Control system and control method

Abstract

The present application provides a controller and a control method, which can reduce the cost of redundancy of the controller. The controller constitutes a redundant controller with another controller, and includes a communication function section that communicates with an external device capable of performing a control operation required for process control of a plant device, and a redundancy management section that switches a state of the controller among a plurality of states including an operation state in which a result of the control operation acquired from the external device via the communication function section is reflected in the process control, and a standby state in which the result of the control operation is not reflected in the process control, the redundancy management section switching the state of the controller so that one of the controller and the other controller is in the operation state.

Description

Technical Field

[0001] This invention relates to controllers and control methods. Background Technology

[0002] A controller that uses the results of control calculations to perform process control of factory equipment is known (see, for example, Patent Document 1).

[0003] Existing technical documents

[0004] Patent Document 1: Japanese Patent No. 4099816

[0005] Sometimes a redundant architecture using two controllers is employed. One controller is in running mode, while the other is in standby mode. In case of an anomaly, the controller in standby mode switches to running mode as needed. However, the switching itself rarely occurs, and the operating rate of the controller in standby mode is extremely low, thus raising cost-effectiveness issues. Summary of the Invention

[0006] The purpose of this invention is to reduce the cost of controller redundancy.

[0007] A controller, together with another controller, constitutes a redundant controller. The controller includes: a communication function unit that communicates with an external device capable of performing control calculations required for process control of plant equipment; and a redundancy management unit that switches the controller's state between multiple states, including an operating state in which the results of control calculations obtained from the external device via the communication function unit are reflected in the process control, and a standby state in which the results of control calculations are not reflected in the process control. The redundancy management unit switches the controller's state so that one of the controllers, or the other controller, is in an operating state.

[0008] One aspect of the control method is a control method performed by a controller that, together with another controller, constitutes a redundant controller. This control method includes: communicating with an external device capable of performing control calculations required for process control of plant equipment; and switching the state of the controller between multiple states, including an operating state in which the results of control calculations obtained from the external device via communication are reflected in the process control, and a standby state in which the results of control calculations are not reflected in the process control. During the switching, the state of the controller is switched so that one of the controllers, or the other controller, is in an operating state.

[0009] According to the present invention, the cost of controller redundancy can be reduced. Attached Figure Description

[0010] Figure 1 This is a diagram illustrating an example of the schematic configuration of a redundant controller using an implementation method.

[0011] Figure 2 This is a flowchart illustrating an example of the processing performed in a redundant controller.

[0012] Figure 3 This is a flowchart illustrating an example of the processing performed in a redundant controller.

[0013] Figure 4 This is a flowchart illustrating an example of the processing performed in a redundant controller.

[0014] Figure 5 This is a flowchart illustrating an example of the processing performed in a redundant controller.

[0015] Figure 6 This is a diagram illustrating a schematic configuration of a modified redundant controller.

[0016] Figure 7 This is a diagram illustrating a schematic configuration of a modified controller and external devices.

[0017] Figure 8 This is a diagram illustrating an example of the hardware configuration of a controller.

[0018] Explanation of reference numerals in the attached figures

[0019] 1. Factory equipment; 2. Field devices; 21. Sensors; 22. Actuators; 3. Input / output devices; 4. Redundant controllers; 41. Controllers (first controller, other controller); 42. Controllers (second controller); 411. Control and computation unit; 412. Redundancy management unit; 413. Field input / output function unit; 414. Redundant input / output function unit; 422. Redundancy management unit; 423. Field input / output function unit; 424. Redundant input / output function unit; 425. Communication function unit; 42a. Communication device; 42b. Display device; 42c. HDD; 42d. Memory; 42e. Processor; 5. External devices; 51. Control and computation unit; 55. Communication function unit; 6. Terminal devices; 100. Control system; N. Network; CB. Control bus; SB. System bus. Detailed Implementation

[0020] The embodiments will now be described with reference to the accompanying drawings. Identical elements are labeled with the same reference numerals, and repeated descriptions are omitted where appropriate.

[0021] Figure 1 This diagram illustrates a schematic example of the configuration of a redundant controller used in an implementation method. The illustrated redundant controller 4 is applied to a control system 100. The control system 100 is used for the control of factory equipment 1. The redundant controller 4 performs process control (operation control, etc.) of the factory equipment 1. Various field devices 2 are installed in the factory equipment 1. Figure 1In the example, sensor 21 and actuator 22 are shown as field devices.

[0022] Field device 2 is connected to input / output device 3. Input / output device 3 is responsible for the data exchange between field device 2 and the redundant controller 4 (described later). For example, input / output device 3 obtains control data from field device 2 and delivers it to redundant controller 4 upon request. Furthermore, input / output device 3 receives control data from redundant controller 4 and provides it to field device 2. Thus, the control data (control calculation results, etc., described later) is reflected in the process control of plant equipment 1.

[0023] "Control data" includes process data, control parameters, etc. Examples of process data are the detection results of sensor 21 (e.g., pressure, temperature, flow rate, etc.). Examples of control parameters are the set parameters in the operation control of plant equipment 1, such as the set value of actuator 22. Since control data is obtained from or provided to field equipment 2 via input / output device 3, in this invention, "control data" is sometimes also referred to as "input / output data".

