Elsewhere on this site we saw the fundamentals of SCADA and how it has emerged. In this article we will examine some of the challenges and applications that need to be met in order for SCADA to remain relevant to the new needs.
When SCADA was developed a few decades back, it was a relatively simple system and the various components were all developed and put together by the manufacturer of the hardware or the vendor who supplied it to clients. However the variety and complexity of requirements in the recent times have given rise to the need for specialist developers. Companies often buy the different components according to their requirements and put them together, in a mix and match manner.
Therefore the specialist developers have to ensure interoperability of the component they take care of. In other words, the components have to be developed in such a way that they can be used with a variety of applications developed by different vendors.
The challenge here is that most SCADA systems are very application specific and each component is tailor made to its specific application. Therefore, the components have to also work across a number of application-specific platforms.
The Promise of Wireless Sensor Networking
The static, inflexible and centralized architecture of the system further limits the interoperability of a SCADA system with other systems as well as their coverage of data. Wireless Sensor Networking is an emerging area that can tackle this problem. With this technology, sensors can be deployed with more ease and flexibility. For example, in a SCADA system developed for gas/oil fields, sensors are typically placed at production wells and injection walls. With wireless sensor networking technology, sensors can be placed at other crucial places like pipelines and tanks at relatively lower costs. This greatly enhances the efficiency of the SCADA system by making more information available.
The current SCADA systems are not enabled to be integrated with wireless networking systems and new systems and software with this capability may have to be developed to exploit this possibility.
Another area where the current SCADA systems are found lacking is extensibility. In other words they are not equipped to be connected to new applications like safety alarm systems, real-time communication networks based on new technology etc. This in turn limits the ability of the RTUs to take proactive measures to prevent accidents.
What Needs to be Done
We may broadly divide the requirements into three categories.
First of all, the communication architecture has to move on from being rigidly centralized- they have to develop a flexible structure that allow communication between different RTUs and other systems like embedded sensor networks and mobile users on field. This can be achieved by adopting internet technologies for networking, rather than the hitherto followed proprietary or link-level connections. The use of IP empowers the physical network with software and logical networks.
Further, open and interoperable protocols for communication and data management have to be developed. The protocols have to address the issue of what types of data is sent and to whom. For instance, raw data can be sent only to the data server for archival. The supervisors, engineers or managers have to be sent only status summaries and so on.
Finally, the RTUs and other components have to be designed in such a way that unauthorized accessing and altering is not possible. In other words, data security has to be maintained. Use of IP and open protocols especially can cause more vulnerability security threats. The need for specialized industrial firewalls and VPN solutions is thus another high priority area.