Monitoring control system and control device

FIELD

0001The present invention relates to a control device that performs a device control process, and to a monitoring control system that monitors a device control process.

BACKGROUND

0002A PLC (Programmable Logic Controller) is a control device that is used to control an automated machine in a factory or the like. Such a control device is connected to various devices (apparatuses) such as a sensor and an actuator, so as to control operations of these devices by executing a control program. The process of controlling operations of these devices is hereinafter referred to as “device control process”.

0003In recent years, a technique of performing integrated information management in cooperation with control devices such as the PLC and an external information system has been put to practical use. As this kind of technique, MES (Manufacturing Execution System) and ERP (Enterprise Resource Planning) can be mentioned.

0004In a large scale plant such as a water treatment plant or a chemical plant, high-speed and large-capacity data is handled. In such a large scale plant, a monitoring control system referred to as “SCADA (Supervisory Control And Data Acquisition)” is generally used. As functions of the SCADA, a data collection function and a user interface function can be mentioned. The data collection function is a function of collecting device data from devices such as a sensor in a plant and storing the collected device data in a database. The user interface function is a function of displaying device data on a display screen of a monitoring terminal and receiving data manipulation from the user. The user can monitor the device control device in the plant and perform required data manipulation, based on the data displayed on the display screen of the monitoring terminal.

0005As a control device that transfers data between an external information system and the device itself, the following devices have been known.

0006Patent Literature 1 discloses a distributed control device. This distributed control device includes a main processor for device control and a communication processor for data communication. Owing to this configuration, even if the distributed control device receives large-amount data acquisition requests from a high-order system, influences thereby on the device control process can be reduced.

0007Patent Literature 2 discloses a technique for remotely controlling a PLC through the Internet. The PLC receives a data transmission request related to a user program from a remote control computer. In response to the transmission request, the PLC transmits the user program and control information in a database to the remote control computer.

CITATION LIST

Patent Literatures

0008Patent Literature 1: Japanese Patent Application Laid-open No. 2008-282323

0009Patent Literature 2: Japanese Patent Application Laid-open No. 2009-86863

SUMMARY

Technical Problem

0010In the case of conventional SCADAs, a monitoring terminal executes SCADA software. In this case, high reliability and high quality in software execution are required in a plant, and therefore, an expensive dedicated PC such as an industrial PC (an FA personal computer) is required as the monitoring terminal that executes the SCADA software. This leads to a cost increase.

0011An object of the present invention is to provide a technique that can realize a monitoring control system that monitors a device control process at a low cost.

Solution to Problem

0012According to an aspect of the present invention, there is provided a monitoring control system. The monitoring control system includes: a control device that performs a device control process of controlling an operation of a device; and a high-order system that is connected to the control device and monitors the device control process. The control device includes a control CPU that performs the device control process, and an information CPU that is connected to the control CPU via an internal bus. The control CPU includes a device memory that stores therein device data to be used for the device control process, the device data being related to the device. The information CPU includes a built-in database, and a data collection unit. The data collection unit performs a data collection process of reading the device data from the device memory via the internal bus, and storing the read device data in the built-in database.

0013According to another aspect of the present invention, there is provided a control device. The control device performs a device control process of controlling an operation of a device, and is connected to a high-order system that monitors the device control process. The control device includes a control CPU that performs the device control process, and an information CPU that is connected to the control CPU via an internal bus. The control CPU includes a device memory that stores therein device data to be used for the device control process, where the device data is related to the device. The information CPU includes a built-in database and a data collection unit. The data collection unit that performs a data collection process of reading the device data from the device memory via the internal bus, and storing the read device data in the built-in database.

Advantageous Effects of Invention

0014According to the present invention, it is possible to realize a monitoring control system that monitors a device control process at a low cost.

BRIEF DESCRIPTION OF DRAWINGS

0015<figref idref="DRAWINGS">FIG. 1</figref> is a block diagram schematically illustrating a configuration example of a monitoring control system according to a first embodiment of the present invention.

0016<figref idref="DRAWINGS">FIG. 2</figref> is a block diagram illustrating a configuration example of a control device according to the first embodiment of the present invention.

0017<figref idref="DRAWINGS">FIG. 3</figref> is a conceptual diagram illustrating an example of signal definition data according to the first embodiment of the present invention.

0018<figref idref="DRAWINGS">FIG. 4</figref> is a conceptual diagram illustrating an example of operation definition data according to the first embodiment of the present invention.

0019<figref idref="DRAWINGS">FIG. 5</figref> is a flowchart illustrating an operation of a data collection unit of the control device according to the first embodiment of the present invention.

0020<figref idref="DRAWINGS">FIG. 6</figref> is a flowchart illustrating an operation of a data operation unit of the control device according to the first embodiment of the present invention.

0021<figref idref="DRAWINGS">FIG. 7</figref> is a flowchart illustrating an operation of an external transfer processing unit of the control device according to the first embodiment of the present invention.

