JP2012150621A - Control system and soe device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control system in which constant periodicity of data for controlling is ensured in a system in which an input/output device and an SOE device are connected through a common communication line.SOLUTION: The control system comprises a processing unit; the input/output device that transmits a state signal input from a control target to the processing unit, and outputs a control signal transmitted from the processing unit to the control target; and the SOE device that receives the control signal or the state signal, and records a predetermined change as event data. In the control system in which the processing unit, the input/output device, and the SOE device are connected through a common transmission path, the SOE device is equipped with a communication control unit that receives a reading request from the processing unit in a predetermined reception period, and transmits the event data for the reading request to the processing unit in a predetermined transmission period. The above problem is solved by the control system.

Description

  The present invention relates to a control system and an SOE device.

  Data handled by a general plant control system includes data for control that is constantly processed by the arithmetic unit to monitor and control the control target, and temporary processing by the arithmetic unit to analyze the behavior of the control target when an abnormality occurs. There is event data to be processed automatically.

  As such event data collection and management method, for example, Patent Document 1 discloses a method of collecting event data by placing an event input module incorporating an event collection function in the same hierarchy as a plurality of process input / output devices. Yes.

JP 2000-10604 A

  For example, in a control system such as a power plant, the control data requires immediacy and constant periodicity. Therefore, data transmission between the arithmetic device and the process input / output device is performed quantitatively and continuously by periodic memory transfer. It is desirable to do it. On the other hand, event data is temporarily transmitted between the arithmetic device and the SOE device by an interrupt process or the like only when an event data collection device (hereinafter referred to as “SOE device”) detects and records a predetermined event. There is a need to do.

  Here, for example, when the technique described in Patent Document 1 is applied to an SOE device, transmission to an arithmetic device required when the SOE device detects an event uses the same communication line as the communication line to which the input / output device is connected. Need to be done. Therefore, when transmission between the SOE device and the arithmetic device is performed, there is a problem that the periodic transmission between the input / output device and the arithmetic device is affected, and the regularity of the control data is impaired. In addition, if a system is constructed with separate lines for control data and event data in order to ensure the regularity of the control data, there is a problem that the entire control system becomes large.

  In view of the above problems, an object of the present invention is to provide a control system in which fixed periodicity of control data is ensured in a system in which process input / output devices and SOE devices are connected by a common communication line.

  In order to solve the above problems, for example, the configuration described in the claims is adopted.

  The present application includes a plurality of means for solving the above-described problems. To give an example, an arithmetic device that monitors and controls a control target, and a state signal that is connected to the control target and is input from the control target. The input / output device that transmits to the arithmetic device and outputs the control signal transmitted from the arithmetic device to the control target, the control signal or the state signal is captured, a predetermined change is detected as an event, and the event A control system in which the control signal or the state signal at the time of detection is recorded as event data, and the arithmetic device, the input / output device, and the SOE device are connected via the same transmission path; The SOE device receives a read request for the event data from the arithmetic device at a predetermined reception cycle, and records the read request to the own device in response to the read request. It is a communication control unit for the transmission of event data to the arithmetic unit at a predetermined transmission cycle, characterized in that provided are.

  According to the present invention, in a control system in which process input / output devices and SOE devices are connected by a common communication line, data transmission can be performed without impairing the regularity of control data.

The block diagram of a control system. Periodic control by memory transfer. Event data collection operation flow of the SOE device. The event data collection block diagram of a SOE apparatus. Initial state signal capture operation of the SOE device. Event detection operation of SOE device (with event). Event detection operation of SOE device (no event). Event data format. Event write and write pointer of SOE device. Input memory transfer operation flow of the SOE device. The input memory transcription | transfer block diagram of a SOE apparatus. Communication frame format for input memory transfer. Event read and read pointer of SOE device. Event buffer management method for SOE device. SOE device event data empty judgment. Event buffer initial state of the SOE device. Event read response of the SOE device (pattern 1). Event read response of the SOE device (pattern 2). Event read response of the SOE device (pattern 3).

