US-12619207-B2 - SCADA web HMI system

Abstract

A SCADA server apparatus includes a communication driver, and a client management unit connected to the HMI client apparatuses in one-to-one relationship. The client management unit includes a reception thread receiving signal data transmitted from the communication driver, first and second signal data buffers capable of storing the signal data received by the reception thread in association with a signal data identifier for each data type, and a transmission thread reading out the signal data stored in the first or second signal data buffer and transmitting the read signal data to the HMI client apparatuses. During a period when the transmission thread reads out the signal data from one of the first and second signal data buffers and transmits the signal data to the HMI client apparatuses, the signal data stored in another of the first and second signal data buffers is overwritten.

Inventors

• TAKAHARU HASHIZUME
• Akira Nojima
• Nobuo Shimizu

Assignees

• TOSHIBA MITSUBISHI-ELECTRIC INDUSTRIAL SYSTEMS CORPORATION

Dates

Publication Date

20260505

Application Date

20220621

Claims (3)

1. 1 . A SCADA web HMI system comprising a plurality of programmable logic controllers (hereinafter, PLCs), a plurality of HMI client apparatuses, and one SCADA server apparatus that are connected to one another through a computer network, wherein each of the PLCs transmits block data including a set of input/output signals relating to a field device group configuring an industrial plant, to the computer network at a fixed period, each of the HMI client apparatuses includes a screen displaying a web browser, the SCADA server apparatus includes a communication driver, and a client management unit connected to the plurality of HMI client apparatuses in one-to-one relationship, the communication driver is configured to receive the block data transmitted from each of the PLCs at the fixed period, to decompose the received block data into signal data for each data type, to add a signal data identifier to the decomposed signal, and to transmit the decomposed signal data to the client management unit for each data type, the client management unit includes a reception thread receiving the signal data transmitted from the communication driver, first and second signal data buffers capable of storing the signal data received by the reception thread in association with the signal data identifier for each data type, and a transmission thread reading out the signal data stored in the first or second signal data buffer and transmitting the read signal data to the HMI client apparatuses corresponding to the read signal data, and during a period when the transmission thread reads out the signal data from one of the first and second signal data buffers and transmits the signal data to the HMI client apparatuses, the signal data stored in another of the first and second signal data buffers is overwritten.
2. 2 . The SCADA web HMI system according to claim 1 , wherein the reception thread is configured to store the signal data in the first and second signal data buffers using the signal data identifier as an index.
3. 3 . The SCADA web HMI system according to claim 2 , wherein each of the first and second signal data buffers includes an update flag that is turned on when the stored signal data is updated, in association with the index, the reception thread generates an index list storing the indexes in which the update flag is ON, and the transmission thread is configured to transmit the signal data of the index in which the update flag is ON, to the HMI client apparatuses with reference to the index list.

Description

CROSS-REFERENCE TO RELATED APPLICATION The present application is based on PCT filing PCT/JP2022/024703, filed Jun. 21, 2022, the entire contents of which are incorporated herein by reference. FIELD The present invention relates to a SCADA web HMI system, and in particular to a technique for reducing a processing load in a large-scale system. BACKGROUND A SCADA (Supervisory Control And Data Acquisition) is known as a mechanism supervising and controlling a social infrastructure system. The social infrastructure system includes a steel rolling system, a power transmission and transformation system, a water and sewage treatment system, a building management system, a road system, and the like. The SCADA is a type of industrial control system, and performs system supervision, process control, and data collection by a computer. The SCADA needs quick responsiveness (real-time property) corresponding to processing performance of the system. The SCADA generally includes the following sub-systems. (1) HMI (Human Machine Interface) An HMI is a mechanism that presents data on a supervisory object device to an operator, and enables the operator to supervise and control the supervisory object device. (2) Supervisory Control System A supervisory control system includes a Programmable Logic Controller (PLC) and the like. The supervisory control system collects the data on the supervisory object device, and transmits a control command to the supervisory object device. (3) Remote Input/Output Device (Remote Input Output: RIO) A remote input/output device is connected to a sensor installed in the supervisory object device, converts a signal of the sensor into digital data, and transmits the digital data to the supervisory control system. (4) Communication Base A communication base connects the supervisory control system and the remote input/output device. As an example of a SCADA HMI sub-system, PTL 1 discloses a system including an HMI client apparatus and an HMI server apparatus. In the existing SCADA such as disclosed in PTL 1, the HMI server apparatus transmits data (input/output signals, and alarm signal) received from the PLC to the HMI client apparatus, and accumulates all of collected data as history data. The input/output signals are signals relating to the supervisory object device (field device group configuring industrial plant), and include an actuator control signal and a sensor detection signal. CITATION LIST Patent Literature [PTL 1] JP 2017-27211 A[PTL 2] JP H11-120104 A SUMMARY Technical Problem Issues in development of the HMI sub-system that is one of the above-described sub-systems are described. In the large-scale system, the HMI sub-system connects hundreds of thousands of signals to the PLC in some cases. The existing HMI server apparatus performing both of supervisory control and data collection needs a high-performance processor and a large-capacity memory in order to process the large number of signals in real time. Therefore, it is desirable to realize the HMI sub-system applicable to the large-scale system, at low cost. To realize low cost of the SCADA HMI sub-system, the inventor of the present application has developed a browser-based SCADA HMI sub-system. This makes it possible to realize an HMI screen as a web application operating on a web browser. One of advantages of realization of the HMI screen on the web browser is easy acquisition of data from different web servers by switching a URL (including port number). In other words, data on a history screen can be acquired from an online data gathering (ODG) device that collects and accumulates all of PLC data, and data on a supervisory screen required to have real-time property can be acquired from the HMI server apparatus. A function relating to the history that is a part of SCADA functions is separated and is taken on by the online data gathering device, which enables the HMI server apparatus to specialize in a real-time supervisory function. To process the large number of signals by the low-cost HMI server apparatus, it is desirable to reduce a processing load for the input/output signals (including actuator control signal and sensor detection signal) and the alarm signal. In the large-scale SCADA web HMI system, it is anticipated that a large number of client apparatuses are connected to one server apparatus. In this case, there is a possibility that the HMI server apparatus cannot perform real-time data processing. For example, when 128 HMI client apparatuses are connected to one server apparatus, and each of the HMI client apparatuses displays the same screen, it is necessary for the HMI server apparatus to receive signal data included in the screen and to transmit the signal data to all of the HMI client apparatuses. In the browser-based SCADA HMI sub-system, the screen on each of the HMI client apparatuses is displayed by a web browser, and the signal data is transmitted from the HMI server apparatus to the HMI client apparatuses by u