In a previous post I recommended that SCADA testers and technicians brush up on their UNIX/LINUX command line skills. (You may run into these systems) I also presented my opinion that UNIX the most powerful and flexible operating platform that can handle very large SCADA systems. There is a big difference between scanning 250 remote devices and scanning 250 power plants each connected to multiple devices. (Just one device can hold hundreds of points) You also need to factor in the update speed for all those points. 250 plants is a big system. My experience with MS Vista has not given me the amount of confidence in it’s stability that would have me recommend it’s use as the operating system of choice for very large and complex control systems – yet. This may change as the operating system continues to evolve and improve and as more drivers become available. I have had very positive experiences with XP and Server 2003 running some SCADA HMI packages for smaller systems. In fact I have also had very good luck pushing one Windows based HMI from a company based in Calgary way beyond the role of a typical HMI where I would have confidence in using it for a very large SCADA master. There are quite a few Windows based SCADA systems available that are built to run on the Windows platform that handle large amounts of data and remote sites. I still would gravitate more to Linux for very large systems with heavy workload demands. Windows is a major player and you need to have the tools and abilities to support these systems. Each customer will have their own unique requirements and will have to decide which operating system and applications best fits their needs and budget. If you test the system and it works for you then by all means go for it. A lot will depend on what type of hardware you run your system on and how you allocate your system resources for different processes. I have received some interesting emails regarding my opinion on this subject. Remember this is still just my humble opinion. Security issues will also be a major issue, along with system updates. All these issues play a factor in the strength and weakness of the application and the operating platform or system. You’ll probably have your own view of this subject based on your own experience. Whatever the case, I would still recommend brushing up on your LINUX. If you are looking for an “easy” system, make sure it’s also powerful. Sometimes this is not the case. Power requires complexity; complexity often has issues with stability. Learn them both, Windows and Unix/Linux and then judge for yourself what your likes and dislike are for each. There’s always testing, that’s what your supposed to be doing anyways right? Test the system, push it to it’s limits – not just by running one single test device. Test the full load. Run your tests at expected loads for as long as you can. You will still most likely come across issues during regular service, but try to keep these issues to a minimum by testing your system before you ever put it into normal service operation. There is a big difference between a HMI and a true master station. The lines are blurred between the systems at some levels, but you will have to discover what level you’ll be working at, and what type of system you’ll need to support. If it works, it works. If it crashes, then you’ll know it doesn’t work - right? Maybe it works, but you don’t know how to keep it working. Ahh, that’s another problem all together.
