WO2012143047A1

WO2012143047A1 - A method for displaying energy-related data on a workstation of a process control system.

Info

Publication number: WO2012143047A1
Application number: PCT/EP2011/056322
Authority: WO
Inventors: Martin Olausson; Susanne TIMSJÖ; Magnus L LARSSON
Original assignee: Abb Research Ltd
Priority date: 2011-04-20
Filing date: 2011-04-20
Publication date: 2012-10-26

Abstract

The invention is a method for displaying energy-related data on a workstation of a process control system upon receiving a request by a user. Energy-related measurement data is obtained which is dependent on a physical property of at least one apparatus in a process in a process plant monitored and controlled by the process control system. The method comprises displaying a graphical control object on a graphical user interface of the workstation connected to the process control system, detecting user input to the graphical control object as a request for energy-related data, displaying the energy-related data for the at least one apparatus as an overlay superimposed on or beside the at least one apparatus in the graphical user interface. Both the energy-related data and a part of the at least one apparatus are visible on the graphical user interface at the same time. In other aspects of the invention a workstation, system and a computer program for carrying out the method are described.

Description

A method for displaying energy-related data on a workstation of a process control system.

TECHNICAL FIELD.

The present invention is concerned with a method for displaying energy-related data on a workstation of a process control system, and a workstation and system of a process control system using the method. In particular it is concerned with a method for displaying energy related data based on measurement data of a physical property from one or more apparatuses in a process, which apparatuses are connected to a process control system for monitoring and control.

TECHNICAL BACKGROUND

Process control systems for monitoring and/or controlling manufacturing processes in chemical, pharmaceutical, food, metal, mines, and pulp and paper industries are well known.

Other examples of industries and utilities where control systems are used are automotive, steel mills etc., power generation, power distribution, pure and waste water handling, oil

refineries, gas pipe-lines and off-shore platforms. Exemplary devices that consume energy in such processes include from basic components such as a motor running a pump up to more complex equipment, for example a gas turbine or a paper machine or a rolling line in a steel mill.

It is often the case that energy related information and data for energy-consuming devices and processes in a process resides in a number of different systems serving different purposes. Examples of such systems are power management systems,

computerized maintenance systems, process control systems, energy management systems, and systems for process simulations and optimisation. Examples of information to be found in such systems are efficiency curves, references to load

characteristics of drive solution, energy consumption logs, ratings for electric motors, and energy costs. A separate system may be used to provide energy related information, such as a system described in JP 2005258916, entitled Energy saving examination support system, assigned to Mitsubishi Electric Corp .

Efficient and effective use of energy is very important and it is exceptionally likely that the area of energy effectiveness will be even more important in the future as energy consumption will be vital for decisions taken in process control and in the process automation industry. Energy related information is required in order that owners and operators can determine current energy use and to make decisions about how to run a process efficiently with regard to energy consumption so as to limit costs and to reduce undesirable effects such as impact on the environment.

Energy related information is necessary to plan production and make decisions about when to run which parts of a process.

Scheduling is necessary to arrange to run parts of an industrial process or other automated process that are most energy

consuming so that it may be run at times when the energy

required in the process is less or when the necessary supply of energy is of better quality, or more stable, or has a lower price. In the longer term, energy related information is

required to identify process modification and equipment

modification so that energy use by a process is optimized for present conditions and kept optimal during changing or future conditions. For example energy related information is necessary for identification of process bottle necks and the users can decide which machines that are worth investing in - all to strive for optimal, in this case lower energy consumption. Then a user can: -Schedule the process to run in the most engineering efficient time,

-Calculate return on investment from an engineering perspective. -Identify which parts of a process or a line that are most energy consuming and load balance the process based on that information, so as to consume less energy and/or reduce costs.

