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Digitalisation is changing society and the requirements on employees who operate plants and equipment. New concepts are therefore needed.
Standardisation and modularisation in plant engineering and design enable plant operators to respond quickly and flexibly to new production demands. At the same time, they increase system availability and reduce downtime. In a modular system, even relatively serious faults can be corrected quickly because defective modules can be replaced by equivalent modules with little effort.
However, the full deployment potential of modules can only be achieved with automation solutions based on uniform standards and interfaces for the integration of modules in process control systems. That avoids or reduces the number of isolated proprietary solutions, to the benefit of the user.
Leading automation suppliers and plant operators have been working on this task for a good while. The Module Type Packaging (MTP), a manufacturer-independent module description, enables module integration in the process management level. The system-independent interface description allows module suppliers to implement their package units in systems very quickly.
System safety is a decisive factor for plant operation, and the module type package concept provides a solution here as well. The safety instrumented system (SIS) can be integrated into the process control system through MTP. This form of SIS integration gives users standardised data at the process management level (PML).
With conventional SIS integration in process control systems, the SIS information level in the PML depends on the plant operator.
The supplier must adapt the information level and interface of an automation device to the PML according to customer specifications. If instead the automation device is integrated into the process management level through MTP, this is done over standardised interfaces with corresponding dedicated conditioning of the information content. Operators and system engineers receive uniform, manufacturer-independent standardised information.
Other safety-related components can also be integrated into a plant over MTP and networked with each other. This increases system availability, and this modularisation allows plants to be built faster and made more flexible and more reusable. Modular automation therefore gives plant operators access to the structured information of their safety instrumented systems (SIS). A system integrated over MTP has standardised libraries at the SIS level and at the human-machine interface (HMI) level.
How SIS integration works
The first requirement is a specific MTP library for programming of the SIS, in order to define the information content for integration into the PML in the SIS programming stage. The module is integrated into the PML by means of MTP. Then an MTP import tool in the control system (distributed control system, DCS) generates DCS-specific HMI screens from the MTP. These only differ from the screens generated with the DCS screen editor in the libraries that are used and the fact that the information from the SIS is always marked with a safety flag.
Now the module supplier is able to carry out system-independent engineering. The result is an MTP container that holds the specific information of the module or the package unit, with all of its dynamic parameters as a dynamic part and a container as a statistical part. Using the system-independent MTP, the plant operator can import the module into a specific DCS. The import process automatically generates an HMI screen with all necessary links to other screens or faceplates.
In summary, standardisation and easier system integration with modular automation in the area of functional safety increase the profitability as well as the availability of process control systems. Plant operators receive standardised information in the process control system about fault causes in the event of a malfunction and are better able to avoid emergency shutdowns.
With SIS integration over safety MTP, safety-related data or parameters can be modified through the HMI. In addition, the information level is higher and is standardised. The system-independent interface description allows module suppliers to implement their package units in systems very quickly. Module integration yields time savings of up to 70% compared to current practice.
With the aid of modules, plant operators can not only erect their systems even faster, but also correct fault cases more promptly because defective modules can be replaced by equivalent units with little effort. Furthermore, standardisation as well as differentiation with the safety flag make system management more operator-friendly.
About the author:
Christoph Kotsch holds a graduate engineering degree and has been responsible for the integration of HIMA controllers in ABB systems since 2009. In addition to ABB, for two years he was responsible for the integration of HIMA controllers in Honeywell systems. He is an active member (since 2015) of the ZVEI and Namur modular automation committees for Technology Evaluation (AK 1.12.1), Process Management (AK 2.3), HMI (AK 2.9.1) and Standardisation (GMA 5.16).
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