Abstract:
One embodiment relates to modernizing a technical system, in particular a producing system with the aim of obtaining economic and technical advantages. The technical system comprises at least one drive mechanism provided with at least one drive motor powered by a power element, a torque controller controlling the power element and a speed controller prescribing the nominal value of the torque (Msoll) for the torque controller. When the determination of the nominal value of the torque (Msoll) for the torque controller by the speed controller is deactivated, a standard drive element is available. The drive element comprises at least one speed controller, a torque controller and a power element. The nominal value of the torque (Msoll) of the torque controller of the drive motor is determined by a speed controller of the standard drive element.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is the US National Stage of International Application No. PCT/EP2004/004911, filed May 7, 2004 and claims the benefit thereof. The International Application claims the benefits of German application No. 10320826.7 DE filed May 8, 2003, both of the applications are incorporated by reference herein in their entirety. 
     FIELD OF INVENTION 
     The invention relates to a method for modernizing a technical system, especially a production system as well as a drive element. 
     BACKGROUND OF INVENTION 
     Many technical systems, especially production systems for manufacturing products on a production line system (e.g. paper, textiles, plastic foils, metal foils) have drive technologies which are no longer up to date, e.g. analog technology-based drives. This outdated technology has serious disadvantages since it exhibits an increased susceptibility to faults because it is getting older and as a result of external influences for example, an inability to repeat operations accurately and only limited diagnostic facilities. This results in unsatisfactory system availability, high scrap quotas and high failure costs. 
     To avoid these problems and to increase the productivity of the system, a modernization of the system can be undertaken, in which for example the drive and automation systems implemented in outdated analog technology are replaced by modern systems employing digital technology. Since the budget available for such upgrading however does not generally extend to a complete upgrading of the system, the system is subdivided into a number of subsections which are then modernized gradually. Each of these subsections, e.g. a multi-motor unit along with the power units feeding the motors (e.g. rectifiers, dc or ac converters), drive control and possibly higher-ranking automation, can then be planned and modernized separately in accordance with the available budget. 
     However such modernizing involves a high overall expenditure, since modifications will be required as a rule for an upgrading step both in the new, modernized part of the system as well in the existing system parts, especially at the existing automation level, to enable the new and old parts of the system to communicate with each other. Furthermore it is not possible with this process to implement a contemporary drive and automation concept which increases productivity while an old part of the system is still present. An implementation of the concept in the last step, i.e. for upgrading of the last part of the system, can also no longer be implemented at acceptable expense. Consequently all conventional approaches to solutions are not optimum from either a technical or a financial standpoint. Many system operators therefore put up with the disadvantages of the existing system and forego modernization of the complete system. 
     SUMMARY OF INVENTION 
     An object of the present invention is therefore to specify a method and an appropriate drive element which allows a technical system to be modernized in a way which is favorable from a financial standpoint as well as being advantageous from a technical standpoint. 
     In accordance with the invention this object is achieved by a method, drive element, and a production system with a drive element. Advantageous embodiments are in the dependent claims. 
     The invention is based on the idea that a commercially and technically useful modernizing of the technical system is possible by, instead of the conventional “vertical” segmentation of the system into a number of subsections and its step-by-step modernization i.e. the exchange of a complete drive unit along with the costly power section and the motors, a “horizontal” cross-section at the level of the nominal required torque of the individual drives is performed. This interface as a rule involves a standard interface and it is mostly possible without major problems to have the required torque value specified by another, new speed controller instead of by the existing speed controller of the drive motor. 
     In accordance with the invention this speed controller is located in a standard drive component which, in addition to the speed controller, features a torque controller and a power element. Such standard drive components are available in a very wide diversity of power classes and because of their standardized construction can be manufactured and also procured in high volumes. At the same time modern standard drive components make it possible to connect the drive element to a modern, higher-ranking automation system, which provides technological functions such as machine control, maintenance of nominal values, technological controlling etc. with the associated operation and monitoring functions (HMI—Human Machine Interface) and thus makes it possible to achieve the desired productivity improvements, availabilities etc. The costly drive components such as the power element and the motor are at this point not yet replaced by new components, so that the upgrade can be performed at relatively low cost. Because of the low costs of standard drive components, the fact that the torque controller and power element which they contain are not initially needed is not of any great importance, especially if power elements of a very low power class are provided. 