  DESCRIPTION OF EMBODIMENTS Embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a configuration diagram of a control system showing one mode of an embodiment of the present invention. In a control system that performs turbine control and the like of a power plant, a control object 6 including a turbine, a sensor, and an auxiliary machine, a computing device 1 that constantly monitors the state of the control object 6 and performs optimum feedback control, and a state of the control object 6 One or more process input devices 2 that change the signal indicating the data to be transmitted to the arithmetic device 1 and one or more process outputs that convert the feedback data transmitted from the arithmetic device 1 into a signal that is transmitted to the controlled object 6 One or more event data collection devices (hereinafter referred to as SOE devices) 7 that record the state and time of occurrence when the device 3 and the controlled object 6 indicate a specific control state are connected via an RS-485-based serial communication line. A signal and feedback data indicating that the control target 6 and the process input / output devices 2 and 3 are connected by a communication line 4 and indicate the state of the control target 6 It is configured to be connected by the control signal line 5 and a signal for transmitting the controlled object 6.

  Further, the SOE device 7 includes a reception buffer 79 and a transmission buffer 83 as buffers for performing memory transfer. Although not shown, the arithmetic device 1, the process input device 2 and the process output device 3 similarly include a reception buffer, a transmission buffer and A communication control function is provided. Hereinafter, memory transfer using the reception buffer 79 and the transmission buffer 83 will be briefly described.

  In the reception buffer 79, transmission data periodically received from the arithmetic device 1, the process input device 2 and the process output device 3 via the communication line 4 is stored by the communication control function 78. After determining whether the data stored in the reception buffer 79 is destined for the own apparatus, the SOE apparatus 7 executes the processing requested by the data if it is destined for the own apparatus, and sends the destination of the request source apparatus. The response data marked with is stored in the transmission buffer 83. The data stored in the transmission buffer 83 is simultaneously transmitted to the arithmetic device 1, the process input device 2, and the process output device 3 at a predetermined cycle by the communication control function 78, and stored in the reception buffer of each device. The requesting device confirms whether the stored response data is addressed to its own device, and recognizes that its own request has been executed.

  Such processing is similarly performed in the process input device 2 and the process output device 3, and in this embodiment, the request is transmitted to the process input device 2, the process output device 3, and the SOE device 7 mainly by the arithmetic device 1. It is.

  Next, processing of the status signal 51 by the SOE device 7 will be described. The SOE device 7 captures one or more state signals 51 indicating the control state of the controlled object 6 by the signal capturing function 71. The fetch value of the status signal 51 only for the first time is held as the current value 72 and the previous value 73. From the second time on, the data held at the current value 72 is held as the previous value 73, and the captured value is held as the current value 72. The comparison function 74 compares the held previous value 73 with the current value 72 and outputs a comparison result signal 741 to the event detection function 75. The event detection function 75 indicates that “there is an event” when the value of the state signal 51 changes from the comparison result signal 741 to a specific state, and “no event” when the value of the state signal 51 does not change to a specific state. Is determined.

  When it is determined that “there is an event”, the event detection function 75 outputs an event detection signal 751 to the event write instruction function 76. The event write instruction function 76 outputs information related to the change of the state signal 51 (hereinafter referred to as “event data”) to the event buffer control function 81 as an event write instruction signal 761. At this time, the current time acquired by the current time count signal 771 output from the current time counter 77 is attached to the event data. Upon receiving the event write instruction signal 761, the event buffer control function 81 records event data in the event buffer 82.

  Here, when the event data is recorded in the event buffer 82, the pointer control of the address of the event buffer 82 for recording the event data is performed by the write pointer control function 84 and the event buffer management function 88. When the instruction signal 762 is input from the event write instruction function 76, the write pointer control function 84 generates a write pointer signal 841 indicating that the address to be recorded in the event buffer 82 is updated, as an event buffer management function 88 and an event buffer control function. 81. As a result, the write pointer signal 841 is output every time an event is detected, and the address of the event buffer 82 for recording event data is updated. Thereby, event data can be stored in the event buffer 82 each time an event is detected.