[0024] The control system 100 includes a redundant controller 4, external devices 5, and terminal devices 6. The aforementioned field devices 2 and / or input / output devices 3 may also be components of the control system 100.

[0025] The redundant controller 4 uses the results of the control calculations described later to perform process control of the plant equipment 1. The redundant controller 4 is communicatively connected to the input / output device 3 so as to obtain data from or provide data to the field device 2. The communication line connecting the redundant controller 4 and the input / output device 3 is referred to as the control bus CB for illustration.

[0026] The redundant controller 4 includes a redundant structure (redundant structure) to meet a high level of availability. Availability refers to the ability to continue operating even in the event of an anomaly. The redundant controller 4 is redundant by including multiple controllers, each capable of performing process control of the plant equipment 1.

[0027] Specifically, the redundancy controller 4 includes controller 41 and controller 42. For example, controller 42 may be the controller used in the implementation of the redundancy controller 4. Viewed from controller 42, controller 41 is another controller constituting the redundancy controller 4. Controller 41 is a first controller used for process control of the plant equipment 1 using the results of control calculations. Controller 42 is a second controller used for process control of the plant equipment 1 using the results of control calculations.

[0028] Controllers 41 and 42 are respectively connected to input / output device 3 via control bus CB. Thus, controllers 41 and 42 are able to send and receive control data with input / output device 3.

[0029] Controllers 41 and 42 are interconnected via the system bus SB. Various data required for redundancy are transmitted and received between controllers 41 and 42. Details will be described later.

[0030] Controller 41 includes: a control calculation unit 411, a redundancy management unit 412, a field input / output function unit 413, and a redundancy input / output function unit 414. Controller 42 includes: a redundancy management unit 422, a field input / output function unit 423, a redundancy input / output function unit 424, and a communication function unit 425.

[0031] The control calculation unit 411 of the controller 41 performs the control calculations required for process control. It can perform any control calculation related to process control. Examples of control calculations include PID control using control data. Various controls specified by a given control application program can also be included in the control calculations. By reflecting the results of the control calculations (control calculation results) into the process control of the plant equipment 1 (sent to the input / output device 3 and provided to the sensor 21), the plant equipment 1 is actually controlled.

[0032] The redundancy management unit 412 of controller 41 and the redundancy management unit 422 of controller 42 are the parts that manage redundancy and perform various processes required for redundancy. Some examples of specific processes are explained below.

[0033] The processing of redundancy management units 412 and 422 is an example of equivalence. Equivalence involves copying the data required for control operations from one controller (41) to the other (42). Examples of data required for control operations include control data (input / output data) and internal data required for control operations. Through equivalence, the data required for control operations is shared between controllers 41 and 42.

[0034] Another example of the processing by the redundancy management unit 412 and redundancy management unit 422 is obtaining control calculation results. The redundancy management unit 412 can obtain control calculation results from the control calculation unit 411. The control calculation unit 411 requests the input / output data (control data) required for control calculation from the redundancy management unit 412. The redundancy management unit 412 delivers the requested input / output data to the control calculation unit 411. The control calculation unit 411 uses the received input / output data to perform control calculations and delivers the control calculation results to the redundancy management unit 412. Thus, the redundancy management unit 412 can obtain control calculation results from the control calculation unit 411. Furthermore, the redundancy input / output function unit 424 can obtain control calculation results from the control calculation unit 51 of the external device 5, which will be described later. This will be explained again later.

[0035] Other examples of the processing by the redundancy management units 412 and 422 include anomaly detection of controllers 41 and 42. One example of anomaly detection is out-of-synchronization detection. For example, the redundancy management units 412 and 422 control controllers 41 and 42 to synchronize their operation. The synchronization method is not particularly limited, but for example, a method in which controllers 41 and 42 notify each other of the step count (see also Patent Document 1) can be used. Alternatively, a program can be prepared to perform the synchronization processing itself, and the synchronization processing can be performed by this software. Information required for synchronization is sent and received via the system bus SB. Various anomaly detection methods can be employed, not limited to these examples.

[0036] Other examples of the processing by the redundancy management unit 412 and the redundancy management unit 422 are the state management of controllers 41 and 42. For example, the redundancy management unit 412 and the redundancy input / output function unit 424 manage which of the various states controllers 41 and 42 are in.

[0037] Examples of different states include running state, standby state, and stopped state. The running state is when the control calculation results obtained by the controller in this state are reflected in the process control of plant equipment 1 (sent to input / output device 3 and provided to field device 2). The standby state is when the control calculation results obtainable by the controller in this state are not reflected in the process control of plant equipment 1 (not sent to input / output device 3 and not provided to field device 2). The stopped state is when the controller does not obtain control calculation results.

[0038] Another example of the processing handled by the redundancy management unit 412 and the redundancy management unit 422 is the switching of the states of controller 41 and controller 42. This will be explained separately for controller 41 and controller 42.

