Don’t underestimate the feeling of being in control
20 March 2012
Hannu Paunonen and Jaakko Oksanen of Metso Automation, discuss the importance of usability in the overall design of a process control system.
The control system plays a central role in visualising the production process.
Traditionally an engineering automation project will being with automating the process followed by design of the user interface. This is mirrored by automation education, where automating the process is a strong focus. The end result of this approach is that the user must adapt to the solution dictated by the designers of the automation system. However, adoption of a more comprehensive concept of usability, sees the automation systems, user interfaces and user work tasks all being designed to form a functional and productivity-oriented whole. This can be achieved by creating seamless interaction between the user and the system. The target is not just to minimise the user workload but to give the user the opportunity to use their abilities in tasks where human characteristics are at their best. Process control is slowly developing towards more fluent interaction, which creates a stronger feeling of control for individual employees
A process control system is an organisation’s tool for managing production and the process. Its usability is an important consideration because process situations can be highly demanding, with even small slip-ups leading to major losses.
There are two issues connected to usability of a product: what the product offers its users and how it is realised. For example, a drill can be used to bore a hole in the wall in an efficient manner (what it offers) and the tool is easy to hold in your hand (how it is realised). Many times, usability is only considered in terms of the latter ñ an approach that involves the familiar concept of ease of use. Although both viewpoints are equally important, in this article our emphasis is on the functionalities provided by automation systems as a factor of usability. In addition, examples are presented on how these two perspectives are connected in system development.
The product functionalities provided to users often facilitate work tasks, enabling the user to better achieve their goals. For example, a system operator does not need to watch changes in numeric values on a screen if a trend tool is available.
Many discussions about usability only cover the user interface but this is a narrow view. The automated functions of a system and the other services it provides are an essential part of usability, which means that they must also be designed with the user in mind. Automation is a means for improving usability and thereby making the userís work tasks easier. Focusing solely on the usability of the user interface is not the way to remedy shortcomings that arise when designing the inner functionalities of a system.
Therefore, the aim of system development should be to facilitate work, which means that the developers must be able to visualise the future possibilities of the work enabled by the tool. Developers also need to gain an understanding of production work. In addition to the practical issues of work, they must be in touch with the emotions of users as well. The feeling of control and competence is an integral element in the user experience created by control systems in particular. Users may also get the feeling that they can interact with others and improve in their tasks.
Today, the organisation involves a diverse community of experts from many fields – from research to maintenance – making production work a communal effort. Modern networking technology allows the whole organisation to be conscious of what is happening with regard to the production, process and organisation. The means for viewing data can be a large screen in a control room, an office terminal, field device, laptop and tablet computer, or a mobile phone.
Production work comprises supervision and control; performing preplanned tasks, modifications and tests; management of exceptions; communication and collaboration in the production community; further development of the tasks, controls and process; and learning. Control systems need to support all of these aspects.
Creating and maintaining the feeling of control is important in the development of systems or tools for process control environments. When the operator supervises the production process, he wants to be sure that he sees everything that is essential. So information needs to be shown so that it is easy to visualise the situation across the process and the organisation. It should also be easy for the operator to detect a deviation and, if something exceptional happens it must be easy to access relevant supporting information and get help from the rest of the organisation.
Feeling of control or lack of it may also be shown when the operator makes an action that has comprehensive consequences, for example when starting a large machine. The system must give clear indications that they are operating the right target and it is correct to do so in this particular situation. The operator should also rely on being prevented from making the action if some damage could be caused. After giving the command, they must get clear indication that the particular action was done correctly. Furthermore, it must be easy to follow the consequences from the action.
Often operators do not trust automation even though it would make better decisions with higher reliability than they would do themselves. That is because an automation function by its nature hides things from its users. It is obvious that if something happens by itself the user is excluded from knowing the details. So, it is important to keep operator updated to the level needed for building trust. It could, for example, give notices and even rationales about its actions. It could also consult the user when a broader perspective is needed. This kind of joint human-automation interaction keeps the operator in the loop.
Good usability can sometimes go unnoticed. An efficient, straightforward and simple tool may seem routine and is rapidly developed simply because it works as expected. However, it is too easy to develop a complicated, difficult-to-use product, whereas creating a usable tool requires a more focused effort. Another reason why a good tool may not draw attention is that the user can concentrate on the work instead of the tool itself. In the best case, they may not even think there is a tool between the task and themselves.
The development of usability and user experience is an iterative process, where the designer learns to understand the goals and tasks involved in the userís work. In the course of the process, both the tools and the work methods are developed. In order to ensure good user experience, systematic methods are required that make sure that the users, their experiences, the goals of the work and the user environments are taken into consideration throughout the development process.
Users are also able to participate, in parts of the development process, such as usability tests. Naturally, the methods and user participation do not always guarantee a good end result. Important factors affecting success are the attitude, innovation skills and expertise of the developer.
During product development, especially at the start of the process, user stories are collected and are used to create, evaluate and test concepts, specification, prototypes and the complete products. In order for the user stories to provide new ideas for work development, it is important that they only describe the actual work without any restrictions set by a tool. It is also important for developers to fully understand the practical and emotional aspects in the users’ work.
In the later phases of product development, usability evaluations are used to ensure that the tool’s logic is apparent to the user and that the tool uses terms known to the user. In suitable phases of development, users are involved in the process to test the tool. Usability testing involves assigning the users with actual tasks and monitoring how well they perform them. The previously collected user experiences and knowledge of the content and focus areas of the work are used to support the evaluations and tests.
Many of the successful features of Metso’s control system, Metso DNA, are based on a profound understanding of the work performed by users of the system. These features include efficient and versatile navigation in the operator’s user interface, history and replay mode of process pictures for effective management of exceptional situations, functional descriptions that guide the user, and an electronic diary that supports collaboration and community within the organisation.
The navigation and operation principles are easy to use, versatile, flexible and safe. These goals may appear contradictory and challenging for any user interface. If an operation is safe it may lose something in efficiency, and if the navigation is flexible it may be difficult to learn.
However, if the designer understands the core tasks of the user, an optimal emphasis between the contradicting goals can be found. For example, the user can easily store the current desktop arrangement of process pictures as a favorite. Desktops can be compiled for different situations, or they can be customised for each individual user (flexibility). However, if the user is typing a name for a desktop saved as a favorite when an alarm is triggered, the picture related to the alarm can still be opened with one mouse click (safety).
The concept of the electronic diary (DNA Diary) was conceived about 20 years ago in connection with interviews carried out in control rooms. At that time, the flow of information in the organisation was considered the worst shortcoming in nearly all control rooms around the world. Based on a clear need, the development of the diary began through research. After several prototypes, usability tests and product versions, it has become an established part of the Metso DNA system.
The Diary has become an essential basis for decision-making and the exchange of expertise in the plants where it has been implemented. It combines the process information provided by the system with the organisation’s interpretations and discussions. DNA Diary has helped operation and maintenance organizations to develop collaboration and create a feeling of unity and relatedness. The experience of a production manager well illustrates the feeling of relatedness DNA Diary has created: “Earlier when I went to the control room I had to ask what the situation was. Now that we have the electronic diary, I already know and we can start our conversation on a higher level.”
DNA Diary is also designed to be easy to use. The low threshold for inputting entries was regarded as a particularly important goal in the development phase. This was achieved through tight integration with other tools used in process control. Users can point at a target on the process picture (for example, a pump) and start writing an entry about it. It is also possible to copy and paste a process picture in order to illustrate your entry.
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