of the automobile factories of America, which took control unit is unique, and they use these factories before the invention huge numbers of timers and the governors and controllers closed-loops to accomplish the tasks of control and Cascade commands digital and protect their values from jamming , but the development of the annual associated with the models and the models produced annually to make the process of the development of the industrial system is a heavy and time-consuming , as it requires a process of rehabilitation systems governors experiences electrical intense and accurate in order to return it to its status optimum at work, and in 1968 introduced a GM request for the system replaces the system of governors user previously named Hard -Wired Relay System.
So , he invented the PLC to replace the complex system of thousands of Governors and timers , and then , it was possible for a single device from the PLC to program to take the place of that gear giant of the governors and timers , have adopted this device large groups of plants manufacturing cars since been replaced by the re- rehabilitation program of governors holds periodically PLC control units in the event of product development factory.
And has taken the development of this device walks several over the years , where he became meets the needs of most of the operations control cascade of Governors , movements and processors and systems, the distribution of tasks and networks , and the unique capabilities of this device stores the data , the data ( and archiving ) and processes the commands and operations and to communicate with more than one unit and the transmission of data it made him a real contender for the computer , but the competition later took the form of friendship and cordial relationship after enable manufacturers to make them integrated unit for data transmission and control of mutual control system to achieve optimum industrial facility .
How do you choose the device best for your facility PLC Industrial :
1-Twafiqith with devices that operate at the facility , where some devices can not be governed by this device, while the other is capable of , but need a certain quality of the PLC then you remains the task of finding the best and most device compatibility .
2- working conditions and environment , which will be placed where the PLC ( temperature , electromagnetic jamming , dust and dust , mechanical vibration … etc) where the PLC vary in their capacity to built these circumstances, depending on the patterns and their applications.
3-the number of devices to be controlled by the unit of the PLC, as well as the units vary among themselves in terms of entrances and exits of the data and the associated currents and types (continuous or alternating ) .
4- jobs to be Aiezha to the PLC where the manufacturers offer additional benefits for each model depending on the functions entrusted to him , such as counters or rapid real-time hours . And the study of this subject is essential as you will discover that the plant may save you a model independent of means for independent entity did not take in mind that you may offer to buy the price by purchasing a microcontroller to the advantage of additional functionalities .
What are the HMI ..
One of the most important requirements in industrial control system is a permanent capacity to control this system and give data and information on the status of the system that controls it when you need to , for example , when driving a car or vehicle specific driver uses the steering wheel to control the region of the wheels, and thus hand the vehicle , and the brakes and switch at optimal speed control , and the control of this process by looking at the outside through the glass facade of the car and the speed indicator : So , the index consists of interface and speed are the tools of the driver to achieve better control the functions of the vehicle.
Called interface control system pal industrial HMI or Human Machine Interface, and manufacturers offer huge collections of these devices to give as much of the direct control of the technical work of the observer and the plant control system.
SCADA systems SCADA Systems:
The interfaces direct interaction between the control system and the human element requires software super power to achieve this purpose and relevance with the advantages offered by the interface , thus : the SCADA system system Kmpiotraa great to achieve the goal , as it allows full control of all units connected with the PLC using PC is far from the place of manufacture , and name an acronym for Supervisory Control and Data Acquisition system or data and gain control guideline .
Competencies required in the United Arab Emirates to engineer SCADA:
– Site investigation, data collection, project planning and implementation
– Preparation of tender documents, contract procedures, technical specification, BOQ and evaluation of bids;
– Responsible for Design, drawings & calculations for SCS & Substation automation, RTU hardware & software, Data communication and interlocking with telecom system, Interlocking with protection relays,
– Input interfacing to CTs, VTs, Transducers and interposing relay;
– Knowledge on Control center software and hardware;
– Design review, review of inspection and testing procedure;
– Supervising and controlling testing & commissioning;
– Shop inspection and FAT of major equipments and ensure conformity with technical specifications.
Companies (plc) Emirates:
‘ Lamprell is a leading engineering and contracting services provider for various oil and gas industries , renewable energy, land and sea .
‘ Dale power solutions the supply of safe power solutions for all major sectors in the national and international market – a safe backup power delivery all over the world .
‘ Programmable Logic Controllers – By :W. Bolton .
‘ Programmable Logic Controllers: An emphasis on Design and Application”, by Kelvin T. Erickson; a professor at University of Missouri, Rolla.
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