     The drive control and the automation level of the system can thus, in a single upgrade step in which all for the major components for production are renewed, be upgraded to a technical and technological state which corresponds to that of a modern, new system. The horizontal section at the level of the required torque value means that there are no resulting complex interfaces between new and old system parts. The outlay for interface adaptations can thus be kept low and technically less complex solutions which are appropriate to the functional requirements of modern systems and thereby advantageous from the technical standpoint can be implemented. 
     Execution of this method for all the drive elements present in the existing system enables a corresponding modern automation system to be provided for the overall system and thereby a new control and operating concept with all the advantages of modern technology to be implemented in the overall system, i.e. the parallel operation of different concepts associated from the technical standpoint with restrictions, e.g. parallel operation of an automation system with analog technology and an automation system with modern, digital technology does not occur. 
     Whereas the old technology was frequently identified by a plurality of widely different modules with the correspondingly large inventory of spares, the inventory of spares is reduced after the upgrade to the few elements remaining in the remaining power elements and motors. 
     In accordance with an advantageous embodiment of the invention there is provision for the speed controller of the standard drive component to obtain at least one required speed value from an automation system and thus to be linked into a system automation. As well as the nominal speed value, the standard drive component can in addition receive switch-on and switch-off commands from the higher-ranking automation system and can return fault and diagnostic messages to the automation system. 
     A further modernization of the system, especially if the power element of the standard drive component is not suitable for the power or the technology of the drive motor, is possible by replacing in a subsequent step the power element of the drive motor by a further power element adapted to the power and the technology of the drive motor, with the further power element being adapted to the torque controller of the standard drive component and being controlled by this, and with the torque controller of the standard drive component receiving a nominal torque value from the speed controller of the standard drive component. The (old) torque controller and power element which previously existed are then no longer needed. 
     The subsequent step can In this case then be arranged to be especially cost effective if the further power element is adapted to the standard drive component and replaces the power element of the standard drive component in the standard drive component. 
     In accordance with an alternative embodiment of the invention there is provision in the subsequent step for the further power element to be part of a further standard drive component. It is also possible in this way to cost effectively replace the previous (old) power element by a modern new power element tailored to the power of the drive motor. 
     Major outlay for setting the parameters of the drive controller can be avoided in this case by the further standard drive component being adapted to the speed controller and the torque controller of the standard drive component, and the speed controller and the torque controller removed from the standard drive component and integrated into the further standard drive component. The speed controller or torque controller which are already present and for which the control parameters are set can thus continue to be used, and setting new parameters for controlling can very largely be avoided. The previously used (modern) power element and the remaining part of the standard drive component are no longer needed. 
     If the further standard drive component also features a speed controller and a torque controller, the effort of setting parameters can also be avoided if the parameter-setting software of the speed controller and torque controller of the standard drive component can be loaded into the corresponding components of the further standard drive component. 