  The event buffer management function 88 manages the storage state and pointer position of event data in the event buffer 82, and outputs the state of the event buffer 82 to the event buffer control function 81 as an event buffer state signal 881. Here, for example, when the unread event data is full in the event buffer 82 and cannot be written any more, the event buffer control function 81 recognizes the state of the event buffer 82 by the event buffer state signal 881 and writes to the event buffer 82. Stop. As a result, it is possible to prevent the unread event data from being overwritten and the continuity of the event data from being lost.

  On the other hand, the SOE device 7 receives communication frames from the communication line 4 at a constant cycle as described above. The memory transfer block of the SOE device 7 includes a communication control function 78 that receives a communication frame flowing through the communication line 4 and sends a communication frame to the communication line 4, and a reception buffer 79 that holds the communication frame received by the communication control function 78. A reception determination function 86 for determining the content of the communication frame in the reception buffer 79; an event read instruction function 80 for instructing reading of event data when the content of the communication frame is “event read request”; and a read pointer control function 85 A read pointer instruction function 87 for giving a read pointer instruction, a read pointer control function 85 indicating the address of the event buffer 82 for reading the event data, an event buffer management function 88 for determining the presence or absence of event data in the event buffer 82, and an event read Instruction signal 801 and read pointer signal 851 Accordingly, an event buffer control function 81 for reading event data from the event buffer 82, an event buffer 82 for recording or reading event data according to an instruction from the event buffer control function 81, a transmission buffer 83 for holding event data read from the event buffer 82, an event A dummy response function 810 that stores dummy event data in the transmission buffer 83 when no event data exists in the buffer 82. With such a memory transfer block configuration, an event data read request and an event data read response are periodically transmitted / received to / from the arithmetic unit 1.

  FIG. 2 shows constant cycle control by memory transfer by the arithmetic unit 1. In the system steady state, the computing device 1 always repeats a constant control cycle. Further, as shown in the figure, the control cycle of each time is the input memory transfer in which the arithmetic device 1 acquires data by data transmission with the process input device 2 and the SOE device 7, and the data acquired by the arithmetic device 1 is transferred to the control object 6. And the output memory transfer for transmitting the feedback data calculated by the arithmetic device 1 to the process output device 3.

  Further, in each input memory transfer, a fixed size data read request is transmitted and a fixed size data read response is received between the process input device 2 and the SOE device 7. That is, the arithmetic unit 1 transmits a data read request to the process input device 2 and receives a data read response to which data corresponding to the request is attached from the process input device 2. Next, computing device 1 transmits a data read request to SOE device 7 and receives a data read response to which data corresponding to the request is attached from SOE device 7. In the output memory transfer, the arithmetic device 1 transmits a data output request to the process output device 3 and receives a data output response indicating that the data output has been executed from the process input device 2.

  As described above, in this embodiment, the arithmetic unit 1 includes the SOE in the control period of the memory transfer performed between the process input device 2 and the process output device 3 in order to ensure the regularity of the control data. Data transmission / reception with the device 7 is also incorporated. As a result, even in a control system in which the process input device 2 and the process output device 3 and the SOE device 7 are connected by the same communication line, data transmission can be performed without impairing the periodicity of the control data. .

  FIG. 3 shows an event data collection operation flow of the SOE device 7. The signal capture function 71 captures one or more state signals 51 indicating the control state of the controlled object 6 (S30). The current value holding function 72 and the previous value holding function 73 hold the captured value of the status signal 51 as the current value and the previous value only for the first time (S31). After the second acquisition of the status signal 51 (S32), the current value is held as the previous value, and the acquired value is held as the current value (S33). The comparison function 74 compares the held previous value with the current value (S34), and the event detection function detects whether the value of the state signal 51 has changed to a specific state from the comparison result (S35). If there is a change to the state, “there is an event”, and if the value of the state signal 51 does not change to a specific state, it is determined that there is no event (S36). If it is determined that there is no event, the process returns to the acquisition of the status signal 51. When it is determined that “there is an event”, event data is recorded in the event buffer 82 by the event buffer control function 81 (S37). Recording of event data in the event buffer 82 is repeated until all detected event data is recorded (S38).

