SCADA Web HMI System

Abstract

This SCADA web HMI system comprises a PLC, an HMI client machine, and a SCADA server machine connected via a computer network. The PLC transmits block data relating to a field apparatus group that constitutes an industrial plant to the SCADA server machine at prescribed periods. The SCADA server machine comprises a communication driver that receives the block data, and a client management unit that is connected one-to-one with a plurality of HMI client machines, and performs WebSocket communication with each HMI client machine. The HMI client machines each execute a web browser that displays an HMI screen on which parts showing the status of the industrial plant are disposed, and update the status of the parts according to the signal data received from the client management unit. The HMI client machine comprises a client installer for installing SCADA web programs loaded during startup of the web browser.

Description

[Technical Field]

[0001] The present invention relates to a SCADA web HMI system, and more particularly to a technique for reducing the processing load in a large-scale system. [Background technology]

[0002] SCADA (Supervisory Control And Data Acquisition) is known as a system for monitoring and controlling social infrastructure systems. Social infrastructure systems include steel rolling systems, power transmission and transformation systems, water and sewerage treatment systems, building management systems, and road systems. SCADA is a type of industrial control system that uses computers to monitor systems, control processes, and collect data. SCADA requires responsiveness (real-time performance) that matches the system's processing performance.

[0003] SCADA generally consists of the following subsystems: (1)HMI(Human Machine Interface) The HMI is a mechanism that presents data from the monitored device to the operator, allowing the operator to monitor and control the monitored device. (2) Monitoring and control system A monitoring and control system is composed of a programmable logic controller (PLC), etc. The monitoring and control system collects data from the monitored devices and sends control commands to the monitored devices. (3) Remote Input Output (RIO) The remote input / output device is connected to a sensor installed in the monitored device, converts the sensor signal into digital data, and sends the digital data to the monitoring and control system. (4) Communications infrastructure The communications infrastructure connects the monitoring and control system with remote input / output devices.

[0004] As an example of a SCADA HMI subsystem, Patent Document 1 discloses a system including an HMI client machine and a SCADA server machine. In a conventional SCADA such as that disclosed in Patent Document 1, the SCADA server machine transmits data (input / output signals, alarm signals) received from a PLC to the HMI client machine. The input / output signals are signals related to the monitored devices (field devices that make up an industrial plant) and include actuator control signals and sensor detection signals. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2017-27211 Summary of the Invention [Problem to be solved by the invention]

[0006] This section explains the challenges in developing the HMI subsystem, which is one of the subsystems mentioned above.

[0007] In large-scale systems, the HMI subsystem may connect more than 200,000 signals to the PLC. Conventional SCADA servers, which handle both supervisory control and data collection, require high-performance processors and large-capacity memory to process a large number of signals in real time. For this reason, there is a demand for low-cost HMI subsystems that can be applied to large-scale systems.

[0008] To reduce the cost of SCADA HMI subsystems, the inventors of this application have developed a browser-based SCADA HMI subsystem, which allows HMI screens to be implemented as web applications that run on a web browser.

[0009] One of the benefits of implementing an HMI screen on a web browser is that data can be easily obtained from different web servers by switching the URL (including port number). In other words, data for the history screen can be obtained from an online data gathering device (ODG) that collects and stores all PLC data, while data for the monitoring screen, which requires real-time performance, can be obtained from a SCADA server. By separating the history-related functions, which are part of the SCADA functionality, and entrusting them to the online data gathering device, the SCADA server can specialize in real-time monitoring functions. In order to process a large number of signals on a low-cost SCADA server, it is desirable to reduce the processing load of input / output signals (including actuator control signals and sensor detection signals) and alarm signals.

