All in a day’s work if you plan ahead and manage your assets properly
Who said that Asset Management is only for Fieldbus?
Let us consider these two scenarios:
- Kevin, a senior operator in a power plant, is observing the large screen in front of him, everything seems to be in top shape, power production is steady, and so he can relax. But the all of a sudden an alarm goes off: a crucial pump in the feed water cycle suddenly stops. A trip could have been avoided, because the system has been designed with back-up pumps. Unfortunately, the backup fails to start. “I knew there was something wrong with that pump”, mumbles Kevin while he forces the dreaded plant trip.
- Julie, responsible for instrumentation and control for the same power plant, receives on her smartphone an alarm from a Profibus temperature transmitter, a smart device, with embedded diagnostic features. The transmitter is still operational, but it requires a quick check and possibly some low-level, inexpensive maintenance. Julie dispatches one of her maintenance engineers to take care of the problem, and the plant continues to operate undisturbed. “All in a day’s work”, she quips.
In one case, a proper asset management policy was in place, preventing a failure, while in the other the lack of it resulted in a plant trip causing significant losses. From the plant owner perspective, both issues had the potential of disrupting production, and should have been treated and possibly prevented applying the same asset management functions to both. However, there is a difference between the two, when looked from the automation supplier perspective: the feed water pump is not in the automation scope of supply, while the Profibus transmitter is.
Oftentimes, automation suppliers have the tendency to consider the control system as an island, with well-defined boundaries, and to respond to the request for an Asset management functionality by covering whatever is in our scope of supply. More to the point, it has been a common approach to associate the concept of assets to fieldbus devices, with on-board intelligence providing early diagnostic information, in addition to the standard process values. It is not a case that the first vendors to offer asset management products or solutions focused their attention on fieldbus management.
The flaw in this approach is well described by the scenarios above: by addressing only the assets we provide as part of the control systems, we are not responding to the plant owner’s need to increase the reliability of the plant as a whole. A holistic approach to Asset Management must start with a clear definition of boundaries and features. Several standardization bodies have undertaken the effort to formalize the description of a conceptual model. These are valuable references, but for the purpose of this conversation, I believe we can simplify scope and features in a two-dimensional map: scope and functionality:
- Scope defines the class of assets: Instrumentation and control assets and plant assets. Hierarchy and groups can be used in both classes. For example, in the case of plant assets we may look at individual pumps and motors or at a whole plant component, like the feed water cycle
- Functionality refers to the different tasks comprising Asset Management. In broad terms we can identify three main tasks: Monitoring, Maintenance and Optimization
On this basis, we can clearly identify the major components of a well-structured Asset management solution:
- A plant cockpit, which must be integrated in the system infrastructure to support visualization and navigation of the entire plant and system. From here, all control system users (operators, maintenance, managers) must have the ability to access any device in the system or the plant and retrieve equipment data, documentation, real time status and historical data
- A library of additional software modules which can be added to the cockpit to perform more advanced, device specific monitoring and diagnostic
- A set of maintenance support features, making diagnostic and prognostic data available to the maintenance crew for fast identification of the problem source and execution of the necessary corrective actions
- A library of more advanced software modules addressing optimization and proactive maintenance strategies
Let’s go back to our friend Kevin, still grappling with his pump failure. How could the scenario have changed? Well let’s see: for example, by using a condition monitoring solution like the MCM800 and Analyst, Kevin’s hunch that something was not quite right would have been confirmed well in advance, and the pump could have been looked after before it shut down. Also, the backup pump failure could have been avoided by including in the maintenance planning, driven by the automation system, a periodic test run to ensure that it was in proper working order. The plant trip could certainly have been avoided. All in a day’s work!