  FIG. 4 shows an event data collection block diagram of the SOE device 7. The event collection block of the SOE device 7 includes a signal capturing function 71 for capturing the state signal 51, a current value retaining function 72 for retaining the captured value of the state signal 51 as a current value, and the captured value or current value of the state signal 51. Previous value holding function 73 that holds the previous value, comparison function 74 that compares the current value with the previous value, event detection function 75 that determines whether there is an event or no event from the comparison result, and the current time that keeps counting the current time The counter 77 includes an event write instruction function 76 that records event data in the event buffer 82 when it is determined that “there is an event”.

  Next, event detection by taking in the status signal 51 will be described with reference to FIGS. FIG. 5 shows the initial state signal 51 fetch operation of the SOE device 7. The signal capture function 71 captures the status signal 51 at a predetermined cycle. When the first status signal 51 is captured, the signal capture function 71 merely holds the captured value as the current value and the previous value. Take in. That is, in the state signal fetching (1), since ch0 to ch3 are “1, 0, 1, 0” as the state signal 51, these are held as the current value and the previous value.

  FIG. 6 shows an event detection operation when an event has not occurred in capturing the status signal 51 for the second and subsequent times of the SOE device. The SOE device 7 acquires the status signal 51 by the status signal acquisition (2), and holds the current value as the previous value and the acquired value as the current value. The captured current value and the previous value are compared by the comparison function 74 for each channel of ch0 to ch3. The comparison is performed, for example, by taking an exclusive OR of the current value and the previous value. In this case, ch0 to ch3 are “1, 0, 1, 0”, respectively, and since there is no difference between the previous value and the current value in any of ch0 to ch3, it is determined that “no event”. After determining that there is no event, the next state signal 51 is captured.

  FIG. 7 shows an event detection operation when an event occurs when the SOE device 7 fetches the status signal 51 for the second and subsequent times. Similar to the event detection operation shown in FIG. 6, the SOE device 7 fetches the status signal 51 by fetching the status signal (3), holds the current value as the previous value, and holds the fetched value as the current value. The captured current value and the previous value are compared by the comparison function 74 for each channel of ch0 to ch3. In this example, ch0 to ch3 are “1, 1, 0, 0”, ch1 changes from the previous value “0” to the current value “1”, and ch2 changes from the previous value “1” to the current value “0”. Therefore, it is determined that there are two “events” in total for ch1 and ch2. After determining that “there is an event”, the event data of ch1 and ch2 are recorded in the event buffer 82. Further, the subsequent change of “ch3” from “0” to “1” shown in the figure is detected as an event when the status signal 51 is fetched next time.

  Thereby, for example, when the status signal ch3 is a signal indicating the presence or absence of any alarm, it is possible to analyze how the status signal 51 indicated in ch0 to ch2 has undergone the alarm. Further, as shown in FIGS. 5 to 7, in this embodiment, an event is detected by monitoring a change in the digital signal. For example, an analog signal is monitored as the status signal 51, and the difference between the current value and the previous value is monitored. An event may be detected when the value exceeds a predetermined threshold.

  FIG. 8 shows the format of event data. The event data for one event is the channel number of the channel determined to be “event present” by the above-described event detection, the current value of the status signal 51, and the current time when it is determined to be “event present” by the above-described event detection. It consists of an event detection time which is a value indicated by the time counter 77. In this embodiment, when the current time counter 77 indicates “0x11” when it is determined that “there is an event”, the ch1 event data has the ch number / current value / event detection time “1/1 / 0x11”, respectively. It becomes. Similarly, the event data of ch2 is “2/0 / 0x11”.

  FIG. 9 shows the event write and write pointer control of the SOE device 7. When event data is recorded in the event buffer 82 (hereinafter referred to as “event write”), it is performed by a write pointer signal 841 by the write pointer control function 84. The write pointer signal 841 is an address of the event buffer 82 that records event data. The write pointer signal 841 is updated every time the event write instruction signal 761 is input, and the write pointer signal 841 always records event data next. Indicates the address of the event buffer 82. When there are two or more event data, the update of the event write instruction function 76 and the write pointer signal 841 is repeated by the number of event data.