0022<figref idref="DRAWINGS">FIG. 8</figref> is a block diagram illustrating a configuration example of a monitoring terminal according to the first embodiment of the present invention.

0023<figref idref="DRAWINGS">FIG. 9</figref> is a flowchart illustrating an operation of the monitoring terminal according to the first embodiment of the present invention.

0024<figref idref="DRAWINGS">FIG. 10</figref> is a flowchart illustrating a procedure of setting information by using a setting terminal according to the first embodiment of the present invention.

0025<figref idref="DRAWINGS">FIG. 11</figref> is a block diagram illustrating a configuration example of a control device according to a second embodiment of the present invention.

0026<figref idref="DRAWINGS">FIG. 12</figref> is a block diagram illustrating a configuration example of a control device according to a third embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

0027Exemplary embodiments of the present invention will be explained below with reference to the accompanying drawings.

First Embodiment

<Monitoring Control System>

0028<figref idref="DRAWINGS">FIG. 1</figref> is a block diagram schematically illustrating a configuration example of a monitoring control system <b>1</b> according to a first embodiment of the present invention. The monitoring control system <b>1</b> includes a high-order system <b>10</b> and a control device <b>100</b>. The high-order system <b>10</b> and the control device <b>100</b> are communicably connected with each other via an information network NET.

0029The control device <b>100</b> performs a device control process. Specifically, the control device <b>100</b>, which is connected to various devices (apparatuses) such as a sensor and an actuator in a factory, executes a control program so as to control operations of these devices. As the control device <b>100</b>, a PLC can be exemplified. Further, in the factory, a plurality of control devices <b>100</b> are communicably connected with each other via a controller network.

0030The high-order system <b>10</b> is a system that monitors the device control process performed by the control device <b>100</b>, and is connected to the control device <b>100</b> via the information network NET. For example, the high-order system <b>10</b> is provided in an office outside a factory area. The high-order system <b>10</b> includes a setting terminal <b>20</b>, a database terminal <b>30</b>, and a monitoring terminal <b>40</b>.

0031The setting terminal <b>20</b> is a terminal that performs various types of setting for the control device <b>100</b>. Details of a setting process using the setting terminal <b>20</b> are described later. Note that the connection means between the setting terminal <b>20</b> and the control device <b>100</b> is not limited to the information network NET. The setting terminal <b>20</b> and the control device <b>100</b> can be directly connected via a cable, or connected wirelessly by WiFi or the like.

0032The database terminal <b>30</b> includes an external database <b>35</b>. Database processing such as high-speed search is possible for the external database <b>35</b> by using a database language such as SQL. As described later, the external database <b>35</b> is used for saving device data collected by the control device <b>100</b>. Note that the device data is data related to devices controlled by the control device <b>100</b>, and used for the device control process.

0033The monitoring terminal <b>40</b> is a terminal that monitors the device control process performed by the control device <b>100</b>. The monitoring terminal <b>40</b> can display device data collected by the control device <b>100</b> on a display unit and can receive data manipulation from a user. Based on the data displayed on the display unit, the user can monitor the device control process in a plant and can perform required data manipulation. Details of the monitoring terminal <b>40</b> are described later.

<Configuration Example of Control Device>

0034Details of the control device <b>100</b> are described below. As illustrated in <figref idref="DRAWINGS">FIG. 1</figref>, the control device <b>100</b> according to the present embodiment is equipped with a control CPU <b>200</b> and an information CPU <b>300</b> separately. The control CPU <b>200</b> and the information CPU <b>300</b> are connected with each other via a bus <b>400</b> (internal bus).

0035The control CPU <b>200</b> is a CPU for the device control process. That is, by executing the control program, the control CPU <b>200</b> controls operations of devices such as a sensor and an actuator.

0036Meanwhile, the information CPU <b>300</b> is a CPU for a data collection process. Here, the data collection process is a process of collecting device data and saving collected device data in a database. That is, according to the present embodiment, the information CPU <b>300</b> of the control device <b>100</b> functions as a part of conventional SCADA functions.

0037<figref idref="DRAWINGS">FIG. 2</figref> is a block diagram illustrating a configuration example of the control device <b>100</b> according to the present embodiment. The control device <b>100</b> is described here in more detail with reference to <figref idref="DRAWINGS">FIG. 2</figref>.

0038The control CPU <b>200</b> that performs the device control process includes a sequence control unit <b>210</b> and a device memory <b>250</b>.

0039The sequence control unit <b>210</b> executes sequence control of devices such as a sensor. The sequence control unit <b>210</b> is realized by the control CPU <b>200</b> for executing a sequence control program described in a ladder language or the like. The sequence control program may be recorded on a computer readable recording medium.

0040The device memory <b>250</b> is an internal memory. Device data to be used for the device control process is stored in the device memory <b>250</b>.

