Abstract:
Disclosed herein is an apparatus for relaying data transmission in a SCADA server. The apparatus includes: a communications unit configured to receive a data transmission request from the host server and transmit a target data request by the host server to the host server; a update unit configured to update event data corresponding to the target data among event data in the SCADA server and transmit the target data requested by the host server to the communications unit; and a synchronization management unit configured to synchronize the event data updated by the update unit with a backup SCADA server. Data transmission to a host server and control instruction reception from the host server in a SCADA system can be processed quickly and accurately.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of Korean Patent Application No. 10-2016-0044841, filed on Apr. 12, 2016, entitled “APPARATUS FOR RELAYING DATA TRANSMISSION IN SCADA SYSTEM”, which is hereby incorporated by reference in its entirety into this application. 
       BACKGROUND 
     1. Technical Field 
       [0002]    The present disclosure relates to an apparatus for relaying data transmission in a SCADA server. 
       2. Description of the Related Art 
       [0003]    A supervisory control and data acquisition (SCADA) system is a large-scale system that processes and monitors a large volume of data and provides a variety of functions associated therewith. A SCADA server monitors and processes a number of data items including data transmitted from remote terminals such as RTUs and a PLC, state data of the devices, and state data of the system. In order to appropriate operate a number of data items in the environment where the SCADA server is installed, it is necessary to optimize the system by engineering. However, a variety of errors may occur during the process of optimizing depending on the system environment and a user&#39;s capability. Accordingly, when an error occurs, it is necessary to easily determine the cause of the error and cope with it.  FIG. 1  is a block diagram of an existing SCADA system. 
         [0004]    Referring to  FIG. 1 , a SCADA system  10  includes a host server  102 , a SCADA server  104 , a front end processor (FEP)  106 , remote terminal units (RTUs)  108 , and remote installation devices  110 . 
         [0005]    The SCADA server  104  sends a request to connect to the FEP  106  by using network configuration information for conducting communications with the FEP  106 . If the FEP  106  accepts the request, the connection between SCADA server  104  and the FEP  106  is established. 
         [0006]    Once the connection is established, the SCADA server  104  sends a control instruction to the FEP  106 . The FEP  106  delivers the control instruction to the RTUs  108 . 
         [0007]    The RTUs  108  may control their respective remote installation devices  110  pursuant to the received control instruction. 
         [0008]    The FEP  106  may receive data generated by the remote installation devices  110  from the RTUs  108  to deliver it to the SCADA server  104 . The communications between the FEP  106  and the RTUs  108  may be carried out by using transmission control protocol (TCP) based on serial communications or Ethernet communications. 
         [0009]    The SCADA server  104  may manage and control the RTUs  108  based on the data generated by the remote installation devices  110 . In addition, the SCADA server  104  may receive a control instruction from the host server  102  at a higher level or may transmit data requested by the host server  102 . 
         [0010]    In the related art, however, to transmit data from the SCADA server  104  to the host server  102  or to transmit a control instruction from the host server  102  to the SCADA server  104 , an additional relay is required, such as a gateway. Due to such additional relay, there is a problem in that data reception by the host  102  or the control instruction reception by the SCADA server  104  may be delayed. In addition, due to such additional relay, there is another problem in that it is not flexible to build a database and process data. 
       SUMMARY 
       [0011]    It is an object of the present disclosure to provide an apparatus for relaying data transmission that is capable of quickly and accurately process data transmission to a host server and control instruction reception from the host server in a SCADA system. 
         [0012]    It is another object of the present disclosure to provide an apparatus for relaying data transmission that is capable of improving data transmission and processing speed of a SCADA system and building a flexible database. 
         [0013]    Objects of the present disclosure are not limited to the above-described objects and other objects and advantages can be appreciated by those skilled in the art from the following descriptions. Further, it will be easily appreciated that the objects and advantages of the present disclosure can be practiced by means recited in the appended claims and a combination thereof. 
         [0014]    In accordance with one aspect of the present disclosure, an apparatus for relaying data transmission between a SCADA server and a host server includes: a communications unit configured to receive a data transmission request from the host server and transmit a target data request by the host server to the host server; a update unit configured to update event data corresponding to the target data among event data in the SCADA server and transmit the target data requested by the host server to the communications unit; and a synchronization management unit configured to synchronize the event data updated by the update unit with a backup SCADA server. 
         [0015]    According to an exemplary embodiment of the present disclosure, data transmission to a host server and control instruction reception from the host server in a SCADA system can be processed quickly and accurately. 
         [0016]    According to another exemplary embodiment of the present disclosure, data transmission and processing speed of a SCADA system can be improved and a flexible database can be built. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0017]      FIG. 1  is a block diagram of an existing SCADA system; 
           [0018]      FIG. 2  is a block diagram of a SCADA system and an apparatus for relaying data transmission according to an exemplary embodiment of the present disclosure; and 
           [0019]      FIG. 3  is a diagram illustrating duplicated operation process of the SCADA system according to an exemplary embodiment of the present disclosure. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    The above objects, features and advantages will become apparent from the detailed description with reference to the accompanying drawings. Embodiments are described in sufficient detail to enable those skilled in the art in the art to easily practice the technical idea of the present disclosure. Detailed descriptions of well known functions or configurations may be omitted in order not to unnecessarily obscure the gist of the present disclosure. Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Throughout the drawings, like reference numerals refer to like elements. 
