The future of the process control system

Author: Thoralf Schulz Technology Manager Business Unit Control Technologies, ABB Automation

Process control engineering has undergone a number of metamorphoses over the past few decades. These technological developments mean that it is now possible to achieve a much higher level of automation in plants and production. The demands placed on automated systems have become bigger and more complex. Current automation systems help to master these complex requirements and tap the full potential available for optimisation in production. They have become the control centre for the entire production facility and thus represent a key productivity factor, the significance of which is set to grow further in future.

To reach higher levels of automation and meet the requirements for optimisation, it has been necessary to continually expand the functional range of control systems. Functions such as the integration of intelligent devices for configuration and diagnosis, information management, Advanced Process Control, enhanced alarm management, and connection to maintenance and business systems are just some examples of this. The guideline for the integration of these additional functions was the proposal recommending integration into the control system kernel using standardised and open interfaces. The ABB automation system 800xA in its current form is considered to be a prime example of the implementation of this recommendation.

In addition to standards, technologies from the field of IT (standard operating systems, commercial networks and PC technology) have also found their way into all levels of the control system. As well as the sought-after benefits in terms of optimisation potential, the additional functions have also led to an increase in the level of complexity in classic control systems, which is why the term ‘automation system’ is now more appropriate. Integration through standard interfaces has demonstrated that interoperability is not necessarily 100 % guaranteed, unless both service providers and users deploy additional resources.

The demand for additional functions (and implementation of these) and the use of IT technology may have a negative impact on the basic requirements for reliability, predictability and safety in the production process if no careful consideration is given to this and no precautionary measures are taken. As a result, the control system supplier is tasked with meeting a range of requirements for upgradable functions and openness in the control system’s basic design, while at the same time not infringing on the basic requirements for ‘control and regulation’. With this in mind, it will be increasingly important in future to protect any hardened, ‘unbreakable’ kernel in the control system from the negative effects of enhanced functions using non-interactive interfaces.

The hardening of the kernel in the control system also helps to meet one other challenge which service providers and users had to pay increasing attention to over the past decade, namely the topic of IT security. The number of security gaps brought to light in IT systems has risen steadily over the last few years. This is also an issue that affects process control systems, not least as a result of the introduction of IT technology, i.e. commercial operating systems and standard communications, into control technology. Just a few years ago, it was thought that virus scans and automated system firewalls were adequate and fit for purpose; however, it has now become clear that these measures alone do not provide sufficient protection. IT security can only be achieved through close collaboration between the service provider and the user. Control technology manufacturers need to assist customers with their security requirements by providing design notes and operating instructions, setting secure default settings which keep the area under attack in the system as small as possible, incorporating security requirements into the design of all components, and ensuring open communication with users. The automation system must protect itself and the service provider must support the user in using the system securely. Everyone involved in this process must understand that long-term security can only be achieved if these challenges are addressed on an ongoing basis.

In the past, standards were created to support integration and openness. This task is ongoing even today and is set to continue in future. Unfortunately, it has not always been possible to press ahead with these standards in a way that could achieve real openness, reduce the complexity of the integration process, and prevent repercussions. Device integration is a good example of this. Here overlapping standards have led to an increase in outlay and unnecessary complexity. The FDI initiative for device integration represents a milestone, with experience and findings being implemented in practice. It represents a move away from conflicting approaches, increasing the added benefits of device integration while also reducing the re-percussions in terms of both the control system itself and the related expenses.

Wireless technology (WLAN, etc.) is no longer just beginning to creep into our daily lives – it is now an indispensable part of it. It is even finding its way into automation technology and is now being used to integrate new and tempo-rary measuring points, thus further improving the potential for optimisation. This applies in particular to measuring points which cannot usually be reached with a justifiable cost/benefit ratio due to the complex or expensive cabling required. Diagnosis and secondary data not previously accessible with conventional devices can now be integrated if the devices are retrofitted with wireless adapters. In future, wireless technologies will perform other tasks, too, but they still need time to develop if they are to become a standard option and meet the aforementioned basic requirements for automation. In contrast to the use of this technology in the private sector or in daily office life, requirements such as coexistence, reliability and real-time behaviour must be guaranteed at all times. Other challenges such as IP protection classes, explosion protection, EMC compatibility and the power supply to wireless devices also require solutions. It is therefore important to ensure that the stand-ards for wireless are consolidated and that the technologies meet the requirements for use in automation systems. In future, self-sufficient devices will get their power supply from environmental and process energy, as already demonstrated by the ABB temperature transmitter.

At the start of this article we discussed the process control system as a factor in productivity. This begs the question of whether the potential has already been tapped in full and whether it is only a case of guaranteeing reliability and making it possible to utilise technological options in a cost-effective way once advanced functions have been implemented. There is only one conclusion to draw from all the factors affecting productivity and profitability: the potential for automation and optimisation has not been tapped in full. Even at this stage, there are still various systems which are integrated only point-to-point or which require manual actions. The integration of all these systems, and replacement of manual and unsynchronised interactions as much as possible will lead to the closure of further control loops.

One example of this integration is the incorpo-ration of power engineering into process automation concepts. The introduction of the IEC 61850 standard removes many obstacles from both a technical and an organisational perspective. The technological prerequisites are already in place and are being implemented in a wide range of industries. The benefits include lower investment costs, shorter commissioning times, and optimised energy requirements, which is certainly in the interests of sustainable production.

Another example is PAT (Process Analytical Technology). This technology can be used to replace manual samples, which can only be used only for retrospective quality controls because of their time delay and are unsuitable for proactive quality management. The introduction of analysis technology into automated processes supports real-time process adjustments, since quality indicators can be factored into the process control and not merely checked at the end. This ultimately reduces the variability of the end product and lowers the number of faulty products, while at the same time decreasing production costs and production times.

These two examples illustrate how integration of additional sub-systems into the automation system can most certainly bring significant gains in productivity. The process control system of the future will as a coherent automation system bring together all factors affecting productivity and optimum operation.

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