Distributed plc edge computing system and data processing method thereof

Abstract

The application discloses a kind of distributed PLC edge computing systems, comprising: including several PLC units, the PLC unit includes CPU card piece, IO card piece, edge computing card piece and alarm device, the CPU card piece is connected with IO card piece and edge computing card piece respectively, IO card piece and alarm device are connected;The IO card piece is used to obtain the original data required for edge computing and is transmitted to CPU card piece, and receives alarm instruction from CPU and drives alarm device;The CPU card piece is used to forward the model parameter required for edge computing, original data to edge computing card piece, and decides whether to issue alarm instruction according to the calculation result of edge computing card piece;The edge computing card piece is used to calculate according to the original data received to determine whether to alarm;The alarm device is used to alarm according to the received alarm instruction;The application can greatly improve the efficiency and stability of system processing data.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of industrial control, and particularly relates to a distributed PLC edge computing system and a data processing method thereof. BACKGROUND

[0002] In a conventional PLC-based monitoring system, the processing and analysis of raw data collected by PLC are implemented on the host computer side. The host computer side includes an independent PLC communication process, stores the collected raw data into a database, and processes and analyzes the data by one or more independent processes. These processes need to access the database to extract raw data for analysis and calculation.

[0003] The early processing and analysis method of raw data on the host computer side of the PLC monitoring system is relatively simple. Most of them realize the abnormal value filtering and out-of-limit alarm function of some key measurement point data. Moreover, the collection frequency of most raw data is not high, so the raw data processing and analysis task on the host computer side does not require high throughput of the database and high CPU power. However, with the application of various big data analysis algorithms, the amount of raw data and the time complexity of the algorithm increase by orders of magnitude. In a large PLC monitoring system, even the highest throughput performance of the database and the speed of the CPU cannot meet the demand of the host computer to process and analyze all measurement point data. Most importantly, data processing and analysis occupy a large amount of database throughput, which may block the PLC communication process, affect the real-time interaction between the host computer and the PLC, and further affect the real-time data collection or control of the system by the PLC. In some cases, it may cause fatal results.

[0004] In addition, concentrating all data processing and analysis tasks in one database is also a potential risk for the robustness of the entire system. Once the host computer database crashes, all functions and services will stop. SUMMARY

[0005] To solve the problems in the prior art, the present application provides a distributed PLC edge computing system and method, which can improve the stability of data processing.

[0006] The technical problem to be solved by the present application is solved by the following technical scheme:

[0007] In a first aspect, a distributed PLC edge computing system is provided, comprising:

[0008] The PLC unit includes a CPU card, an IO card, an edge computing card and an alarm device. The CPU card is connected with the IO card and the edge computing card respectively, and the IO card is connected with the alarm device.

[0009] The IO card is used for obtaining raw data required by edge computing and transmitting the raw data to the CPU card, and receiving an alarm instruction from the CPU to drive an alarm device;

[0010] The CPU card is used for forwarding model parameters and raw data required by edge computing to the edge computing card for calculation, and determining whether to issue an alarm instruction according to a calculation result returned by the edge computing card;

[0011] The edge computing card is used for calculating according to the received raw data to determine whether to alarm;

[0012] The alarm device is used for alarming according to the received alarm instruction.

[0013] With reference to the first aspect, further, each PLC unit only processes one type of service data.

[0014] With reference to the first aspect, further, the CPU card and the edge computing card are connected through a high-speed bidirectional data transmission interface, and the IO card is connected through a bus.

[0015] With reference to the first aspect, further, the edge computing card comprises a plurality of Ethernet interfaces for data interaction with other devices.

[0016] With reference to the first aspect, further, the edge computing card is connected with the alarm device, and the edge computing card can also directly drive the alarm device.

[0017] With reference to the first aspect, further, the CPU card obtains the model parameters and the raw data required by edge computing and sends them to the edge computing card.

[0018] The edge computing card pre-processes the received raw data.

[0019] The edge computing card calculates characteristic values of the pre-processed raw data.

[0020] The edge computing card determines whether to generate alarm information according to a comparison result of the characteristic values and the raw data and outputs the alarm information to the CPU card.

[0021] The CPU card drives the alarm device through the IO card to alarm according to the received alarm information.

[0022] With reference to the second aspect, further, the characteristic value calculation is performed in

[0023] The edge computing card starts after the pre-processed raw data reaches a threshold value, and replaces the earliest set of raw data with the latest set of raw data after the latest set of raw data is obtained to perform characteristic value calculation again.

