Login| Sign Up| Help| Contact|

Patent Searching and Data


Title:
A METHOD FOR DISPLAYING CONFIGURATION AND STATUS OF A PLANT
Document Type and Number:
WIPO Patent Application WO/2010/121671
Kind Code:
A1
Abstract:
The invention relates to a method for supervising a technical system. The method comprises the steps of: retrieving a set of system data which represent a status and/or a configuration of the technical system to be supervised; outputting on a display unit of an operator terminal a first picture showing a part of the set of system data; generating at least a first and a second type of graphical information from the set of system data; associating a first data layer with the first type of graphical information and a second data layer with the second type of graphical information; receiving from a user input unit of the operator terminal a first selection signal indicating if the first and/or said second data layer or parts thereof is to be output on the display unit; generating a second picture as an integration of the graphical information corresponding to the selected data layer or parts thereof and the first picture; and outputting the second picture on the display unit.

Inventors:
MIKKELSEN CHRISTINE (SE)
Application Number:
PCT/EP2009/058133
Publication Date:
October 28, 2010
Filing Date:
June 29, 2009
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
ABB RESEARCH LTD (CH)
MIKKELSEN CHRISTINE (SE)
International Classes:
G05B23/02; G05B19/409
Domestic Patent References:
WO2006103541A12006-10-05
Foreign References:
EP1331536A12003-07-30
US20030005486A12003-01-02
US20060294260A12006-12-28
Attorney, Agent or Firm:
KOCK, Ina (T2 Floor E, Västerås, SE)
Download PDF:
Claims:
Claims

1. A method (60) for supervision of a technical system (21), comprising the steps of:

- retrieving (61) a set of system data which represent a status and/or a configuration of said technical system (21),

- outputting (62) on a display unit (34) of an operator terminal (12, 14) a first picture (40) showing a part of said set of system data,

- generating (63) at least a first and a second type of graphical information from said set of system data,

- associating (64) a first data layer with said first type of graphical information and a second data layer with said second type of graphical information, receiving (65) from a user input unit (32) of said operator terminal (12, 14) a first selection signal indicating if said first data layer or parts (42) of said first data layer and/or if said second data layer or parts (49) of said second data layer is to be output on said display unit (34), - generating (66) a second picture (50) as an integration of said graphical information corresponding to the selected data layer or parts thereof (42, 49) and said first picture (40) and

- outputting (67) said second picture (50) on said display unit (34) .

2. The method (60) according to claim 1, comprising the further steps of:

- receiving from the user input unit (32) a second selection signal indicating if said first or said second data layer, or parts thereof, is to be removed from said second picture (50), generating a third picture by removing said graphical information corresponding to said selected data layer or parts thereof from the second picture (50) and outputting said third picture on said display unit (34) .

3. The method (60) according to claim 1, wherein a first location signal indicating where in said first picture (40) said first or said second data layer or parts (42, 49) thereof is to be shown is received from said user input unit (32) and wherein said second picture (50) is generated by integrating, into said first picture (40), said graphical information corresponding to said selected data layer or parts thereof (42, 49) at the desired location.

4. The method (60) according to claim 3, wherein one or more subparts (42, 49) of said selected data layer are integrated into said second picture (50), said subparts comprising parts (42, 49) of said selected data layer corresponding to said desired location.

5. The method (60) as claimed in any of the preceding claims, wherein said first and/or said second data layer and/or parts (42, 49) thereof comprises one of: a predefined mode, said predefined mode in turn comprising two or more data layers or a user defined mode, said user defined mode being based on made user selections of data layers.

6. The method (60) as claimed in any of the preceding claims, wherein said graphical information is visualized by changing a font colour thereof.

7. The method (60) as claimed in any of the preceding claims, wherein said graphical information comprises: physical units of measurements, such as V (Volt), A (Ampere) or W (Watt) ; lines of said technical system, including power lines and other electrical lines as well as signal connection lines; graphical representation of breakers; graphical representation of isolators; measurement values; alarm limits .