0041The information CPU <b>300</b> is connected to the device memory <b>250</b> in the control CPU <b>200</b> via the bus <b>400</b> (internal bus). The information CPU <b>300</b> includes a processing unit <b>310</b>, a storage unit <b>320</b>, a built-in database <b>330</b>, and an external communication unit <b>340</b>.

0042The processing unit <b>310</b> is a data processing device that performs various types of data processing. As illustrated in <figref idref="DRAWINGS">FIG. 2</figref>, the processing unit <b>310</b> includes, as functional blocks, a configuration unit <b>311</b>, a data collection unit <b>312</b>, a data operation unit <b>313</b>, and an external transfer processing unit <b>314</b>. These functional blocks are realized by the processing unit <b>310</b> for executing a data processing program. Note that the data processing program may be recorded on a computer readable recording medium. Details of processes performed by the processing unit <b>310</b> are described later.

0043The storage unit <b>320</b> is a memory that stores therein definition data and the like. For example, signal definition data D<b>1</b> and operation definition data D<b>2</b> are stored in the storage unit <b>320</b>.

0044The signal definition data D<b>1</b> is data that defines an attribute of a signal (including device data) handled in a plant. <figref idref="DRAWINGS">FIG. 3</figref> illustrates an example of the signal definition data D<b>1</b>. Signal numbers are numbers for identifying each signal. The attribute of each signal includes “type of variables”, “name”, “data type”, “network number”, “station number”, “device type”, and “address”.

0045The “type of variables” indicates a category of the signal, and elements such as analog, digital, pulse, and counter are exemplified as this category. The “name” is a signal name described in a mode easily understandable by a human. As the “data type”, elements such as integer (16-bit integer), float (a 32-bit floating decimal point), long (32-bit integer), and double (a 64-bit floating decimal point) can be mentioned.

0046The “network number” is an identification number of a network to which the control device <b>100</b> handling the signal is connected. The “station number” is an identification number of the control device <b>100</b> that is handling the signal in the network indicated by the network number. That is, the control device <b>100</b> handling the signal is uniquely specified by the network number and the station number.

0047The “device type” indicates a type of a memory that is included in the device memory <b>250</b> of the control device <b>100</b>, and the memory in which the signal is stored. As the device type, a data memory, a latch memory, and an internal register can be mentioned. The “address” indicates a storage location of the signal in the memory indicated by the device type. That is, the storage location of the signal is uniquely specified by the device type and the address.

0048The operation definition data D<b>2</b> defines arithmetic processing (described later) to be performed by the information CPU <b>300</b>. <figref idref="DRAWINGS">FIG. 4</figref> illustrates an example of the operation definition data D<b>2</b>. An operation number is a number for identifying each of arithmetic processing. The attribute of the arithmetic processing includes “activation condition expression”, “output signal”, and “arithmetic equation”.

0049The “activation condition expression” indicates a condition for starting the arithmetic processing. That is, if the condition indicated by the activation condition expression is satisfied, then the arithmetic processing is performed. The “output signal” indicates a signal number of a signal being designated as a storage location, as a result of the arithmetic processing. The “arithmetic equation” indicates the contents of the arithmetic processing.

0050In the example illustrated in <figref idref="DRAWINGS">FIG. 4</figref>, the arithmetic processing of an operation number <b>001</b> is performed when a value of the signal S<b>2000</b> becomes larger than 100, and a mean value of the value of the signal S<b>1010</b> and the value of the signal S<b>1020</b> is output as a signal S<b>1000</b>. The arithmetic processing of an operation number <b>002</b> is performed when a timer set to 100 milliseconds is timed up, and a value obtained by multiplying a value of a signal S<b>1030</b> by 10 is output as a signal S<b>1001</b>.

0051As another example of the arithmetic processing, it is also conceivable to convert the unit of the device data to a unit that the high-order system <b>10</b> can easily handle. For example, it is assumed that an output of a sensor that detects the water level of a pump well is expressed as a signal current X [mA] normalized in a range of 4 mA to 20 mA. There is considered a case where the signal current X [mA] is converted to a water level [m] in a range of 0 to 5 meters. In this case, arithmetic processing expressed by the following equation (1) is required.

0000<br />Equation (1)

0000<br />water level [m]=(5[<i>m]−</i>0[<i>m]</i>)×(<i>X[mA]−</i>4[<i>mA]</i>)/(20[<i>mA]−</i>4[<i>mA]</i>)  (1)

0052The signal definition data D<b>1</b> and the operation definition data D<b>2</b> are set by the setting terminal <b>20</b> of the high-order system <b>10</b>. Specifically, a user uses the setting terminal <b>20</b> to perform inputting and editing of the signal definition data D<b>1</b> and the operation definition data D<b>2</b>. The setting terminal <b>20</b> transfers the signal definition data D<b>1</b> and the operation definition data D<b>2</b> to the control device <b>100</b>. The information CPU <b>300</b> of the control device <b>100</b> receives the signal definition data D<b>1</b> and the operation definition data D<b>2</b> from the setting terminal <b>20</b>. The configuration unit <b>311</b> of the processing unit <b>310</b> of the information CPU <b>300</b> stores the received signal definition data D<b>1</b> and operation definition data D<b>2</b> in the storage unit <b>320</b>.