[0010] In a large-scale SCADA web HMI system, a large number of client devices (e.g., 128) are expected to be connected to a single SCADA server. Even in a redundant design where two SCADA servers are installed to distribute the load, a large number of HMI client devices are still connected to each SCADA server. When the same HMI screen is displayed on each HMI client device's monitor, the SCADA server must receive the signal data contained in the HMI screen and transmit it to all HMI client devices. In a browser-based SCADA HMI subsystem, the HMI screen on the HMI client device is displayed using a web browser, and signal data is transmitted from the SCADA server to the HMI client devices using a point-to-point connection such as WebSocket. In other words, multicast transmission cannot be used to transmit data from the SCADA server to the HMI client devices. Therefore, when 128 client devices are connected to a SCADA server, the SCADA server must transmit 128 times the amount of signal data it receives to the HMI client devices. In this way, while the system is in operation (while the industrial plant is being monitored), a large amount of data flows between the SCADA server and each HMI client.

[0011] Generally, web applications run on a web browser, downloaded from a SCADA server. In other words, the web browser on each HMI client device requires a SCADA web program, which is loaded from the SCADA server via WebSocket. As shown in Figure 12, if a web browser is launched on each HMI client device before system operation begins, even if the SCADA web program is loaded via WebSocket into the web browsers on all HMI client devices, the amount of communication between the HMI client devices and the SCADA server device will be below the communication capacity limit (communication capacity), and there will be no problems in system operation. On the other hand, if a web browser is launched during system operation, communication errors may occur due to the amount of communication exceeding the network's communication capacity, or web content may take a long time to load. This may result in periods when the industrial plant cannot be monitored, posing a problem in system operation.

[0012] The present invention has been made to solve the above-mentioned problems, and aims to provide a SCADA web HMI system that can prevent the amount of communication between an HMI client device and a SCADA server device from exceeding the communication capacity, even when a web browser is launched during system operation. [Means for solving the problem]

[0013] A first aspect of the present disclosure relates to a SCADA web HMI system. The SCADA web HMI system includes a programmable logic controller (hereinafter, referred to as PLC), an HMI client device, and a SCADA server device, which are connected via a computer network. The PLC transmits block data related to a group of field devices constituting an industrial plant to the SCADA server device at predetermined intervals. The SCADA server device includes a communication driver that receives the block data and a client management unit that is connected to the HMI client devices one-to-one and communicates with each HMI client device via WebSocket. The HMI client devices each execute a web browser that displays an HMI screen on which parts indicating the status of the industrial plant are arranged, and update the status of the parts according to the signal data received from the client management unit, thereby monitoring the industrial plant. The HMI client device includes a client installer that installs the SCADA web program to be loaded when the web browser is started. The SCADA server device downloads application-dependent data, which is data dependent on an application running on the SCADA web program, and transmits the downloaded application-dependent data to the HMI client device. In things When connected to the HMI client machine, it determines whether the SCADA web program has been updated, and transmits the application-dependent data to the HMI client machine only if it has been updated.

[0014] The second aspect has the same features as the first aspect, and further has the following characteristics: the SCADA server machine includes a client installer that is the same as the client installer, and prior to monitoring the industrial plant, the client installer is downloaded from the SCADA server machine to the HMI client machine via the client management unit using the web browser.

[0015] A third aspect has the following characteristics in addition to the first or second aspect: the SCADA server machine includes a communication module including content that runs on the SCADA web program; the HMI client machine loads the communication module from the SCADA server machine; and the web browser exchanges data between the SCADA web program running on a domain of the HMI client machine and the communication module running on a domain of the SCADA server machine using inter-domain communication.

[0017] No. 4 The perspective is 1 In addition to the above, the present invention further has the following feature: when the SCADA web program connects to the SCADA server machine, the HMI client machine transmits a revision of the application-dependent data contained in the SCADA web program to the SCADA server machine, and the SCADA server machine performs the determination by comparing the revision received from the HMI client machine with the revision of the application-dependent data downloaded from the SCADA server machine. [Effects of the Invention]

