Abstract:
A system for operating and controlling technical processes having at least one component fashioned as a measuring instrument and a control device, which is connected by electrical lines to sensor and actuators of processes, and having a control program, a measurement and control unit, an operating and observation component, optionally a database, optionally a process printer and further components of a process automation, as appropriate, which are connected to one another via data channels and a control program.

Description:
BACKGROUND OF THE INVENTION 
   The invention relates to a method of operating and controlling technical processes. A large group of products, used chiefly for controlling machines, is generally known. They are known as stored-program controllers or programmable logic controllers (PLCs). These devices are equipped with governing control programs that have the task of controlling machines and installations (processes) through sensors and actuators. Visualization software independent of the control software is employed for operator guidance. Control software and visualization do not fit together because they are different in concept, relate to different platforms, so that these approaches are not consistent. This manifests itself in an inadequate adaptation to the differentiated requirements of the distinct processes. In practice, this often leads to problems and complicated approaches. 
   There is further known a group of products that are employed primarily in research and development. They date back to the end of the 1980s, when PCs had attained a sufficient level of performance, chiefly of graphical capabilities. These are the so-called virtual measuring instruments. Measuring instruments with knobs, buttons, switches and indicating instruments had been known up to that time. Measuring circuits were physically constructed from wire and filters and the like. This was now replaced by virtual measuring instruments and measuring circuits. Now there were images of such devices on the screen. Turning knobs and actuating buttons and switches was replaced by clicks of the mouse. In this way a process could be operated and observed. 
   Automatic control, however, was not possible in this way. In order to remedy this defect, a programming language was superimposed thereover. In the opinion of many users, the institution of automation on the basis of such approaches is very complicated and demands a long familiarization time. Users need special knowledge, which they must master. The effort is substantial. Consistency between operating and observing and automation was not achieved with these approaches. Particularly in laboratory automation, it would be very advantageous if there were simple approaches making it possible to develop automation tasks quickly and without great effort, without the need for special knowledge or the employment of specialists. 
   SUMMARY OF THE INVENTION 
   It is an object of the invention to remedy the before mentioned shortcomings. In order to effect the distinct tasks, a method is furnished that integrates the various components of process automation, such as control program, process visualization, specification of parameters and documentation, into a consistent method. The user is enabled to configure control sequences, so that there is no need of programming and the learning of a programming language. The object of the invention is achieved in that: 
   A. the control modules are invoked and invoke other control modules according to simple rules, 
   B. a start module being started by a program invocation and in turn being able to invoke a sequence module or a function module, 
   C. a sequence module being invocable by a start module, another sequence module or an event module and being able in turn to invoke a further sequence module, a function module or an end module, 
   D. a function module being invoked by a sequence module, a start module, an end module or an event module, 
   E. an event module being started by an event that takes place in the process or by an operator action and in turn invoking a sequence module, a function module or an end module, and 
   F. an end module being invoked by a start module, another sequence module or an event module. 
   The data exchange between the components is effected with standard transmission protocols that allow the individual components either to be run on one device or to be distributed among various devices. The devices can then be subscribers of a standard data network, for example Ethernet. In this way, applications can be conceived that permit advantages in terms of effort and operational organization, because the data network of an enterprise can also be utilized for the tasks of automating processes. 
   A further inventive concept is concerned with control sequences. First, the overall sequence of process control is split into control modules, these control modules being assigned to the sequences, events and functions categories, and these control modules being containers for program code. Three types of control modules result, namely, sequence modules, event modules and function modules. 
   The sequence module, as the name expresses, is responsible for the temporal sequencing of various activities. It takes over the process guidance. Process guidance means the control program of the process sequence. This will be explained for the example of a mixing process. In a mixer, the process sequence results from controlling the charging of the species that are to be mixed, the heating of the mixing stock through temperature control, through rotation speed control of the stirrer and mixing time, emptying of the mixer, and cleaning. 
   The event module handles operations that affect process guidance and can take place at a time that cannot be determined in advance. As soon as the event takes place, activities are initiated that affect the sequence. For example, the event can be the attainment of a temperature of a heating operation. A further example would be an operator action via the operating and observation component in which the operator changes the setpoint of a controller. Event modules can either momentarily interrupt the sequence and themselves take over process guidance during the interruption, or be executed in parallel with the sequences. 