[0039] In controller 41, the redundancy management unit 412 obtains the control calculation results from the control calculation unit 411 and reflects these results into the process control of plant equipment 1 (sent to input / output device 3 via field input / output function unit 413), thereby switching controller 41 to the running state. The redundancy management unit 412 switches controller 41 to the standby state by not reflecting the control calculation results of the control calculation unit 411 into the process control of plant equipment 1. In the standby state, the redundancy management unit 412 may or may not obtain the control calculation results of the control calculation unit 411. The redundancy management unit 412 switches controller 41 to the stop state by not obtaining the control calculation results from the control calculation unit 411 and (of course) not reflecting them into the process control. In the stop state, the control calculation of the control calculation unit 411 itself may also be stopped.

[0040] In controller 42, the redundancy management unit 422 obtains the control calculation results from the external device 5 (described later) and reflects these results into the process control of factory equipment 1, thereby switching controller 42 to the operating state. The redundancy management unit 422 switches controller 42 to the standby state by not reflecting the control calculation results of the control calculation unit 51 of the external device 5 (described later) into the process control of factory equipment 1. In the standby state, the redundancy management unit 412 may or may not obtain the control calculation results of the control calculation unit 51 of the external device 5. The redundancy management unit 422 switches controller 42 to the stop state by not obtaining control calculation results from the external device 5 and not reflecting them into the process control. In the stop state, the control calculation of the control calculation unit 51 of the external device 5 may also be stopped.

[0041] An example of switching will be explained. The redundancy management unit 412 of controller 41 and the redundancy management unit 422 of controller 42 switch the states of controller 41 and controller 42 so that one of controller 41 and controller 42 is in an operating state. For example, the redundancy management unit 412 and the redundancy input / output function unit 424 switch the states of controller 41 and controller 42 based on anomaly detection (based on the occurrence of an anomaly). For example, if an anomaly occurs in the controller in the operating state, the controller in the standby state switches to the operating state. In the switching decision, the self-diagnostic results described later may also be considered.

[0042] Not limited to the examples above, various switching methods can be used. Controllers 41 and 42 are connected via a dedicated system bus SB. Furthermore, redundancy-related functions (such as redundancy management unit 412 and redundancy management unit 422) are installed in these controllers, thereby enabling rapid anomaly detection and switching.

[0043] In addition, the configuration in which redundancy-related functions are installed in the controllers 41 and 42 connected by the aforementioned system bus SB will also be referred to as "dedicated hardware configuration".

[0044] Other examples of processing by the redundancy management units 412 and 422 include self-diagnosis. Examples of self-diagnosis include determining the cause of an anomaly, whether process control of plant equipment 1 can be performed (whether it is necessary to switch from operating state to standby state, etc.). Self-diagnosis results can be communicated to each other via the system bus SB. Thus, the redundancy management units 412 of controller 41 and 422 of controller 42 grasp (share) their respective self-diagnosis results.

[0045] Not limited to the examples above, various self-diagnostic methods can also be employed. Through the dedicated hardware configuration described above, self-diagnostic results can be quickly shared between controller 41 and controller 42. This allows for rapid determination of the cause of an anomaly and whether a switchover is necessary.

[0046] Field input / output function units 413 and 423 transmit and receive input / output data (control data) with input / output device 3 via control bus CB. For example, field input / output function unit 413 or field input / output function unit 423 requests input / output data from input / output device 3. Input / output device 3 obtains the requested input / output data from field device 2 and sends it to field input / output function unit 413 or field input / output function unit 423. Furthermore, field input / output function unit 413 or field input / output function unit 423 sends the input / output data to be provided to field device 2 to input / output device 3. Input / output device 3 provides the received input / output data to field device 2 and reflects it in the process control of plant equipment 1.

[0047] Here, the transmission and reception of input / output data between controller 41 and input / output device 3, as well as between controller 42 and input / output device 3, are performed exclusively. Specifically, only the controller in the running state transmits and receives input / output data with input / output device 3. The controller in the standby state obtains input / output data from the controller in the running state through the aforementioned equivalence.

[0048] Redundancy input / output function unit 414 and redundancy input / output function unit 424 exchange necessary information via system bus SB. Various information required for processing by redundancy management unit 412 and redundancy management unit 422, as described above, are exchanged via redundancy input / output function unit 414 and redundancy input / output function unit 424.

[0049] The communication function unit 425 of the controller 42 communicates with the external device 5. In this example, the external device 5 is connected to the controller 42 via a network N. The external device 5 is, for example, a cloud server device capable of cloud computing. Examples of network N are the Internet, LAN, etc. Network N is a communication path different from the system bus SB.

[0050] External device 5 includes a control calculation unit 51 and a communication function unit 55. The control calculation unit 51 has the same functions as the control calculation unit 411 of the controller 41 described above. The communication function unit 55 communicates with the communication function unit 425 of the controller 42.

