After 20 years working with process control and personally helping steel users design some of their systems I would like to open a discussion and share some insight on how I see current technologies and needs for those applications regarding control systems.
Something that still amazes me is the collection of buzz words that gravitates around any new or control system upgrade: DCS (Distributed Control Systems), PLC (Programmable Logic Controllers), PAC (Process / Programmable Automation Controller), HCS (Hybrid Control System), PC based control, open systems, open architecture, etc. What is the future of these technologies? And are these technologies still different today?
I see convergence in the hardware of these technologies. Years ago it was very easy to differentiate DCS hardware from PLC hardware, just by its appearance. Today, theoretically, any of these solutions can deliver some answers for a given application. However, the secret is how easy such solutions can address problems and make the user’s life easier. The secret resides in a simple word: software.
From the problem to the solution
Regardless of all the solutions names listed above, users are looking for a system that addresses the application and brings peace of mind from engineering to operations and includes some basic requirements:
- Easy to engineer
A single package able to have several programmers simultaneously tackling different areas of the program under the same environment and ability to mix them later. Object oriented programming allowing project engineering based on objects: A single entity that contains its faceplate, graphical elements & alarms (for supervision), logic blocks (for control) and documents (for maintenance) – Easy to use, re-use and customize on the same or new projects.
The control design of any system is much easier if visualized and configured as a whole. The system must also be process driven where the user designs the process first and worries about controllers’ topologies and configuration later.
- Easy to operate/maintain
A system needs to have seamless navigation, so the operator can jump from any motor graphic element (on the supervision screen) to the motor logic control residing in the controller. Past systems had distinctive control/supervisory software where, if any deeper analysis was required, operators needed to bounce between applications (and even computers) to search for variables and tags to find the root cause hidden in the logic.
- Easy to integrate
Any control system today is part of a major picture – motor control, energy systems, MES, asset management, instruments, video monitoring – and that control system needs to be open enough to talk easily to those other elements. The good news is the consolidation of Ethernet (and WEB services) as the industry communication backbone and its quick patch and acceptance to the device level.
- Advanced functionalities
From process to energy optimization, advanced libraries are a must for any control system. Years ago such advanced capabilities were easily attributed to DCS systems, that is no longer true and must be part of any modern and major control system.
What kind of control system do you have at your steel mill? Any experiences you would like to share?