Process control systems comprise a large number of devices in the process which are connected to various controllers; which controllers are in turn connected through different data busses to servers and workstations which are often connected to a local area network. Servers are computers that include software that provides various forms of system functionality. Workstations are computers that include software that provides various forms of user interaction. Controllers are computers that include

software that performs the actual control functions. To the controllers, sensors and actuators are connected for measuring and affecting various forms of process variables, such as temperature, flow, pressure, level, position, on/off position etc. Variations of this basic structure are of course possible. For example, server and workstation functionality may reside in the same computer, or server and control functionality, or any other combination. Besides functions for controlling a process, process control systems normally also include monitoring or supervisory

functions, including functions for generating events dependent on various conditions related to the controlled and supervised process. Other sources of events include software applications such as applications for condition monitoring, optimization, calculations etc. Events are stored in one or more event logs for later retrieval for presentation to users as event lists, and for various other functions such as analysis of courses of events, etc. Events may also be used to generate alarms.

Figure 3 is a schematic diagram of a known type of graphical user interface (GUI) 1 showing a process diagram view for a process controlled by a known process control system. The figure shows a visualization in a main part of the display of equipment in a process, three tanks 12-14, interconnecting piping, and three control devices or valves 15-17. In a smaller part or window in the left side of the display, equipment is displayed for control purposes in alternative groupings or overview groups of process equipment. In such a schematic diagram shown there is normally a great deal of additional information that is also displayed; information about alarms, information showing values for process parameters, equipment faceplates, information or tag names for each device, symbols to show flow direction and so on. Process parameter information may be displayed as current alarms or values, past events or historic values, and/or predicted values or trends. In a process control system it is important that the physical properties as well as process control unit status data is visualized. Furthermore, a system may be complex and include a number of interconnected process control units. This together with there being a lot of data that may be needed to be displayed may clutter the view so that the overview is of the system hard for an operator to gather.

When a multitude of data is displayed, there is thus a problem in that the view presented may be cluttered, i.e. that the view of the operator includes so many different details that it may be hard to get an overall understanding of the functioning of the process. This may cause an operator to make bad decisions, for instance in relation to alarms. This could have an extremely serious consequence if a operator may accidentally miss a serious alarm or fail to understand the consequences of it. The view thus needs to be simplified. However, it is at the same time important that important data is retained, including energy related data that provides information on energy consumption in different parts of a process. There are then competing

priorities, to show or visualize necessary process information and at the same time to provide simplified views or

visualizations that limit screen clutter cluttering. There is therefore a need for displaying process control data in a more economical or more condensed way.

SUMMARY OF THE INVENTION

The aim of the present invention is to remedy one or more of the above mentioned problems. This and other aims are obtained by a method characterised by claim 1.

In a first aspect of the invention a method is disclosed for displaying energy-related data on a workstation of a process control system upon receiving a request by a user, the method comprising obtaining energy-related measurement data dependent on a physical property of at least one apparatus in a process in a process plant monitored and controlled by the process control system, displaying a graphical control object on a graphical user interface of the workstation connected to the process control system, detecting user input to the graphical control object as a request for energy-related data for the at least one apparatus displayed by the graphical user interface, displaying the energy-related data for the at least one apparatus as an overlay superimposed on or beside a graphical object

representing the at least one apparatus in the graphical user interface such that both the energy-related data and a part of the at least one apparatus are visible on the graphical user interface at the same time.

According to another embodiment a method is disclosed for displaying energy-related data on a workstation of a process control system upon receiving a request by a user, and for displaying a current value or a predicted value for the energy- related data for at least one apparatus in the process.

According to another embodiment a method is disclosed for displaying energy-related data on a workstation of a process control system upon receiving a request by a user, displaying a current value or a predicted value for the energy-related data together with a graphic element indicating for which at least one apparatus the energy related data has been obtained or calculated .

According to another embodiment a method is disclosed for displaying energy-related data on a workstation of a process control system upon receiving a request by a user and by the further step of calculating a cost for the energy-related data for the at least one apparatus in the process and displaying the cost superimposed on or beside the graphical object representing the at least one apparatus; and further displaying a current value or a predicted value for a calculated cost of energy- related data for at least one apparatus in the process.

