Friday, June 26, 2015

Benefits and Applications of Programmable Logic Controller in Industrial Control System

Why Should Using a Programmable Logic Controller (PLC)?

Background Control System in the Industry

The development of the industrial world need fast production processes, lower costs, and better the quality. It should be back up by good performance automatic production machines. At the beginning of the year before the 1970 method of machine control system using mechanical switch which is controlled manually by humans. There are many disadvantages when we used manual control system. In the next stage, the engine control system is already using the relay system without using mechanical switch again. The rapid development of computers has brought a relay control system connected to the computer program so that the automatic control technology was born with the name of a Programmable Logic Controller (PLC).

What is the Programmable Logic Controller?

PLC is a control machine that receives input, manipulate and execute the data input with microprocessor-based to produce output that has been specified. This control machine tool works by sensors mounted on each panel that has been determined. Input data from the sensor into the computer program without going through a series of relay circuits commonly found in conventional control systems. PLC works with logical basic program namely logic 0 (off) and 1 (on) to produce a specified output.

PLC in the control panel

Why we should use PLC? What is benefit in the industrial control system?

The more complex production process that must be handled by the machine, then the use of the system of control must be increasingly sophisticated. Automatic control systems such as PLC used as a substitute absolute control system manual. Some weaknesses of the system control manual as follows:
  • Not practical, especially when setting up cables connected to some other production machines
  • It's difficult to reset when had to make changes to the production machine settings
  • It took a long time to detect the problem if an error occurs the engine system
If you use the PLC control machine, some of the benefits that can be obtained as below:
  • Save power consumption, easily and quickly detection in the event of error system
  • Easy to accommodate the event of changes in the production process, simply by changing the program via a terminal console or PC;
  • More efficient and cost-effective because it does not require a lot of spare parts
  • Save costs, especially costs for cable connections some increasingly complex production machines that can be controlled in a computer program system
  • Zero human error, more assured quality and production time
  • Easy trouble shooting so down time is also reduced
  • The machine is controlled via PLC production is more durable than the auto-mechanical relays.

Which Industry related directly PLC control system applications?

Nearly all industries ranging from home industry to a large industry using basic concepts PLC system. Some basic functions of production that can be handled by the PLC, for example in the process of packing, material handling, automated assembly and so forth. It has long been some of industrial use as machine PLC automatic control from the tobacco industry, automotive, petrochemical, paper, even to the mining industry to control the gas turbine and the unit continued mining industry. The use of PLC is becoming more popular due to the ease of transition from mechanical relay-based control systems and trouble-shooting in the system configuration.

Basic operating system control PLC

PLC works based on input data from the sensor, then if the microprocessor to generate an electrical signal output referred to settings that have been specified. The output electrical signal is used for controlling an engine system of production. Process control occurs through several stages sequentially and continuously.

Hardware and supporting software PLC

To support advanced system performance, PLC contains four parts (devices) the following key:

MELSEC L Mitsubishi

1. Power Supply Module

This requires a tool control DC voltage supply to various other PLC modules for 20A- 50A. The current requirement is equivalent to the integral lithium battery as well as memory backup. Memory back-up power supply is required if the power down so that the memory contents will remain intact to ensure process control continues to run well. Some products such as artificial Triconex PLC, USA, the TS3000 Trisen even have double power supply.

2. CPU Module.

CPU module has a vital role as processor input data to produce output data in accordance with predefined settings.
The function of the processor is as follows:
  • Linking multiple PLC module through a serial bus and then execute data through the control program.
  • Processing of digital data input and convert tabular data, the image registers, or RLL (Relay Ladder Logic) to produce a good output data.

3. Software Module.

Program modules are the most widely used is RLL (Relay Ladder Logic). The programming language is based on sequential processes that occur in the production process makes this module very popular to control the process without disrupting the control that is being done.

4. Module I / O.

This module serves to regulate the relationship PLC with external devices or peripherals that can be run in sequence according to a command from the control system. External Pirnati could be a host computer, switches, motor drive unit, and a wide variety of signal sources contained in the plant.


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