This Puffin is looking set to fly

So long as nobody gets hurt, I usually applaud people who buck the system. And that's why I admire the programmers who have devoted so much of their time to developing the Linux operating system. They have decided that the commercial off-the-shelf operating systems do not meet their needs and, despite the massive dominance in the market place of the COTS systems, these programmers have decided to go against the grain and build a 'better' operating system from the ground up. Three cheers!

In a similar vein, an open-source PLC has been developed (PuffinPLC) and an open-source Scada system will become available later this year, to be known as PuffinScada. This software runs on Linux and is supplied as a modular software toolkit and a reference application (a Scada system that has been built using the toolkit). Credit where it is due: PuffinScada is being developed by Greg Goodman of Chiron Consulting and Bob Hampton of Optimizations. According to these two, only a little more work is required to have PuffinScada ready for launch, mainly completing the documentation.

The appeal of an open-source system is that it offers high reliability, peer-reviewed software that has lower production costs. Furthermore, having access to the source code frees the user from the mercy of a single vendor's, oftentimes limited, capabilities. So PuffinScada is intended for integrators and in-plant automation developers who need the versatility and widespread support that is available with open source software.

But where will the 'widespread support' for PuffinScada come from? The answer lies in the control.com community (www.control.com), which is committed to the advancement of interoperability in the industrial controls industry. No doubt Goodman and Hampton will initially perform a significant role in that community in the early days of PuffinScada.

In terms of the actual tools contained in the software toolkit, PuffinScada is a collection of C-based libraries, mechanisms, and conventions that allow the user to implement a client/server-based Scada system. A wide range of Scada features are included, such as alarm processing, message logs, and a data historian. In addition, the software provides a protocol for inter-process communications, and several database management systems. Libraries are available for operating on memory, files, and strings; managing high-level socket and FIFO connections; and manipulating time and date at millisecond resolution.

This all sounds good, but sceptics will be starting to ask: "Where's the catch?" Well it is unlikely that PuffinScada will be an all-singing, all-dancing solution from day one. The system has been designed for performance and versatility, and it is hoped that users will start to contribute to enhance the system. For instance, the number of I/O protocols and supported languages will gradually increase and, as different users with different HMI requirements participate, there will be a proliferation of data viewers, web access methodologies, and integration with external HMI tools.

Already there are varying degrees of 'openness' within the world of Scada applications, so it may be that you can achieve what you want to by carefully selecting the system or components without having to go down the rocky path of a truly open source system. The other side of the coin is that you may not be able to do what you want with PuffinScada unless you are prepared to spend a great deal of time on further development - remember, it's still very early days for this fledgling package.

It is fair to say that to make the most of PuffinScada, you really need to know what you are doing - probably more so than if you are using a COTS Scada package. And you have to be prepared to work with Linux, which may put off some potential users. Indeed, there could be pressure from project managers who feel that implementing a Scada package and an operating system together represents too great a technical risk. However, the control.com community is sure to come up with plenty of arguments in favour of Linux and PuffinScada. After all, the benefits could well outweigh the risks, so long as nobody gets hurt...