[0024] With the second aspect, further, the edge computing card comprises an embedded database, which generates a data table for each service subcategory in the process of edge computing to store data, and if the edge computing card restarts, the data is reloaded from the data table to the memory.

[0025] With the second aspect, further, the edge computing card sends the computing result data to other edge computing cards in the form of multicast.

[0026] With the second aspect, further, the characteristic value calculated by the edge computing card is also sent to the edge computing card of the PLC unit of other services for calculation, and if the calculation result according to the characteristic value exceeds the alarm threshold of the service, a linkage alarm is generated for the service.

[0027] The present application has the following advantages: by adding an edge computing card to the PLC unit and distributing data processing, the present application realizes the decentralization of big data analysis and processing, so that it is no longer necessary to spend high cost to improve the performance of the host computer, and since the distributed data processing is adopted, the pressure of the host computer is effectively relieved, the data is dispersed everywhere, and a problem in one place will not affect the whole, thereby reducing the cost and greatly improving the reliability of the whole system in processing data. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Fig. 1 is a structural schematic diagram of a distributed PLC edge computing system in the present application;

[0029] Figure 2 Fig. 3 is a flow chart of PLC edge computing data communication and processing in an embodiment of the present application. EMBODIMENT

[0030] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme of the present application will be described clearly and completely below in conjunction with the drawings. Obviously, the described embodiments are some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0031] In order to better understand the present application, the related technologies in the technical scheme of the present application are described below. EMBODIMENT

[0032] As Figures 1-2As shown, in the embodiment, the application provides a distributed PLC edge computing system, which comprises two PLC units, i.e., a unit PLC unit and a temperature measuring PLC unit, each of which comprises a CPU card, an IO card, an edge computing card and an alarm device, the alarm device can be an audible and visual alarm device according to the required computing amount, wherein the number of the edge computing cards contained in each PLC unit can be multiple, and the edge computing cards contained in each PLC unit only process the business related data corresponding to the PLC unit, for example, the edge computing cards in the unit PLC unit only undertake the data processing tasks related to the unit, such as the edge computing tasks of the unit power, the rotor speed, the current voltage, the technical water flow and the like; the edge computing cards in the temperature PLC unit only undertake the data processing tasks related to the temperature, such as the edge computing tasks of the temperature data, such as the temperature of the upper guide, the temperature of the lower guide and the temperature of the water guide.

[0033] In the application, the IO card is used to obtain various original data (various switch values and analog signals) for edge computing from the unit components, and is also used to receive the control instructions of the CPU to drive the alarm device to alarm.

[0034] The CPU card is used to forward the model parameters and the original data required for edge computing to the edge computing card, and decides whether to issue an alarm instruction according to the calculation result of the edge computing card; the IO card and the CPU card interact through a bus.

[0035] The edge computing card is a hardware device, which has embedded algorithms for various different edge computing, according to the different model parameters configured during operation, the corresponding algorithms are called to realize the corresponding edge computing functions. The original data calculated by the CPU through the IO card, the results of the calculation and the generated alarm information are transmitted to the CPU card, other edge computing cards or the alarm device (in some cases, different edge computing cards can interact data to realize linkage alarm, and the alarm can not be forwarded by the CPU, but directly driven by the edge computing card). The edge computing card is provided with multiple Ethernet interfaces, in the application, the edge computing card is connected with the CPU card through the high-speed Ethernet interface, the interface must be separated from the data interface of the CPU and the IO card to prevent the real-time performance of data acquisition and control of the PLC unit from being affected during operation. The number of the edge computing cards in each PLC unit can be multiple, which share the calculation of the business data.

[0036] The alarm device can be a hardware device for displaying text, images or sound, or a PC pushed in the form of a short message or an email. The alarm device can be driven by the CPU card through the IO card or directly driven by the edge computing card (for example, in some cases where only text display alarm is required, the edge computing card can be directly driven to save resources).

[0037] Each type of edge computing task includes the basic functions of raw data acquisition, data preprocessing, feature value calculation, and alarm judgment. Taking the edge computing of the temperature measurement PLC as an example, the edge computing card mainly calculates and analyzes the unit start-up temperature data. The software code thereof includes four tasks. The first task is responsible for receiving the start-up temperature data sent by the temperature measurement CPU card and saving the data to the corresponding data structure instance. The second task is responsible for preprocessing the raw temperature data received by the first task by high-pass and low-pass filtering methods to remove obviously abnormal measurement values. When the cumulative start-up number reaches the required number for start-up temperature feature value calculation, the third task uses weighted average combined with mean filtering to obtain a set of feature envelope line values for each temperature measurement point at a fixed time. The fourth task is responsible for comparing the raw data and the feature value data. When the absolute value difference between the raw measurement value and the feature value exceeds a set dead zone range, the fourth task generates an alarm information for the temperature measurement point and sends the information to the CPU card or the matching temperature alarm device.

[0038] The raw data is the sample data required for feature value calculation of the edge computing task corresponding to the main function of the PLC, which is transmitted by the CPU card to the edge computing card.

[0039] The data preprocessing refers to the process of making a reasonable judgment and filtering abnormal values on the sample data required for feature value calculation after the edge computing card obtains the sample data from the CPU card. The data preprocessing method can use, but is not limited to, low-pass filtering, high-pass filtering, mean filtering, and median filtering.

[0040] The feature value calculation refers to the calculation of feature data representing the running state of the PLC by the edge computing card on the preprocessed sample data according to the embedded specific algorithm. The feature data is not limited to one or more data at a certain time or one or a group of data within a period of time.

[0041] The alarm judgment and output refer to the process of determining whether to generate an alarm information and output it to the alarm device or the CPU card by comparing the difference between the raw data and the feature data corresponding to the current edge computing task of the PLC after the edge computing card calculates the feature data by a specific algorithm. Embodiment

[0042] On the basis of the distributed PLC edge computing system provided in Embodiment 1, we take the temperature measurement PLC unit as an example to describe its data processing process, which mainly includes the following steps:

[0043] S1, the CPU card sends the model parameters required for edge computing (the model parameters are obtained from the configuration software, which includes the related series of software for running the PLC unit, and the main function is to configure the CPU card required for running the PLC, various IO cards and their related working parameters, edit and debug programmable logic) to the temperature measurement edge computing card, and waits for its response. If a response is received within time T1 (1 second), go to step S2, otherwise continue to send the model parameters to the temperature measurement edge computing card and repeat step S1.

[0044] S2, the edge computing card loads the model parameters, and the CPU card queries the loading status of the model parameters from the edge temperature measurement card according to the time interval T2 (not greater than 1 second). If the received response is that the loading is not completed, the CPU card continues to query the loading status until it exceeds time T3 (10 seconds) and still does not complete the loading, then gives up the query and returns to step S1. If the loading is completed, go to step S3.

[0045] S3, the CPU card sends the raw data required for temperature measurement edge computing to the edge computing card according to the time interval T4 (1 second), and waits for the response of the temperature measurement edge computing card. If the edge computing card does not respond within time T5 (10 seconds), go to step S1, otherwise go to step S4.

[0046] S4, the edge computing card performs edge computing according to the received raw data and model parameters, and generates an alarm information when the absolute value of the characteristic value and the absolute value of the raw data exceed the alarm threshold. Specifically, the temperature measurement edge computing card compares the raw data and the characteristic value data. When the absolute value difference between the raw measurement value and the characteristic value exceeds a set dead zone range, an alarm information is generated. The alarm information includes the corresponding temperature measurement value at the time of alarm, the envelope line of the temperature characteristic value corresponding to the measurement point in the start-up process, and other related unit operation data at the time of alarm section. The temperature measurement edge computing card sends the alarm information to the CPU card, and the CPU card sends the alarm instruction to the audible and visual alarm device matched with the PLC through the IO card, which displays the alarm information.

[0047] After completing the characteristic value calculation, the temperature measurement edge computing card will send the current calculation result to the unit PLC edge computing card in a multicast manner. After receiving the data, the unit PLC edge computing card will substitute the data into the linkage alarm model for temperature measurement data. When the output result of the linkage alarm model (some scene alarms are linked, for example, when a certain temperature business-related alarm occurs, the unit-related business may also generate an alarm) is that the current unit speed running at the temperature will cause the metal fatigue degree to increase by 20% and the average service life of the rotor to decrease by 5%, the unit PLC edge computing card will output the alarm information to the alarm device matched with the PLC unit.

[0048] The temperature measurement edge computing card contains an embedded database, in which seven database tables are designed to store unit start-stop information, start-up process temperature measurement values, steady-state process temperature measurement values, start-up temperature characteristic value envelope, steady-state temperature characteristic value envelope, alarm section data, and alarm information. When the temperature measurement edge computing card is restarted after power failure, it needs to reload these data from the database into the memory to improve the speed of raw data preprocessing and characteristic value calculation.

[0049] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer usable program code.

[0050] The present application is described with reference to flowcharts and / or block diagrams according to the methods, devices (systems), and computer program products of the embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, and the combination of flows and / or blocks in the flowcharts and / or block diagrams can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices produce a device that implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The device that implements the functions specified in one or more flows and / or blocks. Figure 1 The device that implements the functions specified in one or more flows and / or blocks.

[0051] These computer program instructions can also be stored in a computer readable storage medium that can guide the computer or other programmable data processing devices to work in a specific way, so that the instructions stored in the computer readable storage medium produce a manufactured product including instruction devices that implement the functions specified in the flowcharts and / or block diagrams. Figure 1one or more processes and / or blocks Figure 1 the function specified in the one or more blocks.

[0052] These computer program instructions can also be loaded into computer or other programmable data processing devices, so that a series of operational steps are performed on the computer or other programmable data processing devices to generate a computer-implemented process, so that the instructions executed on the computer or other programmable data processing devices provide a process for implementing the flowchart Figure 1 one or more processes and / or blocks Figure 1 the function specified in the one or more blocks.

[0053] The above description is only the preferred embodiment of the present application, it should be pointed out that for those skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can also be made, these improvements and modifications should also be considered as the protection scope of the present application.

Claims

1. A distributed PLC edge computing system, characterized by, The PLC unit comprises a CPU card, an IO card, an edge computing card and an alarm device, the CPU card is connected with the IO card and the edge computing card respectively, and the IO card is connected with the alarm device; The IO card is used for obtaining original data required by edge computing and transmitting the original data to the CPU card, and receiving an alarm instruction from the CPU to drive the alarm device; The CPU card is used for forwarding model parameters and original data required by edge computing to the edge computing card for calculation, and deciding whether to send an alarm instruction according to a calculation result returned by the edge computing card; The edge computing card is used for calculating according to the received original data to determine whether to alarm; The alarm device is used for alarming according to the received alarm instruction; The edge computing card is used for pre-processing and characteristic value calculation on the received original data, and generating alarm information according to a comparison result of the characteristic value and the original data and outputting the alarm information to the CPU card; The edge computing card is connected with the CPU card through a high-speed Ethernet interface, and the high-speed Ethernet interface is separated from data interfaces between the CPU card and the IO card; After the edge computing card completes the characteristic value calculation, the edge computing card sends calculation result data to edge computing cards of PLC units of other services in a multicast mode; The edge computing card of the PLC unit of the other service receives the calculation result data, substitutes the calculation result data into a linkage alarm model, and generates linkage alarm when an output result of the linkage alarm model exceeds an alarm threshold of the service. 2.The distributed PLC edge computing system of claim 1, wherein, Each PLC unit only processes one type of service data.

3. The distributed PLC edge computing system of claim 1, wherein, The CPU card and the edge computing card are connected through a high-speed bidirectional data transmission interface, and the IO card is connected through a bus.

4. The distributed PLC edge computing system of claim 1, wherein, The edge computing card comprises a plurality of Ethernet interfaces for data interaction with other devices.

5. The distributed PLC edge computing system of claim 1, wherein, The edge computing card is connected with the alarm device, and the edge computing card can also directly drive the alarm device.

6. A distributed PLC edge computing method, characterized by, The CPU card obtains model parameters and original data required by edge computing and sends the model parameters and the original data to the edge computing card; The edge computing card pre-processes the received original data; The edge computing card calculates characteristic values of the pre-processed original data; The edge computing card decides whether to generate alarm information according to a comparison result of the characteristic values and the original data and outputs the alarm information to the CPU card; The CPU card drives the alarm device to alarm through the IO card according to the received alarm information; The edge computing card is connected with the CPU card through a high-speed Ethernet interface for data interaction; After the edge computing card completes the characteristic value calculation, the edge computing card sends calculation result data to edge computing cards of PLC units of other services in a multicast mode; The edge computing card of the PLC unit of the other service receives the calculation result data, substitutes the calculation result data into a linkage alarm model, and generates linkage alarm when an output result of the linkage alarm model exceeds an alarm threshold of the service. ​ 7. The distributed PLC edge computing method of claim 6, wherein, The characteristic value calculation is started after the original data quantity preprocessed by the edge computing card reaches a threshold, and when the latest set of original data is acquired, the earliest set of original data after preprocessing is replaced by the latest original data to perform characteristic value calculation again. 8.The distributed PLC edge computing method of claim 6, wherein, The edge computing card contains an embedded database, which generates a data table for each business subcategory to store data in the process of edge computing. If the edge computing card restarts, the data is loaded from the data table to the memory again.

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