8. The method (60) as claimed in any of the preceding claims, wherein said first and said second data layers comprises one of: an alarm list layer, a measurement layer, a circuit breaker layer, alarm limit layer, a configuration layer and an isolator device layer.

9. The method (60) as claimed in any of the preceding claims, wherein said step of receiving (65) comprises the substeps of:

- receiving a third selection signal selecting one of said first and said second data layer, and

- receiving a fourth selection signal indicative of which parts of said selected data layer is to be output on said display unit (34) .

10. An operator terminal (12, 14) of a supervisory control system (10) comprising a user input unit (32), a display unit (34) and a control unit (30), said control unit (30) comprising means for performing steps of the method (60) according to any of the previous claims.

11. A supervisory control system (10) for supervision of a technical system (21), said technical system (21) comprising system interface units (20, 22, 24, 26) for taking measurements from and performing control actions on said technical system (21), said supervisory control system (21) comprising processing means (16, 17) for processing signals received from or sent out to said system interface units (20, 22, 24, 26), data storing means (18) for storing results from said measurements as well as data generated by said processing means (16, 17) from the processing of measurements and said supervisory control system (10) further comprising an operator terminal (12, 14) according to claim 10.

12. A computer program product loadable into a computer of a supervisory control system (10) , comprising software code portions for carrying out the method as claimed in any of claims 1-10 when said product is run on said computer.

13. A computer program product stored on a computer readable storage medium, comprising computer readable program code means for causing a computer of a supervisory control system (10), to carry out the method as claimed in any of claims 1- 10.

Description:
A METHOD FOR DISPLAYING CONFIGURATION AND STATUS OF A PLANT

Field of the invention

The invention relates generally to the field of supervision and monitoring of technical systems or processes, such as an electrical power generation, transmission and/or distribution system or process, and in particular to graphical tools for such supervision.

Background of the invention Supervision and monitoring of technical systems or processes is of great importance for ensuring proper functioning of the system or process and for enabling right action to be taken. It is important that the operator of such a system or process is enabled to quickly detect any fault conditions and also to act rapidly upon such fault conditions.

The general task of supervision results in the same kind of problems for the operator, as described below, independently of if a system or a process is supervised, and the following description is therefore directed to systems alone but is applicable to processes as well.

The operator is supported in his or her task by a supervisory control system, which in the art is also known under the term SCADA (Supervisory Control and Data Acquisition) system. Such a supervisory control system interacts with the technical system via system interface units which units take measurements from the system or perform control actions on the system. A supervisory control system typically comprises processing means to process the information coming from and going to the system interface units, data storing means to store measurements as well as data generated from the processing of measurements, such as alarms, statistical calculations etc., The supervisory control system further comprises human-machine interface in the form of at least one operator terminals and communication means for signal transmission from and to the system interface units and for data transmission between the processing means, the data storing means and the human- machine interface.

The operator terminal comprises one or several display units showing different parts and data of the technical system. It is inevitable that for large technical systems, such as a power network, a huge amount of data is available to be displayed and needs to be monitored by an operator. A problem in that respect is how to best present the data as visual information to the operator.

In order for the operator to get an overview and to maintain the context of what is happening in the system an overview picture of the technical system, shown in the display unit, represents valuable information. The overview picture presents a graphical representation of the system as a whole and comprises besides that only the most essential information. However, more information is usually needed in order for the operator to understand the current situation of the system and in order to take appropriate decisions.

Therefore, so called system or process pictures are further available for displaying in the display unit, wherein the system pictures contain different graphical or textual representations of the measured and processed system data, such as the measurement values themselves, calculations and alarms. If all such system data would be visible at the same time, the output on the display unit would be too cluttered. In addition, the operator is usually interested only in a particular subset of the system data at a time, depending on the situation of the system. Theoretically a lot of the visual information could therefore be omitted without affecting the supervision efficiency. On the other hand, since it is essential that no important information is missed, there is a constant strive to improve the way of generating graphical representations of the system data in order to facilitate the task of supervision.