According to an embodiment of the invention a method is

disclosed for displaying energy-related data on a workstation of a process control system upon receiving a request by a user by obtaining the energy measurement data and displaying the energy- related data for the at least one apparatus in the process using a computer application running as a module which is not part of the computer program running the process control system.

The invention provides and discloses a method for displaying energy related information for a process in the domain of a process control system. Measurement data underlying the energy related information is accessed or interfaced through the process control system, processed as necessary by means of calculations or algorithms and added to the graphic interfaces of the process control system and displayed such that the energy related information appears as a visual and transparent layer on top of a normal operator graphic user interface on a workstation of the process control system.

Access to energy related information based on measurement data of physical properties in the process is immediate and simple for an operator. When the operator (or other user) is interested in examining energy related information for the different parts of the process the operator simply provides an input or otherwise signals to the process control system. This may for example be a keyboard command such as pressing a key combination ^xAlt-Space' , activating a computer mouse, or selecting with a click or a touch from a menu, one from a number of alternative ways to display, on request, energy related data when operator input is detected by the workstation. The operator may choose most often to display a control panel panel or control bar 30 containing icons or control objects that will be activated, for example, when the operator hovers a computer mouse pointer. The input may be pre-configured to recognise different sorts of input relative to the control object 35 as well as or instead of mouse hover. Other examples of an input that may be recognised as a request for energy related information include: a movement of the mouse pointer on the GUI in a direction towards the control object 35, or a right click of a mouse selection button close to the control object 35.

Upon activation, when a request for energy related information has been recognised, a visual information layer is displayed that may contain

i) energy related information,

ii) details about energy related information for a selected device or object,

iii) alarm status in terms of energy-related set points,

events or alarms.

By selecting the energy related information add-on the energy information will be layered on top of the process display. Then the energy related information will be displayed presented as a visual layer or an overlay superimposed visually on top of the operator graphic user interface on the workstation.

The energy related information can be presented in different ways, for example energy related information may be of current consumption in real-time, current consumption extending back over a configurable time window, or for historical consumption and may comprise calculated values of the consumption such as mean values or other statistical measures. It will also be possible to see the actual cost in real-time by use of a

connection to sources of data including price information, such as to an electrical management system. In this case the price information is used to calculate a cost for energy consumption by a process, part-process or device in a process currently and/or at a particular point in time.

By means of this overlay of energy related information

associated with a particular device or equipment displayed in a process graphic the operator has an immediate overview of energy consumption and use by the device or part of the process of interest. In addition, the display of the overlay is provided as required by the operator, and does not add to density of

information on the GUI when not required. Because the energy related information is displayed as an overlay, superimposed on graphic representations of the equipment of interest, the amount of additional visual information, or visual clutter, is kept to a minimum. The energy-related data is displayed when required in response to a user request, and may be removed by an operator command or a configured setting when not required, so that visual clutter is kept to a minimum.

The information and functionality of the energy-related

information may be varied, expanded and developed as conditions change or as the need arises. The present invention is carried out by a computer program or computer application or software which is not an integral part of the process control system. Rather, the application is a separate application that has access to information and data interfaces maintained by the process control system. The provision of energy related

information as a layer on top of the process control GUI displays and process graphics of the existing process control system provide a relation between the real process and actual energy consumption for the operator that may be immediately understood. The operator can choose to view selected energy consumption trends for a device or for a particular time of interest when the process is run. For example the operator may select energy-related information presenting the history of energy information for a device or part process as a cost over time .

Another advantage is that additional forms of historical

comparisons, comparisons of current consumption with setpoints or target and calculations, estimates or models of energy consumption in a process or part process may be added or

developed after installation and commissioning. This adds to the usefulness of the inventive methods, and of the software and workstations or other system hardware used for carrying out the invention over time.

