Web SCADA HMI Authority Control for Multi-Screen Browsers
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Solution Overview
Problem
Existing SCADA HMI systems require multiple client devices to display multiple screens, which increases costs, installation space, and communication load, and lack efficient authority settings for operators and users in large-scale industrial plants.
Innovation Solution
A browser-based SCADA HMI system that allows multiple web browsers to display HMI screens on a single client device, with user and screen authority settings implemented through a web server and client device to manage operation and display states based on user access levels and specific part permissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If one HMI client device displays one HMI screen, then the system is simple to manage, but multiple client devices are required for multiple screens, increasing costs and installation space
Solution Approach 1:
Multiple HMI screens are merged into a single HMI client device through the web browser architecture. The HMI server transmits multiple screen data sets to one client device, which then displays them through multiple web browser instances or tabs, eliminating the need for separate physical client devices for each screen.
Solution Approach 2:
The HMI client device is given universal functionality to display multiple different HMI screens through a single web browser interface. The device can access and display various screens from different sections of the plant by retrieving data from the HMI server, making one device perform the function of multiple dedicated devices.
2Quantity of substance
If multiple HMI screens are displayed on one client device, then costs and installation space are reduced, but authority management becomes more complex
Solution Approach 1:
Authority management is segmented into two independent levels: web browser-level authority (controlling which screens can be accessed from which browsers) and user-level authority (controlling what operations each user can perform on screens). This segmentation allows granular control without requiring complex permission systems, as each level operates independently.
Solution Approach 2:
Different authority settings are applied locally to different web browsers and different users. Each web browser can have its own authority configuration for accessing specific screens, and each user has individual operation permissions. This local quality approach allows flexible, context-specific authority management rather than a one-size-fits-all system.
3Reliability
If traditional HMI systems are used, then each screen has dedicated display capability, but communication load increases with multiple client devices
Solution Approach 1:
Multiple screen display functions are merged into a single HMI client device. The HMI server maintains the master data and transmits screen data to one client device, which then distributes it to multiple web browser instances. This eliminates redundant communication channels that would exist if each screen had its own dedicated client device.
Data Source
AI summary
A SCADA web HMI client device comprises a processor and a memory. The memory stores a user access level, image data for an HMI screen, and screen access authority information, all received from a web server. The screen access authority information includes an operation access level of the HMI screen and operation permission/prohibition of the HMI screen by the web browser. The processor draws the HMI screen in an operable state on the web browser in a case where the user access level is greater than or equal to the operation access level and where operation of the HMI screen by the web browser is permitted. The processor draws the HMI screen in an inoperable state on the web browser in a case where the user access level is less than the operation access level or operation of the HMI screen by the web browser is not permitted.