Process Controllers

In this cycle of introduction to automation I have described some fundamental components that make up this cycle by sharing photographs that I have taken while working to present equipment for industrial use and to give a brief description that allows us to familiarize ourselves with them. I have already described the sensors and actuators so it is time to close the cycle with the controllers.

As I said in previous topics, controllers are responsible for making decisions about the process, they receive signals from the sensors and through pre-programming take control actions over the process through the actuators.

To begin with I want to introduce the most popular PLC or programmable logic controller, in the image we can see a modular one, we can say that a PLC is a cpu with processor, ram memory and storage memory but these are dedicated for industrial use and their programming is done in ladder language, a language used by electricians in the past to create relay logic and that is adapted in PLC programming to facilitate the transition. A single PLC can replace huge relay panels to provide better applications, the PLC theme is so extensive that in the theoretical part I am sure I will have enough material for a huge article. However, suffice it to say for now that these are programmed with a PC and compatible software which depends on the PLC manufacturer and that these are the "brains" of the process.

The DCS or Distributed Control System as its name indicates is a system that consists of several control panels distributed throughout the plant to facilitate the acquisition of signals, a module can be installed in the field and receive all the wiring and transmit the signals via a single fiber optic cable over long distances to the main panel which in this case is made up of a PLC, A DCS is required in large plants that handle a large number of instruments as it significantly reduces cable lengths and construction times that would take long distances to wire, there could be many panels distributed throughout the plant and in the end all converge by a single high-speed communication cable to the main panel.

Remote Terminal Unit or RTU are controllers based on smart electronic cards that act according to a program, these cards have a dedicated microcontroller and memories to store the execution code. They can also communicate using different communication protocols and allow control of specific systems without the need for a PLC or DCS. They are generally used in processes where control is less complex.

With this description we only need to show the monitoring process in which the programming software and the monitoring software are mentioned, that will be the next God topic through which I finish the introduction to automation and then go into a little more theoretical content that will allow us to lay the groundwork for then go deeper into each topic in a more specific way taking advantage of the fact that I am currently working on some projects to show real examples of application.

Once again thank you for accompanying me in this delivery, I leave you a hug and see you next time.

---

Posted from my blog with SteemPress : https://automation80.000webhostapp.com/2018/08/process-controllers

---