The effect of the display of a layer of energy related

information is not limited to the immediate visualization. Based on the presented information the operator can also, for example: a) Schedule the process in an optimal way from an energy

consumption aspect,

b) Calculate a cost or price effect and effect of that on a return on investment from an energy consumption aspect,

c) Find bottle necks in a process and provide energy consumption measures such as key performance indicators (KPI's) related to other process sites.

The operator or other qualified person may also use the energy related information so provided to identify a case to automate the process system, or selected parts of the process, from an energy consumption aspect where the system itself gives

recommendations how to tune the process. For example the system can provide energy related information such that an operator may then recommend running a part of the process at a time when the energy cost is low.

A computer program, and a computer program recorded on a

computer-readable medium is disclosed in a second aspect of the invention . In a third aspect of the invention, a workstation is disclosed for use in a process control system for the purpose of

displaying energy-related data upon receiving a request by a user, wherein energy-related measurement data is obtained dependent on a physical property of at least one apparatus in a process in a process plant monitored and controlled by the process control system, the workstation comprising a display unit for displaying a graphical control object on a graphical user interface on a display unit of the workstation connected to the process control system, and configured to display the energy-related data for the at least one apparatus as a an overlay superimposed on or beside a graphical object

representing the at least one apparatus on the graphical user interface such that both the energy-related data and a part of the at least one apparatus are visible in the graphical user interface at the same time.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the method and system of the present invention may be had by reference to the following detailed description when taken in conjunction with the

accompanying drawings wherein:

Figure 1 shows a schematic graphical user interface displaying a plurality of graphical objects each representing apparatus in a process in a process plant wherein energy related data is displayed superimposed on one or more graphical objects

representing the apparatus according to an embodiment of the invention;

Figure 2a shows a schematic graphical user interface of the invention of figure 1 and in particular details of a menu bar or control panel part showing a graphical control object for the energy related data, and Figure 2b shows a close-up view of the graphical control object, according to another embodiment of the present invention;

Figure 3 (Prior art) shows a schematic graphical user interface displaying a plurality of graphical objects each representing apparatus in a process in a process plant according to a known process control system,

Figure 4 shows a schematic diagram of a process control system including a workstation configured to display the graphical user interface of the invention of figure 1 according to an

embodiment of the invention,

Figure 5 shows a schematic diagram of a workstation connected to a process control system, the workstation configured display the graphical user interface of the invention of figure 1, showing component parts of the workstation according to an embodiment of the invention,

Figures 6 and 7 are schematic flowcharts illustrating methods for carrying out the invention of figure 1 according to another embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention will now be described more fully

hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. For example, the visual appearance of active or

executable graphic objects such as a control panel, icon or a control object 35 shown in the figures and described below may be embodied in different ways on a graphical user interface

(GUI) . Rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the invention.

Figure 2a shows a schematic graphical user interface of the invention of Figure 1 and in particular details of a menu bar control panel part showing a graphical control object for the energy related data, described here in detail as an exemplary practice of an embodiment of the present invention. The figure shows representations of apparatus in a process, in this example three separate process vessels or tanks 12-14, connected in a process by piping arrangements and flow or control devices such as valves 15-17. In another part, or window, of the graphical user interface (GUI) a group 11 is represented which comprises another view of the group of apparatuses 12-14. Shown at one side of the display, in this case along the bottom, is a panel or control bar 30 containing icons or control objects 31-35 for manipulating and controlling graphic objects in the GUI. The panel may be placed along any edge of the display which is convenient for the operator, and is displayed along the bottom of the GUI as an example. Figure 2b is a close-up view of a control object 35 which is configured, upon receiving user input, to call up, generate or otherwise display energy related data for one or more apparatuses 10-17 in the display of the present GUI. For example when control object 35 is displayed, an operator may move a pointer 37 of a computer mouse (or other input arrangement) so that the pointer 'hovers' 2 over the control object. This type of mouse hover input is received by the control system and recognised as user input requesting energy-related information.