  In this embodiment, event data is stored at addresses “3” and “4” of the event buffer 82 by the event write for two events of ch1 and ch2, and the write pointer signal 841 is changed from “4” to “5”, “ Update from “5” to “6”. Here, the event buffer 82 is composed of, for example, a ring buffer, and is updated again from the address “1” when the write pointer reaches the end point of the address of the event buffer 82. However, in the state where the unread event data must be overwritten when the address is updated, the event buffer control function 81 recognizes the state by the event buffer status signal 881 from the event buffer management function 88 and sends it to the event buffer 82. Stop writing. As a result, it is possible to prevent the unread event data from being overwritten and the continuity of the event data from being lost.

  FIG. 10 shows an input memory transfer operation flow of the SOE device 7. The SOE device 7 always receives a communication frame from the communication line 4 by the communication control function 78 and stores it in the reception buffer 79 (S100). When receiving the communication frame from the computing device 1, the reception determination function 86 determines the received content (S101). Further, the reception determination function 86 determines whether the received communication frame is “addressed to own node” (S102). If the received content determination result is “to other node”, the communication frame is discarded or ignored, and the process returns to S100. If the determination result of the received content is “addressed to own node”, the reception determination function 86 determines whether the received communication frame is an “event read request” (103). If it is not “event read request”, the SOE device 7 executes processing other than the event read requested in the communication frame, and returns to S100. If it is an “event read request”, event data is read from the event buffer 82 and repeated until all event data is read (S105). When all the event data has been read, a communication frame including the event data read from the event buffer 82 is transmitted to the arithmetic device 1 as an event read response (S106). After transmitting the event read response, it waits for reception of a communication frame from the arithmetic device 1 again.

  FIG. 11 shows a memory transfer block of the SOE device 7. The communication control function 78 always receives a communication frame from the communication line 4 and stores it in the reception buffer 79 via the reception path 781. Each time a communication frame is stored in the reception buffer, the reception determination function 86 determines whether the communication frame is “addressed to own node” or “event read request”. The reception determination function 86 outputs a reception determination result signal 861 to the read pointer instruction function 87 and the event read instruction function 80 when the content of the communication frame is “addressed to own node” and “event read request”. The event read instruction function 80 to which the reception determination result signal 861 is input outputs the event read instruction signal 801 to the read pointer control function 85 and the event buffer control function 81. The event buffer control function 81 to which the event read instruction signal 801 is input reads the event data from the event buffer 82 and stores it in the transmission buffer 83.

  Here, when reading event data from the event buffer 82, pointer control of the address of the event buffer 82 from which the event data is read is performed by the read pointer control function 85 and the event buffer management function 88. When the event read instruction signal 801 is input from the event read instruction function 80, the read pointer control function 85 generates a read pointer signal 851 indicating that the address read from the event buffer 82 is updated, as an event buffer management function 88 and an event buffer. Output to the control function 81. That is, the read pointer control function 85 outputs a read pointer signal 851 every time the SOE device 7 receives an “event read request”, and updates the address of the event buffer 82 from which event data is read.

  Further, the read pointer instruction function 87 outputs a read pointer instruction signal 871 to the read pointer control function 85 so as to read the already read event data, for example, when the arithmetic unit 1 fails to receive the event data. That is, when the content of the “event read request” from the arithmetic unit 1 is a request to read the already read event data again, the read pointer is set to the read address by the read pointer instruction signal 871. The read pointer control function 85 is output to stop updating the read address. Thus, in the process of sequentially updating the read address of the event data every time an “event read request” is received, it is possible to cope with failure of transmission / reception of event data.

  The event buffer management function 88 manages the storage state and pointer position of event data in the event buffer 82, and outputs the state of the event buffer 82 to the event buffer control function 81 as an event buffer state signal 881. Here, if the event buffer status signal 881 indicates that the read pointer and the write pointer are the same address, it can be seen that there is no unread event data even if the address is updated further. Therefore, the event buffer management function 88 stores the dummy event data in the transmission buffer 83 by the dummy response function 810 in the event buffer management function 88 without updating the read address. The dummy event data stored in the transmission buffer 83 is transmitted to the computing device 1 at the transfer timing of the SOE device 7, and the computing device 1 determines that the received event data is dummy, so that there is no unread event data. Recognize that.

