PLC is Programmable Logic Controller. PLC user friendly It's a microprocessor-based special type of computer, which works with complex functions. It controls the program and it can easily control any unskilled person. PLC Operator line, ladder diagram, through the keyboard and monitor screen. Converting the computer's machine language, the result is expressed through the image and used as a user program.

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PLC is designed in such a way that only computer programmers can change it. PLC has multiple inputs and outputs. Different types of switches or transducer outputs are used as inputs. PLC outputs are used to control machine processes.

Features of PLC

• Operation changeable
• Processing elements are used
• Cheap to price
• More faithful

PLC Functional Block Diagram

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PLC consists of 4 parts. Each part is interconnected with each other.
1CPU:

• Microprocessors perform mathematical and logical work.
• Mammary saves the CPU's data and information.
• Power supply transforms AC current to DC current.

1. Input / Output module:
   Outputs of various sensors, transducers, etc. are used as PLC inputs. Different motors, devices, switches, etc., are used as output modules.

2. Programm monitor PM:
   Here the PLC handling program is written. The Programmer draws the Ladder diagram and sends it to the CPU, then the memory stored it.

3. Racks and chassis:
   Various parts of PLC such as CPU, PM, input output module are bound by racks and chassis.