The effect of a user input requesting energy related data is illustrated schematically in Figure 1. Figure 1 shows the graphical user interface shown in Figure 2a with the control object (also shown in Figure 2b) and in addition a number of graphical overlays 20-27 superimposed on or beside

representations of apparatuses 10, 11, and 12-17. Each overlay 20-27 displays energy related information superimposed on top of the device or part of the process to which the energy

information is associated with or dependent on. In most cases the energy related information is superimposed on top of the device from which measurements of a physical property have been made, measurements eg such as a temperature, a material flow, a pressure, a machine rotation speed, and so on. The overlays may be in a numeric/alphanumeric form, and display numbers and letters as in the examples 20-27. The overlays may comprise a graphic element identifying which part or parts of the device or process the displayed information relates to, as shown by the coloured outlines drawn in the shape of a rounded square in overlay examples 20', 21'. The overlays may also display symbols or graphics, or a combination of numeric and graphic information such as in the form of a heat map, a pie chart, as bar graphs, and as semitransparent layers. Graphics displayed in an overlay may be in the form of a trend for the energy related data displayed.

A representation of a process vessel or tank 12 is shown with an overlay 22 showing energy related data for tank 12 in the form of a numeric display of the value 14kW superimposed such that the tank can still be seen and the energy related data in the overlay 22 can also be seen. Other apparatus in the process is not obscured by the overlay. An operator may, by requesting the energy related data, then compare the current value of the energy consumption or energy flow in a device with any of a setpoint or a value for the same device within a predetermined time period or production scenario or a predicted time period or production scenario.

A representation of a valve 15 is shown with an overlay 25 showing energy related data for valve 15 in the form of a numeric display of the value 18kW superimposed such that the valve 15 can still be seen and the energy related data in the overlay 25 can also be seen. Other apparatus in the process is not obscured.

A representation 11 of a group of apparatus 12-14 and 15-17 is shown with an overlay 21 showing energy related data for the group or part of the process containing tanks 12-14 and valves 15-17. The overlay is shown here in the form of a numeric display showing the numeric value 14kW superimposed such that the group of apparatus or part process 11 and the energy related data in the overlay 21 can still be seen clearly. The overlay 21 also shows graphic element 21' in this example in the form of a coloured outline, a visualisation that identifies for the operator to which apparatus or group of apparatus the energy related data refers.

An advantage of the display of the overlay is that it is

provided as required by the operator, and does not add to density of information on the GUI when not required. The energy- related data is displayed when required in response to a user request, and may be removed by an operator command or a

configured setting when not required, so that visual clutter is kept to a minimum.

The energy related information is based on measurement data dependent on a physical property of at least one apparatus (11- 17) in a process (49) in a process plant. The energy related information is generated by automatically gathering the

measurement data from an interface of the process control system, performing calculations where necessary, and displaying the resulting energy related information is summarised in the flowchart of Figure 6. Figure 6 shows the following steps:

62 Obtain energy related measurement data related to a physical property of an apparatus in a process 49 controlled by the process control system;

64 Display an icon or graphic control object 35 on a GUI of the process control system;

66 Detect user input 37 relative to the graphic control object 35 on the GUI of the process control system;

68 Display the energy-related measurement data related to the physical property of the apparatus in the process superimposed as an overlay on or beside a graphic object representing the apparatus on the GUI . It should be noted that the energy related measurement data, measurements of temperature, pressure, material flow and so on, made by sensors, transducers, flow meters and so on, on or from apparatus such as tanks 12-14 and valves 15-17 in the process 49 are made available by one or more interfaces in the process control system, as described below in relation to Figure 4. The energy related information may be obtained via interfaces of an object-based computerised system for automating or controlling a process such as the 800xA control system supplied by ABB by running the method (s) in a computer application that is separate from the 800xA process control system, or its software

architecture. A suitable control system terminal or workstation may be arranged with an operator control application called 800xA Operator Workplace, and the energy related overlays automatically generated by the computer application may be superimposed upon the graphic user interfaces provided by 800xA Operator Workplace as connected to an 800xA control system. The energy related overlays based on the obtained energy measurement data and displayed (20-27) for at least one apparatus in the process is carried out by a computer application running as a module which is not part of the computer program running the process control system. The measurements from one or more apparatus may then be

processed to calculate or otherwise determine current values, historic values, comparisons of current and historic values, and so on. Historical values may also be obtained from databases connected to the process control system, such as exemplary database 44 in Figure 4 (described below) .