[0051] The functions of the control calculation unit 411 and redundancy management unit 412 of the controller 41, as described above, are realized through the control calculation unit 51 of the external device 5, the communication function unit 55, the communication function unit 425 of the redundancy controller 4, and the redundancy management unit 422. Specifically, the control calculation unit 51 requests the input / output data (control data) required for control calculation from the redundancy management unit 422. The redundancy management unit 422 sends the requested input / output data to the control calculation unit 51. The control calculation unit 51 performs control calculations using the sent input / output data and sends the control calculation results to the redundancy management unit 422. Thus, the redundancy management unit 422 can obtain the control calculation results from the external device 5. From the perspective of the control calculation unit 51 of the external device 5, it can also be considered that the function of the redundancy management unit 422 of the redundancy controller 4 is invoked through the communication function unit 55 of the external device 5. From the perspective of the redundancy management unit 422 of the redundancy controller 4, it can also be considered that the function of the control calculation unit 51 of the external device 5 is invoked through the communication function unit 425 of the redundancy controller 4.

[0052] Terminal device 6 is used by users of the control system 100 to operate controllers 41 and 42. Terminal device 6 is, for example, a general-purpose PC, and can be connected to controllers 41 and 42 respectively via signal lines (not shown). Terminal device 6 can provide an interface for receiving user operations. An example of user operations received by terminal device 6 is switching the states of controllers 41 and 42. For example, switching information (commands, etc.) is sent from terminal device 6 to the redundancy management unit 412 of controller 41 and the redundancy management unit 422 of controller 42 to perform the switching. Thus, the states of controllers 41 and 42 can also be manually switched. Switching can also be performed without using terminal device 6. An example of such user operation is setting up or removing controllers 41 and 42 (e.g., inserting or removing a control card). For example, if controller 41 is removed while it is in the running state, causing an abnormality detection in controller 41, controller 42 can be switched to the running state. Switches for state switching can also be provided for controllers 41 and 42 respectively. Users can switch the states of controllers 41 and 42 by operating these switches.

[0053] The redundant controller 4 is redundantly configured by including the controllers 41 and 42 described above. In the redundant controller 4, the controller 42 does not have internal control calculation functions; instead, the control calculation unit 51 of the external device 5 can perform the control calculations and obtain the results of those calculations. Since no calculation function is required, the function of the controller 42 is simplified accordingly, thereby reducing the cost of the controller 42 and consequently reducing the cost of the redundant controller 4.

[0054] External device 5 can be implemented using any computing environment within the scope of enabling the functions of control arithmetic unit 51. By using a general-purpose computer or the like, the possibility of further reducing the cost of control arithmetic is increased.

[0055] In redundancy, one of controllers 41 and 42 operates in the running state, while the other operates in the standby state. If an anomaly occurs in the controller in the running state, the controller in the standby state switches to the running state to continue process control of plant equipment 1. As described above, state switching can be performed using dedicated hardware. Therefore, compared to using a general-purpose computer (platform, etc.) external to the controller to implement redundancy-related functional blocks, or requiring additional network communication, high-speed switching is possible.

[0056] Figures 2-5 This is a flowchart illustrating an example of the processing (redundancy method, control method) performed in a redundancy controller.

[0057] Figure 2 Examples of actions such as equivalence to obtain a redundant structure are illustrated. With the controller 42 prepared (installed, etc.) together with the controller 41 in operation, this action is initiated, for example, by a user operation. Examples of user operations include user operations via the aforementioned terminal device 6, operations performed by the operator of the factory equipment 1 while observing a screen (such as a monitoring screen).

[0058] In steps S1 to S3, a notification is sent to initiate the replication of control data. The redundancy management unit 422 of the controller 42 sends the replication start notification to the external device 5 via the communication function unit 425. The control calculation unit 51 of the external device 5 receives the replication start notification via the communication function unit 55.

[0059] In steps S4 to S6, permission is granted to begin copying control data. The control calculation unit 51 of the external device 5 sends the copy start permission to the controller 42 via the communication function unit 55. The redundancy management unit 422 of the controller 42 receives the copy start permission via the communication function unit 425.

[0060] In steps S7 and S8, a copy request is made. The redundancy management unit 422 of controller 42 sends the copy request to controller 41 via the redundancy input / output function unit 424. Controller 41 receives the copy request.

[0061] In step S9, controller 41 switches to copy mode. Steps S10 to S17, described below, are performed on the control data of each copied object, and the control data is copied from controller 41 to controller 42 and external device 5 (after equivalence).

[0062] In steps S10 and S11, the redundancy management unit 412 of the controller 41 sends control data to the controller 42, for example, when the control calculation unit 411 performs control calculations. The redundancy input / output function unit 424 of the controller 42 receives the control data.

[0063] In steps S12 and S13, the redundancy input / output function unit 424 of the controller 42 delivers control data to the redundancy management unit 422 and reflects the control data in its own memory (e.g., a storage device not shown stored in the controller 42).

[0064] In steps S14 to S17, the redundancy management unit 422 sends control data to the external device 5 via the communication function unit 425. The control calculation unit 51 of the external device 5 receives the control data via the communication function unit 55 and reflects the control data in its own memory (e.g., a storage device not shown stored in the external device 5).

