Abstract:
A programmable logic controller (PLC) system is provided. The programmable logic controller (PLC) system divides a memory region into a plurality of regions according to a function, and reads or transmits data from or to the divided regions according to an operation mode to be performed, wherein the plurality of regions obtained through division includes: a first storage region storing log data on the PLC system; and a second storage region storing a hyper text markup language (HTML) file.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    Pursuant to 35 U.S.C. §119(a), this application claims the benefit of earlier filing date and right of priority to Korean Patent Application No. 10-2014-0148902, filed on Oct. 30, 2014, the contents of which are hereby incorporated by reference herein in its entirety. 
       BACKGROUND 
       [0002]    The present disclosure relates to a programmable logic controller (PLC) system, and more particularly, to a PLC system that may divide memory cards in the PLC system according to a function to minimize a time taken to search the memory card. 
         [0003]    An automation facility at the industrial site is configured by mechanical equipment including a relay, etc. In order to change the automation facility including the mechanical equipment, there is a difficulty of changing the wiring of the internal circuit of the facility. In order to overcome such a difficulty, a PLC is used. 
         [0004]    The PLC generally performs a function similar to a computer. That is, the PLC receives a signal coming from the facility, processes the signal according to programming in the PLC and then outputs the processed signal to the facility. That is, the smoothness of the operation of the PLC means that automation facilities in the factory are efficiently operating. 
         [0005]      FIG. 1  is a block diagram for explaining the operation of a typical PLC system. 
         [0006]    Typically, a memory card  20  is installed in the PLC system  10  in order to be capable of mutually transmit and receive data. 
         [0007]    A micro processing unit (MPU)  11  operates according to a set program to control the entire PLC system  10  and enables, especially, a data log module  12  and a web server module  13  to operate. 
         [0008]    The data log module  12  performs a data log function according to the control of the MPU  11 . That is, it collects a device value set in a programmable and debugging tool (PADT) and transmits the collected value to the memory card  20 . 
         [0009]    The web server module  13  performs a web server function according to the control of the MPU  11 . That is, it transmits a hyper text markup language (HTML) file stored in the memory card  20  to a web browser. 
         [0010]    A file system  14  is structured so that a search for and access to files or data in the memory card  20 , data output from the data log module  12  is transmitted to the memory card  20  through the file system  14 , and data transmitted from the memory card  20  is delivered to the web server module  13  through the file system  14 . 
         [0011]    The memory card  20  stores data transmitted from the PLC system  10  in a comma separated value (CSV) file and previously stores an HTML file in order to transmit a web page. 
         [0012]    As such, the data log and the web server are functions that use the memory card, and the data log module  12  and the web server module  13  alternately accesses the memory card  20  to read data from the memory card or write data to the memory card. 
         [0013]    In this example, when many modules access the memory card  20  to read data from the memory card or write data to the memory card, there is a limitation in that it takes a long time to search for a sector in the memory card  20 . 
       SUMMARY 
       [0014]    Embodiments provide a PLC system that divides a memory card in the PLC system according to a function to be capable of reducing a time taken to search the memory card. 
         [0015]    According to an embodiment, the PLC system divides the memory card into a CSV file storage region and an HTML file storage region, stores log data in the CSV file storage region, and reads the HTML file from the HTML file storage region. 
         [0016]    Thus, since the region of the memory card which the PLC system accesses varies according to the function to be performed, it is possible to reduce a time taken to search the memory card in order to allow the PLC system to read or write data. 
         [0017]    In one embodiment, a programmable logic controller (PLC) system divides a memory region into a plurality of regions according to a function, and reads or transmits data from or to the divided regions according to an operation mode to be performed, wherein the plurality of regions obtained through division includes: a first storage region storing log data on the PLC system; and a second storage region storing a hyper text markup language (HTML) file. 
         [0018]    In another embodiment, an operating method of a PLC system includes dividing a memory according to a function in initialization operation when a driving request is sensed; sensing an operation mode according to the driving request; and reading or writing data from or to the divided memory according to the sensed operation mode, wherein the plurality of regions obtained through division includes: a first storage region storing log data on the PLC system; and a second storage file storing an HTML file. 
         [0019]    The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  is a block diagram for explaining the operation of a typical PLC system. 
           [0021]      FIG. 2  is a block diagram of a PLC system according to an embodiment. 
           [0022]      FIG. 3  is a flowchart for explaining the sequence of operation of the PLC system according to an embodiment. 
           [0023]      FIG. 4  is an example of a code used when the PLC system according to an embodiment divides a memory card. 
       
    
    
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0024]    The terms or words used in the detailed description and claims should not be imitatively construed as typical meanings or meanings indicated in dictionaries but should be construed as meanings and concepts matching the technical spirit of the inventive concept based on the principle that the inventor may properly define the concepts of terms in order to describe his or her invention in the best mode. 
         [0025]    Thus, since embodiments described in the detailed description and configurations shown in the drawings are only examples and do not cover all the technical spirits of an embodiment, it should be understood that there may be various equivalents and variations that may replace them upon filing the present application. 
         [0026]      FIG. 2  is a block diagram of a PLC system according to an embodiment. 
