PLC, HMI & SCADA based system

PLC, HMI & SCADA based system


PLCWhen it comes to the hardware-based part of the SCADA or HMI system, we can’t dismiss a PLC, as a crucial component in the system. PLC stands for Programmable Logic Controller and it is an industrial computer that is used for industrial automation. PLCs can differentiate in sizes and capabilities, depending on the company’s need. This powerful industrial computer works by continuously monitoring the state of input devices and makes decisions about controlling the state of output devices.

The great thing about PLCs is that they can control huge chunks of a production line, as well as the whole production line itself. Any kind of production line can be vigorously enhanced by using this technology, but the biggest advantage of PLCs lies in repetitiveness. This computer is able to replicate the operation or process over and over again, all while collecting vital information.

Because of its minuscule size, PLCs are modular and highly portable. This means that the PLC can be brought to the production line, hooked up to a computer, programmed, and put into work the exact same moment.


The reason we left HMIs for the end is that they are used to communicate with Programmable Logic Controllers and as such, the whole system is completed. Whereas SCADA represents a remote system used to communicate and collect data, HMI is a local machine capable of doing the same thing. But, the only difference is, as we said, that HMIs are local machines. The Human-Machine Interface is the user interface that
connects the operator to a system, device or machine.

An HMI isn’t a particular piece of hardware but rather a screen that allows a user to interact with a device. HMIs can also be called Operator Terminals, Local Operator Interface, Graphical User Interface, etc. If some of these names (OT, LOI, and GUI) sound familiar to you, it’s because you’ve already used some of them. Simply put, HMIs are used for visualization of particular data, for easier understanding and control.

The prime modern example of an HMI is a tablet. A tablet is a GUI that allows you to control various processes. If you’re connected to your TV via Bluetooth, you can use your HMI (tablet or a smartphone) to control it. HMIs come in a variety of shapes and sizes – computer monitors and machines with built-in screens.

We provide automation solution to all the areas listed in our areas served. Automation has following levels.

1 Level-1 of automation: With the use of PLC (Programming Logic Controller) if we make some logic by using sensors, push buttons, Indication, Hooter, etc. in hardware & implement them on hardware without any user interface. This type of automation we consider as Level-1 of automation. To develop logic Computer system is used. In some Micro PLC’s there is option to develop logic in same PLC.

2 Level-2 of automation: With Level-1 of automation if we give user interface using HMI (Human Machine Interface) that we call Level-2 of automation. In this type of automation, we get software-based control of hardware. HMI gives facility to see the status of machines, controlling & alarms in single platform in customized form. To develop software for HMI Computer system is used.

3 Level-3 of automation: With Level-1 or Level-2 of automation if we give user interface using SCADA (Supervisory Control & Data Acquisition System) then that type of automation we call as Level-3 of automation. SCADA system needs Computer system to develop software & that software can be implemented on same or any other computer system. SCADA system provides flexibility to record data, more space for programs, real time monitoring of data & system. This SCADA system acts as server for automation. From this we can access the things in remote.

4 Level-4 of automation: With the use of server system if we access the data & remote controlling of things in local then that type of system, we call local network control. If we do the same thing on internet, then we call it as IOT (Internet of things) or cloud-based system

SCADA Systems

SCADA Systems SCADA didn’t get its name by luck, it is actually an abbreviation that stands for Supervisory Control and Data Acquisition. As we said earlier, it’s a system that has both software and hardware elements and is usually used for a couple of things:
  • Control of various processes from a remote location or locally
  • Interaction with sensors, pumps, motors, and valves through an HMI (Human-Machine Interface) software
  • Monitoring, acquiring, and processing real-time data
  • Recording the events into a file.
  • In the modern time, there isn’t a serious organization that doesn’t take advantage of SCADA systems. These systems help save some time, they increase efficiency, they process data faster and with accuracy, and they allow for smooth communication between various parts of the system. As such, the SCADA architecture consists of two basic parts – an RTU (Remote Terminal Unit) and a PLC (Programmable Logic Controller). A PLC is essentially a microcomputer that directly communicates with a plethora of objects such as end devices, sensors, or numerous factory machines.
  • A PLC, however, is directly hooked to the factory machine, while the RTU is used remotely, as its name implies. The sheer power of SCADA software allows us to process, distribute, and display the required data, thus making it easier for employees to analyze it and come up with solutions if needed. It works exactly as it sounds. If there’s an error somewhere in the process, it notifies the operator who can then pause the production process and check the data from the SCADA system. This data can be checked via an HMI, which we’ll talk about later.

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