   A characteristic of the function modules is that they take over activities that run in parallel with other control modules. In the filling of a vessel, for example, a plurality of species can be charged at the same time, the filling operation of the individual species being controlled by one function module each. Function modules are usually invoked by sequence modules, less frequently by event modules. Typical further operations that are executed by function modules are control actions, heating operations, monitoring operations, etc. Function modules can acquire measurement data, which are depicted in the form of trend curves on the operator interface. Function modules open up opportunities for optimizing the process sequence. Control programs can be more fully and easily understood in terms of function modules. 
   One category of technical processes is referred to as batch processes or discontinuous processes. The characterizing feature of such processes is a start phase and an end phase (termination of the process). An example would be a pumping station, which is turned on as soon as a water reservoir is to be filled. Starting operation and termination are to be assigned to the sequences category. For this reason, it is desirable to provide a start module type and an end module type in the sequences category. This typization is not mandatory, because a sequence module could also control starting operation and termination. 
   As a consequence of this definition, the sequences category includes the three module types, namely, start module, sequence module and end module. In the case of process sequences, critical states not provided for in the normal operating sequence can occur. For example, suppose a controller is malfunctioning so that a temperature exceeds a critical limiting value. For safety reasons, it is then often necessary to terminate the process. This is referred to as emergency termination. According to the invention, therefore, a security module is defined. The security module reacts to events that do not happen in the normal operating sequence. It is therefore assigned to the events category. The security module has the task of interrupting the normal process sequence and terminating the process. As a consequence of this definition, the events category includes the module types event module and security module. 
   Distinct graphical symbols are assigned to the various module types. These graphical symbols are clearly distinguishable from one another. In the operating and observation component, which can contain a number of screens, module diagrams are provided. A user creates module diagrams in configuration mode. In this way, a very good overview of the process sequences is advantageously made possible. The control modules are placed as graphical symbols in the module diagram and linked with lines. These lines show symbolically how control modules are invoked by other control modules and can themselves invoke other control modules. The arrangement of the symbols and the linking lines, which are subject to set rules, make it possible to identify at a glance the structure and the sequences of the automation task. According to the invention, the control modules whose program contents are currently being carried out are highlighted in runtime mode, that is, during the execution of a process. In this way an observer can identify in what stage the process sequence is. 
   The control modules are linked in accordance with set rules. The software checks whether the user is complying with these rules, so that errors are largely avoided. These rules state that control modules of the sequences category (sequence modules, start modules and end modules) are linked only vertically, that event modules and security modules are not invoked by other control modules but can invoke other control modules, that function modules are linked horizontally with the invoking control module. 
   It is important to note that the linking lines in the case of vertically arranged control modules must also allow of a lateral offset, that the linking lines in the case of horizontally linked function modules must also allow of an offset in the vertical direction, depending on how the control modules are arranged in the module diagram. This becomes apparent from the images in the examples. 
   A user will desirably arrange the control modules from top to bottom in a manner corresponding to the program procedure. It is regarded as self-explanatory that the respective directions vertical and horizontal are interchangeable. The simple rules with which control modules are invoked and invoke other modules, symbolized by the linking lines between modules, and the fact that the invention makes it possible to get by with only a very few distinct module types should be emphasized. The modules serve as virtual containers for program code. They are accessed for example by double-clicking on the symbol of the control module in the module diagram. An interface containing the program code of the control program then opens, and the program code can now be edited. 
   The individual instructions of the control program contain keywords serve as placeholders for further keywords and elements of program code. The keywords in the code of the control program, which are emphasized in clearly visible fashion, for example by underscoring and/or color coding, must necessarily be replaced by program code. Only when all keywords have been replaced by program code is the control program of the control module released as finished. 
   According to one embodiment of the invention, the keywords permit access to selection lists. By clicking on the keyword, the selection list associated with the keyword is opened in simple fashion. The contents of the individual list items of the selection list in question are formulated such that they generate a meaningful and error-free program code when they replace the keyword. It is therefore necessary that all keywords must be replaced by a program code. Only when all keywords have been replaced by a program code is the control program of the control module released as finished. Thus, if a list item is selected from the selection list, this list item automatically replaces the keyword. 
   Because of this way of creating program code, a user has no need to learn the language. Aside from the values of constants, he writes no program text. The program text is automatically generated with the aid of the computer mouse; as a consequence, syntax errors are eliminated. Further, illogical or meaningless program sequences are eliminated, because the selection list as replacement for the keyword in question makes possible only meaningful and logical entries. This implies that error messages, such as are always necessary otherwise, do not happen. With the exception of an error message that appears if not all keywords have been replaced. 
