JP2006285734A - Method for diagnosing controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize the diagnostic method of a controller for detecting any abnormality in various processing tasks without omission, and for detecting that necessary processing is normally executed in an intended order. <P>SOLUTION: This diagnostic method for monitoring the task executing circumstances of a controller which executes various processing tasks is provided with execution order information for storing the execution order of processing units in the processing tasks, and characterized to diagnose the actual executing circumstances of the processing units based on the execution order information. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a diagnostic method for monitoring the execution status of various processing tasks in a control operation in a plant control system that manages and controls field devices arranged in a plant.

  In such a plant control system, a safety system is introduced in order to ensure plant safety. A safety system is a system for notifying an alarm and performing necessary measures when an abnormality is found in a field device, etc., and as a part of the plant control system or independent of the plant control system. Provided.

  FIG. 8 is a configuration diagram illustrating an example of a control device having a conventional diagnostic function. In the figure, 1 is a control device that captures process data from a field device and outputs a control signal for driving an operation end such as a control valve. 2 is a method for changing a set value of the control device 1 or monitoring an operation state. An engineering station 3 is a control bus for connecting these devices. The control device 1 has various processing tasks. Here, the diagnosis task 10 and the control task 20 are illustrated.

  The diagnosis task 10 operates in a set diagnosis cycle (for example, 1 second), performs field device abnormality diagnosis, self-diagnosis of the control device 1 (diagnosis processing 11), and when an abnormality is recognized. Notify alarms, take necessary measures or shut down the system.

  The control task 20 operates in a set control cycle (scan cycle), and executes an INPUT process 21 for fetching process data, a LOGIC process 22 for performing various calculations, and an OUTPUT process 23 for outputting a control signal. Further, in order to detect an abnormality in processing, WDT (watch dock timer) processing 24 for starting a watch dock timer is performed.

  Therefore, a hardware failure or the like of the field device or the control device 1 can be detected by the diagnostic processing 11, and a software runaway can be detected by the WDT processing 24.

JP 07-056773 A

  However, in the control device diagnosis method as described above, no abnormality is detected in the following situation, which causes a safety problem.

  FIG. 9 is a flowchart showing the flow of various diagnoses (processing units) in the diagnostic processing 11. In the figure, (a) is a flow showing the original processing order. For example, diagnosis 11-1 of field device (1), diagnosis 11-2 of field device (2), diagnosis 11- of field device (3). Execution of diagnosis is set in order of 3,.

  On the other hand, as shown in (b), if a part of the processing (diagnosis 11-2) is lost, the failure of the field device (2) cannot be detected, and the control operation is performed by the failed device. There is a risk of being continued.

  FIG. 10 is a flowchart showing the flow of various processes (processing units) in the LOGIC process 22. In the figure, (a) is a flow showing the original processing order. For example, in the order of calculation (1) 22-1, calculation (2) 22-2, calculation (3) 22-3,. Calculation execution is set.

On the other hand, as shown in (b), if the order of computation is changed, the intended computation result cannot be obtained and normal control operation cannot be performed.
Also, in the INPUT process 21 and the OUTPUT process 23, if the processing order is out of order, there is a possibility that inappropriate data is read or written.

  FIG. 11 is a flowchart showing a state of erroneous detection in the WDT processing 24. In the figure, (a) is a flow showing the original processing order. For example, each processing in the order of processing (1) 25-1, processing (2) 25-2, processing (3) 25-3,. Is executed, and WDT is triggered according to the end of each process.

  Here, as shown in (b), when the same processing 25-4 is repeated and the trigger continues to be supplied to the WDT, the WDT cannot perform the expected monitoring operation and detects a processing abnormality. Can not do it.

  Conventionally, with respect to the processing order in such processing tasks, there is no means for monitoring and it is not possible to detect whether or not necessary processing is normally executed in the intended order.

  The present invention eliminates the drawbacks of the conventional apparatus as described above, detects abnormalities in various processing tasks without omission, and can detect that necessary processes are normally executed in the intended order. The purpose is to realize a diagnostic method.

  In order to achieve the above object, in claim 1 of the present invention, in the diagnostic method for monitoring the task execution status of the control device that executes various processing tasks, the execution order of the processing units in the processing tasks is stored. It has an execution order information, and the execution status of an actual processing unit is diagnosed based on the execution order information.

  According to a second aspect of the present invention, in the control device diagnosis method according to the first aspect, the processing unit in the processing task is a function unit of a program.

  According to a third aspect of the present invention, in the diagnosis method of the control device according to the first or second aspect, the execution order information associates a processing unit to be processed at that time with a processing unit to be processed next, using the processing order as an index. And memorize it.

  According to a fourth aspect of the present invention, in the method for diagnosing a control device according to any one of the first to third aspects, the execution order information is constructed based on a program when the processing task is first executed.