From US 2008/0109175 Al a method of monitoring the movement of fluid through a fluid distribution network is known. Measurement data taken from the distribution network is received from sensor units by a computer system, and the measurement data is processed in the computer system to generate information indicative of movement of fluid in the fluid distribution network. The information can be displayed on a geographic map. Further, detailed information about a particular location in the map, such as longitude and latitude, is displayed in a separate window and simultaneously with the window of the geographic map, when the user clicks on that particular location.

Summary of the invention It is a general object of the invention to provide means and methods to improve the visual information presented in the supervision of a technical system.

It is another object of the invention to provide means and methods to improve the generation of graphical representations of system data of a technical system, in particular a power network, in order to facilitate supervision tasks for the operator of the system.

These objects, among others, are achieved by a method, by an operator terminal and by a supervisory control system as claimed in the independent claims .

In accordance with the invention, a method for supervising a technical system is provided. The method comprises the steps of: retrieving a set of system data which represent a status and/or a configuration of the technical system to be supervised; outputting on a display unit of an operator terminal a first picture showing a part of the set of system data; generating at least a first and a second type of graphical information from the set of system data; associating a first data layer with the first type of graphical information and a second data layer with the second type of graphical information; receiving from a user input unit of the operator terminal a first selection signal indicating if the first and/or said second data layer, or parts thereof, is to be output on the display unit; generating a second picture as an integration of the graphical information corresponding to the selected data layer or layers or selected part thereof and the first picture; and outputting the second picture on the display unit. By means of the invention, an improved way of obtaining relevant information is provided in that selectable layers of data or parts of these layers can be shown to an operator supervising the technical system. Further, since the first picture remains visible and additional layers are integrated into it, it is ensured that the desired detailed information is shown while an overview is maintained.

In accordance with an embodiment of the invention, the method comprises the further steps of: receiving from the user input unit a second selection signal indicative of if the first or the second data layer or parts thereof is to be removed from the second picture; and generating a third picture by removing the graphical information corresponding to the selected data layer from the second picture and outputting the third picture on the display unit. The invention enables a rapid change of data layers and thus the kind of information shown on the display, which is most important when supervising fast-changing technical systems.

In accordance with an embodiment of the invention, a first location signal indicating where in the first picture the first or the second data layer is to be shown is received from the user input unit. The second picture is then generated by integrating, into the first picture, the graphical information corresponding to the selected data layer at the desired location. The operator may thus choose where the data layer is to be shown, which is beneficial in many situations.

In accordance with an embodiment of the invention, one or more subparts of the selected data layer are integrated into the second picture. The subparts comprise parts of the selected data layer corresponding to the desired location. By means of this feature, the output picture is made very foreseeable, comprising only details necessary for the current situation. For example, only parts of a data layer relevant for a particular location may be illustrated. In accordance with an embodiment of the invention, the first and/or the second data layer comprises predefined modes, the predefined modes in turn comprising two or more data layers. By means of this feature, the operator is able to quickly make several data layers visible, which is advantageous for example during a failure during which for example alarm limits and relevant measurements is of high interest for determining e.g. the type fault. The operator is thus able to swiftly take appropriate action.

In accordance with an embodiment of the invention, the graphical information is visualized by changing a font colour thereof. An additional aid for the operator supervising the technical system is thereby provided.

According to the invention, an operator terminal, a supervisory control system and computer program products performing the method steps are provided.

Further features and advantages of the invention will become clear from the detailed description below and the attached drawings .

Brief description of the drawings

Figure 1 illustrates a supervisory control system in accordance with the present invention.

Figure 2 illustrates a user terminal in accordance with the present invention.

Figure 3 illustrates a picture of visual information in accordance with the present invention. Figure 4 illustrates another picture of visual information in accordance with the present invention.

Figure 5 illustrates a flow chart over steps of a method in accordance with the present invention.

