Types of SCADA systems
There are different types of SCADA systems that can be considered as SCADA architectures of four different generations:
1. Monolithic or Early SCADA Systems
Minicomputers are used earlier for computing the SCADA systems. In earlier times, during the time of first generation, monolithic SCADA systems were developed wherein the common network services were not available. Hence, these are independent systems without having any connectivity to other systems.
Monolithic or Early SCADA Systems
All the remote terminal unit sites would connect to a back-up mainframe system for achieving the first generation SCADA system redundancy, which was used in case of failure of the primary mainframe system. The functions of the monolithic SCADA systems in the early first generation were limited to monitoring sensors in the system and flagging any operations in case of surpassing programmed alarm levels.
2. Distributed SCADA Systems
In the second generation, the sharing of control functions is distributed across the multiple systems connected to each other using Local Area Network (LAN). Hence, these were termed as distributed SCADA systems. These individual stations were used to share real-time information and command processing for performing control tasks to trip the alarm levels of possible problems.
Distributed SCADA Systems
The cost and size of the station were reduced compared to the first generation system, as each system of the second generation was responsible for performing a particular task with reduced size and cost. But even in the second generation systems also the network protocols were not standardized. The security of the SCADA installation was determined by a very few people beyond the developers, as the protocols were proprietary. But generally the security of the SCADA installation was ignored.
3. Networked SCADA Systems
The current SCADA systems are generally networked and communicate using Wide Area Network (WAN) Systems over data lines or phone. These systems use Ethernet or Fiber Optic Connections for transmitting data between the nodes frequently. These third generation SCADA systems use Programmable Logic Controllers (PLC) for monitoring and adjusting the routine flagging operators only in case of major decisions requirement.
Networked SCADA Systems
The first and second generation SCADA systems are limited to single site networks or single building called as sealed systems. In these systems, we can not have any risk compared to the third generation SCADA system which are connected to the internet causing the security risks. There will be several parallel working distributed SCADA systems under a single supervisor in network architecture.
4. Internet of Things
In fourth generation, the infrastructure cost of the SCADA systems is reduced by adopting the internet of things technology with the commercially available cloud computing. The maintenance and integration is also very easy for the fourth generation compared to the earlier SCADA systems.
Internet of Things
These SCADA systems are able to report state in real time by using the horizontal scale from the cloud computing facility; thus, more complex control algorithms can be implemented which are practically sufficient to implement on traditional PLCs.
The security risks in case of decentralized SCADA implementations such as a heterogonous mix of proprietary network protocols can be surpassed using the open network protocols such as TLS inherent in the internet of things which will provide comprehendible and manageable security boundary.
Applications of SCADA
SCADA systems are used for monitoring a variety of data like flows, currents, voltages, pressures, temperatures, water levels, and etc., in various industries. If the system detects any abnormal conditions from any monitoring data, then the alarms at the central or remote sites will be triggered for alerting the operators through HMI.
There are numerous applications of SCADA systems, but a few most frequently used SCADA applications include:
1. SCADA In Manufacturing Industries
In manufacturing industries the regular processes like running the production systems to meet the productivity targets, checking the number of units produced and counting the completed stages of operations along with temperatures at various stages of the manufacturing process, and so on, are taken care by using the SCADA application.
2. SCADA Application in Waste Water Treatment and Distribution Plants
Wastewater treatment plants are of different types such as surface-water treatment and a well water treatment system in which many control systems and automation processes are involved in water treatment and distribution systems. SCADA systems are used for controlling the automatic operations of the equipment used like backwashing the filters based on the hours of working or amount of water flow through the filters.
Waste Water Treatment and Distribution Plants
In distribution plants the water tank levels, pressure of system, temperature of plant, sedimentation, filtration, chemical treatment and other parameters or processes are controlled using the SCADA applications such as PLCs, PC based workstations which are connected each other using Local Area Network (LAN) such as Ethernet.
3. SCADA in Power System
Power system can be defined as constituent of power generation, transmission and distribution. All these sectors are needed to be monitored regularly for improving the system efficiency. Thus, the application of SCADA in power system improves the overall efficiency of the system by providing the supervision and control over the generation, transmission and distribution systems. SCADA in the power system network increases the system’s reliability and stability for integrated grid operation.
SCADA in Power System
Wireless SCADA
In large scale industries like power plants, steel plants and so on, many processes and operations such as movement of conveyer belts for coal or product transport, boiler heat temperature, etc. are to be monitored continuously and there is need to control the factors affecting these parameters. So, application of wireless SCADA will provide better control over the required control systems and operations.
Wireless SCADA Block Diagram
In this project 2.4 GHz wireless transmitter and USB receiver are used for sending and receiving the data collected from the temperature sensors which interface with 8051 microcontroller. If the temperature goes beyond the set limit whether the low limit or high limit, then the microcontroller sends commands to the relays to turn on or off based on the command signal.
Monitoring and controlling of multiple operations in maximum number of industries are being automatically controlled by most advanced SCADA technology implementations. Already we are observing that many industrial operations are automatically controlled using the application of SCADA system technology, but still many researchers are working to develop more efficient SCADA systems for adopting full automatic control of all types of industrial operations. Having any queries and ideas? Post your comments in the comment section below for any technical help for implementing your ideas to develop real time projects.