A Detailed Overview of SCADA Systems and Their Various Uses

SCADA is the acronym for "Supervisory Control and Data Acquisition". It is an automation control system closely attached to almost all industrial processes today, and has become one of the most essential functional elements in modern industries. In other words, the SCADA system basically is a software-based system that receives information from a utility process in order to manage that same process.

Whether you see it in function or not, there is some kind of SCADA system functioning everywhere, mostly at the back end of the industrial process. Starting from your own house to the world’s most complex enterprises, you won’t get a place where SCADA system is not used. The SCADA system is deployed to monitor, control and analyze all industrial, facility and infrastructure processes.

In order to have some good solid knowledge and understanding of the SCADA software system, let’s take a look at its history.

A Brief History

SCADA systems grew from the monitoring systems developed for space programs in 1960’s. At that period of time, everything was completely analog and the bandwidth was pretty much limited, so the projects were not fully controlled.

However, with the advancement in technology, microprocessors and Programmable Logic Controllers (PLU) were introduced in the mid 1970’s. This gave rise to digital microprocessor-based systems that helped in receiving multiplex data from all the units and providing the collective information to the central office. This, in turn, helped bigger organizations or enterprises to monitor and control all the industrial processes better.

With further advancement in computer technology and introduction of local area networks (LAN) SCADA continued to evolve, and today you can see SCADA systems almost everywhere.

Basic Components of a SCADA System

The SCADA system, in its basic form, consists of 3 components such as:

• Master SCADA System

The Master SCADA system, also known as the control centre, is the main functional component of the SCADA software unit. It can be a PC or HMI (Human Machine Interface). It also has a Database in it.

• A Data Collection System

The data collection system may consist of several RTUs (Remote Terminal Units) and/or Sensor devices. It’s there to collect the requested data from filed instruments.

• Communication Network

The communication network is actually a 2-way network path that carries the requested data from the field instruments to the control centre in the Data Acquisition phase, and takes the command or signal from the control centre to the field instruments in the Supervisory Control phase.

Real-time Example

Let’s now understand how a SCADA system operates in the real-time world. One of the best real-time examples would be a system that’s connected to control the process in which a water pump supplies water to a water tank.

In this case, we have 3 major units such as:

• Control Centre

The main control centre receives information such as water flow, pump speed, water level in the tank etc. and stores these data in a database connected to it. The control centre could be your PC or HMI (Human Machine Interface).

• Field Instruments

Your field instruments in this case are your water pump and tank.

? The pump is connected with a PLC unit (say PLC1 in this case), which is then connected to the control centre. PLC1 records the flow of water and compares the value with the value stored in the database of the control centre. This helps adjust the pump speed accordingly.

? The water tank is connected with another PLC (say PLC2 here) and is then connected to the control centre via the communication network. PLC2 records the water level inside the tank and compares the measured value with the value obtained previously and stored in the database. This helps adjust the water flow through the value connected between the tank and the PLC2. A sensor device is connected to the water tank to provide the information about water flow to PLC2. The entire process is automatic.

• Communication Network

In this case, our communication network receives the data from the pump and tank through the 2 PLCs and carries the information to the database of the control centre, which constitutes our Data Acquisition phase. In the Supervisory control phase, it takes the command from the master SCADA system to the pump and tank through the PLCs.

Our entire 4-step automated process can be illustrated as: Information Display? Supervisory Control? Alarm & Tagging?Data Logging.

Hey myself Archer Finch. Even though I took extra care about my systems, but still it was more prone to hacking. With the introduction of the SCADA systems, my system is now very much safe from all sorts of threats, as most of the SCADA are connected to web based portals or products.

Pioneer in the industry of automation, flexible manufacturing systems, Cncs and so on, has presented his views here about Scada Free.