Abstract:
Flexible extension of a control system needs to be possible without touching the original object model and hence the control software. To this end, the invention proposes attaching data elements which contain registration information for existing and newly added tools to object data. An object type can then be instantiated selectively for the existing or new tools. This allows extensions to be instantiated subsequently without affecting the essence of the existing object model.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    Modem industrial controllers generally comprise an “engineering system” and a “runtime system”. The engineering system is used to develop a control program which is then subsequently loaded into the runtime system. The runtime system then ensures the time sequence control for the system to be controlled.  
           [0002]    The functionality of the system to be controlled and/or of the runtime system can be expressed by an object model. The object model is effective in the engineering system and/or runtime system and is the basis for the engineering of the controller, for example, startup and programming etc. Furthermore, the object model is the basis for the data storage of the controller. The elements of the object model can be categorized into various object types. The object type is the software engineering form of a description of object instances. In the simplest form, this description relates to the data structure represented by an object instance in the memory. In systems today, the object type also describes operations which can be carried out on these data structures and thus also lends functionality to the object instances. An example of one of these object types is program containers used for managing and storing user programs. Other object types are technological object types, such as for positioning axes, synchronism axes, measuring gages, cam disks etc., the functionality of these object types being stored in the respective object type on a data engineering basis. Another significant object type is “devices” used for managing and storing hardware configuration settings.  
           [0003]    All object types can be instantiated, i.e. can be embodied specifically. Thus, for example, a synchronism object can be allocated a specific transmission ratio. The technological object types can be organized in the form of technological packets. Instantiation is generally effected in the engineering system. Loading the instantiated objects into the runtime system initiates the instantiation of corresponding objects in the runtime system, to which objects the data of the objects from the engineering system are transmitted.  
           [0004]    An object instance is first a data structure in the memory of a computer system. From one object type, it is possible to instantiate any desired number (to the extent permitted by the underlying computer system) of object instances. In this context, the size and organization of the data structure of each object instance follows the description provided by the object type. Object instances are set up at the execution time of an editor, that is to say while the program system is being executed on a computer system in the engineering system.  
           [0005]    The object model comprises a set of object types and describes the relationships between object instances instantiated from the object types. The complexity of creating new object types to be inserted into a complex object model can be comparatively great.  
           [0006]    In the engineering system, various tools can be used to access objects (instances) of particular object types. That is to say that the object types are defined when the software system is created and cannot be changed again in the engineering system. Accordingly, the engineering system permits one or more views to the instances of particular object types. Within the context of programming, these may be, by way of example, various editors for textual or graphical user programming. The tools and views of the engineering system are also called SnapIns. Besides the SnapIns present in the basic system, other SnapIns can be added to the engineering system.  
           [0007]    An object type is more than just the description of a data structure. It also comprises operations which can be carried out on and using instances of this data structure. The internal tools of the basic engineering system access instances of the object types. Object types themselves are generally not changed again by the user.  
           [0008]    In principle, engineering systems, like any other software, are also subject to constant renewal, extension and improvement. However, with today&#39;s implementation mechanisms for control extensions, the problems discussed below often arise. The introduction of a new programming view, e.g. the introduction of graphical programming in addition to textual programming, is today not possible in integrated fashion without extending the basic functionality of the engineering system. A possible external extension using external tools requires dedicated data storage, which is then not integrated into the existing system. The extension of an existing, for example graphical, programming language by additional programming icons, which requires extension of the data storage, is generally not possible without touching or extending the existing engineering system. Thus, for example, an existing flowchart editor cannot readily be extended by icons for particular library functions. In addition, today&#39;s OEM interfaces afford only a specific and restricted depth of integration into the engineering system. Finally, extensions of the engineering system functionality using external tools generally entail consistency problems in the data storage.  
         SUMMARY OF THE PRESENT INVENTION  
         [0009]    The objective of the present invention is to describe, in relation to controllers, a method for flexibly extending control systems which does not require the original object model to be touched. The present invention achieves this objective by means of an apparatus for controlling or regulating a system based on a basic object model which represents the functionality of a runtime system and/or of the system to be controlled or to be regulated. The apparatus has a data processing device for processing a first object type which has a predetermined data structure which is part of the basic object model and which can be instantiated for objects. The data processing device is able to be used to attach at least one type data field to the first object type.  