[0065] Through the processes described in steps S10 to S17, all control data of the copied object is copied from controller 41 to controller 42 and external device 5. Afterward, the process proceeds to step S18.

[0066] In steps S18 to S20, a notification of copy completion is sent. Controller 41 sends the copy completion notification to controller 42 and waits for processing (waiting). The redundancy management unit 422 of controller 42 receives the copy completion notification via the redundancy input / output function unit 424.

[0067] In steps S21 to S27, the process proceeds towards the start of redundancy.

[0068] The redundancy management unit 422 of controller 42 prepares for redundancy and sends a redundancy start notification to controller 41 via the redundancy input / output function unit 424. Controller 41 receives the redundancy start notification, starts redundancy, and sends the redundancy start notification to controller 42. The redundancy management unit 422 of controller 42 receives the redundancy start notification via the redundancy input / output function unit 424 and starts redundancy.

[0069] In step S28, controller 41 begins control. The redundancy management unit 412 of controller 41 obtains the control calculation results from control calculation unit 411 in the same manner as described above. In this example, controller 41 is in operation, and the control calculation results are reflected in the process control of plant equipment 1.

[0070] In steps S29 to S32, controller 42 also begins control. The redundancy management unit 422 of controller 42 sends control data to external device 5 via communication function unit 425. The control calculation unit 51 of external device 5 receives the control data via communication function unit 55 and begins control calculation using the received control data. In this example, controller 42 is in standby mode, and the control calculation results are not reflected in the process control of plant equipment 1.

[0071] For example, as described above, a redundant controller 4 is obtained, consisting of a controller 41 in the running state and a controller 42 in the standby state.

[0072] Figure 3 Examples of the processes performed when controllers 41 and 42 are in running and standby states are shown.

[0073] In steps S41 to S44, the control calculation unit 51 of the external device 5 requests the input / output data required to perform control calculations. The control calculation unit 51 of the external device 5 sends the input / output request to the controller 42 via the communication function unit 55. The redundancy management unit 422 of the controller 42 receives the input / output request via the communication function unit 425.

[0074] In step S44, the redundancy management unit 422 of the controller 42 waits for processing (equivalence waiting) until the requested input / output data is obtained through equivalence.

[0075] In steps S45 and S46, controller 41 requests the input / output data required to perform control operations. Controller 41 sends the input / output request to input / output device 3. Input / output device 3 obtains the requested input / output data from field device 2 and sends it to controller 41. Controller 41 receives the input / output data.

[0076] In steps S47 to S51, input / output data is copied from controller 41 to controller 42 and external device 5. Controller 41 sends the input / output data to controller 42. The redundancy management unit 422 of controller 42 receives the input / output data via the redundancy input / output function unit 424 and reflects it in its own memory. The redundancy management unit 422 releases the equalization wait and sends the input / output data to external device 5 via the communication function unit 425. The control and calculation unit 51 of external device 5 receives the input / output data via the communication function unit 55 and reflects it in its own memory.

[0077] In step S52, controller 41 performs control calculations. In this example, controller 41 is in operation, and the results of the control calculations are reflected in the process control of plant equipment 1.

[0078] In step S53, the control calculation unit 51 of the external device 5 performs control calculations. In this example, the controller 42 is in standby mode, and the control calculation results are not reflected in the process control of the factory equipment 1.

[0079] For example, as described above, control calculation results based on the same data can be obtained in both the controller 41 and controller 42 in the running state and the standby state. Among them, the control calculation results obtained in the controller 41 in the running state are reflected in the process control of the plant equipment 1.

[0080] Figure 4 Examples of the processes performed when controllers 41 and 42 are in standby and running states are shown.

[0081] In steps S61 to S67, the control calculation unit 51 of the external device 5 requests and obtains the input / output data required for performing control calculations. The control calculation unit 51 of the external device 5 sends the input request to the controller 42 via the communication function unit 55. The redundancy management unit 422 of the controller 42 receives the input / output request via the communication function unit 425. The redundancy management unit 422 sends the input / output request to the input / output device 3 via the field input / output function unit 423. The input / output device 3 obtains the requested input / output data from the field device 2 and sends it to the controller 42. The redundancy management unit 422 of the controller 42 receives the input / output data via the field input / output function unit 423.

[0082] In step S68, the controller 41 waits for processing (equivalence waiting) until the input and output data required for the control operation are obtained through equivalence.

[0083] In steps S69 to S71, equivalence is performed. The redundancy management unit 422 of controller 42 sends input / output data to controller 41 via the redundancy input / output function unit 424. Controller 41 receives the input / output data and reflects it in its own memory (e.g., a storage device not shown stored within controller 41). The redundancy input / output function unit 424 of controller 42 notifies the redundancy management unit 422 that equivalence is complete.

[0084] In steps S72 to S74, input / output data is also sent to the external device 5. The redundancy management unit 422 of the controller 42 sends the input / output data to the external device 5 via the communication function unit 425. The control calculation unit 51 of the external device 5 receives the input / output data via the communication function unit 55.

