PLC

PLC (Programmable Logic Controller) was first introduced in 1969 by Richard E. Morley who was the founder of Modicon Corporation. According to the National Electrical Manufacturing Association (NEMA) PLC is defined sebagasi a digital electronic device with a programmable memory to store instructions that perform specific functions such as logic, sequence, timing, counting, and arithmetic to control an industrial machine or process in accordance with the desired industry. PLC is capable of doing a continuous process based on input variables and provide the programming decisions at will so that the value of output under control.

PLC is a "special computer" for applications in industry, to monitor the process, and to replace the hard wiring controls and has its own programming language. But the PLC is not the same because the PLC will be a personal computer designed for installation and maintenance by a technician and an electrician in the industry who do not have to have a high electronics skills and provide flexibility based on the instruction execution control logic. That's why the PLC is increasingly well developed in terms of number of inputs and outputs, the amount of available memory, speed, communication between the PLC and how or programming techniques. Almost all kinds of production processes in industry can be automated using a PLC. The speed and accuracy of operation can be increased so much better using this control system. The advantage of PLC is its ability to change and replicate the process at the same operation with the communication and information-gathering vital information.


Operations on the PLC consists of four essential parts:

1. observation value of inputs

2. run program

3. provides output value

4. control

From an excess of PLC also has shortcomings, among others, which often highlighted is that to program a PLC takes someone who is skilled and fully understands what is needed by the plant and understand about the security or safety that must be met. Meanwhile, a trained person like that is quite rare and the programming must be made directly to the place where the servers are connected to the PLC, while it is not unusual location of the computer playing it in dangerous places. Therefore we need a device capable of observing, edit and run programs remotely.