Detailed description of embodiments of the invention

Figure 1 schematically shows a supervisory control system 10 in accordance with the present invention. The supervisory control system 10 is in an embodiment of the invention an object based computerized system for controlling a technical system or part of a technical system. The technical system may for example be an electrical power generation, transmission and distribution system. An electrical power generation, transmission and/or distribution system is in the following denoted a power network. Other examples of technical systems to be supervised, and which may benefit from the present invention, comprises water purification and distribution systems, oil and gas production and distribution systems, other petrochemical, chemical, pharmaceutical or food processing systems, as well as a pulp and paper production systems.

The technical system, parts of which is indicated at reference numeral 21 in figure 1, may be supervised and monitored through an operator terminal, which communicates with a control server handling monitoring and control of the process. One preferred field within which the present invention is to be implemented is in the supervision of a power network.

In figure 1 the supervisory control system 10 comprises two operator terminals 12 and 14 connected to a first communication bus Bl. There is furthermore a second communication bus B2 and between the first and second communication busses there are connected a first server 16 providing control of the technical system 21, a second server 17 providing monitoring of the technical system 21 and a database 18 wherein data relating to control and/or monitoring of the technical system as well as data representing the configuration of the technical system 21 is stored. All such data is in the following also denoted system data.

To the second communication bus B2 there are furthermore connected system interface units 20, 22, 24, 26 for providing control of and measurements in the technical system 21. The first server 16 may therefore be considered as a part of a control system, while the second server 17 may be considered as a part of a monitoring system.

In the figure 1 there are provided four such system interface units 20, 22, 24 and 26 connected to the technical system 21, here exemplified by a power network comprising a power line 28. The system interface units 20, 22, 24, 26 may be considered as being a part of the technical system 21, or simply interfaces connecting the technical system 21 to the supervisory system 10 and thus constituting neither part of the supervisory system 10 nor the technical system 21. It is noted that some of these system interface units 20, 22, 24, 26 may be provided only for control purposes, some only for measurement purposes and some for both control and measurement purposes. Such system interface units 20, 22, 24, 26 are thus involved in controlling the power network 21 or measuring properties of the power network 21. System interface units 20, 22, 24, 26 may include elements directed towards measuring for example currents and/or voltages and power measurement elements such as current transformers and voltage transformers, as well as elements directed towards control operation like circuit breakers, relays, power semiconductor switches and tap changers. These are just a few of several different possible types of elements that can be provided in the system interface units 20, 22, 24, 26 of the power network 21.

In an embodiment of the invention, the first server 16 receives measurements of the technical system 21 via the system interface units 20, 22, 24, 26 and controls the technical system 21 via the system interface units 20, 22, 24, 26 based on these measurements. The first server 16 also preferably stores historical process control data in the data base 18. The second server 17 receives measurements via the system interface units 20, 22, 24, 26 as well as status data concerning the operation of system interface units 20, 22, 24, 26 and is also able to generate alarm and event data that may be presented to the operator via the operator terminals 12 and 14. The second server can also shut down parts of or the entire technical system 21. Alarm and event data may also be stored in the database 18. In the example of figure 1, a so called Network Manager system, developed by and available from ABB, runs on the supervisory control system 10, which belongs to the group of SCADA (Supervisory Control And Data Acquisition) systems. The Network Manager system is particularly suitable for the supervision and control of power networks or gas systems. The operator terminals 12 and 14 in the supervisory control system 10 each provide a user interface to the Network Manager system. In the following, the details of such an operator terminal are explained based on the exemplifying operator terminal 12, shown in figure 2. The operator terminal 12 comprises a user input unit 32, a display unit 34, a control unit 30 and an interface 36 for communicating with the supervisory control system 10 via the first bus Bl. As mentioned earlier, the operator terminal 12, 14 provides a graphical user interface for the operator of the supervisory control system 10.

The control unit 30 may for example be a processor with an associated program memory including program code for performing the functionality of the present invention. The control unit 30 may alternatively comprise means 35 for performing the functionality of the present invention, for example processing means, software, firmware, hardware or any combination thereof for performing the steps of a method in accordance with the invention. The user input unit 32 is a unit through which the user of the operator terminal 12 may enter data. As such it may be a keyboard, a keypad or a mouse. It may alternatively be combined with the display unit 34 in order to form a touch screen. The operator terminal 12 may also comprise 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 terminal 12, 14 in other ways than through the display and keyboard. The operator terminal 12, 14 in the supervisory control system 10 is only one example of a computer in which the present invention may be realized. It is further noted that the above described layout of supervisory control system is an exemplifying layout. For example, the number of communication buses could be another than the exemplifying two, the first and second servers could be integrated into a single server or yet additional servers could be provided, etc.