           [0010]    Further, the objective of the present invention is achieved by a method for controlling or regulating a system based on a basic object model which represents the functionality of a runtime system and/or of the system to be controlled or to be regulated. The object model comprises a first object type which has a predetermined data structure and can be instantiated for objects, by reading in or creating a virtual object type having a type data field, and instantiating the virtual data type for an object for which the type data field is filled with associated information relating to an additional tool which is not part of the basic object model.  
           [0011]    The inventive extension mechanism advantageously permits scalable functional extension of the control software with a great depth of integration in the engineering system without touching the underlying software. The extensions can be in a form such that all existing engineering operations and transactions on the object types, e.g. browser, viewer, copying, inserting, importing, exporting, etc., also act on the extensions and can be used in a familiar manner.  
           [0012]    Another advantage is that OEM extensions for new object types and new viewers are generically possible and require no changes to the basic software in the engineering system. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0013]    The present invention is now explained in more detail below with reference to the drawings, in which:  
         [0014]    [0014]FIG. 1 shows a diagram of the inventive functional connection between tools and objects;  
         [0015]    [0015]FIG. 2 shows a data structure diagram of an extension mechanism; and  
         [0016]    [0016]FIG. 3 shows a combination of the structures shown in FIGS. 1 and 2. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0017]    The exemplary embodiment of the invention as shown and discussed below illustrates one preferred application of the present invention. A few significant modules of the engineering system relate to the provision of a (graphical) user interface which the user uses to access the project data. Object instances contained in the project are represented in the user interface (e.g. display in the project browser, opening of editors, menus presented) on the basis of particular rules. In a nonextendable system known to date, the rules relate to the object type of the individual object instances (e.g. a program object instance is associated with a structured text editor using the rule: “instances of the program type are processed using the structured text editor”). In the system of the present invention, to which new views/editors can be introduced in the form of “Snaplns”, the rules are entered by the SnapIns as they are registered in the engineering system. In this context, the object types are identified by unique designators.  
         [0018]    The present invention thus makes it possible to introduce rules for “virtual types” which are not yet known or included in the programming of the basic object model and are subsequently adopted by the user or system constructor in a “private object model”. In this context, the rules are formulated in a similar way to the formulation for object types which are actually present in the object model, the only difference being that the indicated designators do not denote any object types which are present in the object model (e.g. the rule “instances of flowchart object types are processed in the flowchart editor”, the object model containing no “flowchart” object type but only the “program” object type. The “flowchart” object type is thus a virtual type.)  
         [0019]    Associated with this is the introduction of one or more additional data fields into the data structures described by object types in the object model. This allows an additional data value to be stored on any object instance of these object types. SnapIns can fill this data value, e.g. when a new object instance is created-specifically, using a designator for a virtual type (e.g. “flowchart”). This means that the user interface no longer uses the rules which were indicated for the actual object type of the object instance, but rather the rules which were indicated for the virtual type whose designator is stored in the object instance&#39;s data field reserved for this.  
         [0020]    The identifier for the virtual type can be entered or modified even after the object instance has been created. In this way, the user interface can present the user with a larger number of available object types than have actually been defined in the object model. In addition, new virtual types can be introduced at any time without the need for extension of the object model.  
         [0021]    A prerequisite for this method is strict distinction between the functionalities in the engineering system: a class of functionalities relates to the actual object type of an object instance. By way of example, these are all functions concerning data storage, transfer into the runtime system or the lifecycle (creation, access, deletion) of object instances. By contrast, the other class of functionalities relates to the virtual type, provided that such a type has been entered in the newly introduced data field of the object instance. If a virtual type has not been entered, then the rules for the object type of the object instance are also used for these functionalities. This class includes, above all, the already cited functionalities of the user interface.  
         [0022]    A project browser in the engineering system shows the project structure by displaying object instances and their links. There is a direct connection between project structure and object model to the extent that the object model contains, among other things, information regarding which object instances can possibly be created in a project and which relationships can arise between the instances of particular types.  
         [0023]    [0023]FIG. 1 shows a specific example of the novel registration of a plurality of editors for an object type and the instantiation thereof in a plurality of objects. As is shown, an existing structured text editor, or one which is to be newly added, Editor_ 1  and also an existing flowchart editor, or one which is to be newly added, Editor_ 2  are registered for an Object type_ 1 . The Object type_ 1  can thus be instantiated in the structured text format and likewise in the flowchart format. A respective Instance View link then ensures that the Structured Text object instance is edited by the structured text editor and the Flowchart object instance is edited by the flowchart editor on request.  
