What is a PLC? How does it work?
You want to know what is a PLC? You have come to the right blog, because here we will explain everything you need to know to understand what a programmable logic controller (Programmable Logic Controller – PLC).
A PLC is a "brain" that activates the components of the machinery so that they develop potentially dangerous activities for people, very slow or imperfect.
It is important that you do not confuse the PLC (Power Line Communications) used in communication networks with the automaton industryHe, then, although they share a name, the uses are totally different.
This second one, which we are not going to delve into, transmits the internet connection through the electrical network. This type of PLC repeater It is used to extend the Wi-Fi network and Ethernet connection.
now that you know What does the acronym PLC mean?, it is time for you to understand how it works and the utility that an industrial automation computer can provide.
HOW DOES A PLC WORK?
It is important to know that functionality is a custom aspect in PLC development. Well, the provider develops the functions according to the needs of control, registration, monitoring... of the project that is being developed.
This equipment like a computer, where the main parts They are the CPU, a memory and input/output module, the power supply and the programming unit. In order for it to work, then, it is necessary to carry out a programming prior to the function that it is going to perform.
To carry out this programming, specific software adapted to the brand and the programming language to be developed is needed.
Basically, the function of a PLC is to detect various types of signals from the process, and prepare and send actions according to what has been programmed. In addition, it receives configurations from the operators (programmers) and reports to them, accepting programming modifications when necessary.
How are PLC devices created?
With the development of the internet and electronic technologies, a way was sought to replace control systems based on electrical circuits of combinational logic, with relays and switches.
In the late 60's the first appeared types of programmable controllers, with very simple characteristics and a very long useful life.
The aim was to achieve industrial automation, where the use of electronic devices would alleviate the burden of repetitive tasks in factories. Thus, a labor evolution took place where the professional stopped doing the work and began to monitor that the machine worked correctly.
In 1982 the first commercialized PLC in a standardized form was sold for more than a million dollars. However, now this type of technology is available from 49 dollars (43 €).
When history was still understanding what a PLC is, microprocessors were incorporated into its composition. Thus, PLCs with the ability to communicate with each other and control the processors telematically were created. In addition, technological improvements were implemented to improve the data obtained.
In the 80s, the programming and communications protocol was standardized, making improvements to the programming system so that it could be done with personal computers instead of programming terminals. In addition, other design improvements were implemented that improved its performance.
Starting in the 90s, and up to now, the physical characteristics of the devices and the programming modules have been modernized, opening the possibilities of programming, control and communication channels.
WHAT TYPES OF PLCs EXIST?
As we have seen in the evolution of PLCs, the modifications and improvements that have been made have resulted in different types of PLCs that can be grouped into four main categories.
CONTACT TYPE
Want to know what a compact PLC is? It's one that meets the generic specifications of PLCs: it has the power supply, CPU, and various modules built in.
There are compact PLCs in nano size, which have a super small size, although the basic operation of the PLC is more limited by its characteristics. All our equipment has inputs to connect our sensors of temperature, pressure, humidity, etc.. With which you can perform a precision control of your machinery and equipment.
MODULAR TYPE
This type of PLC is characterized by its expandable modules, which give it more powerful features than the compact model. It works with more complex programs and has greater memory capacity and operational capabilities.
RACK MOUNT
Once you understand what a modular PLC is, rack mounting becomes easier. It's practically the same, but there are differences in the rack where the PLC modules are installed.
In the case of rack mounting, the exchange of information between the different modules is allowed, this allows a higher speed of information transmission and, therefore, optimizes the operation of the PLC.
PLC WITH BUILT-IN HMI
He HMI (Human Machine Interface) is a programmable device, a graphic interface, which combined with the PLC allows to optimize the experience of programming and use of the machine. Reduces wiring of PLC elements and displays them on a graphical display as programmed.
WHAT USE CAN I GIVE TO THIS TECHNOLOGY?
This technology of simple implementation and fast execution, allows us to automate the processes of our project with low maintenance and customized installation.
To finish understanding what this equipment is and how it works, we are going to give the example of an automatic car wash:
It will be programmed so that, every 500 meters, it collects the signals from different sensors of temperature, pressure, presence of vehicles, levels of oxide and carbon dioxide, and the water level of the tank.
Depending on the sensors, the input and output devices will be activated: traffic light, warning lights, fans and water pump. In addition, by having remote access, operators can access the machine interface and view the status of the process, as well as modify it if necessary.
In short, safety levels will be established in the presence of toxic gases, vehicle speed, etc., and the PLC will check that the data is within that parameter and, if it is not, it will activate the measures scheduled security.
Now that you know exactly what a PLC is, we inform you that at SRC we have a development line for these products. Our engineers are also in charge of developing the automation systems to couple our sensors of temperature, pressure, humidity, etc.. With which you can perform a precision control of your machinery and equipment.
get in contact Contact us and we will solve all the doubts that have arisen in this regard, in addition to informing you in depth about the types of PLCs with which we work.
DO YOU NEED ADVICE?
Send us your inquiry and our technical department will contact you as soon as possible.