  As described above, the arithmetic device 1 communicates with the process input device 2 and the like by memory transfer, and communication with the SOE device 7 is also determined in a predetermined control cycle of the arithmetic device 1. Here, when there is no unread event data as described above, it is possible to construct a control system without disturbing periodic transmission with the computing device 1 by transmitting dummy event data.

  FIG. 12 shows a communication frame format for input memory transfer. (A) The upper part shows the format of the communication frame when the communication frame is stored in the reception buffer 79 by the input memory transfer from the arithmetic unit 1. In the input memory transfer, the type of communication frame addressed from the arithmetic unit 1 to the SOE device 7 is an event read request, and the contents of each area of “request / response”, “read / write”, “destination node address”, and “event read size”. Determine. In this embodiment, “request / response” indicates whether the communication frame is a request “1” or a response “0” from the computing device 1 with 1 bit, and “read / write” indicates 1 bit with the communication frame being the computing device. 1 indicates whether the read is “1” or write “0”, and “destination node address” indicates 10 bits and indicates which of the node addresses 0 to 1023 is the destination of the communication frame. The “event read size” is 5 bits, and the requested data size from the computing device 1 can be set to 1 to 32 events, and is set when the system is constructed. In this embodiment, the following description will be made assuming that the read size is set to 4.

  For example, when an event read request frame as shown in the lower part of FIG. 12A is received, the reception determination function 86 indicates that the value of the “request / response” area of the communication frame in the reception buffer 79 is the request “1”. , It is determined whether the value of the “read / write” area is read “1” and the value of the “destination node address” area matches the own node address of the SOE device 7, and the received communication frame is addressed to the own node. It is determined that this is an “event read request”.

  When the reception determination function 86 determines that it is an “event read request” addressed to its own node, the event read instruction function 80 outputs an event read instruction signal 801 so as to read event data from the event buffer 82 to the event buffer control function 81. The event buffer control function 81 reads one unread event data from the area indicated by the read pointer signal 851 of the event buffer 82 in accordance with the event read instruction signal 801, and stores the read event data in the transmission buffer 83.

  The event read instruction function 80 repeats the reading of event data from the event buffer 82 by the event read instruction signal 801 by the request data size in the “read size” area described above, and stores the event data for the request data size in the transmission buffer 83.

  Here, the upper part of FIG. 12B shows the communication frame format of the event read response.

  In the input memory transfer, the type of the communication frame addressed from the SOE device 7 to the arithmetic device 1 is an event read response, and the contents of each area of “request / response”, “read / write”, “destination node address”, and “event read size”. Determined. In this embodiment, an event read response frame as shown in the lower part of FIG. When event data for the requested data size is stored in the transmission buffer 83, the communication control function 78 transmits the event data in the transmission buffer to the arithmetic device 1 as an “event read response”.

  FIG. 13 shows operations of the event buffer 82 and the read pointer control function 85 by the event read of the SOE device 7. The read pointer in the event buffer indicates an address at which event data to be read at the next request is stored. When a read request is received, the read pointer is updated after reading the event data. The event buffer management function 88 and the event buffer control function 81 repeat this cycle for the number of requested event data. In this embodiment, since the event read size is 4, the read cycle is repeated four times, and four read pointers are updated as shown.

  FIG. 14 shows an event buffer management method. Each of the read pointer and the write pointer indicates an address to be read or written at the next read or write request. Therefore, when the read pointer and the write pointer indicate the same address, it indicates that the “next read address” and the “next write address (= currently blank)” are equal, which means that unread event data is stored in the event buffer. No (event data empty).

  FIG. 15 shows a method for determining event data empty. As described above, if the addresses indicated by the read pointer and the write pointer are equal, the event data is empty. Therefore, the event data empty is determined by comparing the respective addresses with the pointer address comparator 9. The pointer address comparator 9 may be provided in the event buffer management function 88 or in the event buffer control function 81.

  FIG. 16 shows the initial state of the event buffer. Since the event buffer 82 immediately after the reset is empty without any data, the read pointer and the write pointer are in the event data empty state indicating the same address.