         [0024]    The user can observe and edit object data in appropriate windows of the project browser. In the present example, the original software contains a structured text editor as SnapIn_ 1  in the workbench for the controller shown in FIG. 2. The basic engineering system of a development department or the engineering system of a system constructor provides an object Obj_ 1 , registered for the structured text editor, after an object type has been instantiated. This means that the structured text editor is retrieved automatically when navigating onto the object Obj_l in the project browser, so that the object Obj_ 1  thus becomes editable.  
         [0025]    In addition, the basic engineering system provides an object Obj_ 2  which can, in principle, also be edited using the structured text editor. The object Obj_ 2  has been extended by two extension data elements Ext_ 1  and Ext_ 2 . The number of extension data elements which are linked to the basic object can be chosen at random. The object Obj_ 2  having the two extension data elements Ext_ 1  and Ext_ 2  is registered for the additional flowchart editor SnapIn_ 2  in the present case. This means that the flowchart editor SnapIn_ 2  is automatically retrieved when navigating onto the extended object Obj_ 2  in the project browser, and the object is available for editing in the flowchart editor. In addition, the extension data elements can contain user-specific data, e.g. relating to an editor preferred by the user.  
         [0026]    [0026]FIG. 2 illustrates an extension mechanism which can be used to extend a basic engineering system by an additional editor SnapIn_ 2  without changing the original functionality. The tools and the views for an object type are extended by adding additional data on the object type. In this context, data extensions are attached to existing object types and are homogeneously integrated into the existing data storage without extending the underlying engineering system software. A registration mechanism allows SnapIns or similar extension tools (SnapIn_ 2 ) to register on the object type with the respectively provided number of extensions and to create appropriate object instances for the tools and views.  
         [0027]    First, this type of extension allows them to be integrated into the existing project data storage, and hence permits consistent data storage; and second allows them to be integrated into the existing object model, i.e. permits integration into all engineering functionalities connected to the object model, such as project browsers.  
         [0028]    A combination of the embodiments of FIG. 1 and FIG. 2 is shown in FIG. 3. A “program” object type is provided with a data field DV for a virtual type when created in the engineering system. The data field DV can store a Virtual Type ID list or a Virtual Type ID field which can hold the registration information for an additional cool or SnapIn. In addition, a data field DE for attaching extensions is appended to the “program” object type.  
         [0029]    The “program” object type can now be instantiated in the engineering system in two ways. First, it is instantiated for an object Obj_l, for which the data field DV is not used. The association with an editor is therefore made on a standard basis using the “program” object type. The other possible instantiation produces an object Obj_ 2 . In this case, the data field DV is used for registration for a virtual type which is not part of the basic object model. In the present case, the object Obj_ 2  has been registered for the flowchart editor. This is to say that the Virtual Type ID field DV contains association information for the flowchart editor. The flowchart editor uses flowchart-specific information which cannot be stored in standard objects. Since the object Obj_ 2  has a data field DE available, however, the flowchart-specific information can be stored in one or more extensions Ext_ 1 , Ext_ 2 . The user can thus use individual SnapIns to the full extent.  
         [0030]    In summary, the control system described above has the following advantages:  
         [0031]    the functionality is represented using an object model;  
         [0032]    the object model is effective in the engineering system and/or runtime system;  
         [0033]    the object model is the basis for the engineering of the controller (e.g. for startup, programming, etc.);  
         [0034]    the object model is the basis for the data storage of the controller;  
         [0035]    the controller&#39;s engineering system based on the object model can be flexibly extended without touching the engineering system by introducing extensions;  
         [0036]    all existing engineering operations and transactions on the object types (e.g. browser, viewer, copying, inserting, importing, exporting etc.) also act on the extensions and can be used in the same way, because the extensions are made directly on the object;  
         [0037]    OEM extensions for extensions of the object types, new views to existing object types, new object types are generically possible and require no change to the basic software (engineering system);  
         [0038]    an extension mechanism having a generic interface is available in order to make extensions in the user interface (new editors, new views) and/or in the data storage;  
         [0039]    new engineering functionalities and new engineering views to existing object types in the object model can be added;  
         [0040]    existing object types can be extended by creating additional data on the object type; and  
         [0041]    new object types can be added to the available object model at any point.