The control unit 30 fetches or retrieves from the database 18 of the supervisory control system 10 a set of system data representing a status and/or a configuration of the technical system 21. Status data may for example comprise measurement values, calculation results and alarm or event information. Configuration data may comprise data relating to objects and devices in the power network 21 and their physical interconnection.

The set of system data is divided into different types of graphical information. For example, a first type of graphical information is all the physical units of measurements, such as V (Volt), A (Ampere) or W (Watt) . A second type could be the lines, including power lines and other electrical lines as well as signal connection lines. A third and fourth type is the graphical representation of all breakers or isolators, respectively. A fifth type may be the measurement values themselves, i.e. the numbers, and the sixth type can be alarm limits.

In figure 3, a first picture 40 is shown which picture is output on the display unit 34 by the control unit 30. The first picture 40 shows a schematic view of a substation named Troy Station and measurement values, calculations and alarm data relating to this substation. The substation is part of the power network 21 to be supervised. Accordingly, the first picture 40 shows a part of the set of system data, and it gives an overview of the connections and relationships between different physical objects within the substation as well as of the situation in the substation. Physical objects within the substation comprise for example power lines A, B, C, D, E, transformers, breakers and isolators .

In accordance with the invention, each type of graphical information is associated with a corresponding data layer which is made selectable. The selection may for example be done by providing an appropriate selection menu or by allowing the user to click on an object in the first picture 40 wherein the object belongs to or represents one of the layers .

There is a vast amount of information in the supervisory control system 10 that could further facilitate the operator's task of supervising the power network 21. There is for example information about alarm limits, i.e. about the limits which a measurement value or a calculated value has to exceed before an alarm is generated. This is valuable information for the operator in order to see how close a measurement is from causing an alarm. If all alarm limits would be visualized in the first picture 40, the picture would in most cases get too cluttered. In accordance with an embodiment of the invention, alarm limits, and preferably selected ones, are therefore shown only upon request by the operator .

Figure 4 illustrates a second picture 50 showing an integration of the first picture 40 and further pictures. In some situations, in which the alarm limits become important to the operator, he or she may add an "alarm limit layer" to the first picture 40. In the figure 4, a picture 41 showing a subpart 42 of such an alarm limit layer is illustrated as being integrated with the first picture 40. In such "alarm limit layer", selective ones of the alarm limits are preferably shown with a suitable graphical representation.

Other data layers may be created in a corresponding manner. For example a data layer denoted "measurement layer" may be created comprising measurement values. That is, the data layer "measurement layer" is associated with actual measurement values. As another example, a data layer denoted "Breakers" may be created comprising all the circuit breakers of the technical system 21. The data layer "Breakers" is thus associated with the circuit breakers. As yet another example, a data layer denoted "Stations" may be created comprising all power stations of the technical system 21. The data layer "Stations" is thus associated with all the power stations of the technical system 21. In most cases only a part of the different data layers is of interest at a particular point of time, for example a certain breaker or a certain station. Therefore, only part of the respective data layers is preferably output on the display.

In a specific embodiment, the operator may further choose where in the first picture 40 he wants the "alarm limit layer" to appear, i.e. where the first picture 41 showing a subpart 42 of the alarm limit layer should be placed. In this embodiment, only a subpart of the entire available alarm limit layer, i.e. only selective ones of the alarm limits, is integrated into the first picture 40 and output as the picture 41 on the display unit 34. The subpart of the alarm limit layer contains graphical information corresponding only to the location selected by the operator. In the illustrated case only the part of the alarm limit layer related to alarms limits between Troy station and Bowman 1 are shown.

