PLC is designed to replace circuit relay sequential in a control system. In addition to being programmable, this tool also is controlled and operated by people who do not have knowledge of computer operation in particular.
PLC Stands for the programmable logic controller, which has the following meaning:
Demonstrate ability in terms of memory to store programs that have been made that have made that easily altered function or usefulness.
Demonstrate the ability to process input in the arithmetic and logic (ALU), which compares the operation, add, multiply, divide, subtract, negation, AND, OR, and so forth.
Demonstrate the ability to control and manage the process to produce the desired output. The basic elements of a PLCconsists of a Power supply, Programming Console, Memory, CPU, input modules, output modules, following we describe each of these elements. The power supply is used to provide power supply to all parts of the PLC (including CPU, memory, etc.,) Most PLC work on the power supply 24 VDC or 220 VAC.
Programming Console is a programming panel in which there is RAM(Random Access Memory) that functions as semi-permanent storage in a program that was created or modified. Programs written to the console must be in the form of mnemonic. This device can be connected directly to the CPU by using a cable that can be installed the extension and removed at any time.
Memory is a component for storing the program. To the PLC will work as expected then needed a program to run it. The program should be stored in a certain way so that the PLC can access commands according to the instructions. One also needed to store data temporally during the implementation of the program.
CPU( Central Processing Unit) is the central data processor and controller of the entire work system PLC. The process is conducted by the CPU and other international control of all operations, cultivating existing programs in the memory, as well as managing communication between the input-output, memory, and the CPU through the BUS system. CPU also serves to execute and process the functions desired by the program that has been determined.
Input module functions to receive signals from sensors peripheral units and provides signal settings, termination, isolation, and input signal condition indicator. The signals from peripheral devices will be scanned and it will be communicated through the interface module in the PLC.
The output module activates a variety of devices such as hydraulic actuators, pneumatic, solenoid, starter motor, and display the status of peripherals points are connected in the system. Other output module functions conditioning, termination, and also isolating the signals exist. The activation process is of course done by sending signals to discrete and analog relevant, based on his own character which is a PLC digital device.