[0018] According to the present disclosure, a client installer is provided on the HMI client device, so when the web browser is launched, the SCADA web program is loaded from the HMI client device itself, rather than being loaded from the SCADA server device via WebSocket. This prevents the amount of communication between the HMI client device and the SCADA server device from exceeding the communication capacity, even when the web browser is launched during system operation. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a diagram illustrating an example of the configuration of a SCADA web HMI system according to an embodiment of the present invention. [Figure 2] 1A is a diagram illustrating the data type of signal data, and FIG. 1B is a diagram illustrating an identifier. [Figure 3] FIG. 1A is a diagram illustrating the format of signal data, and FIG. 1B is a diagram illustrating the format of screen update data. [Figure 4] FIG. 10 is a diagram for explaining the processing in the client management unit of the SCADA server machine. [Figure 5] FIG. 1 is a diagram for explaining a method for loading a SCADA web program. [Figure 6] FIG. 10 is a diagram for explaining advance distribution of a client installer to an HMI client machine. [Figure 7] FIG. 10 is a diagram for explaining a method for loading a communication module. [Figure 8] FIG. 10 is a diagram illustrating another method for loading a communication module. [Figure 9] FIG. 10 is a diagram illustrating a method for loading application-dependent data. [Figure 10] 10 is a flowchart illustrating a method for loading application-dependent data. [Figure 11] FIG. 2 is a block diagram showing an example of the hardware configuration of a SCADA server machine and an HMI client machine. [Figure 12] FIG. 1 is a diagram for explaining a problem in the related art. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Note that elements common to the various drawings will be assigned the same reference numerals and redundant explanations will be omitted.

[0021] 1-1.SCADA Web HMI System Fig. 1 is a diagram illustrating an example of the configuration of a SCADA web HMI system according to the first embodiment. The SCADA web HMI system 1 shown in Fig. 1 includes a PLC 2, a SCADA server machine 3, and an HMI client machine 4, which are interconnected via a computer network 5. The computer network 5 is, for example, Ethernet (registered trademark). The SCADA web HMI system 1 may also include an online data gathering (ODG) (not shown).

[0022] The PLC 2 is connected to a group of field devices (including actuators and sensors) that make up the industrial plant via a control network (not shown). The PLC 2 transmits packets containing block data to the computer network 5 by multicast or broadcast at predetermined intervals. Block data is a collection of PLC signals. One block of data contains tens to hundreds of PLC signals. Types of PLC signals include input / output signals (including actuator control signals and sensor detection signals) and alarm signals. Block data contains at least one of a collection of input / output signals and a collection of alarm signals. The total number of alarm signals is smaller than the total number of input / output signals.

[0023] The block data is transmitted periodically regardless of whether the value of the PLC signal has changed from the previous value. Therefore, even if a packet containing transmitted block data is lost, it is retransmitted in the next transmission cycle, and the latest status is reflected in the SCADA server machine 3 and the online data collector.

[0024] The SCADA server machine 3 includes a communication driver 31 and a client management unit 32. The communication driver 31 is configured to receive block data from the PLC 2 at regular intervals and execute unpacking, which breaks down the received block data into signal data of each data type. As the data type, in addition to the bit type shown in FIG. 2(a), short type, float type, etc. can be used. Furthermore, the communication driver 31 is configured to execute packet processing, which adds a signal data identifier (see FIG. 2(b)) corresponding to each piece of signal data to generate packets for each data type and transmits the generated packets to the client management unit 32. That is, the signal data transmitted from the communication driver 31 to the client management unit 32 is a pair of a signal data identifier and a signal data value (see FIG. 3(a)).

[0025] Here, the signal data identifier corresponds to a character string written by the application designer. The data size of the signal data identifier is, for example, 23 bits. This allows the signal data identifier to represent approximately 8 million pieces of signal data, making it fully compatible with large-scale SCADA web HMI systems 1. For bit-type data, the signal data identifier is 23 bits and the data value is 1 bit, so the data size per signal is 24 bits (= 3 bytes). For float-type data, the signal data identifier is 23 bits and the data value is 4 bytes, so 1 bit of padding is added, making the data size per signal 7 bytes. Note that when generating packets, only the signal data of the signal data identifier related to the HMI screen 41 currently displayed on the web browser 40 may be extracted.

