Abstract:
A method of controlling an industrial process by a programmable process control has the steps of taking data in form of resulting values which are decisive for the process, storing the data in a storage of a programmable process control, during starting a control program reading pre-defined configuration data which are stored in a storage in the control and connected with a control program, based on the configuration data selecting a subset of the resulting values adapted to a resulting value storage available in the control, and subsequently storing it in this storage.

Description:
BACKGROUND OF THE INVENTION 
     The present invention relates to a method of and an apparatus for controlling and/or regulating of an industrial process by means a programmable process control. 
     Industrial controls operate with shorter cycle times, and the data quantities which must be managed increase correspondingly. For testing the quality of a process the data are taken online in real time, stored in fast storage, and subsequently evaluated. When the process is repeated in fast cycle, it always happens that the fast data storage (RAM) of the control is not sufficient to protect all resulting values of the process. In this case data are lost unintentionally. The quality of statistic evaluation of the data therefore suffer and subsequently also the quality of the process. 
     SUMMARY OF THE INVENTION 
     Accordingly, it is an object of the present invention to provide a method of and apparatus for controlling and/or regulating an industrial process, which provides a better capacity use and in particular a better efficiency of the corresponding control and/or regulation systems. 
     In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in a method of controlling an industrial process, in which during starting a control program, predefined configuration data stored in a storage of the control and connected with the control program are read, and based on these configuration data a subset of resulting values adapted to resulting value, storage available in the control, is selected and subsequently stored in this storage. 
     In accordance with another feature of the present invention an apparatus is proposed with a process control which is connected with at least one operating device through a communication interface or a bus system, wherein the configuration data contained in the storage of the process control can be changed via the operating device by an operating program provided for this purpose. 
     When the method for controlling and/or regulating an industrial process with a programmable process control is performed in accordance with the present invention, the data in the form of resulting values which are decisive for the process are taken and stored in the storage of a programmable process control provided for this purpose. During starting a program, the predefined configuration data which are connected with the program are read from a data table stored in the storage of the control, and based on these configuration data a subset of the resulting values, adapted to the resulting value storage available in the control, is selected and subsequently stored in this storage. The method makes possible the optimized use of the available data storage of the control and prevents that the data are unintentionally lost, so as to increase the efficiency of the prescription process. 
     Preferably, the configuration data are stored in a flash storage which is slower but for this purpose cheaper and before the beginning of the process are read “offline”, and the system is adjusted correspondingly. The configuration data are subjected preferably to a CRC testing to avoid errors in the configuration phase and to store the received resulting values in SRAM. Preferably the SRAM-battery is buffered, for avoiding data losses, for example because of power failure. The device can be drawn from the network over longer time without losing the data of the last course. 
     For adapting the available storage to the process, it is proposed to define the storage as a ring storage or stack. The advantage is that the storage can be configured in accordance with the cycle time and repetition rate, that the desired process data are automatically canvassed. 
     Preferably, it is also provided that the program-specific data can be stored in form of text strings, or in other words in the configuration data both numerical elements and also text elements can be predefined. 
     For adapting the control to the requirements of all system users it is proposed that the user or users can adapt the configuration data by software application provided for this purpose, to their requirements. This functionality increases the flexibility of the system and minimizes the demand for expensive, battery-buffered data storage. 
     Preferably, in accordance with the present invention a control, for example a screwing control, is provided with a communication bus system and an HMI (human machine interface) connected with the bus system. The configuration data and the control can be adapted themselves by the HMI to the requirements of the user and to the process. Thereby it is also provided that the company merchandise updates can be transmitted by the HMI to the control. 
     The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a view schematically showing a storage of a control in accordance with the present invention; 
         FIG. 2  is a view showing a software flow chart of one implementation of the present invention; 
         FIG. 3  is a view showing a process control in accordance with the present invention; and 
         FIG. 4  is a view schematically showing a flash for storage of the control in accordance with the present invention. 
     