0053Note that the control device <b>100</b> may transfer the signal definition data D<b>1</b> and the operation definition data D<b>2</b> to another control device <b>100</b> via the controller network. That is, data may be shared among the plurality of control devices <b>100</b> that are connected to the same network. Any of these control devices <b>100</b> can access all the pieces of data.

0054Referring back to <figref idref="DRAWINGS">FIG. 2</figref>, the built-in database <b>330</b> is a database that saves device data. For the built-in database <b>330</b>, database processing such as high-speed search can be performed by using a database language such as SQL.

0055The external communication unit <b>340</b> is a network interface for the information network NET. The processing unit <b>310</b> can access the information network NET via the external communication unit <b>340</b>.

<Functions of Information CPU>

0056Functions of the processing unit <b>310</b> of the information CPU <b>300</b> are described below.

0057The configuration unit <b>311</b> receives the signal definition data D<b>1</b> and the operation definition data D<b>2</b> from the setting terminal <b>20</b>. The configuration unit <b>311</b> stores the received signal definition data D<b>1</b> and operation definition data D<b>2</b> in the storage unit <b>320</b>.

0058The data collection unit <b>312</b> performs a data collection process. Specifically, the data collection unit <b>312</b> refers to the signal definition data D<b>1</b> stored in the storage unit <b>320</b> to collect device data defined in the signal definition data D<b>1</b> from the device memory <b>250</b>. In this case, because the information CPU <b>300</b> and the device memory <b>250</b> are connected with each other via the high-speed bus <b>400</b>, the data collection unit <b>312</b> can read the device data from the device memory <b>250</b> via the bus <b>400</b> at a high speed. The data collection unit <b>312</b> stores the read device data in the built-in database <b>330</b>. For example, the data collection unit <b>312</b> regularly performs the data collection process.

0059The data operation unit <b>313</b> performs data operation processing. Specifically, the data operation unit <b>313</b> refers to the operation definition data D<b>2</b> stored in the storage unit <b>320</b> to perform the arithmetic processing defined in the operation definition data D<b>2</b>. That is, if the activation condition of the arithmetic processing is satisfied, then the data operation unit <b>313</b> performs the specified arithmetic processing on the device data read from the device memory <b>250</b> in the data collection process. Thereafter, the data operation unit <b>313</b> writes a result of the arithmetic processing (“output signal” in <figref idref="DRAWINGS">FIG. 4</figref>) in the device memory <b>250</b>.

0060If an external transfer condition is satisfied, then the external transfer processing unit <b>314</b> performs an external transfer process. The external transfer process is a process of transferring at least a part of the device data stored in the built-in database <b>330</b> to the external database <b>35</b> of the high-order system <b>10</b>. That is, in the present embodiment, the built-in database <b>330</b> is used as a “cache”, and the contents of the built-in database <b>330</b> are reflected in the external database <b>35</b> as required.

0061As an example of the external transfer condition, it is conceivable that “the data collection unit <b>312</b> is not performing a data collection process”, that is, it is “idle time”. As another example of the external transfer condition, it is conceivable that “a usage rate of the built-in database <b>330</b> has exceeded a predetermined threshold (usage rate threshold)”. As still another example of the external transfer condition, it is conceivable that “a load (communication traffic or the like) of the control device <b>100</b> is lower than a predetermined threshold (load threshold)”. The external transfer condition may be any one of these conditions or may be arbitrary combinations of these conditions.

0062An example of a processing flow by the processing unit <b>310</b> is described next with reference to <figref idref="DRAWINGS">FIG. 5</figref> to <figref idref="DRAWINGS">FIG. 7</figref>.

0063<figref idref="DRAWINGS">FIG. 5</figref> is a flowchart illustrating an operation of the data collection unit <b>312</b>. If a system is activated, then the data collection unit <b>312</b> activates a timer registered in the system (Step S<b>1</b>). The timer defines a cycle to perform a data collection process. The cycle to perform the data collection process may be individually defined for each signal in the signal definition data D<b>1</b>. Further, the cycle to perform the data collection process may be different for each signal. When a plurality of cycles are present, a plurality of timers that define the respective cycles are prepared.

0064If a certain timer is timed up (YES at Step S<b>2</b>), then the data collection unit <b>312</b> reads device data related to the timer from the device memory <b>250</b> (Step S<b>3</b>). At this time, it is preferred that the data collection unit <b>312</b> reads the device data only when the current value has been updated from the previous value.