         [0027]    Referring to  FIG. 2 , a PLC system  100  according to an embodiment may be connected to a memory card  200  to transmit collected log data to the memory card  200  or read an HTML file from the memory card  200  to transmit the read file to a web browser. 
         [0028]    In this case, data transmission between the PLC system  100  and the memory card  200  may be performed by serial peripheral interface (SPI) communication. In addition to the above communication method, the data transmission between the PLC system  100  and the memory card  200  may be implemented by various communication methods. 
         [0029]    The PLC system  100  may include a micro processing unit (MPU)  110 , a data log module  120 , a web server  130 , and a file system  140 . 
         [0030]    The MPU  110  may operate according to a set program to control the entire PLC system  100 . In particular, it is possible to control the data log module  120  and the web server module  130 . 
         [0031]    The data log module  120  may perform a data log function according to the control of the MPU  110 . The data log module  120  may collect a device value (‘log data’) set in a programmable and debugging tool (PADT). 
         [0032]    Log data collected by the data log module  120  may be stored in the memory card  200  via the file system  140 . 
         [0033]    The web server module  130  performs a web server function according to the control of the MPU  110 . That is, it may transmit an HTML file stored in the memory card  200  to a web browser. 
         [0034]    The file system  140  may perform data transmission between the data log module  120  and the memory card  200  and data transmission between the web server module  130  and the memory card  200 . 
         [0035]    That is, the file system  140  may receive log data from the data log module  120  to transmit the received data to the memory card  200 , and receive an HTML file from the memory card  200  to transmit the received file to the web server module  130 . 
         [0036]    In this case, when the file system  140  is initialized after the execution of the PLC system  100 , the file system  140  may divide the memory card  200  according to a function. That is, the file system  140  may divide the memory card  200  into a comma separated values (CSV) file storage region  210  for storing log data and an HTML file storage region  220  for storing an HTML file. In addition, the file system  140  may divide the memory card  200  into more storage regions according to a function. 
         [0037]    In the case of performing log data transmission, the file system  140  may transmit log data to the CSV file storage region  210  of the memory card  200 , and in the case of performing the operation of reading the HTLM file, the file system may access the HTML file storage region  220  of the memory card  200  to read the HTML file. 
         [0038]    The memory card  200  that is connected to the PLC system  100  according to an embodiment to transmit and receive data stores data received from the PLC system  100  in a CSV file and previously stores an HTML file for transmitting a web page. 
         [0039]    In this case, the memory card  200  may be divided into the CSV file storage region  210  and the HTML file storage region  220  by the PLC system  100  according to an embodiment. 
         [0040]    Thus, the memory card  200  may receive log data from the PLC system  100  and stores the received data in the CSV file storage region  210 , and when there is a request from the PLC system  100 , the memory card may transmit the HTML file stored in the HTML file storage region  220  to the PLC system  100 . 
         [0041]    The configuration and function of the PLC system according to an embodiment has been described above. In the following, the particular operation of the PLC system that has the configuration as shown in  FIG. 2  is described in detail with reference to the accompanying drawings. 
         [0042]      FIG. 3  is a flowchart for explaining the operation of a PLC system according to an embodiment. 
         [0043]    Referring to  FIG. 3 , when a request for a driving mode for a PLC system  100  is sensed in step S 310 , the PLC system  100  may be initialized and it is possible to divide a memory card  200  according to a function in step S 320 . Such a division of the memory card  200  may be performed by a file system  140  of the PLC system  100 . 
         [0044]    That is, the file system  100  divides the memory card  200  into a CSV file storage region  210  for storing log data and an HTML file storage region  220  for storing an HTML file. 
         [0045]    When the PLC system  100  divides the memory card  200 , the PLC system  100  may divide the memory card  200  by using the function sfs_devreg( ) as shown in  FIG. 4 . 
         [0046]    As such, the PLC system  100  divides the memory card  200  in the initialization process in step S 320 , and then the PLC system  100  may determine the current operation mode in step S 330 . Specifically, the PLC system  100  may determine whether the current state is a data log function execution mode or a web server function execution mode in step S 330 . 
         [0047]    When it is determined that the current operation mode is the data log function execution mode, the PLC system  100  may transmit collected log data to the memory card in step S 340 . In this case, the PLC system  100  may transmit log data to the CSV file storage region  210  of the memory card  200 . 
         [0048]    On the contrary, when it is determined that the current operation mode is the web server function execution mode, the PLC system  100  may read an HTML file from the memory card  200  in step S 350 . In this case, the HTML file may be read from the HTML file storage region  220  of the memory card  200 . 
         [0049]    As described above, the PLC system according to an embodiment may divide the memory card into the CSV file storage region and the HTML file storage region, store the log data in the CSV file storage region, and read the HTML file from the HTML file storage region. 
         [0050]    Thus, since the region of the memory card which the PLC system accesses varies according to the function to be performed, it is possible to minimize a time taken to search the memory card in order to allow the PLC system to read or write data. 
         [0051]    Exemplary embodiments are mainly described above. However, they are only examples and do not limit the inventive concept. A person skilled in the art may appreciate that many variations and applications not presented above may be implemented without departing from the essential characteristic of embodiments. For example, each component specifically represented in embodiments may vary. In addition, it should be construed that differences related to such a variation and such an application are included in the scope of the inventive concept defined in the following claims.