PLC (Programmable Logic Controller) introduced the first time in 1969 by Richard E. Morley is the founder of Modicon Corporation. According to the National Electrical Manufacturing Assosiation (NEMA) PLC is defined sebagasi a digital electronic device with a memory that can be programmed to store instructions that run specific functions such as logic,

Sequence, timing, counting, arithmetic and to control a machine or process industry industry in accordance with desired. PLC is able to do a process of continuously variable inputs and appropriate decision according to the desire to provide programming so that the value of output remains controlled.

PLC is a "special computer" for application in the industry, to monitor the process, and to replace the hard wiring and control has its own programming language. PLC but will not be the same as the personal computer PLC is designed for installation and maintenance by engineers and experts in the electricity industry that should not have the skills electronics and high flexibility control logic based on execute the instructions. Therefore, the PLC-day growing both in terms of the number of input and output, the amount of available memory, speed, communication between the PLC and programming techniques or methods. Almost all production processes in the industry can diotomasi using PLC. Speed and accuracy of operation can be improved far better to use this control system. Excellence from the PLC is the ability to change and falsify the operation at the same time with communication and information-collecting vital information.


Operations on the PLC consists of four important part:

1. predictive value of observation

2. run the program

3. value of output

4. control

From the excess above the PLC also has shortcomings, among others, which often highlighted is that for a PLC memrogram needed someone who is very professional and understand what is needed by the factory and understand about the safety or security that must be met. Meanwhile, people who trained as it is quite rare and in pemrogramannya must be done directly to the place where the server is connected to the PLC, while it is not uncommon location of the main computers in places dangerous. It is therefore needed a device that is able to observe, to edit and run programs from the distance.