0065Subsequently, the data collection unit <b>312</b> communicates with the data operation unit <b>313</b> (Step S<b>4</b>). If the data operation processing by the data operation unit <b>313</b> is completed, then the data collection unit <b>312</b> writes the device data read from the device memory <b>250</b> in the built-in database <b>330</b> (Step S<b>5</b>). In this case, the data written in the built-in database <b>330</b> includes not only the device data read from the device memory <b>250</b> at Step S<b>3</b>, but also the device data updated by the data operation processing at Step S<b>4</b>.

0066Subsequently, the data collection unit <b>312</b> notifies the external transfer processing unit <b>314</b> of the completion of the data collection process (Step S<b>6</b>). If the system has not been shut down (NO at Step S<b>7</b>), then the procedure returns to Step S<b>2</b>. If the system has been shut down (YES at Step S<b>7</b>), then the processing flow finishes.

0067<figref idref="DRAWINGS">FIG. 6</figref> is a flowchart illustrating an operation of the data operation unit <b>313</b> at Step S<b>4</b> described above. The data operation unit <b>313</b> refers to the operation definition data D<b>2</b> to acquire an attribute (an activation condition expression, an output signal, an arithmetic equation) of each of the arithmetic processings in order of operation numbers (Step S<b>11</b>). Thereafter, the data operation unit <b>313</b> performs the next process according to the acquired attribute.

0068Specifically, the data operation unit <b>313</b> determines whether an activation condition specified by the acquired “activation condition expression” has been satisfied (Step S<b>12</b>). If the activation condition has not been satisfied (NO at Step S<b>12</b>), then the procedure proceeds to Step S<b>15</b>. If the activation condition has been satisfied (YES at Step S<b>12</b>), then the data operation unit <b>313</b> performs an operation specified by the acquired “arithmetic equation” (Step S<b>13</b>). Further, the data operation unit <b>313</b> stores an operation result in a signal specified by the acquired “output signal” (Step S<b>14</b>). That is, the data operation unit <b>313</b> writes the operation result in the device memory <b>250</b>. Thereafter, the procedure proceeds to Step S<b>15</b>.

0069At Step S<b>15</b>, the data operation unit <b>313</b> determines whether the process has been completed for all the operation numbers defined in the operation definition data D<b>2</b>. If the process has not been completed (NO at Step S<b>15</b>), then the procedure returns to Step S<b>11</b>, where the above process is performed for the next operation number. If the process has been completed for all the operation numbers (YES at Step S<b>15</b>), then the data operation processing is completed.

0070<figref idref="DRAWINGS">FIG. 7</figref> is a flowchart illustrating an operation of the external transfer processing unit <b>314</b>. The external transfer processing unit <b>314</b> receives a data collection completion notification transmitted from the data collection unit <b>312</b> at Step S<b>6</b> described above (Step S<b>21</b>).

0071In response to the data collection completion notification, the external transfer processing unit <b>314</b> calculates a redundant time to the start of the next data collection process (Step S<b>22</b>). The redundant time is a time obtained by subtracting the current time from the next data collection time. The next data collection time can be ascertained by referring to all the timers activated at Step S<b>1</b> described above.

0072Subsequently, the external transfer processing unit <b>314</b> transmits at least a part of the device data remaining in the built-in database <b>330</b> (Step S<b>23</b>). The external transfer processing unit <b>314</b> then calculates an elapsed time at Step S<b>23</b> (Step S<b>24</b>). The external transfer processing unit <b>314</b> updates the redundant time by subtracting the elapsed time from the redundant time (Step S<b>25</b>).

0073If there is still the redundant time (YES at Step S<b>26</b>), then the procedure returns to Step S<b>23</b>. If there is no redundant time (NO at Step S<b>26</b>), then the external transfer process finishes.

0074In this manner, in the example illustrated in <figref idref="DRAWINGS">FIG. 5</figref> to <figref idref="DRAWINGS">FIG. 7</figref>, the data collection unit <b>312</b> regularly performs the data collection process. When the data collection unit <b>312</b> is not performing the data collection process, that is, during the idle time, the external transfer processing unit <b>314</b> performs the external transfer process.

<Monitoring Terminal>

0075The monitoring terminal <b>40</b> in the high-order system <b>10</b> is described next. <figref idref="DRAWINGS">FIG. 8</figref> is a block diagram illustrating a configuration example of the monitoring terminal <b>40</b> according to the present embodiment. The monitoring terminal <b>40</b> includes a processing unit <b>50</b>, a storage unit <b>60</b>, a display unit <b>70</b>, and a communication unit <b>80</b>.

0076The processing unit <b>50</b> is a data processing device that performs various types of data processing. As illustrated in <figref idref="DRAWINGS">FIG. 8</figref>, the processing unit <b>50</b> includes, as functional blocks, a data acquisition unit <b>51</b>, a screen-data generation unit <b>52</b>, and a display processing unit <b>53</b>. These functional blocks are realized by the processing unit <b>50</b> for executing an HMI (Human Machine Interface) program. Note that the HMI program may be recorded on a computer readable recording medium. Details of the process performed by the processing unit <b>50</b> are described later.