[0085] In step S75, the control calculation unit 51 of the external device 5 performs control calculations. In this example, the controller 42 is in operation, and the control calculation results are reflected in the process control of the factory equipment 1.

[0086] In step S76, controller 41 performs control calculations. In this example, controller 41 is in standby mode, and the results of the control calculations are not reflected in the process control of plant equipment 1.

[0087] For example, as described above, control calculation results based on the same data can be obtained in both the standby state and the running state of the controller 41 and the controller 42. Specifically, the control calculation results obtained in the running state of the controller 42 are reflected in the process control of the plant equipment 1.

[0088] Figure 5 The switching steps when an anomaly occurs are illustrated. The steps include anomaly detection, identification of the anomaly location, and switching.

[0089] In steps S81 to S84, an anomaly is detected. Controller 41 sends the anomaly detection to controller 42. The redundant input / output function unit 424 of controller 42 detects the anomaly by receiving the anomaly detection, and further notifies the field input / output function unit 423 of the anomaly.

[0090] In steps S85 to S87, an exception notification is also sent to the external device 5. The redundancy management unit 422 of the controller 42 sends the exception notification to the external device 5 using the communication function unit 425. The control calculation unit 51 of the external device 5 receives the exception notification via the communication function unit 55.

[0091] In step S88, the control calculation unit 51 of the external device 5 waits for processing (waiting). This waiting can also be considered as a special state (irregular processing) that occurs when an anomaly occurs.

[0092] In step S89, the redundancy management unit 422 of the controller 42 determines the abnormal part by performing self-diagnosis, for example, and determines whether the controller 42 can be switched to the running state (whether the control can be replaced from the controller 41 to the controller 42).

[0093] Based on the judgment result of the redundancy management unit 422, the following processing branches occur. The processing diagram for when the controller 42 can be switched to the operating side is shown as steps S90 to S94. The processing diagram for when it cannot be switched is shown as steps S90X to S94X.

[0094] In steps S90 to S94, the controller 42 switches to the running state. The redundancy management unit 422 of the controller 42 performs control replacement processing. Specifically, the redundancy management unit 422 notifies the external device 5 to restart control via the communication function unit 425. The control calculation unit 51 of the external device 5 receives the notification to restart control via the communication function unit 55 and restarts control calculation. The control calculation result is reflected in the process control.

[0095] In steps S90X to X94X, the controller 42 restarts from standby mode. The redundancy management unit 422 of the controller 42 performs the restart process. Specifically, the redundancy management unit 422 sends a restart request to the external device 5 via the communication function unit 425. The control calculation unit 51 of the external device 5 receives the restart request via the communication function unit 55 and restarts. Control calculations are performed in the same manner as described above. The results of the control calculations are not reflected in the process control.

[0096] For example, as described above, when an anomaly occurs, the states of controller 41 and controller 42 are switched as needed (e.g., based on diagnostic results).

[0097] According to the redundant controller 4 described above, the computational functions in the controller 42 constituting the redundant controller 4 are implemented by an external device 5. This reduces the cost of the controller accordingly. By using a general-purpose computer or similar device as the external device 5, the possibility of reducing the cost of control computation is increased. Therefore, the cost of redundancy in the controller can be reduced. Furthermore, by installing redundancy-related functions (redundancy management unit 412, redundancy management unit 422, etc.) within the controller, high-speed switching between the states of controller 41 and controller 42 is possible.

[0098] Because redundant controller 4 can be implemented at a lower cost compared to the past, its application scope is expanded. For example, the redundant structure can be used temporarily. A redundant structure can be implemented by adding a low-cost controller 42 only when necessary in a single structure where process control is performed only by controller 41 during normal operation. As described above, controller 42 also switches to a stop state where it does not obtain control calculation results (and therefore may not perform control calculations itself). If controller 42 switches between a standby state and a stop state, the redundant structure is only obtained when controller 42 is in the standby state (i.e., temporarily). Switching can be performed at any time through user operation, etc. That is, the redundancy management unit 412 of controller 42 switches controller 42 between a standby state and a stop state at any time while controller 41 is in the running state. Thus, temporary use of the redundant structure can be achieved.

[0099] For example, redundancy can be used to avoid temporary risks. Redundancy can also be used only when the risk is relatively high, depending on the level of risk in the controlled processes. Furthermore, redundancy can be dynamically implemented while monitoring operational status and managing processes.

[0100] It can also be used in operations (dynamic migration) that do not stop the process control of plant equipment 1. For example, it can provide a redundant structure at low cost for engineering operations such as replacing or repairing controllers that have been identified as malfunctioning. It can also be used for operations such as updating the controller software.

[0101] The fee can also be set based on the usage of the external device 5. For example, the user can be charged for the usage time of functions such as the control and calculation unit 51 of the external device 5. By adopting this charging system, the possibility of further reducing the cost of redundancy is increased.

[0102] The above describes one embodiment of the present invention. The disclosed technology is not limited to the above embodiment. Some variations are described.

[0103] In one implementation, the first controller may also be able to obtain the control calculation results using the external device 5. (Refer to...) Figure 6 This needs to be explained.