Alternatively, more than one area or location can be selected by the operator, and accordingly, more than one subpart of the data layer (the alarm limit layer) is integrated into the first picture 40 and output as a picture 41 on the display unit 34.

To achieve the displaying of the second picture 50, i.e. the picture 41 integrated with the first picture 40, as illustrated in figure 4, the operator may perform the following two interaction steps:

1. The operator selects, in a suitable manner, one or several areas or locations where he wants to add a layer or multiple layers. The selection may for example be performed by clicking on the several areas or locations of the picture 40 by means of an input device, for example a pointing device such as a computer mouse.

As another example, the selection may be performed by surrounding the desired area(s) by means of an encircling tool. In particular, in a manner known per se, the operator may use a button on a computer mouse to indicate one spot on the display unit, keep the button pressed while moving the computer mouse cursor. A rectangle surrounding the selected area will then be visible, and the operator releases the button at a diagonal corner of the created rectangle. The desired area is thus selected. It is noted that numerous other ways to select a desired area are conceivable.

For example, in figures 3 and 4, the Troy station is illustrated as well as all stations that are connected to the Troy station. If the operator wishes to see the part of the alarm limit layer 41 relevant for the connection, i.e. power line, between Troy station and the station Bowmanl, he makes the selection for example by clicking on square 44 by means of a computer mouse. Thereby the corresponding alarm limit layer 41 comprising the alarm limits relevant for the connection, i.e. power line, between Troy station and the station Bowmanl is shown.

2. The user then selects from a list of layers 43, the list being shown in a third picture 45, one or several layers that he wants to visualize on or in the vicinity of the selected locations. In the list of layers 43 illustrated in figure 4, the user may choose between the following exemplifying layers: units, lines, breakers, isolators, stations, measurements and alarm limits. It is realized that numerous other layers may be implemented and chosen from.

If no location was selected in the first step, then the layer or layers chosen in the second step will be added to the whole first picture 40. That is, if "alarm list layer" is chosen, then all alarm lists of the alarm list layer is shown integrated with the first picture 40.

It is noted that steps 1 and 2 may be performed in the reverse order, i.e. selecting the desired data layers and then selecting for which locations, i.e. which parts of the selected data layers should be shown. The third picture 45, the picture illustrating the list of layers 43, may comprise additional virtual "buttons" that the operator may click on. The third picture 45 may for example comprise a button 46 for adding the selected layers to the first picture 40, a button 47 for clearing a selection that has been made, and/or a button 48 for showing or removing all available layers.

In an embodiment, the operator terminal 12 is adapted to show the system data in some predefined modes, wherein the operator may select which one of the predefined modes that he wants to visualize. For example, during a critical situation, one first selection of layers is interesting for the user/operator, while another second selection of layers is interesting during maintenance. If the operator selects the corresponding mode, i.e. "trouble" or "maintenance", the control unit 30 may then directly output a picture containing an integration of the corresponding first or second selection of layers on the display unit 34.

As an example, during a critical situation alarm limit layers and related measurement values, including measurement values not causing an alarm, may be highly interesting. The alarm list layer and the measurement layer thus constitute a first predefined mode, a mode for example denoted "trouble". As another example, during a maintenance overview of circuit breakers, some measurement values for circuit breakers may be relevant. Layers comprising all circuit breakers of e.g. substation "Troy" as well as layers showing relevant measurement values may constitute a second predefined mode, a mode for example denoted "Maintenance of circuit breakers". It is noted that also only parts of the data layers may constitute predefined modes .

In an embodiment of the invention, alarms may further be visualized by changing the font colour of a displayed measurement value to e.g. red. In an alternative embodiment, the colour of the corresponding device is changed to e.g. red. In some situations this may be of value for the operator in order to immediately understand which actions should be taken.

In accordance with the invention and with reference to figure 5, a method for supervision of the technical system 21 is provided. The method 60 comprises the first step of retrieving 61 a set of system data which represent a status and/or a configuration of the technical system 21. For example, the set of system data may comprise system data, comprising for example configuration data, related to the substation "Troy Station" of the technical system 21.