0077The storage unit <b>60</b> is a memory such as an RAM or an HDD. In the storage unit <b>60</b>, the signal definition data D<b>1</b>, screen definition data D<b>3</b>, and screen data D<b>4</b> are stored. The signal definition data D<b>1</b> is data as described above, and is distributed from the setting terminal <b>20</b>. The screen data D<b>4</b> is data displayed on a monitoring screen <b>75</b> of the display unit <b>70</b>, and indicates the contents of the device data. The screen definition data D<b>3</b> is source data of the screen data D<b>4</b>. For example, the screen definition data D<b>3</b> defines a screen layout, UI (User Interface) components to be used, the signal number of the device data to be displayed, and the like.

0078The display unit <b>70</b> has the monitoring screen <b>75</b> such as a touch panel. The screen data D<b>4</b> is displayed on the monitoring screen <b>75</b>. Based on the screen data D<b>4</b> displayed on the monitoring screen <b>75</b>A, the user can perform monitoring of the device control process in a plant and required data manipulation.

0079The communication unit <b>80</b> is a network interface for the information network NET. The processing unit <b>50</b> can access the information network NET via the communication unit <b>80</b>.

0080<figref idref="DRAWINGS">FIG. 9</figref> is a flowchart illustrating an operation of the processing unit <b>50</b> of the monitoring terminal <b>40</b>. The screen-data generation unit <b>52</b> reads the screen definition data D<b>3</b> from the storage unit <b>60</b>. Subsequently, the screen-data generation unit <b>52</b> sequentially extracts the signal number of the device data defined in the screen definition data D<b>3</b> (Step S<b>31</b>). The screen-data generation unit <b>52</b> then requests the data acquisition unit <b>51</b> to acquire the latest value of the device data having the extracted signal number.

0081The data acquisition unit <b>51</b> acquires the requested latest value of the device data from the external database <b>35</b> or the built-in database <b>330</b> of the control device <b>100</b> by a search process. More specifically, the data acquisition unit <b>51</b> first searches the external database <b>35</b> to acquire the current value of the device data (Step S<b>32</b>). The data acquisition unit <b>51</b> then determines whether the current value acquired at Step S<b>32</b> is the latest value (Step S<b>33</b>). This determination can be performed by referring to a time at which the current value has been written in the external database <b>35</b> and a cycle of the data collection process defined in the signal definition data D<b>1</b>.

0082If the latest value of the device data has been saved in the external database <b>35</b> (YES at Step S<b>33</b>), then the data acquisition unit <b>51</b> transfers the latest value to the screen-data generation unit <b>52</b>. On the other hand, if the latest value of the device data has not been saved in the external database <b>35</b> (NO at Step S<b>33</b>), then the data acquisition unit <b>51</b> searches the built-in database <b>330</b> of the control device <b>100</b>, and acquires the latest value of the device data (Step S<b>34</b>). At Step S<b>34</b>, the data acquisition unit <b>51</b> can ascertain a storage destination of the device data by referring to the signal definition data D<b>1</b>.

0083The screen-data generation unit <b>52</b> acquires the latest value of the device data from the data acquisition unit <b>51</b>. The screen-data generation unit <b>52</b> then replaces the portion of the device data in the screen definition data D<b>3</b> with the acquired latest value (Step S<b>35</b>). That is, the screen-data generation unit <b>52</b> embeds the acquired latest value of the device data in the screen definition data D<b>3</b>.

0084At Step S<b>36</b>, the screen-data generation unit <b>52</b> determines whether the process has been completed for all the signal numbers defined in the screen definition data D<b>3</b>. When the process has not been completed (NO at Step S<b>36</b>), the procedure returns to Step S<b>31</b>, where the above process is performed for the next signal number. When the process has been completed for all the signal numbers (YES at Step S<b>36</b>), the screen data D<b>4</b> is completed.

0085In this manner, based on the device data acquired from the external database <b>35</b> or acquired from the built-in database <b>330</b> by the search, the screen-data generation unit <b>52</b> generates the screen data D<b>4</b>. The display processing unit <b>53</b> displays the screen data D<b>4</b> on the monitoring screen <b>75</b> of the display unit <b>70</b> (Step S<b>37</b>).

0086Note that the functions of the data acquisition unit <b>51</b> and the screen-data generation unit <b>52</b> described above may be realized by the processing unit <b>50</b> for executing a script described in the screen definition data D<b>3</b>.

<Setting Terminal>

0087The setting terminal <b>20</b> is used for setting of setting information including the signal definition data D<b>1</b> and the operation definition data D<b>2</b>. A setting tool is operated on the setting terminal <b>20</b>. A user can input and edit of the setting information including the signal definition data D<b>1</b> and the operation definition data D<b>2</b> by activating the setting tool.