[0104] Figure 6 This is a diagram illustrating a schematic configuration of a modified redundant controller. The illustrated control system 100A's redundant controller 4A includes controller 41A and controller 42. Controller 41A and controller 41 (… Figure 1 The difference lies in the inclusion of a communication function unit 415A instead of a control calculation unit 411. The communication function unit 415A has the same functions as the communication function unit 425 of the controller 42. Both the controller 41A and the controller 42 communicate with their respective external devices 5. In the redundant controller 4A, the calculation function is not required in the controller 41A, resulting in further cost reduction. Furthermore, the functions of the external devices 5 corresponding to the controller 41A (control calculation unit 51, communication function unit 55) and the external devices 5 corresponding to the controller 42 can be integrated into a single external device.

[0105] In one implementation, the external device may be capable of performing multiple different control operations. (See also...) Figure 7 This needs to be explained.

[0106] Figure 7 This diagram illustrates a schematic configuration of a modified controller and external devices. The controller 42AB can communicate with external devices 5A and 5B respectively. The control calculation unit 51A of external device 5A and the control calculation unit 51B of external device 5B perform different control calculations. For example, the redundancy management unit 422AB of the controller 42AB can obtain the result of the control calculation of at least one of the control calculation units 51A and 51B from external device 5A and / or external device 5B. The increased variety of calculation functions expands the possibilities for process control. Alternatively, the redundancy management unit 422AB can obtain the results of the control calculations of both control calculation units 51A and 51B. This enables the realization of higher calculation functions and faster calculation speeds. It is possible to execute three or more different control calculations; in this case, the redundancy management unit 422AB can obtain the result of at least one of the multiple different control calculations. Furthermore, the functions of multiple external devices (such as external device 5A and external device 5B) can be concentrated in one external device.

[0107] In the above embodiment, the example of using two controllers, controller 41 and controller 42, is given as a redundancy structure. However, a redundancy structure can also be implemented using three or more controllers.

[0108] Figure 8 This diagram illustrates an example of the hardware configuration of a controller. This hardware configuration includes a communication device 42a, a display device 42b, an HDD (Hard Disk Drive) 42c, a memory 42d, and a processor 42e, all interconnected via a bus or similar means.

[0109] The communication device 42a is a network interface card or similar device, capable of communicating with other devices. The display device 42b is, for example, a touch panel or a monitor. The HDD 42c functions as a storage unit such as internal memory, for example, storing programs (redundancy programs, control programs) used to execute the processing of the controller 42.

[0110] The processor 42e reads the aforementioned program from the HDD 42c and expands it in the memory 42d to implement the functions of the controller 42. These functions include those of the redundancy management unit 422, the field input / output function unit 423, and the redundancy input / output function unit 424, as described above.

[0111] The program can be distributed via networks such as the Internet. Furthermore, the program can be recorded on computer-readable media such as hard disks, floppy disks (FD), CD-ROMs, MO (Magneto-Optical Disk), and DVDs (Digital Versatile Discs), and executed by a computer from the recording medium.

[0112] Devices other than controller 42, such as controller 41, external device 5, and terminal device 6, may also include the same hardware configuration as described above.

[0113] The techniques described above are determined, for example, in the following manner. (Refer to...) Figures 1-5 The controller 42 described above, together with controller 41 (another controller), constitutes the redundant controller 4. Controller 42 includes a communication function unit 425 and a redundancy management unit 422. The communication function unit 425 communicates with an external device 5 capable of performing control calculations required for process control of the plant equipment 1. The redundancy management unit 422 switches the state of controller 42 between various states, including an operating state that reflects the results of control calculations obtained from the external device 5 via the communication function unit 425 in process control, and a standby state that does not reflect the results of control calculations in process control. The redundancy management unit 422 switches the state of controller 42 so that one of controller 42 and controller 41 is in an operating state.

[0114] According to the controller 42 described above, the computational functions required for process control of the factory equipment 1 are implemented by the external device 5. This allows for a corresponding reduction in the cost of the controller 42. By using a general-purpose computer or similar device as the external device 5, the possibility of reducing the cost of control computation is increased. Therefore, the cost of controller redundancy can be reduced. Furthermore, by installing a redundancy management unit 422 within the controller 42, high-speed switching between the states of the controller 41 and the controller 42 is possible.

[0115] Controller 42 can be temporarily used to form a redundant controller 4. As described above, since the cost of controller 42 is reduced, controller 42 can be appropriately used for such temporary use.

[0116] The redundancy management unit 422 can switch the controller 42 between a standby state and the stopped state at any time while the controller 41 is in the running state. In this case, the cost can be set according to the utilization of the external device 5. By setting the cost corresponding to the temporary utilization of the controller 42, the possibility of further reducing the cost of redundancy is increased.

[0117] The redundancy management unit 412 can copy the data required for control calculations from controller 41 to controller 42, send the copied data to external device 5 via communication function unit 425, and obtain the results of control calculations from external device 5. For example, by obtaining calculation results based on the same data in controller 41 and controller 42, a redundancy structure can be obtained.