     In accordance with a further, alternate embodiment of the invention there is provision in a subsequent step for the torque controller of the drive motor to be replaced by a further torque controller and for the power element to be replaced by a further power element, with the further torque controller obtaining a nominal torque value from the speed controller of the standard drive component. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention, as well as further advantageous embodiments of the invention in accordance with features of the subclaims, is explained below in a simplified and basic form in the drawings which refer to the exemplary embodiments. These show: 
         FIG. 1  a previous (old) drive element of a technical system, 
         FIG. 2  a standard drive component, 
         FIG. 3  a drive element with a standard drive component in accordance with  FIG. 2   
         FIG. 4  the drive element of  FIG. 3  with a feed to the drive motor from a further power element arranged in the standard drive component, 
         FIG. 5  the drive element of  FIG. 3  with a feed to the drive motor from a power element arranged in a further standard drive component, 
         FIG. 6  the drive element of  FIG. 3  with a feed to the drive motor from a further power element controlled by a further torque controller, and, 
         FIG. 7  a number of drive elements linked into an automation system of a technical system 
     
    
    
     DETAILED DESCRIPTION OF INVENTION 
       FIG. 1  shows a previous (old) drive element  1  of a technical system, e.g. of a production system for paper making. The drive element  1  features a drive motor  6 , a power element  5  feeding the motor  6  via a feed connection  5   a , a torque controller  4  controlling the power element  5  via a control connection  4   a  and a speed controller  3  which specifies to the torque controller  4  a nominal torque value M nom  with regard to the motor torque. An actual speed value n act  required for control is recorded by a speed encoder  7  on the motor  6  and made available to the speed controller  3  and to the power element  5 . The drive element  1  is subordinate to an (old) drive automation  2  which specifies a nominal speed value n nom  to the speed controller  3 . Both the drive element  1  and also the higher-ranking automation system  2  are essentially embodied in analog technology or in outdated digital technology and the drive motor  6  is also embodied in outdated direct current technology, so that the requirements as regards productivity, availability and manufacturing quality of the system are no longer fulfilled. 
       FIG. 2  shows a modern standard drive component  17  to be used within the framework of the invention for modernization, which features at least one speed controller  13 , a torque controller  14  and a power element  15 . Such standard drive components are available from the applicant in a wide diversity of power classes as regards the power element, under the product name SIMOVERT MASTERDRIVE for example. By using standardized components, especially also standardized speed controllers, torque controllers and power elements in these components, these can be manufactured and procured at low cost. The standard drive component is embodied in digital technology, advantageously in accordance with the latest prior art. 
     For modernizing the system, in accordance with  FIG. 3 , the specification of the nominal torque value M nom  for the torque controller  4  is deactivated by the speed controller  3  and a standard drive component  17  is provided in accordance with  FIG. 2 . The specification of the nominal torque value M nom  for the torque controller  4  of the drive motor  6  is then undertaken by the speed controller  13  of the standard drive component  17 . The drive element  1  thus features a drive motor  6  fed by the power element  5  and a torque controller  4  controlling the power element  5 , with an output of the speed controller  13  of the standard drive component  17  being coupled to an input of the torque controller  4  of the power element  5  of the drive motor  6  for supplying the nominal torque value M nom . The torque controller  14  and the power element  15  of the standard drive component  17  are not needed; The power element  15  can therefore be dimensioned very small as regards its output power. The standard drive component  17  is advantageously coupled to an automation system  12  for supplying at least one nominal torque value (M nom ) and is controlled and monitored by the latter. The units are advantageously connected by a field bus system, especially a Profibus system. 
     The speed controller  13  of the standard drive component  17  receives from the automation system  12  a nominal torque value and where necessary further switch-on and switch-off commands. In the reverse direction the standard drive component  17  notifies fault messages, diagnostic data, etc. back to the automation system  12  (not shown). The previously used (old) torque controller  4 , power element  5  and drive motor  6  will continue to be used. They can be modernized later relatively inexpensively. 
     If all drive elements of the system corresponding to drive element  1  in accordance with  FIG. 3  are modernized, the previous, old automation system can be completely replaced in the system by a new, modern automation system, where the connection of all drive elements to the new automation system is possible. Since the costly power elements and drive motors are not initially modernized, and not least because low-cost standard drive components are employed, a cost effective modernization of the system is possible. 