         [0021]      FIG. 2  is a block diagram of a SCADA system and an apparatus for relaying data transmission according to an exemplary embodiment of the present disclosure. 
         [0022]    Referring to  FIG. 2 , the SCADA system according to the exemplary embodiment of the present disclosure includes a main SCADA server  22  and a backup SCADA server  24 . The main SCADA server  22  acquires data from remote installation devices (not shown) and issues a control instruction to the remote installation devices. The backup SCADA server  24  has the same functionality as the main SCADA server  22 , and backs up in real-time or periodically the data from the remote installation devices acquired by the main SCADA server  22  and other data generated by the main SCADA server  22 . Accordingly, if there is a fault in the main SCADA server  22 , the backup SCADA server  24  may perform the same functionality as the backup SCADA server  24 . In this manner, according to the exemplary embodiment of the present disclosure, duplicated system is implemented for improving stability of the SCADA system. Further, in order to further enhance the stability, dual physical lines may be implemented between the main SCADA server  22  and the backup SCADA server  24 . 
         [0023]    Referring to  FIG. 2 , the main SCADA server  22  includes an apparatus  26  for relaying data transmission according to the exemplary embodiment of the present disclosure. Likewise, the backup SCADA server  24  may also include an apparatus for relaying data transmission  29  according to the exemplary embodiment of the present disclosure. Hereinafter, the exemplary embodiment of the present disclosure will be described with respect to the apparatus  26  included in the main SCADA server  22 . 
         [0024]    As used herein, event data may refer to data received by the main SCADA server  22  from the remote installation devices via the RTUs  28 . As used herein, event data may also refer to data that is received via a FEP  221  and processed by the data processor  224 . Such event data is stored in a SCADA real-time database  225  in real-time. 
         [0025]    As used herein, target data refers to particular event data selected from among the event data acquired or generated by the main SCADA server  22 . According to an exemplary embodiment of the present disclosure, a user may set as target data particular event data from among the event data acquired or generated by the main SCADA server  22  via an application provided from the main SCADA server  22  or an external terminal. In addition, according to an exemplary embodiment of the present disclosure, the host server  20  may set as target data particular event data selected from among the event data acquired or generated by the main SCADA server  22 . 
         [0026]    According to the exemplary embodiment of the present disclosure, the apparatus for relaying data transmission  26  receives a data transmission request from the host server  20  and acquires target data requested by the host server  20  from the main SCADA server  22  to transmit it to the host server  20 . In addition, the apparatus for relaying data transmission  26  may receive a control instruction from the host server  20  and may transmit the received control instruction to the main SCADA server  22 . 
         [0027]    Referring to  FIG. 2 , the apparatus for relaying data transmission  26  may include an update unit  261 , a communications unit  262  and a synchronization management unit  263 . 
         [0028]    The update unit  261  updates event data corresponding to target data among the event data of the main SCADA server  22 . According to an exemplary embodiment of the present disclosure, the RTUs  28  deliver event data received from the respective remote installation devices to the FEP  221 . The FEP  221  delivers the received event data to the data processor  224 . The event data processed by the data processor  224  is stored in the SCADA real-time database  225 . The update unit  261  loads event data corresponding to target data requested by the host server  20  from among the event data stored in the SCADA real-time database  225  and stores it in a local database  264  periodically. 
         [0029]    According to an exemplary embodiment of the present disclosure, the update unit  261  may scan the SCADA real-time database  225  at predetermined intervals to acquire the event data corresponding to the target data requested by the host server  20 . The intervals at which the update unit  216  scans may be predetermined by the user. The update unit  216  stores the periodically acquired event data in the local database  264 . Accordingly, the local database  264  can be synchronized with the SCADA real-time database  225 . 
         [0030]    In addition, according to an exemplary embodiment of the present disclosure, the update unit  261  may receive the event data corresponding to the target data directly from the FEP  221 . Further, according to another exemplary embodiment of the present disclosure, the event data received by the FEP  221  may be processed by the data processor  224  to then be stored in an event queue  223 . The update unit  216  may store the event data stored in the event queue  223  in the local database  264  or may transmit it to the host server  20 . 
         [0031]    The communication unit  262  receives a data transmission request from the host server  20 . In addition, the communications unit  262  transmits the target data requested by the host server  20  to the host server  20  in response to the request. Upon receiving the data transmission request from the host server  20 , the communications unit  262  searches for the local database  264  to acquire the target data requested by the host server  20 . In addition, the communications unit  262  may also acquire the target data requested by the host server  20  from the event queue  223 . 
         [0032]    In addition, the communications unit  262  may receive a control instruction transmitted from the host server  20  and may transmit the received control instruction to the main SCADA server  22 . In addition, the communications unit  262  may receive a state check request from the host server  20  and may transmit the received request to the main SCADA server  22 . The control instruction or the state check request received by the communications unit  262  may be transmitted to the FEP  221  via a user instruction queue  222 . 
