Commissioning is usually that undefined time between construction and plant start up. If commissioning doesn't go smoothly, you can count on start-up not going smoothly. I have commissioned dozens of plants over the past 27 years and have seen firsthand the difference between a good plan and a bad one. If you avoid these following mistakes I've witnessed over and over again, your efforts will be more trouble free with fewer self-induced headaches.
Isolating A Large Power Generating System When It’s Driving A Variable Load Creates Some Special Control Challenges
Power plant control systems have their own unique design issues, however when dealing with island systems, there are even more things to consider. Take for example a large aluminum smelter complex – such plants can have their own power generation facilities, as large as 2,000 MW, which is enough to power a small city.
Engineering disciplines, just like may other disciplines, have become very narrowly focused. At some level this is a necessary trend, since to be expert in every aspect of a field has become something that is almost impossible to accomplish. Very few mechanical engineers are experts in metallurgy, hydraulics, machine design, HVAC design, thermodynamics, mechanics of materials, strength of materials, metal cutting operations, metal forming operations, and, well, the list goes on. An engineering student attempting to delve deeply enough in every aspect of his or her chosen discipline to be an “expert” would never finish college.
In this post, I would like to share ideas relating to operations management and software development within the problem domain of manufacturing. For this discussion, I will draw on my experience in an industrial / manufacturing engineering capacity within various discrete manufacturing organizations, as a quality engineer for a leading HMI vendor, and as a software developer for control system firms. The ISA 95 specification can assist in this discussion.
I sat through a demo the other day of a software application that extracts all the information from your control system and puts it into an offline readable format that the user can query to create custom reports. While it is a wonderfully done package, it would be absolutely useless in many of the plants I’ve visited recently. Most of those plants are in the process of migrating their existing obsolete systems to a platform with current technology.
Over the last few years, MES (manufacturing execution system) packages have appeared that provide the database framework and programming interfaces to collect, process and provide standardized information links between the production floor below and the ERP (enterprise resource planning) business system above. Even so called “configurable” packages usually require extensive custom coding since the built-in functional capabilities are usually insufficient to handle all but the simplest manufacturing processes and integration to current installed information systems. The reality is that MES installation projects are just as much about custom software development as they are about installation and configuration.
As process control engineers, we are constantly faced with having to choose a type of control system that is a best fit for the application. If you’re an end user, you probably will not need to make this kind of selection as often as we do, so you might not keep up-to-date with the latest technologies. There are many types and manufacturers out there to choose from, and careful consideration must be taken when deciding what type of system to implement into an automatic control application, especially since these systems will often remain in place for many years. A bad decision could haunt you for a long time.
As I walked into the control room the first thing I heard was, “Why can’t I commission this transmitter?” The technician was pointing to the screen where he was trying to commission some Foundation fieldbus transmitters that had been taken out for service. At least this time he’d remembered to decommission them first.