  According to a fifth aspect of the present invention, in the diagnosis method for a control device according to any one of the first to fourth aspects, the processing task includes a watchdog timer process.

  According to a sixth aspect of the present invention, in the control device diagnosis method according to any one of the first to fifth aspects, the processing task is a control task.

  According to a seventh aspect of the present invention, in the control device diagnosis method according to the sixth aspect, the control task includes a diagnostic process for performing self-diagnosis of the device.

  According to claim 8, in the diagnosis method of the control device according to any one of claims 1 to 7, an operation of diagnosing an execution status of an actual processing unit based on the execution order information is executed as a part of the processing task. It is characterized by doing.

As described above, when the execution order information storing the execution order of the processing units in the processing task is provided and the execution status of the actual processing unit is diagnosed based on the execution order information, the necessary processing is intended. It is possible to easily detect whether or not they are executed in order.
In addition, if the execution order information is constructed at the first execution of the processing task, the execution order information can be reconstructed every time the processing task is changed even if the execution contents of the processing task are sequentially changed. It is possible to monitor based on the changed execution contents.
Furthermore, by including the WDT process in the processing task, it is possible to detect an abnormality with respect to the processing time, and it is possible to detect whether or not a series of processes are executed within the time.

  Hereinafter, a diagnosis method for a control device of the present invention will be described with reference to the drawings.

FIG. 1 is a configuration diagram showing an embodiment of a diagnosis method for a control device of the present invention. In the figure, the same components as those in FIG. Reference numeral 30 denotes a control task executed in the control device 1, and this control task 30 includes a diagnosis process 31, an INPUT process 32, a LOGIC process 33, an OUTPUT process 34, and a WDT process 35, and these processes are sequentially executed. To do. The contents of each process are the same as those of the same name in FIG.
Further, the control task 30 has an execution order monitoring function 36 for monitoring the execution order of each process and the execution order of processing units in each process.

  FIG. 2 is a flowchart showing an example of the execution order and execution order monitoring operation of each process in the control task 30. When the control task 30 is started according to the set control cycle, first, a diagnosis process 31 is executed.

FIG. 3 shows an example of the diagnosis process 31. A series of diagnosis processes 1 to N, such as field device failure diagnosis and memory check, are executed in a predetermined order.
Here, at the end of each diagnosis process 1 to diagnosis process N, the execution order is checked, and if an abnormality in the execution order is detected, it is necessary to notify the alarm or shut down the system as an abnormal end. Measures are taken.

FIG. 4 is a flowchart illustrating the execution order check operation. Note that the execution order information in the processing units such as the diagnostic process 1 to the diagnostic process N is stored as an execution order table as shown in FIG.
In this table, Index is the processing order of the processing unit, and Current is the current point designated by an integer other than 0, and if it is the first point, START is designated. Next designates a point to be called next by an integer other than 0, and if it is the first point, START is designated.

  Returning to FIG. 4, when the execution order check is started, the Index pointer of the execution order table is initialized, and the execution order of process 1 (diagnostic process 1) is compared with the table. It is checked whether the information of the process 1 exists at the position indicated by the index of the execution order table, and if there is information, the current and the next of the process 1 match each of the execution order tables. If Current or Next is 0, the information is not registered.

If the comparison result is normal, the Index pointer is sequentially updated in accordance with the end of execution of the processing unit (diagnosis process 1 to diagnosis process N), and the same comparison operation is repeated.
The comparison is made up to the last process N, and if no abnormality is detected, the diagnosis process 31 has been normally completed including the execution order.

  Therefore, the diagnostic process 31 can be monitored including the execution order of the processing units (diagnostic process 1 to diagnostic process N), and a problem due to the missing process as shown in FIG. 9 can be prevented.

Returning to FIG. 2, when the diagnosis process 31 is completed, the execution order of the diagnosis process 31 is checked, and the process is moved to the INPUT process 32.
The execution order information used at this time may be stored in the form of an execution order table as shown in FIG. 5, or the order information held in the control task 30 may be used.

After the INPUT process 32, the process moves to the LOGIC process 33. The contents of the LOGIC process 33 may be changed by an online maintenance operation from the engineering station 2 or the like.
In such a case, before executing the LOGIC processing 33, execution order information is created as shown in FIG.

  FIG. 6 is a flowchart showing an example of the LOGIC process 33. In the LOGIC process 33, it is determined whether or not the process is the first execution before the execution. The first execution corresponds to a case where the control task 30 operates for the first time after the activation of the control device 1 and a case where the control task 30 operates for the first time after the contents of processing are changed.