Figure 4 shows a process control system 40 monitoring and controlling a process 49, for example in an industrial plant. The control system 40 includes a number of operator workstations 41, 42 connected to a first data bus Bl . There is furthermore a second data bus B2 and between the first and second busses there is connected a server 43 providing control and monitoring of the process 49. A database 44 is also connected to the data busses where data, such as historical data relating to control and monitoring of the process 49 is stored. To the second bus B2 there are furthermore connected process interface units 45, 46, 47 and 48 for providing control of the process and for receiving measurement data from apparatus (for example apparatus shown in Figures 1-3 above, items 10-17) in the process 49. In the figure there are provided four such process interface units 45, 46, 47 and 48 that interface with the process 49. It should however be realized that there may be more or fewer of each of these units. It should here also be realized that some of these may only be provided for control, some only for measurements and some for both control and measurements. Such units are thus all involved in controlling the process 49 and in doing this also involved in measuring physical properties related to the process. The measured properties may here be properties of the process itself such as a volume of liquid in a tank, a temperature of a liquid in a tank, the pulp temperature of a fluid in a part of a pulp and paper process or a voltage or a current running in a power line. However the measured properties may also be properties of an interface unit, such as for instance the temperature of a transformer. The process interface units 45, 46, 47 and 48 therefore also provide information on their own properties or status.

Figure 5 shows an operator workstation 41, as shown in Fig. 4 of the process control system 40, which includes a user input unit 50, a display unit 54, a display control unit 52 and an

interface 56 for communicating with the other parts of the process control system 40 via the first bus Bl . An operator workstation provides a graphical user interface for an operator of the system. The control unit 52 may be a processor with an associated program memory including program code for performing the functionality of the present invention, which has been described in this specification and in particular in relation to Figures 5 and 6, in order to obtain measurement data, make calculations as necessary and to generate the energy related information overlays shown in Figure 1. The display unit 54 may be any suitable display unit, such as a liquid crystal display. The user input unit 50 is a unit through which a user of the operator workstation 41, in most cases an operator, may enter data. As such it may be a keyboard, a keypad or a mouse. It may also be combined in some way with the display unit in order to include a touch screen. The operator workstation 41 may also include other user interfaces such as a loudspeaker or a

microphone in order to present and receive data to and from one or more users of the operator workstation in other ways than through the display unit.

Data from the various process interfaces can be collected and stored in a history data base 44 as well as presented in real^¬ time to an operator via the display unit 54. The workstation 41 may connected to a process control system as described in respect of Figures 4 and 5 above in order to select and view the GUI and overlays generated as described in this specification in respect of Figures 1 and 2a, 2b and flow charts of Figures 6, 7.

The workstation 41 and/or 42 in the process control system 40 may present data regarding the process in a number of different ways. It may present the process through a number of

interconnected process control units, which process control units may include process interface units. However they may also include other units where the process is carried out but no measurements are being made or no control is carried out. Along with these units the operator workstation may furthermore display data relating to the process as well as to the process control units, such data may be measurement data of a physical property of the process and/or of process interface units. The data may also include data of a physical property that has been derived from a measured physical property. The data may furthermore include status data of various units in the system.