[0026] The client management unit 32 includes a signal data reception thread, at least one signal data buffer, and a signal data transmission thread. The signal data reception thread receives packets (signal data for each data type) from the communication driver 31 and stores the signal data in the signal data buffer. The signal data buffer has an area (array) for storing signal data for each data type. Even if 8 million signal data items exist, the memory usage would be approximately 24 MB, excluding text data. Considering the specifications of current computers, this memory usage is considered acceptable. Furthermore, the use of indexes can reduce the amount of data stored in the signal data buffer. Upon receiving an instruction from the signal data reception thread, the signal data transmission thread reads the signal data stored in the signal data buffer and transmits the read signal data for each data type to the HMI client device 4. At this time, the signal data transmission thread transmits the screen identifier and component identifier indicating the HMI screen 41 and component (part) 42 to be displayed in FIG. 3(b) and the updated signal data as screen update data to the HMI client device 4 (see FIG. 4). As shown in FIGS. 2 to 4, by binarizing the signal data, the amount of data sent to the HMI client machine 4 can be reduced.

[0027] 11, which will be described later, the SCADA server machine 3 includes a processor 301 that executes various processes, a memory 302 that stores various information, and a network interface 303. The processor 301 executes programs stored in the memory 302, thereby performing the various processes described above and below.

[0028] The HMI client device 4 includes a processor 401, memory 402, monitor 403, network interface 404, and input interface 405, which are shown in Fig. 11 and will be described later. The processor 401 is configured to execute a program stored in the memory 402, thereby executing a web browser 40 that displays an HMI screen 41 on which display parts are arranged. The monitor 403 displays the web browser 40.

[0029] The web browser 40 selects the destination (SCADA server machine 3, HMI Client By switching between the devices 4), various information in HTML documents related to the HMI screen 41 can be obtained from the web server specified by the URL. The HMI screen 41 includes a monitoring screen that requires real-time performance and a history screen that displays history data.

[0030] When the HMI screen 41 currently displayed on the web browser 40 is a monitoring screen, the web browser 40 changes the display state of the display parts 42 in response to input / output signals received from the SCADA server machine 3. Changes in the display state include, for example, changes in numerical values, characters, colors, and shapes. The web browser 40 also changes the display state of the alarm parts 42 arranged on the HMI screen 41 in response to an alarm signal received from the SCADA server machine 3.

[0031] When the screen 41 currently displayed on the web browser 40 is a history screen, the web browser 40 requests history data from the online data collector. The web browser 40 displays the history data received from the online data collector on the history screen.

[0032] The online data collector includes a processor and a memory (not shown). The processor executes a program stored in the memory, whereby the processor is configured to perform web server processing and history data management processing. The online data collector periodically receives block data from the PLC 2. The history data management processing of the online data collector stores history data of all signals included in the received block data in memory (including a database). The web server processing of the online data collector transmits history data in response to a request from the web browser 40. The online data collector also receives and stores alarm packets from the SCADA server 3.

[0033] 1-2. SCADA web program loading method Figure 5 is a diagram illustrating a method for loading a SCADA web program. As shown in Figure 5, the HMI client device 4 includes a client installer 43. The client installer 43 runs when the SCADA web program is updated, and deploys a local web server 45 and a SCADA web program 44 on the client device 4. The web browser 40 can load the SCADA web program via the local web server 45 when started. This differs from the conventional method of loading the SCADA web program 44 from the SCADA server device 3, and allows the communication bandwidth between the HMI client device 4 and the SCADA server device 3 to be entirely allocated to communication traffic during system operation.

[0034] The client installer 43 may be installed on the HMI client device 4 using a CD-ROM. However, as shown in FIG. 6 , if the client installer 43 is pre-distributed (HTTP loaded) from the SCADA server device 3 to the HMI client device 4, the effort required for installing the client installer 43 can be reduced, thereby reducing operational costs. That is, the SCADA server device 3 includes the client installer 43. The client installer 43 includes a local web server 45 that runs on the client device 4, a SCADA web program 44, and a SCADA web program startup script 46. This allows the system operations manager to download the client installer 43 from the SCADA server device 3 using only the web browser 40. When the client installer 43 is executed on the HMI client device 4, the local web server 45 starts up on the HMI client device 4, and the SCADA web program 44 and the SCADA web program startup script 46 are deployed on the client device 4. At this time, a shortcut linked to the SCADA web program startup script 46 is placed on the Windows (registered trademark) desktop of the monitor 403, so the operator can simply double-click the shortcut to load the SCADA web program 44 on the web browser 40. The SCADA web program startup script 46 also includes the communication address of the SCADA server machine 3, so the SCADA web program 44 automatically connects to the SCADA server machine 3, allowing the operator to immediately start monitoring the system.