When the control task 30 is executed for the first time, execution order information is created before execution of a processing unit (LOGIC processing 1 to LOGIC processing N).
Creation of the execution order information is performed according to the procedure shown in FIG. 7 based on the description of the program, and the execution order table is reconstructed as shown in FIG. As shown in FIG. 7, the execution order of process 1 (LOGIC process 1) is set to No. in the execution order table. 1 (Index), and thereafter, processing up to processing N (LOGIC processing N) is sequentially registered in the execution order table. Finally, the execution order table is checked, for example, whether the numbers registered in the execution order table are duplicated or consistent, and the creation of the execution order table is terminated.

Thus, at the first execution time, execution order information (execution order table) is constructed, and thereafter, the execution order is checked using this execution order information together with processing units (LOGIC processing 1 to LOGIC processing N). Is called.
Therefore, even if the execution contents of the processing task are changed sequentially, the execution order information can be reconstructed every time the processing task is changed, and the execution order is always changed based on the changed execution contents. Monitoring can be performed.
In addition, since execution order information (execution order table) is automatically constructed, no special engineering is required to cope with changes in execution contents.

  In this example, only the execution order information (execution order table) for the processing units (LOGIC process 1 to LOGIC process N) in the LOGIC process 33 is rewritten. However, the execution order information (execution order table) for other processes is illustrated. ) Can be rewritten at the same time.

Thereafter, the execution of the task proceeds to the OUTPUT process 34 and the WDT process 35, and the same execution order check is performed for all the processes.
Here, since a process with time constraints, such as the WDT process 35, is included in the execution order check target, whether a necessary series of processes are executed in time along with software runaway etc. Whether or not can be detected.

  In addition, since the diagnostic process 31 is included in the control task 30, the diagnostic operation can be executed every time the control task 30 is activated, and the diagnostic process 31 can be performed in detail in accordance with the control cycle. it can.

As described above, if the execution order information storing the execution order of the processing units in the processing task is provided and the execution status of the actual processing unit is diagnosed based on the execution order information, the necessary processing is performed. It can be easily detected whether or not it is executed in the intended order.
Further, since a special mechanism such as a high-speed CPU computing capacity and a special memory is not required for execution order check, the monitoring operation can be reliably performed without increasing the CPU load.

  In the above description, the control task 30 is illustrated as an example of the processing task. However, the subject of the present invention is not limited to the control task 30 and can be applied to other processing tasks.

  Further, although the case where the execution order monitoring function 36 is provided in the control task 30 is illustrated, the execution order monitoring function 36 can be operated independently of the processing task to be monitored.

FIG. 1 is a configuration diagram showing an embodiment of a diagnosis method for a control device of the present invention. FIG. 2 is a flowchart showing an example of the execution order and execution order monitoring operation of each process in the control task 30. FIG. 3 is a flowchart showing an example of the diagnostic process 31. FIG. 4 is a flowchart for explaining an execution order check operation. FIG. 5 is an execution order table used for execution order check operations. FIG. 6 is a flowchart showing an example of the LOGIC process 33. FIG. 7 is a flowchart for explaining execution order information creation operation. FIG. 8 is a block diagram showing an example of a conventional control device having a diagnostic function. FIG. 9 is a flowchart showing the flow of various diagnoses (processing units) in the diagnostic processing 11. FIG. 10 is a flowchart showing the flow of various processes (processing units) in the LOGIC process 22. FIG. 11 is a flowchart showing a state of erroneous detection in the WDT processing 24.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Control apparatus 2 Engineering station 3 Control bus 10 Diagnostic task 11, 31 Diagnostic process 20, 30 Control task 21, 32 INPUT process 22, 33 LOGIC process 23, 34 OUTPUT process 24, 35 WDT process 36 Execution order monitoring function

Claims (8)

In a diagnostic method for monitoring the task execution status of a control device that executes various processing tasks,
Execution order information storing the execution order of processing units in the processing task;
A diagnosis method for a control device, characterized in that an execution status of an actual processing unit is diagnosed based on the execution order information.   2. The control device diagnosis method according to claim 1, wherein a processing unit in the processing task is a function unit of a program.   The control apparatus according to claim 1, wherein the execution order information stores the processing unit to be processed at that time and the processing unit to be processed next in association with each other using the processing order as an index. Diagnosis method.   The control device diagnosis method according to claim 1, wherein the execution order information is constructed based on a program when the processing task is first executed.   5. The control device diagnosis method according to claim 1, wherein the processing task includes a watchdog timer process.   The control device diagnosis method according to claim 1, wherein the processing task is a control task.   7. The control device diagnosis method according to claim 6, wherein the control task includes a diagnosis process for performing self-diagnosis of the device. 8. The diagnosis of a control device according to claim 1, wherein an operation for diagnosing an execution status of an actual processing unit based on the execution order information is executed as a part of the processing task. Method.

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