  FIG. 17 shows a read response of the SOE device 7 when there is unread event data larger than the read size in the event buffer 82. When there is unread event data larger than the read size in the event buffer 82, the event data is stored in all data areas of the event read response frame and responds. That is, in this embodiment, the read size is 4, whereas the unread event data is 5, so that event data is stored in all four data areas of the event read response frame. The remaining one unread event data is transmitted at the next event read request.

  FIG. 18 shows a read response of the SOE device 7 when there is no unread event data in the event buffer 82 (event data empty). In this case, the event buffer management function 88 informs the event buffer control function 81 that the read pointer and the write pointer indicate the same address by the event buffer status signal 881, that is, there is no unread event data. As a result, the event buffer management function 88 does not update the read address, and dummy response data (invalid values are stored in the event detection time area of the event data, the event detection ch number and the event read response frame are not updated). The status signal current value area stores “don't care” and responds.

  FIG. 19 shows a read response of the SOE device 7 when there is one or more unread event data less than the read size in the event buffer 82. When there is one or more unread event data less than the read size in the event buffer 82, dummy response data (invalid values are stored in the event detection time area of the event data) The area stores “don't care” and responds. In this embodiment, the read size is 4, whereas the unread event data is 2, so that two event data and two dummy response data are stored in the transmission buffer 83.

  As described above, since the read pointer address is not updated before the write pointer address by controlling the read pointer as shown in FIGS. 18 and 19, it is possible to prevent reading of unread event data from being read out. it can. In addition, when there is no unread event data, dummy event data is transmitted, so that a control system can be constructed without disturbing periodic transmission with the computing device 1.

  As described above, according to the present invention, in the control system in which the process input / output device and the SOE device are connected by the same communication line, the arithmetic unit periodically transfers the control data to the process input / output device by memory transfer at a predetermined control cycle. Perform transmission. Then, a data transmission / reception period with the SOE device 7 that is necessary only when a predetermined event is detected within the control cycle of the arithmetic device 1 is determined within the control cycle of the arithmetic device 1. Thereby, event data transmission can be performed without impairing the periodicity of the control data.

  If there is no event data to be transmitted, the SOE device transmits dummy response data. Thereby, since periodic transmission with the arithmetic device 1 can be maintained, a system can be constructed without disturbing the control cycle of the arithmetic device.

  In addition, the control data communication path and the event beta communication path are not configured as separate lines, so that the periodicity of the control data can be secured, so the system can be reduced while maintaining the functions of a general plant control system. Can be scaled.

  In addition, this invention is not limited to an above-described Example, Various modifications are included. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. In addition, a part of the configuration of a certain embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of a certain embodiment. Further, it is possible to add, delete, and replace other configurations for a part of the configuration of each embodiment. Each of the above-described configurations, functions, processing units, processing means, and the like may be realized by hardware by designing a part or all of them with, for example, an integrated circuit. Further, each of the above-described configurations, functions, and the like may be realized by software by interpreting and executing a program that realizes each function by the processor.

  Further, the control lines and information lines indicate what is considered necessary for the explanation, and not all the control lines and information lines on the product are necessarily shown. Actually, it may be considered that almost all the components are connected to each other.

DESCRIPTION OF SYMBOLS 1 Arithmetic unit 2 Process input device 3 Process output device 4 Communication line 5 Control signal line 6 Control object 7 Event data collection device (SOE device)
9 Pointer Address Comparator 51 Status Signal 71 Signal Capture Function 72 Current Value Holding Function 73 Previous Value Holding Function 74 Comparison Function 75 Event Detection Function 76 Event Write Instruction Function 77 Current Time Counter 78 Communication Control Function 79 Reception Buffer 80 Event Read Instruction Function 81 Event buffer control function 82 Event buffer 83 Transmission buffer 84 Write pointer control function 85 Read pointer control function 86 Reception discrimination function 87 Read pointer instruction function 88 Event buffer management function 711 Capture value signal 721 Current value signal 731 Previous value signal 741 Comparison result signal 751 Event detection signal 761 Event write instruction signal 771 Current time count signal 781 Reception path 791 Reception content 801 Event read instruction signal 810 Dummy response function 811 Event data signal 821 Event Data read path 822 Event data write path 831 Transmission path 841 Write pointer signal 851 Read pointer signal 861 Reception discrimination result signal 871 Read pointer instruction signal 881 Event buffer status signal