0088<figref idref="DRAWINGS">FIG. 10</figref> is a flowchart illustrating a procedure of setting setting information by using the setting terminal <b>20</b>. At Steps S<b>41</b> and S<b>42</b>, a user inputs an attribute of a desired signal to generate the signal definition data D<b>1</b> (see <figref idref="DRAWINGS">FIG. 3</figref>).

0089At Steps S<b>43</b> to S<b>51</b>, the user inputs an attribute of desired arithmetic processing to generate the operation definition data D<b>2</b> (see <figref idref="DRAWINGS">FIG. 4</figref>). Specifically, the user first selects the type of activation condition (Step S<b>43</b>). As the type of activation condition, “fixed cycle”, “limit value”, and “conditional expression” can be considered. Note that other types of activation condition can be used as far as the condition can be stylized. In the case of “fixed cycle” (Step S<b>44</b>), the user inputs a cycle to activate the arithmetic processing (Step S<b>45</b>). In the case of “limit value” (Step S<b>46</b>), the user inputs signal name and a limit value of the signal (Step S<b>47</b>). In the case of “conditional expression” (Step S<b>48</b>), the user inputs the conditional expression (Step S<b>49</b>). Subsequently, the user inputs an arithmetic equation to be executed when the activation condition is established (Step S<b>50</b>).

0090If all the inputs of the desired arithmetic processing are completed (YES at Step S<b>51</b>), then the setting information including the signal definition data D<b>1</b> and the operation definition data D<b>2</b> are downloaded from the setting terminal <b>20</b> to the control device <b>100</b> (Step S<b>52</b>). That is, the setting information generated by using the setting terminal <b>20</b> is developed in the control device <b>100</b>.

<Effect>

0091According to the present embodiment, the control device <b>100</b> includes the information CPU <b>300</b> in addition to the control CPU <b>200</b> that performs the device control process. The information CPU <b>300</b> includes the built-in database <b>330</b> and the data collection unit <b>312</b> that performs the data collection process. In the data collection process, the data collection unit <b>312</b> reads the device data from the device memory <b>250</b> for the device control process, and stores the read device data in the built-in database <b>330</b>. The device data stored in the built-in database <b>330</b> can be referred to from the monitoring terminal <b>40</b> by the search process as necessary.

0092In this manner, according to the present embodiment, the data collection function, which is a part of the conventional SCADA functions, is incorporated in the control device <b>100</b>. Therefore, the load on the monitoring terminal <b>40</b> of the high-order system <b>10</b> can be reduced. This means that the requirement of performance for the monitoring terminal <b>40</b> is relaxed. Accordingly, for example, an inexpensive general-purpose PC can be used instead of an expensive industrial PC (an FA personal computer) as the monitoring terminal <b>40</b>. Consequently, costs related to system construction can be reduced.

0093Furthermore, the information CPU <b>300</b> and the device memory <b>250</b> are connected with each other via the high-speed bus <b>400</b>. Therefore, the data collection process can be realized at a higher speed than the case using the network. That is, high-performance data collection process is possible.

0094Further, the information CPU <b>300</b> is provided separately from the control CPU <b>200</b>. Therefore, the data collection process performed by the information CPU <b>300</b> does not affect the device control process performed by the control CPU <b>200</b>.

0095Furthermore, the information CPU <b>300</b> according to the present embodiment includes the external transfer processing unit <b>314</b> that performs the external transfer process in the idle time or the like. In the external transfer process, at least a part of the device data stored in the built-in database <b>330</b> is transferred to the external database <b>35</b> of the high-order system <b>10</b>. That is, according to the present embodiment, the built-in database <b>330</b> is used as the “cache”, and the contents of the built-in database <b>330</b> are reflected in the external database <b>35</b> as required.

0096Accordingly, large-capacity data can be saved for a long time period without increasing the capacity of the built-in database <b>330</b> of the control device <b>100</b>. That is, the large-capacity data can be handled for a long time period without increasing the cost and the size of the control device <b>100</b>.

0097Further, the information CPU <b>300</b> according to the present embodiment also includes the data operation unit <b>313</b> that performs the data operation processing. The contents of the data operation processing can be set as appropriate by editing the operation definition data D<b>2</b>. For example, the unit of the device data indicated by the above Equation (1) can be converted to a unit that can be easily handled by the monitoring terminal <b>40</b>. By performing such unit conversion in the control device <b>100</b>, the load on the monitoring terminal <b>40</b> can be further reduced. This also contributes to the reduction of costs related to the system construction.

0098As described above, according to the present embodiment, the monitoring control system <b>1</b> can be realized at a low cost.