Figure 7 is schematic flowchart illustrating methods according to another embodiment of the invention. Gathering the

measurement data, gathering price information, calculating where necessary and displaying the resulting energy related

information is summarised in Figure 7 as a flowchart. Figure 7 shows the following steps:

74 Obtain energy price information and calculate a cost for the energy-related measurement data related to a physical property for an apparatus in process 49 controlled by a control system; 76 Detect user input relative to the graphic control object or icon in the GUI of the process control system;

78 Display the calculated cost for the energy-related

measurement data related to the physical property of the

apparatus in the process superimposed as an overlay on or beside a graphic object on the GUI representing the apparatus. Cost or price-related information used in step 76 to calculate a cost for energy consumption in a device or a part of the process may be retrieved from internal storage or databases such as database 44 of the process control system. As well, cost or process information may be retrieved from another internal system such as a power management system, computerized

maintenance system, energy management systems and/or a system for process simulation or optimization. As well or instead, a part of the cost information, such as current or future

electricity prices for example, may be retrieved from a source external to the process plant installation or enterprise. As summarised in step 78 the energy costs calculated dependent on measurements of a physical property of an apparatus in the process are then made available to be displayed as an overlay on the GUI of the process control system. The costs thus calculated may be shown overlaid on process graphics or process diagrams representing the apparatus or part process from which the measurement or measurements of one or more physical properties were made.

Thus the overlays of energy related information may be used by an operator or engineer or other qualified person, by requesting the energy related data to then compare the current value of the energy consumption or energy flow in a device with any of a setpoint or a value for the same device within a predetermined time period or production scenario or for a predicted time period or production scenario.

The methods of automatically obtaining, generating and

displaying energy-related data on a workstation of a process control system upon receiving a request by a user as described above and elsewhere in this specification may be carried out by a computer application comprising computer program elements or software code which, when loaded in a processor or computer, causes the computer or processor to carry out the method steps. The computer program or computer application or software is not an integral part of the process control system or process control system architecture. The program or application is instead a separate application that has access to information and data interfaces maintained by the process control system. The processor (or processors) comprises at least one central processing unit CPU performing the steps of the method according to one or more facets of the invention. This is performed with the aid of one or more said computer programs which are stored at least in part in memory and as such accessible by the one or more processors. The or each processor may be in a memory storage unit of a process control system or a control unit connected to or as part of a workstation. It is to be

understood that said computer programs may also be run on one or more general purpose industrial microprocessors or computers instead of one or more specially adapted computers or

processors. The computer program comprises computer program code elements or software code portions that make the computer perform the method using equations, algorithms, data, stored values and

calculations previously described. A part of the program may be stored in a processor as above, but also in a ROM, RAM, PROM, EPROM or EEPROM chip or similar memory means. The program in part or in whole may also be stored on, or in, a non-transitory computer readable memory device or other suitable computer readable medium such as a magnetic disk, such as a CD (compact disc) or a DVD (digital versatile disc) , hard disk, magneto- optical memory storage means, in volatile memory, in flash memory, as firmware, stored on a data server or on one or more arrays of data servers. Other known and suitable media,

including removable memory media such as USB memory stick and other removable flash memories, hard drives etc. may also be used. Data may be accessed by means of any of: OPC, OPC servers, an Object Request Broker such as COM, DCOM or CORBA, a web service .

It should be noted that while the above describes exemplifying embodiments of the invention, there are several variations and modifications which may be made to the disclosed solution and in particular to graphic symbols and elements used to represent control panels, control objects, or icons without departing from the scope of the present invention as defined in the appended claims .

Claims

1. A method for displaying energy-related data on a

workstation (41) of a process control system (40) upon

receiving a request by a user, the method comprising obtaining (62) energy-related measurement data dependent on a physical property of at least one apparatus (11-17) in a process (49) in a process plant monitored and controlled by the process control system, characterised by

-displaying (64) a graphical control object (35) on a graphical user interface (1) of the workstation (41) connected to the process control system,

-detecting (66) user input to the graphical control object as a request for energy-related data for the at least one apparatus displayed by the graphical user interface;

-displaying (68) the energy-related data (20-27) for the at least one apparatus as an overlay superimposed on or beside a graphical object representing the at least one apparatus (11- 17) in the graphical user interface

such that both the energy-related data (20-27) and a part of the at least one apparatus (11-17) are visible on the graphical user interface (1) at the same time.