     In accordance with  FIG. 4 , in a next step for further modernization of the system, the power element  5  of the previous (old) drive motor  6  is replaced by a further power element  25 , with the further power element  25  being adapted to the torque controller  14  of the standard drive component  17  and being controlled by this via a control connection  14   a . The further power element  25  is in this case adapted to the standard drive component  17  and replaces the previous power element  15  of the standard drive component  17  in the standard drive component The power element  15  of the standard drive component  17  is dimensioned smaller, as regards its output power, than the further power element so that cost factors are not a particular factor in its replacement. The torque controller  14  in this case receives a nominal torque value M nom  from the speed controller  13  of the standard drive component  17 . This means that the previous (old) torque controller  4  and the previous (old) power element  5  are thus no longer needed. In addition the drive motor  6  can also be replaced by a modern drive motor  16 , e.g. a low-maintenance asynchronous motor, and can be supplied with power by the power element  25  via feed lines  25   a . Because of the close interrelationship between drive motor and power element it is best to modernize these two components at the same time. Power is then fed to the modernized drive motor  16  via power feed connection  25   b . The power element  25  is adapted both as regards its output power and also its technology to the relevant drive motor  6  or  16  to which power is to be supplied. 
     Alternatively, in accordance with  FIG. 5 , the further power element  25  can also be part of a further standard drive component  47 . The further standard drive component  47  is in this case adapted to the speed controller  13  and torque controller  14  of the standard drive component  17 . The speed controller  13  and torque controller  14  are removed from the standard drive component  17  and integrated into the further standard drive component  47 . The previous standard drive component  17  with the small-dimensioned power element  15  will then no longer be needed. Here too it is best to replace the drive motor  6  by a modern drive motor  16  at the same time. 
       FIG. 6  shows a further alternative for the modernization of the costly power element  5  and/or motor  6  of the drive element  1  undertaken in a subsequent step. In this case, in the subsequent step, there torque controller  4  of the drive motor  6  is replaced by a further modern torque controller  34  and the power element  5  of the drive motor is replaced by a further, modern power element. The further torque controller  34  in this case receives a nominal torque value M nom  from the speed controller  13  of the standard drive component  17  and controls the power element  35  via a control connection  34   a , said element in its turn feeding power via a feed connection  35   a  to the old drive motor  6  or via a feed connection  35   b  to the modern drive motor  16 . The old torque controller  4  and the old power element  5  of the drive element  1  are then no longer needed, the same applies to the torque controller  14  and the power element  15  of the standard drive component  17 . The power element  35  is adapted both as regards its output power and also its technology to the drive motor  6  or  16  to be supplied with power in each case. 
     Even if not explicitly shown and described, for all the drive elements described here, the power element feeding the drive motor and the speed controller specifying the required torque value M nom  receives an actual speed value n act  from one or more speed encoder arranged on the drive motor  6  or  16 . 
     The inclusion of a number of drive elements in accordance with  FIG. 3  into an automation system  70  or a plant  80  will now be illustrated with reference to  FIG. 7 . The plant  80  features a number of drive elements  1 , of which only one is shown in the diagram. The power element and torque controller of the drive element  1  embodied in old technology is accommodated in a drive module  51 . Upstream from the drive module  51  is a modern standard drive component  17 , with the associated speed controller, torque controller and power element not being shown here. Via a communication connection  49  the torque controller of the drive module  51  receives a nominal torque value from the speed controller of the standard drive component  17 . In addition the drive motor  51  receives further commands, e.g. switch-on and switch-off commands, from the automation system  70 . In the other direction the drive module  51  notifies the actual torque value as well as further fault data to the standard drive component  17 . Via the encoder  7  both the drive module  51  and also the standard drive component  17  receive an actual speed value n act  of the drive motor  6 . 
     Each of the standard drive components  17  is assigned at least one drive module  51  with one or more drive motors  6 . The standard drive components  17  are connected via a communication network, especially a Profibus, to a central automation control unit  53 . Via a further communication network  55  operator panels (HMI Interfaces)  54   a - c  communicate with the central automation control unit  53  and allow “local” operation and monitoring of the plant  80 . Furthermore a number of operator stations OS for remote control of the plant by an attendant as well as an engineering station ES for setting the parameters of the drives and of the HMI interfaces are provided, which are connected via communication connections  61 , especially industrial Ethernet connections, and communicate with each other and with the automation device  53  via switch modules  59 . Data from the processes currently executing is stored in the servers  60   a  and  60   b . For reasons of redundancy the data is stored both in the server  60   a  and also in the server  60   b.