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     For understanding of the invention, substantial elements and components are represented in the drawings schematically. Same or identically operating components are identified with the same reference numerals. 
       FIG. 1  schematically shows regions  101 ,  102 ,  103  of a SRAM storage of a screwing control. The storage block as a whole is of a size 125 KB and the region  101  providing the resulting values is of a size 100836 bytes. The size of the regions can be adjusted by software service tools “offline”, wherein an “online” adjustment is also possible in principle. The regions  103  below and  102  above the result storage region  101  are reserved for other system functions. 
     The region  101  can be configured as a stack or a ring storage. In other words the storage  101  can be written either with resulting values until the region  101  is full and then all further resulting values are not stored, or all data can be progressively overwritten. The adjustment, whether of a ring or a stack, depends on the process. 
       FIG. 4  provides a schematic showing of the regions  401 ,  402 ,  403  of a FLASH storage of a screwing control. The storage block as a whole is of a size 1 MB and the region  401  provided for the configuration data has a size of 746 bytes. 
     The content of the region  401  can be changed “offline” by software service tools, wherein an “online” adjustment is also possible in principle. The region  403  below and the region  402  above the result storage region  401  are reserved for other system functions. 
       FIG. 3  schematically shows a screwing process, including the process control  301 , HMI  303 , screwing device  302  and workpiece  307 . The screwing device is connected to the process control through a communication interface  306  and a power connection  305 . The power connection  305  can be electrical or pneumatic, depending on the type of the screwing device  302 . The communication interface  306  is formed preferably bi-directional. The screwing device  302  is provided with several sensors, for example torque sensors, encoders, rotary transmitters and/or pressure sensors, which during the screwing process receive data and transmit the data to the control  301 . 
     The data, based on the configuration available in the configuration storage  401 , are filtered, and the desired variables are stored in the SRAM  101 . The stored data can be evaluated by the screwing control  301 , or can be transmitted to a further control. The further control can be connected either to the data bus  304  or to a further data busus or to a further network such as a Ethernet LAN. 
     The screwing control  301  is connected with an HMI  303  through the data bus  304 . The HMI can be a simple device or a very powerful PC based device. The HMI  303  is mainly used, depending on the computer power and storage capacity, for taking the process control  301  into operation, and for analyzing, adjusting and/or optimizing process parameters. A service software tool is installed on the HMI  303 , that allows the system user to adapt the configuration data to the requirements of the process. When the HMI  303  is a PC based device, the software tool has a graphic surface which allows the user to obtain a simple grasp of the process data. By means of several GUI&#39;s, the desired storage configuration can be graphically adjusted. The nature of the adjustment subsequently can be interpreted by the software tool, and the relevant commands can be transmitted to the control  301 . 
       FIG. 2  shows a flow chart of the resulting data-storage process, wherein first the configuration data are examined in the flash via CRC sum for integrity in the storage. The configuration data contain informations, during starting which programs store which result values in the SRAM  100  of which type. 
     During starting, 48 programs are available for selection (0–47) one program for releasing the screwing. Each bit is provided for a selected program, Bit  0 /Prg 0 , Bit 1 /Prg 1 , etc, special case Bit  63 /Prg 99  (releasing). 
     The user, from all available resulting values can select the different documentation stages and result stages, which resulting values he can store in the SRAM  100 . It can store maximum 20 general informations. These are data which are program-specific, such as for example ID code, program number and etc. For each information there is a definite resource ID. When it is available in the configuration, the corresponding variable is stored in the result storage  101 . With sign chains, such as for example the program names, the user based on the start and stop values can also store only a part of the sign change. Moreover, the required place for the resource ID is provided. For screwing data, such as for example moment, angle and gradient, for each stage a place is available for maximum 80 different resources-ID&#39;s. The stages number is limited to 4. This corresponds to the result stage and up to three documentation stages, which the user can freely select in the screwing program. The “value” corresponds to the storage demand in bytes for the selected resource ID. 
     The storage  101  can be used as a stack, in which always the data are stored. When the SRAM  101  is used, no further screwing data are secured. 
     The second type is to use the storage  101  as a ring storage. Here the data are written always in the SRAM  101 . If this is desired, the oldest data in the SRAM  101  can be overwritten. 
     The resulting data are stored in dependence on the configuration data in the SRAM  101 . This has the advantage that only the data in the SRAM  101  are stored, which are of interest for the user. 
     The process during a screwing is as follows:
         Starting a screwing;   After the evaluation of the screwing by the hardware (signals of the operational means control, such as for example OK, NOK, angle too high, . . . ), the result data are transmitted into the SRAM  101 . The volume of the data written in the SRAM  101  depends on the configuration data, which are stored in the flash  401 .       

     It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of methods and constructions differing from the types described above. 
     While the invention has been illustrated and described as embodied in method of and apparatus for controlling or regulating industrial processes, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention. 
     Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention.