JP7552249B2 - Host management device, production control system, host management method, and host management program - Google Patents

Description

This relates to a host management device that is connected via a network to multiple lower level control devices that control one or more of the processes in a production line that includes multiple processes for producing production objects.

Traditionally, in the field of FA (Factory Automation), attempts have been made to efficiently collect and manage data related to production equipment installed in factories and other facilities.

For example, Patent Document 1 discloses a device that determines whether a workpiece is of good quality or not in a production facility and transmits only the data that corresponds to a defect to a higher-level device.

Patent document 2 also discloses a PLC (Programmable Logic Controller) that collects data in production equipment according to specific collection rules and transmits the data to a higher-level device.

Patent Document 3 also discloses a device that determines whether a workpiece in a production facility exhibits a different behavior (hereinafter referred to as an abnormality) from the normal production state.

Japanese Patent Application Publication No. 9-131648 JP 2020-52441 A JP 2018-97839 A

However, in the conventional technology described above, when a defect occurs in a certain process of a certain production facility, or when certain conditions are met in that process, data for that process is merely sent to a higher-level device. In other words, since only the data for that process is sent to the higher-level device, it cannot be said to be data related to the preceding or following processes. As a result, it is not possible to consider cases where the cause of the defect occurred before that process, or where a defect in that process affects a subsequent process.

One aspect of the present invention aims to transmit data including the preceding and following processes to a higher-level device when a defect or abnormality occurs in a process, thereby enabling more detailed data analysis.

In order to solve the above problems, a higher-level management device according to one aspect of the present invention is a higher-level management device that is connected via a network to a plurality of lower-level control devices that control one or more of the processes in a production line that includes a plurality of processes for producing a production object, and includes a receiving unit that receives abnormal process information from one of the lower-level control devices regarding an abnormal process when an abnormality is detected in the lower-level control device, an identifying unit that identifies a process involved in the production object that was produced in the abnormal process from among the processes included in the production line based on the abnormal process information, a command unit that requests the plurality of lower-level control devices to transmit measurement data regarding the process involved, and a storage control unit that controls the storage of the abnormal process information and the measurement data in a storage unit.

The above configuration makes it possible to identify the process involved in the production object in which the abnormality occurred, and to request the lower-level control device that controls the process to send measurement data. In other words, in addition to the measurement data of the lower-level control device in which the abnormality occurred, it is also possible to obtain measurement data from other lower-level control devices on the production line, making it possible to provide data for cross-sectional comparison and analysis of measurement data from processes including those before and after.

The identification unit may refer to a required time table indicating the order of the processes included in the production line and the required time for each of the processes, and identify the involved process by process information and execution time information based on the abnormal process information, and the command unit may transmit the process information and execution time information to multiple lower-level control devices.

According to the above configuration, it is possible to receive abnormal process information related to the abnormality from the lower-level control device where the abnormality occurred, identify the implementation time of each process involved in the process where the abnormality occurred, and issue a command to the lower-level control device to transmit implementation time information at the implementation time. Therefore, if the process where the abnormality occurred can be identified, it is possible to identify the process and implementation time of the process involved, and it is possible to obtain measurement data to be used for comparing and examining the abnormality.

Each of the production objects produced on the production line may be provided with identification information, and the command unit may transmit the identification information of the production objects produced during the abnormality process to a plurality of the lower-level control devices.

According to the above configuration, since the production object is provided with identification information, it is possible to identify the measurement data relating to the production object in which an abnormality has occurred from the measurement data relating to multiple production objects, and obtain the measurement data to be used for comparison.

The command unit may request each of the lower-level control devices to transmit the measurement data so that the measurement data related to the participation process from one lower-level control device and the measurement data related to the participation process from another lower-level control device are received at different times.

With the above configuration, the timing of transmitting measurement data can be shifted for each lower-level control device, reducing the communication load on the network.

The identification unit may identify the involved process upstream of the abnormality occurrence process.

With the above configuration, the involved processing can be targeted at lower-level control devices upstream of the process where the abnormality occurred. This makes it easier to investigate the cause of the abnormality in the process where the abnormality occurred.

The identification unit may identify the involved process downstream of the abnormality occurrence process.

According to the above configuration, the involved processing can target lower-level control devices downstream of the process where the abnormality occurred. This makes it easier to identify other abnormalities caused by the abnormality in the process where the abnormality occurred.

The production control system according to one aspect of the present invention includes the upper management device and a plurality of the lower control devices connected to the upper management device via a network.

The upper level management method according to one aspect of the present invention is a method for managing an upper level management device connected via a network to a plurality of lower level control devices that control one or more of a plurality of processes for producing a production object in a production line including the plurality of processes for producing the production object, and includes a receiving step of receiving abnormal process information from one of the lower level control devices regarding an abnormal process when an abnormality is detected in the lower level control device, a specifying step of specifying a process involved in the production object that was produced in the abnormal process from among the processes included in the production line based on the abnormal process information, a command step of requesting the plurality of lower level control devices to transmit measurement data regarding the process involved, and a storage control step of controlling the storage of the abnormal process information and the measurement data in a storage unit.

The upper management device according to each aspect of the present invention may be realized by a computer. In this case, the upper management device control reception program, specific program, command program, and storage control program of the upper management device that realizes the upper management device by making the computer operate as each part (software element) of the upper management device, and the computer-readable recording medium on which they are recorded, also fall within the scope of the present invention.

According to one aspect of the present invention, a host management device is obtained that can compare measurement data from processes involved before and after an abnormality occurs.

1 is a block diagram showing a configuration of a main part of a production line according to a first embodiment; 1 is a block diagram showing a configuration of a main part of a control system according to a first embodiment; 13 is an example of a required time table. FIG. 4 is a schematic diagram illustrating an example of an abnormality determination process. 11 is a flowchart of advance preparations for acquiring measurement data in the control system. 10 is a flowchart showing a process for acquiring measurement data in the control system. 13 is an example of a measurement data narrowing-down process according to the second embodiment.

[Embodiment 1]
Hereinafter, an embodiment according to one aspect of the present invention (hereinafter, also referred to as "the present embodiment") will be described with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and the description thereof will not be repeated.

§1. Application Example Fig. 1 is a block diagram showing the configuration of the main parts of a production line 70 according to the first embodiment. The production line 70 is a line that processes workpieces (production objects) through processes A1, A2, A3, B1, B2, B3, C1, C2, and C3 to produce products. Workpieces pass through each process one by one and are processed. For example, as shown in Fig. 1, the fifth workpiece is being produced in process B2, and the fifth workpiece is then moved to process B3, where the fourth workpiece is currently being produced, to continue production. When process C3 is finished, production is completed and the product is completed.

If an abnormality occurs in the production of the workpiece in process B2 that causes the workpiece to behave differently from normal production, it is possible that the workpiece No. 5 itself will become a defective product in process B2, but it may also become a defective product in a later process. Furthermore, the true cause of the defective product in process B2 is not necessarily in process B2, and the cause may lie in a previous process.

In this way, when an abnormality that differs from normal production occurs, the cause of the defect can be identified and the process can be improved by checking the measurement data including the preceding and following processes. Therefore, in this application, a host management device 10 is realized that, when an abnormality that differs from normal production is detected, acquires information on the preceding and following processes related to the work in question as measurement data.

§2. Configuration Example Fig. 2 is a block diagram showing the configuration of the main parts of the control system 1 according to the first embodiment.

(Control System 1)
The control system 1 (production control system) comprises a host management device 10, an upstream lower-level control device 41, an abnormality source lower-level control device 42, and a downstream lower-level control device 43. The upstream lower-level control device 41, the abnormality source lower-level control device 42, and the downstream lower-level control device 43 are collectively referred to as a lower-level control device 40. The lower-level control devices 40 have common functions, and in FIG. 2, the upstream lower-level control device 41 is shown as a representative.

The control system 1 connects the upper management device 10 and the lower control device 40 via a network.

(Production Line)
The control system 1 is a system that comprehensively controls a production line 70. The production line 70 is made up of a plurality of devices 60. Each device 60 processes a plurality of processes 50. Each device includes one or more lower level control devices 40.

When an abnormality occurs, process 50 is broadly divided into abnormality occurrence process 51, where the processing in which the abnormality occurred was performed, upstream process 52, where processing was performed before that processing, and downstream process 53, where processing was performed after that processing. There is one abnormality occurrence process 51, but there may be multiple upstream processes 52 and downstream processes 53, or there may be none.

For example, as shown in FIG. 1, the production line 70 has three devices 60: an upstream device 61, an abnormality source device 62, and a downstream device 63. The upstream device 61 is controlled by the upstream lower control device 41, and processes the upstream process 52, which are process A1, process A2, and process A3. The abnormality source device 62 is controlled by the abnormality source lower control device 42, and processes the upstream process 52, which is process B1, the abnormality occurrence process 51, and process B3, the downstream process 53. The downstream device 63 is controlled by the downstream lower control device 43, and processes the downstream process 53, which is process C1, process C2, and process C3.

Of course, the number of devices 60 that make up the production line 70 is not limited to three. Also, each device 60 (hereinafter, the upstream device 61, the abnormality source device 62, and the downstream device 63 will be collectively referred to as device 60) processes three processes 50, but the number is not limited to three.

In this embodiment, for the sake of explanation, it is assumed that the abnormality source lower-level control device 42 detects that an abnormality has occurred in process B2 processed by the abnormality source device 62 (process B2 is the abnormality occurrence process 51), but this is not limited to this, and the abnormality may occur in any process.

Production line 70 is assumed to be a production line in which work (production objects) are processed sequentially.

(Upper management device 10)
The upper level management device 10 is a control device that manages a plurality of lower level control devices 40, and performs processing to acquire and store measurement data acquired by the lower level control devices 40 and related to a workpiece in which an abnormality has occurred. The control unit 10 includes a control unit 20 and a storage unit 30 .

The control unit 20 comprehensively controls each part of the host management device 10. The control unit 20 includes a receiving unit 21, an identifying unit 22, a command unit 23, and a memory control unit 24. The memory unit 30 stores data and programs used by the host management device 10. The memory unit 30 does not have to be included in the host management device 10, and may be stored on the cloud. The memory unit 30 stores a required time table 31 and a database 32.

The receiving unit 21 receives abnormal process information from one of the lower-level control devices 40 (abnormality source lower-level control device 42) when an abnormality is detected in the lower-level control device 40 during the production of the workpiece. The receiving unit 21 outputs the received abnormal process information to the identifying unit 22. The abnormal process information includes process information that can identify the abnormality occurrence process 51 and implementation time information that is the time when the abnormality occurs.

Based on the input abnormal process information, the identification unit 22 refers to the required time table 31 (described in detail later) and identifies the involved processes involved in the workpiece being produced in the abnormal process 51 from among the processes 50 included in the production line 70. Information on the identified involved processes is output to the command unit 23.

The identification unit 22 may identify an upstream process 52 and a downstream process 53 of the abnormality occurrence process 51 as the involved processes.

Based on the input information on the involved processes, the command unit 23 requests the multiple lower-level control devices 40 to transmit measurement data related to the involved processes. When transmitting, the command unit 23 may transmit the process information of the target process 50 together with the implementation time information (time information when the work is processed).

The command unit 23 may also transmit measurement data transmission commands to two or more lower-level control devices 40 with a time lag. For example, it is possible to repeat the control of transmitting a transmission command to one lower-level control device 40, receiving measurement data from the lower-level control device 40, and then transmitting a transmission command to another lower-level control device 40.

This allows the timing of receiving the measurement data related to the participation process from one lower-level control device to be different from the timing of receiving the measurement data related to the participation process from another lower-level control device, thereby reducing the network load.

The command unit 23 may simultaneously send commands to send measurement data to multiple downstream lower-level control devices 40. This is because the processing in the downstream process 53 is incomplete when an abnormality occurs, and so the measurement data is sent after the processing of each process 50 is completed without intentionally setting a time difference. In other words, as a result, the timing at which the upper management device 10 receives the measurement data from each lower-level control device will differ, which reduces the network load.

The memory control unit 24 controls the storage of the measurement data and abnormal process information received from the lower-level control device 40 in the memory unit 30.

The required time table 31 is a setting that the lower-level control device 40 stores in the memory unit 30 through the upper-level management device 10, and is a table that stores the required time for each process 50 of each lower-level control device 40 and the processing order of the processes 50 on the production line 70.

Figure 3 is an example of the required time table 31. As shown in Figure 3, in addition to the process name, the required time table 31 may also store information (PLC name) that identifies the lower-level control device 40 that manages the process 50.

The database 32 is a database that stores measurement data during the production of a workpiece measured by the lower-level control device 40. Any data may be stored as the measurement data.

(Lower control device 40)
The lower control device 40 controls the production of workpieces in a plurality of processes 50, and notifies the upper management device 10 if an abnormality occurs during the production of the workpiece. Furthermore, the lower control device 40 transmits measurement data during the production of the workpiece to the upper management device based on a command from the upper management device 10. The lower control device 40 comprises an abnormality determination unit 81, a ring buffer 82, a command receiving unit 83, a condition determination unit 84, and a data transmission unit 85. Each lower control device 40 has the same functions.

The abnormality determination unit 81 determines an abnormality that occurs in the process 50 controlled by the lower-level control device 40. An "abnormality" does not mean an abnormality that occurs in the equipment controlled by the lower-level control device 40, but is a concept that refers to the production of workpieces under production conditions that differ from normal production conditions. Furthermore, a workpiece that exhibits an abnormality does not necessarily become a defective product in the pass/fail product determination that determines whether the workpiece satisfies the product functions based on the specified standards for each process 50.

When the abnormality determination unit 81 determines an abnormality, it notifies the upper management device 10 of the abnormality, which is abnormal process information. The abnormal process information includes the time when the abnormality occurred and information about the process where the abnormality occurred. The abnormal process information does not need to include measurement data at the time when the abnormality occurred. Details regarding the abnormality determination process will be described later.

The ring buffer 82 is a buffer that temporarily stores the measurement data of a predetermined number of workpieces, and temporarily stores the data regardless of whether the production status of the workpieces is abnormal. The measurement data temporarily stored in the ring buffer 82 is transmitted to the higher-level management device 10 via the data transmission unit 85 based on the judgment result of the condition judgment unit 84. The ring buffer 82 temporarily stores a certain number of measurement data, but overwrites and saves the oldest measurement data with new measurement data.

The specified number temporarily stored in the ring buffer 82 is the number of workpieces produced before a workpiece has passed through the production line when the production line 70 is operating at a normal takt time, with some surplus.

The command receiving unit 83 has a function of receiving commands from the command unit 23. The command receiving unit 83 outputs to the condition determining unit 84 that a command to transmit measurement data has been received from the higher-level management device 10. The command receiving unit 83 may output to the condition determining unit 84 the process information and implementation time information that have been combined with the command.

The condition determination unit 84 determines whether or not there is relevant measurement data based on instructions from a higher-level management device. If the process information is a downstream process 53 of the process where the abnormality occurred, it may not yet be involved in the production of the workpiece, so the transmission of the measurement data is put on hold until the relevant measurement data is acquired (until the condition is met). If there is relevant measurement data, the condition determination unit 84 outputs the relevant measurement data to the data transmission unit 85.

The data transmission unit 85 transmits the input measurement data to the memory control unit 24 of the higher-level management device 10.

In this embodiment, the lower-level control device 40 may be configured as a PLC or may use a general-purpose computer.

(Abnormality Judgment Processing)
The low-level control device 40 may perform the abnormality determination through the following process. Fig. 4 is a schematic diagram showing an example of the abnormality determination process. As shown in Fig. 4, the low-level control device 40 performs a plurality of processes (processes 401 to 405) on the measurement data to determine whether an abnormality has occurred.

Process 401 is a process for acquiring collected data, which is data related to the production of workpieces. The collected data may be so-called raw data, such as measurement data from various sensors and output data on the operating status of various operating devices. More specifically, examples include the torque value of the drive unit of the operating device in the corresponding process, the measured value of the position of the workpiece or the workpiece gripper of the operating device, and the measured value of the moving speed of the workpiece or the workpiece gripper of the operating device. The collected data in this process is high-speed sampled data, and is a large volume of data. Therefore, since it is difficult to continue to store all the collected data in the storage device in the lower control device 40, it is common to temporarily store the data in the ring buffer 82 and transmit and store only the necessary data in the upper management device 10.

Process 402 is a process for dividing continuous collected data into collected data for each workpiece produced. In other words, it is a task for determining the period of collected data, which is associated with each unique number or identification information within the lower-level control device 40. Specifically, when temporarily storing the collected data in chronological order in a ring buffer, it is possible to temporarily store the workpiece identification information as well, and perform processing to divide the data based on the period of the same identification information.

Process 403 calculates feature data, which is a statistical value, for the collected data for each workpiece. In other words, a feature that represents a large amount of collected data involved in the production of a certain workpiece is derived. Statistical values used for feature data include the average, maximum, minimum, mode, standard deviation, etc., and multiple feature values may be defined for one workpiece.

Process 404 weights at least one or more pieces of feature data and calculates an anomaly score by adding them up. An anomaly detection algorithm may be used to determine the feature data and its weighting used to calculate the anomaly score.

One example of an anomaly detection algorithm is Isolation Forest. Isolation Forest is a method that repeatedly divides a multidimensional space until the number of data in one space falls below a specified value, and determines that data with fewer divisions is anomalous because it is rarer. Feature data is selected and weighted so that anomalous data found by Isolation Forest can be considered anomalous.

Process 405 judges whether the calculated anomaly score is abnormal using a predetermined threshold. By using the anomaly score for anomaly judgment, rather than using the collected data and feature data directly for anomaly judgment, it is possible to perform a multidimensional comparison using multiple feature amounts in one dimension. Therefore, it is possible to judge anomalies under complex conditions, compared to when the collected data and feature data are directly used for anomaly judgment.

The measurement data temporarily stored in the ring buffer 82 may be collected data or feature data. In addition, feature data is small in volume, so storing all of it in the upper management device 10 does not put a strain on the capacity of the database 32, so it is acceptable to store all of it. Storing all of it has the advantage that it is possible to analyze changes in the feature over time.

Furthermore, the abnormality determination process is not limited to processes 401 to 405, and abnormality determination may be performed using various methods that a person skilled in the art can imagine. For example, an abnormality may be determined based on the relationship between the measurement data and a predetermined threshold value.

§3. Example of operation (pre-setting)
FIG. 5 is a flowchart of advance preparations for acquiring measurement data in the control system 1.

In S11, in the upper management device 10, the administrator sets the required time for each process 50 and the process order in the required time table 31. In S12, in the lower control device 40, the administrator sets the abnormality determination conditions for the abnormality determination unit 81. In S13, the administrator sets how the measurement data (collected variables) is to be temporarily stored in the ring buffer 82 of the lower control device 40. Additionally, the method of defining the feature quantities and anomaly score of the measurement data is set.

(Processing flow when an abnormality occurs)
Fig. 6 is a flowchart showing a process for acquiring measurement data in the control system 1. Fig. 6 is described assuming that an abnormality occurs in step B2 (abnormality occurrence step 51) of the abnormality-source low-level control device 42, but the low-level control device 40 that judges the abnormality is not limited to the abnormality-source low-level control device 42 and may be another low-level control device 40.

In S21, the abnormality determination unit 81 in the abnormality source lower-level control device 42 determines whether an abnormality has occurred.

If the result of the determination is that there is no abnormality (No in S21), the process returns to S21 and loops. During this time, the ring buffer 82 always temporarily stores the measurement data.

If the determination result indicates that an abnormality has occurred (Yes in S21), the process proceeds to S22. In S22, the abnormality determination unit 81 outputs to the upper management device 10 that an abnormality has occurred in the abnormality-source lower-level control device 42.

In S23, the receiver 21 receives a notification that an abnormality has occurred in the abnormality source lower-level control device 42. At this time, the upper level management device 10 also receives the abnormal process information and recognizes the time of the abnormality and the process 51 in which the abnormality occurred.

In S24, the identification unit 22 identifies the involved process based on the abnormal process information. Specifically, for the process preceding the abnormal process 51, the identification unit 22 identifies the execution time when the workpiece is produced in each process, taking into account the process order of the production line and the required time from the time when the abnormality occurred, and sets this as execution time information.

For example, an example is shown in the required time table 31 in Figure 3. The fault-source lower-level control device 42 determines that a certain workpiece has an abnormality in process B2 at time 10:00:45 (period 10:00:40 to 10:00:50) and notifies the upper-level management device 10 that an abnormality has occurred (S21, S22). The receiving unit 21 of the upper-level management device 10 recognizes that an abnormality has occurred in the fault-source lower-level control device 42 (S23). The identifying unit 22 of the upper-level management device 10 identifies the upstream process 52 and downstream process 53 for process B2 by the following process (S24).

The required time table 31 is used to identify the period during which the work passes through each process. That is, a certain work passes through process A1 0-10 seconds after production starts. The work passes through process A2 10-20 seconds after production starts. The work passes through process A3 20-30 seconds after production starts. The work passes through process B1 30-40 seconds after production starts. The work passes through process B2 40-50 seconds after production starts. The work passes through process B3 50-60 seconds after production starts. The work passes through process C1 60-70 seconds after production starts. The work passes through process C2 70-80 seconds after production starts. The work passes through process C3 80-90 seconds after production starts.

Considering the time 10:00:45 when an abnormality was detected in process B2 and the workpiece passing period from the start of production in process B2, it is found that production of the workpiece began at time 10:00:00. That is, the upstream lower-level control device 41 determines that the workpiece passing period is from 10:00:00 to 10:00:30 because the workpiece passes during the period 0 to 30 seconds after production starts. The abnormality source lower-level control device 42 determines that the workpiece passing period is from 10:00:30 to 10:01:00 because the workpiece passes during the period 30 to 60 seconds after production starts. The downstream lower-level control device 43 determines that the workpiece passing period is from 10:01:00 to 10:01:30 because the workpiece passes during the period 60 to 90 seconds after production starts.

(Acquisition of measurement data for the upstream lower control device 41)
Through steps S31 to S35, measurement data is obtained from the upstream lower control device 41.

In S31, the command unit 23 issues a query to the upstream lower-level control device 41 to obtain measurement data of the involved process in the upstream lower-level control device 41. The query may include execution time information.

When issuing a query, if multiple processes 50 involved are included in one lower-level control device 40, a query may be issued to acquire measurement data collectively. In the above example, the upper-level management device 10 issues a query to acquire measurement data from the upstream lower-level control device 41 for the period 10:00:00 to 10:00:30.

In S32, the command receiving unit 83 of the upstream lower control device 41 receives the query.

In S33, the condition determination unit 84 of the upstream lower control device 41 processes the query and checks whether measurement data that meets the query conditions is temporarily stored in the ring buffer 82. In the first embodiment, the query specifies a period for transmitting the measurement data, so the condition determination unit 84 checks whether the time of the measurement data is data for the specified period.

If the relevant data is not temporarily stored in the ring buffer 82 (No in S33), the process of S33 is repeated until the query can be processed (until the relevant data is temporarily stored in the ring buffer 82).

If the relevant data is temporarily stored in the ring buffer 82 (Yes in S33), the query has been processed and the process proceeds to S34. Note that since the upstream lower control device 41 controls the upstream process 52 with respect to the abnormality occurrence process 51, data that meets the query conditions is already temporarily stored in the ring buffer 82 at the time the abnormality occurs. Therefore, the process of S33 is carried out without waiting.

In S34, the data transmission unit 85 of the upstream lower control device 41 transmits the measurement data that meets the query conditions to the memory control unit 24.

In S35, the storage control unit 24 stores the received measurement data in the database 32. At this time, in addition to the measurement data, abnormal process information is associated and stored.

(Acquisition of measurement data for the fault source low-level control device 42)
Through steps S41 to S45, measurement data is obtained from the fault-source low-level control device 42. In the above example, the upper management device 10 obtains measurement data from the fault-source low-level control device 42 for the period 10:00:30 to 10:01:00.

S41 to S45 correspond to S31 to S35, respectively, and perform the same processing, except that the processing of the upstream lower-level control device 41 is replaced by the abnormality source lower-level control device 42.

The abnormality source lower-level control device 42 may include an upstream process 52 and a downstream process 53 of the abnormality occurrence process 51, so in S43, it may wait for data that meets the query conditions to be temporarily stored in the ring buffer 82.

(Acquisition of measurement data for downstream lower-level control device 43)
Through steps S51 to S55, measurement data is obtained from the downstream lower-level control device 43. In the above example, the upper level management device 10 obtains measurement data from the downstream lower-level control device 43 for the period 10:01:00 to 10:01:30.

S51 to S55 correspond to S31 to S35, respectively, and perform the same processing, except that the processing of the upstream lower-level control device 41 is replaced by the downstream lower-level control device 43.

Because the downstream lower-level control device 43 includes a downstream process 53 of the abnormality occurrence process 51, in S53, it becomes necessary to wait until data that meets the query conditions is temporarily stored in the ring buffer 82.

§4. Function and Effect When an abnormality occurs in a lower-level control device 40, the lower-level control device 40 notifies the upper-level management device 10 of the abnormality. When the upper-level management device 10 receives the abnormality notification, it identifies the involved process based on the abnormal process information included in the notification. The upper-level management device 10 issues a query to the lower-level control device 40 including the identified involved process, instructing it to transmit measurement data. The lower-level control device 40 transmits the relevant measurement data based on the query from the measurement data temporarily stored in the ring buffer 82 to the upper-level management device 10. The upper-level management device 10 stores the received measurement data in the memory unit 30.

Therefore, the upper level management device 10 can recognize that an abnormality has occurred in the lower level control device 40, and can also obtain measurement data from the processing involved prior to the process in which the abnormality occurred that was involved in the work in question in which the abnormality occurred.

Therefore, when measurement data from upstream process 52 is acquired as the involved process, it becomes easy to examine the true cause of the abnormality in abnormality occurrence process 51 from the process preceding abnormality occurrence process 51. Also, when measurement data from downstream process 53 is acquired as the involved process, an abnormality occurs in abnormality occurrence process 51, but the product may not actually be defective. Even in this case, the product may become defective in downstream process 53, and it is easy to examine the possibility that the true cause of the defective product is the abnormality in abnormality occurrence process 51.

In other words, it is possible to compare and investigate not only the measurement data from the process where the abnormality occurred, but also the measurement data from the upstream process 52 and downstream process 53 of the process where the abnormality occurred. As a result, it becomes easier to identify the true cause of the defective product based on the abnormality, and to take measures.

[Modifications]
Identification information may be given to the workpiece. The identification information is information that makes it possible to identify each workpiece produced. An example of the identification information may be a serial number. The identification information does not have to be actually given to the workpiece itself as a barcode or the like, and may be held as data (so-called shift data) that is transferred between the lower-level control devices 40.

By assigning identification information to the work, in the query to acquire measurement data in the command unit 23, the identification information to be acquired can be specified, rather than specifying the period for acquiring measurement data from the ring buffer 82 of the lower-level control device 40.

For example, if the equipment is stopped due to an emergency stop or if a particular process takes longer than normal, production will not be carried out according to the processing time for each process in the required time table described above. In this case, in the case of a query that specifies a period based on the required time table, it is considered that measurement data for an appropriate period cannot be obtained. However, in the case of a query that specifies identification information, the condition determination unit 84 checks the identification information and processes the query, so that even if the equipment is stopped due to an emergency stop or the like, measurement data for an appropriate period can be selected, output to the data transmission unit 85, and stored in the database 32.

In addition, in the first embodiment, we considered a case where the workpieces pass through and are processed sequentially on a production line, but in the modified example, because identification information is assigned, this is not the case, and the modified example can also be applied to a production line where the order of the workpieces is reversed.

[Embodiment 2]
Another embodiment of the present invention will be described below with reference to Fig. 7. Fig. 7 shows an example of measurement data narrowing down process according to the second embodiment.

The command unit 23 in the first embodiment compiles the involved processes for each lower-level control device 40, and issues a query to the upper-level management device 10 to transmit the period from the start of processing to the end of processing in the lower-level control device 40 that targets the workpiece that caused the abnormality. That is, as shown in table 501 in FIG. 7, a query is issued to obtain measurement data other than that of the workpiece that caused the abnormality.

In contrast, in the second embodiment, the command unit 23 can issue a query to further narrow down the workpieces using the identification information for the measurement data for the above-mentioned period and obtain measurement data such as that shown in Table 502. In other words, a query can be issued that does not obtain measurement data other than that of the workpiece that has caused the abnormality, and the data is not stored in the database 32, thereby preventing the database capacity from being strained.

In addition, the command unit 23 according to the second embodiment can search for measurement data to be obtained from the measurement data temporarily stored in the ring buffer 82 in two stages: the period and the identification information. Therefore, even if the production volume is very large compared to the size of the identification information, causing the identification information to overflow, it is possible to select the identification information by the period.

For example, in a production line, there is a jig that transports workpieces, and the jig itself is given identification information, but the workpieces are not given identification information. Even in a system in which the jig is reused, it becomes possible to uniquely determine the measurement data of the workpiece.

[Software implementation example]
The control blocks of the upper management device 10 (particularly the receiving unit 21, the identification unit 22, the command unit 23, and the memory control unit 24) may be realized by a logic circuit (hardware) formed in an integrated circuit (IC chip) or the like, or may be realized by software.

In the latter case, the upper management device 10 includes a computer that executes the instructions of a program, which is software that realizes each function. This computer includes, for example, one or more processors, and a computer-readable recording medium that stores the program. The object of the present invention is achieved by the processor reading the program from the recording medium and executing it in the computer. The processor can be, for example, a CPU (Central Processing Unit). The recording medium can be a "non-transient tangible medium," such as a ROM (Read Only Memory), tape, disk, card, semiconductor memory, programmable logic circuit, etc. The computer can also include a RAM (Random Access Memory) that expands the program. The program can be supplied to the computer via any transmission medium (such as a communication network or broadcast waves) that can transmit the program. One aspect of the present invention can also be realized in the form of a data signal embedded in a carrier wave, in which the program is embodied by electronic transmission.

[Additional Notes]
The present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

1. Control system (production control system)
10 Upper level management device 20 Control unit 21 Receiving unit 22 Identifying unit 23 Command unit 24 Memory control unit 30 Memory unit 31 Required time table 32 Database 40 Lower level control device 41 Upstream lower level control device 42 Abnormality source lower level control device 43 Downstream lower level control device 50 Process 51 Abnormality occurrence process 52 Upstream process 53 Downstream process 60 Device 61 Upstream device 62 Abnormality source device 63 Downstream device 70 Production line 81 Abnormality determination unit 82 Ring buffer 83 Command receiving unit 84 Condition determination unit 85 Data transmission unit 401, 402, 403, 404, 405 Processing 501, 502 Table

Claims (7)

In a production line including a plurality of processes for producing a production object, a host management device is connected via a network to a plurality of lower level control devices that control two or more of the processes,
a receiving unit that receives abnormal process information related to an abnormal process when an abnormality is detected in one of the lower control devices;
an identification unit that identifies, from among the processes included in the production line, a process involved in the production object that was being produced in the process where the abnormality occurred, based on the abnormal process information;
A command unit that requests the plurality of lower level control devices to transmit measurement data related to the involvement process;
a storage control unit that controls storage of the abnormal process information and the measurement data in a storage unit ,
Identification information is attached to each of the production objects produced in the production line,
The identification unit refers to a required time table indicating the order of the processes included in the production line and the required time of each of the processes, and identifies the involved process by process information and implementation time information based on the abnormal process information;
The command unit includes:
transmitting the process information, the execution time information, and first identification information of the production object that was produced in the abnormality occurrence process to the plurality of lower level control devices;
requesting the plurality of lower level control devices to transmit only the measurement data associated with the first identification information among the measurement data associated with each of the identification information related to the participation process;
Upper management device. The upper level management device described in claim 1, wherein the command unit requests each of the lower level control devices to send the measurement data related to the involved processing from one lower level control device so that the reception timing of the measurement data related to the involved processing from another lower level control device is different . The host management device according to claim 1 , wherein the identification unit identifies the involved process upstream of the abnormality-occurring process. The host management device according to claim 1 , wherein the identification unit identifies the involved process downstream of the abnormality occurrence process. A host management device according to any one of claims 1 to 4 ,
A production control system comprising: a plurality of the lower control devices connected to the upper management device via a network. A method for managing a production line including a plurality of processes for producing a production object, comprising :
a receiving step of receiving abnormal process information relating to an abnormal process when an abnormality is detected in one of the lower control devices from the lower control device;
a step of identifying a process involved in the production object that was being produced in the process where the abnormality occurred, from among the processes included in the production line, based on the abnormal process information;
a command step of requesting a plurality of the lower-level control devices to transmit measurement data related to the participation process;
A storage control step of controlling storage of the abnormal process information and the measurement data in a storage unit ,
Identification information is attached to each of the production objects produced in the production line,
In the identifying step, a required time table showing the order of the processes included in the production line and the required time of each of the processes is referred to, and the involved process is identified by process information and implementation time information based on the abnormal process information;
In the command step,
transmitting the process information, the execution time information, and first identification information of the production object that was produced in the abnormality occurrence process to the plurality of lower level control devices;
requesting the plurality of lower level control devices to transmit only the measurement data associated with the first identification information among the measurement data associated with each of the identification information related to the participation process;
Higher level management methods. A host management program for causing a computer to function as the host management device according to claim 1, the host management program causing a computer to function as the receiving unit, the identifying unit, the command unit, and the storage control unit.

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