[0035] 1-3. Communication module loading method Fig. 7 is a diagram for explaining a method for loading a communication module, and Fig. 8 is a diagram for explaining another method for loading a communication module.

[0036] The communication module 36 provides the functionality required for the SCADA web program 44 to communicate with the server. This type of communication module 36 must be loaded from the SCADA server machine 3, not from the local web server 45. The SCADA server machine 3 includes a server installer 34. When the server installer 34 is started, the server program 35 and the communication module 36 are deployed to the SCADA server machine 3. The communication module 36 must communicate with the client management unit 32 on the SCADA server machine 3 via WebSocket. However, due to security reasons known as the same-origin policy, the communication module 36 must operate in a domain 40b of the SCADA server machine 3. In other words, the communication module 36 must be loaded from the client management unit 32 on the SCADA server machine 3. Therefore, as shown in FIG. 7, data is exchanged between the SCADA web program 44, which operates in a domain 40a of the HMI client machine 4 on the web browser 40, and the communication module 36, which operates in a domain 40b of the SCADA server machine 3, using inter-domain communication. 8, by configuring the SCADA server machine 3 for CORS (Cross Domain Resource Sharing), it becomes possible to accept communication connections from other domains, and therefore the communication module 36 can also be installed in the HMI client machine 4 in advance. This makes it possible to further reduce the communication load between the HMI client machine 4 and the SCADA server machine 3.

[0037] 1-4. Application-dependent data loading method Fig. 9 is a diagram for explaining a method for loading application-dependent data, and Fig. 10 is a flowchart for explaining a method for loading application-dependent data.

[0038] For the SCADA web program 44 to operate, application-dependent data 38, which is dependent on the application, must also be loaded onto the web browser 40. The application-dependent data 38 is downloaded to the SCADA server machine 3 by the application distribution program 37. The application-dependent data 38 includes an application revision, and as described below, is transmitted to the HMI client machine 4 only when the application revision is updated. When the SCADA web program 44 connects to the client management unit 32 on the HMI client machine 4, the routine shown in FIG. 10 is started. According to this routine, the SCADA web program 44 transmits the application revision of the application-dependent data 38 currently held to the SCADA server machine 3 (step S1). The SCADA server machine 3 compares the application revision of the downloaded application-dependent data 38 with the application revision transmitted in step S1 (step S2). If the comparison results in the same application revision, the SCADA server machine 3 transmits a message to the SCADA web program 44 indicating that the application-dependent data 38 has not been updated (step S3). Thereafter, the SCADA web program 44 uses the application-dependent data 38 that it holds (step S4), and ends this routine.

[0039] On the other hand, if the application revision is different, i.e., if the application-dependent data 38 has been updated, the SCADA server machine 3 transmits the new application-dependent data 38 to the SCADA web program 44 (step S5). Thereafter, the SCADA web program 44 retains and uses the transmitted application-dependent data 38 (step S6), and ends this routine.

[0040] Since the application-dependent data 38 will not change unless the application is updated, the application-dependent data 38 once sent to the HMI client device 4 is stored on the HMI client device 4 side and is sent to the HMI client device 4 only when the application is updated, thereby reducing the communication load between the HMI client device 4 and the SCADA server device 3.

[0041] 1-5.Effects As described above, according to this embodiment, the client installer 43 is provided in the HMI client device 4, so when the web browser 40 is started, the SCADA web program 44 is loaded from the HMI client device 4 itself, rather than being loaded from the SCADA server device 3 via HTTP. This prevents the amount of communication between the HMI client device 4 and the SCADA server device 3 from exceeding the communication capacity, even when the web browser 40 is started during system operation. This prevents communication errors from occurring during system operation and takes a long time to load web content, eliminating the time when the industrial plant cannot be monitored.