2. A method according to claim 1, characterized by displaying the energy-related data for a plurality of apparatus (11, 12- 17) in the process.

3. A method according to claim 1 or 2, characterized by displaying a current value or a predicted value for the energy- related data for at least one apparatus in the process.

4. A method according to claim 1 or 2, characterized by displaying a current value or a predicted value for the energy- related data together with a graphic element (20', 21') indicating for which at least one apparatus the energy related data has been obtained or calculated.

5. A method according to claim 1 or 2, characterized by displaying one or more historic values for the energy-related data for at least one apparatus in the process in a numeric display form or in a graphic trend display form.

6. A method according to claim 1, characterized by calculating (74) a cost for the energy-related data for the at least one apparatus in the process and displaying the cost superimposed on or beside the graphical object representing the at least one apparatus.

7. A method according to claim 6, characterized by displaying a current value or a predicted value for a calculated cost of energy-related data for at least one apparatus in the process.

8. A method according to claim 6, characterized by displaying a calculated cost for one or more historic values for the energy-related data for at least one apparatus in the process in a numeric display form or in a graphic trend display form.

9. A method according to any one previous claim, characterized by obtaining the energy measurement data and displaying (68) the energy-related data (20-27) for the at least one apparatus in the process using a computer application running as a module which is not part of the computer program running the process control system.

10. A workstation (41) in a process control system (40) for displaying energy-related data upon receiving a request by a user, wherein energy-related measurement data is obtained dependent on a physical property of at least one apparatus (11- 17) in a process (49) in a process plant monitored and

controlled by the process control system, the workstation comprising a display unit (54) for displaying a graphical control object (35) on a graphical user interface (1) on a display unit (54) of the workstation connected to the process control system, characterised by a display control unit (52) connected to the display unit (54) and configured to detect user input (50, 66) to the graphical-control object 835) as a request for energy-related data for the at least one apparatus displayed by the graphical user interface, and configured to control the display unit to display (68) the energy-related data (20-27) for the at least one apparatus as a an overlay superimposed on or beside a graphical object representing the at least one apparatus (11-17) on the graphical user interface such that both the energy-related data (20-27) and a part of the at least one apparatus (11-17) are visible in the graphical user interface (1) at the same time.

11. A workstation according to claim 10, characterized in that energy-related data is displayed for a plurality of apparatus

(11, 12-17) in the process.

12. A workstation according to claim 10, characterized in that a energy-related data for a plurality of apparatus (11, 12-17) in the process is displayed together with a graphic element (20', 21') indicating for which at least one apparatus the energy related data has been obtained or calculated.

13. A workstation according to claim 10, characterized in that a current value or a predicted value for the energy-related data for at least one apparatus in the process is displayed.

14. A workstation according to claim 10, characterized in that one or more historic values for the energy-related data are displayed for at least one apparatus in the process in a numeric display form or in a graphic trend display form.

15. A workstation according to claim 10, characterized in that a calculated cost or predicted cost for the energy-related data for the at least one apparatus in the process is displayed superimposed on or beside the graphical object representing the at least one apparatus .

16. A workstation according to claim 10, characterized by a current value or a predicted value for a calculated cost of energy-related data for at least one apparatus in the process is displayed.

17. A workstation according to claim 10 or 16, characterized by displaying a calculated cost for one or more historic values for the energy-related data for at least one apparatus in the process in the form of a history or trend.

18. Use of a workstation according to claim 10 for controlling an apparatus in a process control system for monitoring and control of a process in an industrial installation or in an installation for production, transmission or distribution of energy .

19. A computer-readable medium comprising software code portions or computer code which when read into a computer or processor will cause the computer or processor to carry out a method according claim 1.