         [0033]    Upon receiving the state check request from the host server  20 , the main SCADA server  22  interrupts the transmission of the target data to the host server  20  and transmits the information on the operating state of the main SCADA server  22  to the host server  20 . Then, the main SCADA server  22  is switched to a standby mode and remains in the mode until a data transmission request is transmitted from the host server  20 . 
         [0034]    The synchronization management unit  263  synchronizes the event data updated by the update unit  261  with the backup SCADA server  24 . Specifically, the synchronization management unit  263  conducts the synchronization by transmitting the event data stored in the local database  264  to the apparatus for relaying data transmission  29  of the backup SCADA server  24  at predetermined intervals. The intervals at which the synchronization management unit  263  transmits the event data to the apparatus for relaying data transmission  29  of the backup SCADA server  24  may be set by the user. The apparatus for relaying data transmission  29  of the backup SCADA server  24  stores the event data transmitted by the synchronization management unit  263  in a local database  294 . 
         [0035]    According to an exemplary embodiment of the present disclosure, the target data transmitted to the host server  20  by the apparatus for relaying data transmission  26  may include acquisition time information indicative of the time when the target data is acquired by the main SCADA server  22 . Such target data is referred to as sequence of event (SOE). If the target data includes the acquisition time information, the apparatus for relaying data transmission  26  may transmit the target data to the host server  20  at predetermined intervals even when there is no request from the host server  20 . 
         [0036]    As described above, the host server  20  may transmit the data transmission request or the state check request to the apparatus for relaying data transmission  26  of the main SCADA server  22  or the apparatus for relaying data transmission  29  of the backup SCADA server  24 . 
         [0037]    According to an exemplary embodiment of the present disclosure, when the communications unit  262  of the apparatus for relaying data transmission  26  receives the data transmission request, the main SCADA server  22  operates in an active mode. In addition, when the communications unit  262  of the apparatus for relaying data transmission  26  receives the state check request, the main SCADA server  22  operates in the standby mode. The target data is transmitted only when the main SCADA server  22  is in the active mode, not in the standby mode. 
         [0038]    Accordingly, one of the main SCADA server  22  and the backup SCADA server  24  that receives the data transmission request from the host server  20  becomes an active mode server while the other that receives the state check request becomes a standby mode server. The host server  20  sets one of the two servers as the active mode server and the other as the standby mode server by transmitting the data transmission request and the state check request. 
         [0039]      FIG. 3  is a diagram illustrating duplicated operation process of the SCADA system according to an exemplary embodiment of the present disclosure. 
         [0040]    According to the exemplary embodiment shown in  FIG. 3 , the main SCADA server  22  first receives a data transmission request from the host server  20  to enter the active mode, and the backup SCADA server  24  receives a state check request from the host server  20  to enter the standby mode. The main SCADA server  22  transmits the target data requested by the host server  20  to the host server  20  in response to the request from the host server  20 . 
         [0041]    While receiving the target data from the active mode server, i.e., the main SCADA server  22 , the host server  20  may transmit the data transmission request to the backup SCADA server  24  and transmit the state check request to the main SCADA server  22 . 
         [0042]    Accordingly, the main SCADA server  22  may be switched over to the standby mode while the backup SCADA server  24  is switched over to the active mode. 
         [0043]    However, if the main SCADA server  22  did not complete the transmission of the target data requested by the host server  20  yet, the communications unit  262  of the main SCADA server interrupts the transmission of the target data and transmits an unsolicited message to the host server  20 , which notifies that the transmission of the data is not completed. The rest of the target data that is not transmitted yet is stored in the event queue at the time of transmitting the unsolicited message. According to another exemplary embodiment of the present disclosure, the rest of the target data may be stored in another storage, e.g., the local database. 
         [0044]    Upon receiving the unsolicited message, the host server  20  may check the existence and the list of the rest of the target data that is not transmitted from the main SCADA server  22  yet. Accordingly, the host server  20  requests the transmission of the rest of the target data to the backup SCADA server  24 . 
         [0045]    As described above, the data in the main SCADA server  22  is synchronized with the data in the backup SCADA server  24  by the synchronization management unit  263 , and thus the backup SCADA server  24  may check the list of the rest of the target data to transmit it to the host server  20 . According to another exemplary embodiment of the present disclosure, the host server  20  may request the transmission of the rest of the target data to the main SCADA server  22 . 
         [0046]    When the rest of the target data has been received in this manner, the host server  20  transmits a confirm message to the main SCADA server  22 . After the main SCADA server  22  has received the confirm message, the main SCADA server  22  checks if the host server  20  receives the rest of the target data, and deletes the rest of the target data stored in the event queue  223  or other storage. 
         [0047]    Through the above-described processes, the host server  20  can receive the requested target data completely even if a mode switching between the active mode and the standby mode takes place during the process of transmitting the target data. 
         [0048]    The present disclosure described above may be variously substituted, altered, and modified by those skilled in the art to which the present invention pertains without departing from the scope and sprit of the present disclosure. Therefore, the present disclosure is not limited to the above-mentioned exemplary embodiments and the accompanying drawings.