Second Embodiment

0099<figref idref="DRAWINGS">FIG. 11</figref> is a block diagram illustrating a configuration example of the control device <b>100</b> according to a second embodiment of the present invention. As compared to the configuration of the first embodiment illustrated in <figref idref="DRAWINGS">FIG. 2</figref>, transfer definition data D<b>5</b> is further stored in the storage unit <b>320</b> of the information CPU <b>300</b>. This transfer definition data D<b>5</b> is date that defines external transfer conditions. The transfer definition data D<b>5</b> can be also set as appropriate by the setting terminal <b>20</b> of the high-order system <b>10</b>, like other pieces of definition data. The external transfer processing unit <b>314</b> refers to the transfer definition data D<b>5</b> stored in the storage unit <b>320</b> to perform the external transfer process according to the external transfer condition specified in the transfer definition data D<b>5</b>.

0100As an example of the external transfer condition, it is conceivable that “the data collection unit <b>312</b> is not performing the data collection process”, that is, it is “idle time”. As another example of the external transfer condition, it is conceivable that “the usage rate of the built-in database <b>330</b> has exceeded a predetermined threshold (usage rate threshold)”. As still another example of the external transfer condition, it is conceivable that “the load (communication traffic or the like) of the control device <b>100</b> is lower than a predetermined threshold (load threshold)”. The external transfer condition may be any one of these conditions or can be arbitrary combinations of these conditions.

0101According to the present embodiment, by using the setting terminal <b>20</b>, the external transfer condition can be arbitrarily customized. While the system environment varies for each case, according to the present embodiment, the external transfer process can be performed at an optimum timing in accordance with the system environment.

0102Note that the functional extension of the external transfer processing unit <b>314</b> as described above may be realized by Add-in for the data processing program executed by the information CPU <b>300</b>.

Third Embodiment

0103<figref idref="DRAWINGS">FIG. 12</figref> is a block diagram illustrating a configuration example of the control device <b>100</b> according to a third embodiment of the present invention. As compared to the configuration of the first embodiment illustrated in <figref idref="DRAWINGS">FIG. 2</figref>, the processing unit <b>310</b> of the information CPU <b>300</b> further includes a screen-data generation unit <b>315</b>. Further, the screen definition data D<b>3</b> and the screen data D<b>4</b> are stored in the storage unit <b>320</b>.

0104The function of the screen-data generation unit <b>315</b> is similar to that of the screen-data generation unit <b>52</b> of the monitoring terminal <b>40</b> in the first embodiment. However, the screen-data generation unit <b>315</b> reads the latest value of the required device data from the built-in database <b>330</b> or the device memory <b>250</b> at a high speed. The screen-data generation unit <b>315</b> then embeds the acquired latest value of the device data in the screen definition data D<b>3</b>, so as to generate the screen data D<b>4</b>.

0105Note that the function of the screen-data generation unit <b>315</b> may be realized by the processing unit <b>310</b> for executing a script described in the screen definition data D<b>3</b>.

0106The screen data D<b>4</b> generated by the information

0107CPU <b>300</b> of the control device <b>100</b> is downloaded to the monitoring terminal <b>40</b> via the information network NET. The monitoring terminal <b>40</b> displays the screen data D<b>4</b> acquired in this manner on the monitoring screen <b>75</b>. At this time, because the screen data D<b>4</b> has been already completed, the monitoring terminal <b>40</b> does not need to access the external database <b>35</b> or the built-in database <b>330</b> of the control device <b>100</b>.

0108In this manner, according to the present embodiment, the screen-data generation function is transferred from the monitoring terminal <b>40</b> to the information CPU <b>300</b> of the control device <b>100</b>. Further, the monitoring terminal <b>40</b> does not need to access the external database <b>35</b> or the built-in database <b>330</b> of the control device <b>100</b> in order to generate the screen data D<b>4</b> by itself. Therefore, the load on the monitoring terminal <b>40</b> can be further reduced. This also contributes to the reduction of costs related to the system construction.

0109Embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described above, and can be modified as appropriate by persons skilled in the art without departing from the scope of the invention.

REFERENCE SIGNS LIST

0110<b>1</b> monitoring control system, <b>10</b> high-order system, <b>20</b> setting terminal, <b>30</b> database terminal, <b>35</b> external database, <b>40</b> monitoring terminal, <b>50</b> processing unit, <b>51</b> data acquisition unit, <b>52</b> screen-data generation unit, <b>53</b> display processing unit, <b>60</b> storage unit, <b>70</b> display unit, <b>75</b> monitoring screen, <b>80</b> communication unit, <b>100</b> control device, <b>200</b> control CPU, <b>210</b> sequence control unit, <b>250</b> device memory, <b>300</b> information CPU, <b>310</b> processing unit, <b>311</b> configuration unit, <b>312</b> data collection unit, <b>313</b> data operation unit, <b>314</b> external transfer processing unit, <b>315</b> screen-data generation unit, <b>320</b> storage unit, <b>330</b> built-in database, <b>340</b> external communication unit, <b>400</b> bus, D<b>1</b> signal definition data, D<b>2</b> operation definition data, D<b>3</b> screen definition data, D<b>4</b> screen data, D<b>5</b> transfer definition data, NET information network.