[0118] For reference Figure 7 As explained, external devices 5 (e.g., external devices 5A and 5B) can perform multiple different control operations, and the redundancy management unit 422AB can obtain the result of at least one of the multiple different control operations from external devices 5 via the communication function unit 425. This increases the variety of operational functions, thereby expanding the possibilities for process control of the factory equipment 1. Furthermore, it enables the realization of more sophisticated operational functions and higher operational speeds.

[0119] Reference Figures 2-5The control method described is also one implementation method. This control method is performed by controller 42, which together with controller 41 (another controller) constitutes a redundant controller 4. This control method includes: communicating with an external device 5 capable of performing control calculations required for process control of the plant equipment 1 (steps S2, S5, S15, S30, S42, S50, S62, S73, S86, S92, S92X, etc.); and switching the state of controller 42 between various states (step S90, etc.). These various states include an operating state that reflects the results of control calculations obtained from the external device 5 via communication in process control, and a standby state that does not reflect the results of control calculations in process control. During the switching, the state of controller 42 is switched so that one of controller 42 and controller 41 is in an operating state. According to this control method, as described above, the cost of controller redundancy can also be reduced.

[0120] In the control method, as described above, controller 42 can also be temporarily used to form a redundant controller 4. Multiple states are possible, including a stop state where no control calculation result is obtained. During switching, while controller 41 is in the running state, controller 42 can be switched between a standby state and a stop state at any time. Costs can be set based on the utilization of the external device 5. During the process of obtaining the control calculation result, the data required for the control calculation can be copied from controller 41 to controller 42, the copied data can be sent to the external device 5, and the control calculation result can be obtained from the external device 5. The external device 5 can be (e.g., Figure 7 External devices 5A and 5B can perform multiple different control operations. During switching, the result of at least one of the multiple different control operations can be obtained from external device 5 via communication.

Claims

1. A control system, characterized by comprises: a first controller that performs control operations required for process control of a plant; a second controller that constitutes a redundant controller with the first controller and has no function of the control operations required for the process control inside; and an external device that performs the control operations of the second controller, a redundant management section of the first controller switches a state of the first controller among a plurality of states including an operating state in which a result of the control operations is reflected in the process control, a standby state in which the result of the control operations is not reflected in the process control, and a stop state in which the result of the control operations is not acquired, a redundant management section of the second controller switches a state of the second controller among the plurality of states including the operating state and the standby state, and communicates with the external device, the redundant management section of the second controller acquires a result of the control operations performed by the external device, and switches the second controller to the operating state by reflecting the acquired result of the control operations in the process control, the first controller switches the first controller between the standby state and the stop state at any timing when the second controller is in the operating state.

2. The control system according to claim 1, wherein the redundant management section of the second controller switches the second controller to the standby state by not reflecting the result of the control operations performed by the external device in the process control.

3. The control system of claim 1, wherein, A fee is set in accordance with utilization of the external device.

4. The control system of claim 1 or 2, wherein The redundant management section of the first controller copies data required for the control operations from the second controller to the first controller, transmits the copied data to the external device via a communication function section, and acquires the result of the control operations from the external device.

5. The control system according to claim 1 or 2, wherein the external device can perform a plurality of different control operations, the redundant management section of the first controller can acquire a result of at least one of the plurality of different control operations from the external device via the communication function section.

6. A control method characterized by comprises: a step of performing control operations required for process control of a plant by a first controller; and a step of performing control operations of a second controller by an external device, the second controller constituting a redundant controller with the first controller and having no function of the control operations required for the process control inside, a redundant management section of the first controller switches a state of the first controller among a plurality of states including an operating state in which a result of the control operations is reflected in the process control, a standby state in which the result of the control operations is not reflected in the process control, and a stop state in which the result of the control operations is not acquired, a redundant management section of the second controller switches a state of the second controller among the plurality of states including the operating state and the standby state, and communicates with the external device, the redundant management section of the second controller acquires a result of the control operations performed by the external device, and switches the second controller to the operating state by reflecting the acquired result of the control operations in the process control, the first controller switches the first controller between the standby state and the stop state at any timing when the second controller is in the operating state. The redundancy management section of the second controller acquires a result of the control operation performed by the external device, switches the second controller to an operating state by reflecting the acquired result of the control operation in the process control, The first controller switches the first controller between the standby state and the stopped state at an arbitrary timing while the second controller is in the operating state.

7. The control method according to claim 6, wherein The redundancy management section of the second controller switches the second controller to the standby state by not reflecting a result of the control operation performed by the external device in the process control.

8. The control method according to claim 6, characterized by A fee is set in accordance with utilization of the external device.

9. The control method according to claim 6 or 7, characterized by, The redundancy management section of the first controller copies data required for the control operation from the second controller to the first controller, transmits the copied data to the external device via the communication function section, and acquires a result of the control operation from the external device.

10. The control method according to claim 6 or 7, wherein The external device is capable of performing a plurality of different control operations, The redundancy management section of the first controller is capable of acquiring a result of at least one of the plurality of different control operations from the external device via the communication function section.

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