[0042] 2. Hardware configuration example FIG. 11 is a block diagram showing an example of the hardware configuration of the SCADA server machine 3 and the HMI client machine 4.

[0043] Each of the processes of the SCADA server machine 3 described above is realized by a processing circuit. The processing circuit is configured by connecting a processor 301, a memory 302, and a network interface 303. The processor 301 realizes each function of the SCADA server machine 3 by executing various programs stored in the memory 302. The memory 302 includes a main storage device and an auxiliary storage device.

[0044] Each process of the HMI client device 4 described above is realized by a processing circuit. The processing circuit is configured by connecting a processor 401, a memory 402, at least one monitor 403, a network interface 404, and an input interface 405. The processor 401 realizes each function of the HMI client device 4 by executing various programs stored in the memory 402. The memory 402 includes a main storage device and an auxiliary storage device. The input interface 405 is an input device such as a keyboard, a mouse, or a touch panel. Multiple monitors 403 may be provided.

[0045] Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments and can be implemented in various modifications without departing from the spirit of the present invention. When the numbers, quantities, amounts, ranges, etc. of each element are mentioned in the above-described embodiments, the present invention is not limited to the mentioned numbers unless otherwise specified or clearly specified in principle. Furthermore, the structures, etc. described in the above-described embodiments are not necessarily essential to the present invention unless otherwise specified or clearly specified in principle. [Explanation of symbols]

[0046] 1...SCADA web HMI system, 2...Programmable logic controller (PLC), 3...SCADA server machine, 31...Communication driver, 32...Client management unit, 36...Communication module, 37...Application distribution program, 38...Application-dependent data, 4...HMI client machine, 40...Web browser, 41...HMI screen, 42...Parts, 43...Client installer, 44...SCADA web program, 45...Local web server, 46...Program startup script, 5...Computer network, 301, 401...Processor, 302, 402...Memory, 403...Monitor, 304, 404...Network interface, 405...Input interface

Claims

1. A SCADA web HMI system including a plurality of programmable logic controllers (hereinafter referred to as PLCs), a plurality of HMI client machines, and a SCADA server machine, which are connected via a computer network, The PLC transmits block data relating to a group of field devices constituting an industrial plant to the SCADA server at predetermined intervals; the SCADA server machine comprises a communication driver that receives the block data, and a client management unit that is connected to the plurality of HMI client machines on a one-to-one basis and communicates with each HMI client machine via WebSocket; The HMI client machines each execute a web browser that displays an HMI screen on which parts indicating the status of the industrial plant are arranged, and update the status of the parts in accordance with signal data received from the client management unit, thereby monitoring the industrial plant, the HMI client machine includes a client installer for installing a SCADA web program that is loaded when the web browser is started; The SCADA server machine is A method for downloading application-dependent data that is data that depends on an application that runs on the SCADA web program, and transmitting the downloaded application-dependent data to the HMI client machine, When connected to the HMI client machine, it is determined whether the SCADA web program has been updated, and only if it has been updated, the application-dependent data is transmitted to the HMI client machine. SCADA Web HMI system.

2. the SCADA server machine is provided with the same client installer as the client installer; 2. The SCADA web HMI system according to claim 1, wherein the client installer is downloaded from the SCADA server machine to the HMI client machine via the client management unit using the web browser prior to monitoring the industrial plant.

3. the SCADA server machine includes a communication module including content that operates on the SCADA web program; The HMI client device loads the communication module from the SCADA server device; 3. The SCADA web HMI system according to claim 1, wherein the web browser exchanges data between the SCADA web program operating in the domain of the HMI client machine and the communication module operating in the domain of the SCADA server machine using inter-domain communication.

4. 2. The SCADA web HMI system according to claim 1, When the SCADA web program connects to the SCADA server, the HMI client transmits a revision of the application-dependent data contained in the SCADA web program to the SCADA server; The SCADA server machine performs the determination by comparing the revision received from the HMI client machine with the revision of the application-dependent data downloaded from the SCADA server machine.

Images