What is PLC?
For those who do not know the PLC, it is undoubtedly the intelligence part of an automation process, that is, he is responsible for controlling the entire process. PLC stands for Programmable Logic Controller, which is a computer capable of performing specific functions through created programs. Although it is considered a computer, do not confuse PLC with desktops and notebooks that are computers for general use, used at home or at work for example!
Although the PLC is considered a computer, if we compare it with these general-purpose computers, the PLC has less capacity for data processing, storage and is used in specific applications.
Learn what PLC is and what it is for!
What is a programmable logic controller?
Difference between PLC and PLC
It is common to see or hear the terms PLC and PLC, and it is very common for people to think that both refer to two different equipment, when in fact PLC and CLP refer to the same equipment. These two abbreviations exist because PLC (Programmable Logic Controller) corresponding to the equipment’s name in English, while CLP (Programmable Logic Controller) is referring to the equipment’s name in Portuguese.
What is the PLC for?
When there is a need to manage processes in an automated way, it is necessary to use equipment capable of controlling this entire process, that is, receiving signals, processing them and sending command signals to the actuators. In other words, for the system to function intelligently, we need a “brain” that has enough information to make decisions.
The decision maker must be programmable equipment. In industrial environments, the PLC is a piece of widely used equipment, but it is not the only one that is used for this purpose, despite being one of the best known. We can cite several examples of processes in which the PLC is used, such as in level control, flow control, conveyor automation, and other applications!
As we have already seen, the programmable logic controller is considered a computer, as it contains CPU, memory, input and output devices.
CPU is an acronym that comes from English and means Central Processing Unit, which translates to the Central Processing Unit. The CPU is responsible for searching for instructions, interpreting those instructions and executing them.
The PLC has volatile and non-volatile memories, which are responsible for storing all the information necessary for the PLC to be able to perform its functions. For those who do not know, volatile memories are those that lose information when they are de-energized, as is the case with RAM memory. Non-volatile memories are those that do not lose information when they are de-energized as with HD, SSD, and pen drive.
An example of an application of non-volatile memory is to store the operating system and the files that contain the PLC settings. Volatile memories are used by the CPU when the program and functions are being executed, and we cannot select what will or will not be stored in them.
Generally, programmable logic controllers are powered by 24-volt voltage sources. The source is responsible for transforming and regulating voltages to the appropriate levels of each PLC.
Input and output modules
The input and output modules are responsible for making the connection between the actuators and sensors with the PLC. It is important to highlight that the inputs and outputs can be both digital and analog, according to the characteristics of the PLC’s. There are several types of sensors and actuators that can be used in the PLC, such as:
In the past, most of the processes were controlled by electrical commands that occupied a large physical space. If there was a need to make any changes or even repairs, it would be necessary to undo some electrical control panels, resulting in a considerable loss of time.
With the use of a PLC, the need for changes in the installation would be considerably less, requiring only a computer to manipulate the program. With this it is possible to simplify the change of processes, reducing time, labor and consequently obtaining significant profits.
The use of the PLC is growing more and more and although it is commonly used in industries, the PLC is also being applied in residential installations, due to home automation. If you want to learn a little more about industrial automation, below is a video from the Mundo da Elétrica channel that talks about industrial automation.