The world is progressing rapidly, we all know that. But none signifies that change better than the Industrial Infrastructure. As the population grows, so does the demand, and hence, so does the production. But there is only so much humans can do. Their own limitations apply to the machines they operate, too. To avoid that, automation was adopted. And to maintain automation, process control comes into play.
"Process control is an engineering discipline that deals with architectures, mechanisms and algorithms for maintaining the output of a specific process within a desired range." -Wikipedia
Industrial Control Systems, or ICS, encompasses a broad range of control systems used in industrial production, including Process Control Systems.
The most commonly used process control system currently, is undoubtedly Distribute Control system, or DCS. DCS are used to control industrial processes such as electric power generation, oil and gas refineries, water and wastewater treatment, and chemical, food and automotive production.
DCS is generally integrated as a control-architecture to exercise a supervisory level of control to multiple integrated processes. In simpler words, DCS exert the "master" control over all the underlying sub-processes inside the plant.
Another popular control system is the Programmable Logic Controller(PLC). Unlike DCS, PLC operates on discrete signals, providing Boolean values for operations. PLCs are largely used in smaller control system configurations, proving to be quite economic and efficient.
Even though PLCs are also deployed in larger industrial plants, they are often subsidiary control systems under larger ones, like DCS and SCADA.
But the world is large, and no more are industries centralized to a single physical location. To deploy automation in such scenarios, SCADA comes to the rescue.
Supervisory control and data acquisition (SCADA) is a system for remote monitoring and control that operates with coded signals over communication channels. The biggest functionality of SCADA is it's capability to remotely control processes over multiple sites and large distances.
The scope of SCADA in industries is huge: Energy, Food and beverage, Manufacturing, Oil and gas, Power, Recycling, Transportation, Water and waste water, and many more. This is primarily due to SCADA being capable of handling a variety of configuration, be it simple plants or huge, complex projects.
SCADA has not been an overnight success. It had to keep in pace with the developments in the industrial productions. The evolution of SCADA systems took place through following generations:
First Generation: Monolithic
Second Generation: Distributed
Third Generation: Networked
Fourth Generation: Internet of Things
With the advent of Cloud Computing and it’s commercial access, SCADA moved into it’s current, Fourth Generation phase, which focuses on Internet of Things.
“Internet of Things , or IoT, is the internetworking of physical devices, vehicles, buildings and other items—embedded with electronics, software, sensors, actuators, and network connectivity that enable these objects to collect and exchange data.” –Wikipedia
In short, IoT treats real-world objects as Internet entities, each having networking capabilities of it’s own. SCADA adopts this technology hands-on, and that is the sheer brilliance of it. Because Process Automation requires to every component of an industrial plant to be able to send and receive information (via Sensors and Actuators) so as to automate the process. And what could be better than to treat every component as a networking entity, capable of sending and receiving information through the network it is connected to?
The major component of SCADA system is the Remote Terminal Units, or RTUs. In fact, it wouldn’t be wrong to call them the building blocks of SCADA.
A remote terminal unit (RTU) is a microprocessor-controlled electronic device that interfaces objects in the physical world to a distributed control system or SCADA (supervisory control and data acquisition) system by transmitting telemetry data to a master system, and by using messages from the master supervisory system to control connected objects.
RTUs are often used in combination with PLCs, and are responsible for receiving the date: both from sensors and manual input. This data is then sent to the HMI/SCADA Computer or the HIM/SCADA Panel View.
The Human-Machine Interface, or HMI, is perhaps the most attractive feature of the SCADA systems. The HMI is responsible for displaying the data thus obtained via RTUs, to it’s human operator in a comprehensible manner. This is vital, because the operator in-charge of the whole system must have a regular insights into the system processes so as to take decisions or check for alert conditions.
The major drawback of the SCADA systems, is perhaps it’s vulnerability to Network Attacks. Since the SCADA systems operate entirely via networks, it makes them very prone to various types of network attacks, like Phishing, Spoofing, Man-in-the-Middle etc.
The major reason behind the network vulnerability of SCADA has been the various beliefs of it’s designers, like physical security of SCADA systems, being disconnected from the Internet, the benefit of security through obscurity etc. While the authenticity of these beliefs is still debated upon, the vulnerability that came along with it proves to be a major hindrance to the progress of SCADA.
In India, process control systems were a bit late to arrive compared to the rest of the world. However, we are here now, and with some of the biggest players like ABB, L&T, Honeywell and Seimens dipping their hands in the field, India is on it’s way to achieve world-class industrial automation.
With advances in technologies like SCADA, DCS and PLCs, alongside exponential growth in industry requirements, Process Control Systems will keep playing a major role in ensuring a fully-automated world.