Work in control rooms can either be organised around maintenance, engineering/ field service, and error/fault handling, or around planning and process optimisation. In the first case, work in the control room is in some way combined with maintenance and service tasks carried out in the plant itself. In the other case, the control room operator is given the task of carrying out more advanced planning and optimisation work. Here, for example, computers are used to control and monitor the process and also to carry out other tasks, such as simulating various process conditions. These simulations can form the basis either for controlling the process, planning future tasks, or replanning or redesigning the process. It can also be used for learning and development of the operators’ skill and development, including tacit knowledge and mental models.
There are no simple rules about the manning of control rooms, for example, in relation to the number of monitored control units. In general, a pure on-line process without any elements of batch grouping is the most difficult to control. The characteristics of the work to be carried out in the control room depend partly on the type of process and partly on the type of staff available. The latter type of work—that is, planning and optimising—demands access to staff with a more theoretical education and training. If emphasis is placed on service and maintenance, control room operators can be recruited from plant employees. The optimal is often a combination of a rather advanced theoretical background with a good practical experience gained from in-the-plant maintenance work.
Many and varied types of visual display units (VDUs) are used in modern control rooms. Often this means great advantages, but one should not be overconfident about the large flexibility that visual display units offer. Further, there is nearly always a need for some form of general or overall display of the process. Sometimes it can even be of value to keep the old, more traditional type of control panel with both instruments and controls. An alternative would be to simulate some of the control settings on the overview display.
With the transition from traditional controls to keyboards, the modern, computerised control room is in danger of losing an important source of information. Classical control panels or modern simulated versions are often vital in order to achieve efficient production. Other aids, such as knobs, the light pen, joystick, mouse, and so forth can be of additional value. Colour displays should be used with some caution, and for valid purposes. Colour should not be the primary source of information, and the use of colour should be very clear and unambiguous. The use of voice control and speech (and other auditory) information can be of value, particularly for various forms of emergency situations.
Do not overload the visual senses of the human operator. Human beings have more senses than vision. In the next generation of control rooms we will see more use of all the other sense organs. Using the whole range of senses has the potential for the operators to improve their tacit knowledge and mental models of the system. And, in turn, this will improve the total system performance (including the human component).
The control room in its entirety should be designed with a high level of comfort. Low comfort levels result in operating staff becoming unnecessarily fatigued more quickly, which will lead to a reduction in monitoring ability. Sometimes the opposite argument is put forward: if the control room is too comfortable, the vigilance of staff is reduced. This is simply not correct. A comfortable and cosy environment increases the possibility of operators remaining awake and alert. It is also important to create a varied information situation in the control room, for example, easy access to radio and television. However, this secondary source of information should be designed and located so that it does not in any way disturb the primary work tasks, especially during periods of high work stress.
Comfortable, adjustable chairs and an ergonomic layout of the control room furniture are very important issues, and a great deal of consideration should be given to lighting conditions. Visual display units place great demands upon the design and location of light fittings. In order to avoid serious visual problems it is recommended to seek advice from a qualified lighting specialist. Glare can very seriously impede visual performance. Considering the unique conditions found in control rooms (for example, 24 hours of continual operations), it may even be desirable to use full spectral lighting, that is, lighting that provides ‘daylight’ conditions.
When planning a new control system it is important to create situations where, in an unbiased way, alternative forms of automation can be tested. The planners of the system must realise that their way of thinking and thus their concept of the system is often very different from that of the process operator. For example, a solution that seems obvious and correct to a systems designer may be quite alien to a control room operator. Therefore, when planning new systems, new methods must be found in order to bridge the differences in conceptual thinking between designers and operators. The literature, including this handbook, provides us with much information about the operators’ capabilities and limitations. There is also considerable knowledge about the capabilities and limitations of the different senses. Further, there are data about perception, cognition, and decision-making processes, and also about learning, training, and education. By consulting each of these areas, operators can attain a suitable level of skill for control room work.
The trends that are predominant today with regard to the design of control rooms and control systems are not synonymous with a development that creates an optimal system from a human/machine point of view. An increased understanding of humans can result in new products and new systems when developing the process control systems of tomorrow. This will increase safety significantly and enable better production, which is also in harmony with the environment.
Those manufacturers who systematically invest in development of systems and equipment that place humans in the centre have found a business concept that can make the organisation a leader in its field. Over the past hundred years we have learnt that technology more and more balances on the edge of what is possible and desirable from the human point of view. A more humane technology is not only a human demand; it is also a prerequisite if we are to reap further rewards with regard to improvements in productivity and quality from technology usage.