The information is arranged, by the supervisory control system, in different layers as described earlier. The step of retrieving thus typically comprises retrieving a specific layer or parts of a specific layer selected by the user.

The method 60 comprises the second step of outputting 62 on the display unit 34 of the operator terminal 12, 14 a first picture 40 showing a part of the set of system data. For example, the first picture 40 may comprise a schematic view of the substation "Troy Station" and measurement values, calculations and alarm data etc. relating to this substation . The method 60 comprises the third step of generating 63 at least a first and a second type of graphical information from the set of system data. In this step, particular system data is associated with particular types of graphical information. For example, system data such as "measurements" can be represented as graphical information in the form of numbers, system data such as "circuit breakers" may be represented as graphical information in the form of circuit symbols, etc.

The method 60 comprises the fourth step of associating 64 a first data layer with the first type of graphical information and a second data layer with the second type of graphical information. In this step, particular data layers are associated with particular graphical information. For example, a data layer "alarm limit layer" may be associated with alarm limits relevant for "Troy station" and a data layer "measurement layer" may be associated with measurement values relevant for "Troy station".

The method 60 comprises the fifth step of receiving 65 from the user input unit 32 of the operator terminal 12, 14 a first selection signal indicating if the first or the second data layer or parts 42 and 49 of the first or second data layers, respectively, is to be output on the display unit

34. The operator may use a suitable user input unit 32 for accomplishing the selection, for example by clicking on the picture on the display unit 34, thereby creating the selection signal.

The method 60 comprises the sixth step of generating 66 a second picture 50 as an integration of the graphical information corresponding to the selected data layer or parts 42, 49 thereof and the first picture 40 and outputting the second picture 50 on the display unit 34.

The method 60 comprises the seventh step of outputting 67 the second picture 50 on the display unit 34. This step can be performed in any conventional manner.

The method may comprise yet further steps, exemplary ones of which are described in the following.

The method 60 may comprise the further steps of receiving from the user input unit 32 a second selection signal indicative of if the first or the second data layer or parts thereof is to be removed from the second picture 50. The method 60 then comprises the step of generating a third picture by removing the graphical information corresponding to the selected data layer or parts thereof from the second picture 50 and outputting the third picture on the display unit 34. Data layers and/or parts of data layers can thus be removed as well, for example when they are no longer of interest .

The method 60 may also comprise the step of having a first location signal indicating where in the first picture 40 the first or second data layer is to be shown. The first location signal is received from the user input unit 32 and the second picture 50 is generated by integrating, into the first picture 40, the graphical information corresponding to the selected data layer or parts 42, 49 thereof at the desired location.

The step of receiving 65 may, in one embodiment, comprise the substeps of: receiving a third selection signal selecting one of the first and said second data layer; and receiving a fourth selection signal indicative of which parts of the selected data layer is to be output on the display unit 34. That is, the user performs a two-click operation, first choosing type of data layer to be shown and then choosing which parts of the data layer is to be shown, i.e. for example for which objects the data layer is to be shown .

The method 60 may also comprise the step of saving the selections made by the user, i.e. the particular setup of layers/parts of layers visible on the display unit. The saved selection then constitute a user defined mode.

The invention may be implemented in different technical systems. In particular, the method 60 in accordance with the invention may be implemented in the supervisory control system 10 supervising such technical systems by adding suitable computer program product, for example stored on a computer readable medium such as a compact disc or floppy diskette. The method of the present invention can thus be implemented as a computer program product, which is loadable into the computer of the supervisory control system 10. The computer program product comprises software code portions for performing the method 60 when the product is run on the computer .

In summary, in the present invention the system data is divided into different layers and the user or operator gets to decide, which layers he wants to see. The operator may start from a first, default picture, which could be an overview picture of the whole system. He may then add additional layers in order to show more detailed information and this detailed information is integrated into the picture already present on the screen of the display unit. As a result, pictures of the technical system become user defined to show only information of interest for the specific situation. Since the first picture remains visible and additional layers are integrated into it, it is ensured that the desired detailed information is shown while an overview is maintained.