Claims (9)

A computing device that monitors and controls the controlled object;
An input / output device that is connected to the control target, transmits a state signal input from the control target to the arithmetic device, and outputs a control signal transmitted from the arithmetic device to the control target;
An SOE device that captures the control signal or the state signal, detects a predetermined change as an event, and records the control signal or the state signal at the time of the event detection as event data, and includes the arithmetic unit, In the control system in which the input / output device and the SOE device are connected via a common transmission line,
The SOE device receives a read request for the event data from the arithmetic device at a predetermined reception cycle, and receives the event data stored in the own device in response to the read request at a predetermined transmission cycle. A control system comprising a communication control unit for transmitting to The control system according to claim 1,
The SOE device further includes an event buffer that stores the event data, and an event that writes the event data to the event buffer when the event is detected and reads the event data from the event storage unit when the read request is received A buffer controller,
The event buffer control unit reads dummy data indicating that there is no untransmitted event data when there is no untransmitted event data in the event storage unit,
The communication control unit transmits the dummy data to the arithmetic device at a transmission timing determined by the transmission cycle. The control system according to claim 2,
The SOE device further updates a write pointer control unit that updates a write address to the event buffer every time the event is detected, and updates a read address from the event buffer every time the read request is received. A read pointer control unit,
The event buffer control unit determines that there is no untransmitted event data when the write address indicated by the write pointer control unit and the read address indicated by the read pointer control unit indicate the same address. And control system. The control system according to claim 1,
The SOE device further includes
A comparison unit that compares the captured control signal or the status signal with the control signal or the status signal captured before the capture;
An event detection unit that detects the event when a comparison result by the comparison unit indicates a predetermined change;
An event write instruction unit for instructing the event data control unit to write the event data when the event is detected;
A control system comprising: The control system according to claim 4.
The SOE device further includes
A reception determination unit for determining whether data transmitted from another device to the reception storage unit of the own device is a transmission request for the event data;
An event read instruction unit for instructing the event data control unit to read the event data when the reception determination unit determines that the transmission request is received;
A control system comprising: A computing device that monitors and controls the controlled object;
An input / output device that is connected to the control target, transmits a state signal input from the control target to the arithmetic device, and outputs a control signal transmitted by the arithmetic device to the control target;
An SOE device that captures the control signal or the status signal and stores the captured signal as event data, and the arithmetic device transmits data to and from the input / output device and the SOE device at a predetermined control period. In the control system to do
The predetermined control period includes a period for transmitting a read request for the status signal to the input / output device, a period for receiving a read response for the status signal from the input / output device, and a transmission of the event data to the SOE device. A control system comprising: a period for transmitting a read request; and a period for receiving a read response for the event data from the SOE device. The control system according to claim 6,
When the SOE device receives the event data read request from the arithmetic unit, if there is no untransmitted event data, the SOE device sets dummy event data indicating that there is no untransmitted event data as the event data. A control system that transmits the read request to the arithmetic unit during a period during which the read request is transmitted. In an SOE device that periodically captures a status signal input / output to / from a control target and detects a predetermined change as an event,
A transmission storage unit that stores transmission data to the arithmetic device that monitors and controls the control target;
A reception storage unit that stores reception data from the arithmetic device;
An event data control unit that writes the state signal at the time of the event detection to the event storage unit as event data, and reads the event data written to the event storage unit to the transmission storage unit;
A read request for the event data is received from the arithmetic device at a predetermined reception cycle and stored in the reception storage unit, and the event data read in the transmission storage unit in response to the read request is transmitted at a predetermined transmission cycle. Communication control means for transmitting to the arithmetic unit;
An SOE device comprising: The SOE device according to claim 8,
The event data control unit stores dummy data indicating that there is no untransmitted event data in the transmission storage unit when there is no untransmitted event data in the event storage unit,
The SOE device, wherein the communication control unit transmits the dummy data to the arithmetic device at a transmission timing determined in the predetermined transmission cycle.

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