   All program instructions are assigned to the test or action categories. In this way, the first keyword of a program instruction is either Test or Action. A different word with the same meaning can also be chosen. Thus it is made very easy for the user to take a decision if he wishes to write a new line of the program. As soon as he inserts a new line, the Test and Action appear in the selection list. A click on one of the two selection items inserts either the Test or Action program instruction. This contains further keywords, so that the program instruction can be prepared with several steps of the same selection procedure. 
   Process states, operator actions, input parameters can be determined with the Test instruction. For example, it is possible to perform a test to determine whether a temperature has exceeded a certain value, whether a vessel is full, whether an article of equipment is turned on, whether a button has been actuated, and much else. The Test instruction has the straightforward formulation &gt;If (logical operation) then&lt;. Options for the Test instruction being possible in the form &gt;If not then . . . &lt;or &gt;If for the first time then . . . &lt;. 
   The Action instruction makes possible a wide variety of operations that can be assigned to the categories of process control, items of information for operating personnel, storage of data (documentation), mathematical operations (formulas), programming operations (e.g., the “loop” example), output in reports. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Exemplary embodiments of the invention are depicted in simplified form in the accompanying drawings, in which: 
       FIG. 1  shows a schematic arrangement of the components of process control; 
       FIG. 2  shows symbols representing the three categories, namely, sequence modules, event modules, function modules; 
       FIG. 3  shows an excerpt from a visualization diagram; 
       FIG. 4   a  shows a module diagram; 
       FIG. 4   b  shows a module diagram; 
       FIG. 5  shows a finished program code of a module; and 
       FIG. 6   a  to  FIG. 6   i  show interactive creation of a program instruction. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The reference characters in  FIG. 1  have the following meanings:
           1 : a process to be controlled;     2 : sensor and actuator lines, which link the sensors and actuators of the process with the measurement and control units;     3 : a measurement and control unit;     4 : a control program;     5 : an operating and observation component;     6 : a database;     7 : a printer for creating reports;     8 : a data channel; and     9 : data channels.       

   Process  1  of  FIG. 1  is linked to a measurement and control unit  3  via measurement and control lines  2 . The measurement and control lines  2  transport signals of the sensors of process  1  to a measurement and control unit  3  and transport control signals in the reversed sense to the actuators of process  1 . The measurement and control unit  3  is both a measuring instrument and a data-processing device. It makes certain that the process signals are transformed in such fashion that the data can be exchanged with a control program  4  via a data channel  8 . The control program  4  is linked to the other components of the system, that is the operating and observation component  5 , the database  6  and the printer  7  (for creating reports) via data channels  9 . Data transfer via the data channels  8 ,  9  is effected with the Ethernet hardware protocol and the TCP/IP software protocol. As a result, the individual functions can be implemented in one device or in distributed fashion over a plurality of devices. A high degree of flexibility is attained in adaptation to the spatial relationships in question and to the size of the application in question. 
   The control program  4  stands at the center of data transfer because it is linked in star fashion to other components  3 ,  5 ,  6  and  7  via data channels  8 ,  9 . As a result, the control program  4  can send data for observation of the system, under program control, to the operating and observation component  5 , where process states are displayed to the operator. Conversely, operator actions by the operator are supplied to the control program  4 , which in turn, on the basis of the instructions, initiate corresponding state changes in process  1 . Also, the control program  4  can exchange data with the database  6 . On the one hand, it can read out process parameters, process them in the control the program, and control process  1  accordingly. Conversely, data for quality validation can be passed on to the database  6 . Report printer  7  will receive data via one of data lines  9  and can then create reports. 
   Referring to  FIG. 2 , the reference characters have the following meanings:
           10 : the symbol of the start module of the sequences category;     11 : the symbol of the sequence module of the sequences category;     12 : the symbol of the end module of the sequences category;     13 : the symbol of the event module of the events category; and     14 : the symbol of the function module.       

   The symbols in  FIG. 2  represent control modules. They can be put on the interface in the module diagram, arranged and linked or joined with lines. In this way the framework of the control program can be conceived. A click on the module in question gives access to the program code of the control program. The symbols show how they can be joined to other symbols. Sequence module  11  can be joined vertically to other sequence modules or to the start module and an end module. It can be joined horizontally to function modules. Event module  13  can invoke only a sequence module or an end module. It cannot, however, itself be invoked by another module. Function module  14  can be invoked only by a sequence module but cannot itself invoke another module. 
   The reference characters in  FIG. 3  have the following meanings:
           15 ,  16 ,  17 : visualization objects of analog display devices; and     18 ,  19 ,  20 : visualization objects of signal lights.       

   The three (virtual) analog display devices  15 ,  16 ,  17  of  FIG. 3  show the temperatures of three rooms designated as Room 1 , Room 2  and Room 3 . The (virtual) signal lights indicate in which of rooms  15 ,  16 ,  17  the temperature is currently being controlled in accordance with a temperature profile. 
   The reference characters in  FIG. 4   a  have the following meanings:
           21 : a start module;     21 ,  23 ,  24 : sequence modules; and     25 : an end module.       

   The reference characters in  FIG. 4   b  have the following meanings:
           26 : a start module;     27 : a sequence module;     28 : an end module; and     29 ,  30 ,  31 : function modules.       

   The function according to  FIG. 4   a  and  FIG. 4   b  is next described in both of the module diagrams shown in  FIG. 4   a  and  FIG. 4   b , three climate-controlled rooms are represented by symbols  23 ,  24 ,  25  and  29 ,  30 ,  31 . The temperature is being controlled in the climate-controlled rooms. The salient difference is that in module diagram of  FIG. 4   a  only one room  23 ,  23 ,  24  can be controlled at a time, while in module diagram of  FIG. 4   b  the rooms can be controlled at the same time. The reason for the difference is that control in  FIG. 4   a  is effected by sequence modules  22 ,  23 ,  24 , while in  FIG. 4   b  the control is brought about by three function modules  29 ,  30 ,  31 . 
   In using the sequence modules in  FIG. 4   a , only one of these modules can function at a time, because the sequence module takes over process guidance. In  FIG. 4   b , this task is entrusted to three function modules  29 ,  30 ,  31 . Function modules work in parallel and independently of one another. The rooms can thus be controlled at the same time. In  FIG. 4   b , sequence module  27  takes over process guidance. Its only function is to wait while the rooms are controlled by function modules  29 ,  30 ,  31 . 
     FIG. 5  shows the finished program code of the sequence module  23  and of the function module  30 . The temperature is first controlled at 45° C. during a defined time, then at 65° C., likewise during a fixed time interval. Afterward there is a regression to room temperature. The individual program instructions belong exclusively to the test and action categories. The Test instruction is a block of instructions made up of two lines in which Action instructions are commonly included. The Action instruction in the second line turns on a digital channel (HeatingSystem 1 ) of the connected process. Further Action instructions and Test instructions correspond to the process. The Action instructions in the third line from the top and in the next to last line correspond to the visualization object DisplayRoom 2  (reference character  19  in  FIG. 3 ) and turn the signal lights on and off. 
     FIG. 6   a  shows the finished Action instruction created interactively by clicking the mouse. The instruction causes the digital output of type DigOut, with the name HeatingSystem 1 , to be set to an “on” status.  FIG. 6   b  shows how the instruction is set up if a free line is not yet available. The mouse pointer is moved onto the line below the line to be inserted. Clicking the right mouse button causes the selection list Test/Action/Info to open as shown in  FIG. 6   b . Action is selected. Referring to  FIG. 6   c , clicking the left mouse button causes Set to be selected from the Action/Set selection list. 
   Referring to  FIG. 6   d , the instruction still shows the underscored keywords Object and var. According to the rules, all keywords must be replaced by program code. In the  FIG. 6   e , the left mouse button is clicked on the keyword Object. The selection list opens as a result. Channel and Digital Output are selected. The instruction has the appearance shown in the  FIG. 6   f , with the keywords ChannelName and var still underscored. 
   Referring to  FIG. 6   g  clicking on the keyword ChannelName causes the available channels to be displayed. “HeathingSystem 1 ” is selected.  FIG. 6   h  shows that clicking on the keyword “var” causes “Heating System  1 ” to be replaced by H/L. Clicking on H/L causes the selection list to open as shown in the  FIG. 6   h . “On” is selected and  FIG. 6   i  shows the finished instruction, which was generated by a few clicks of the mouse.