PLC-AI Control Network Segmentation for Secure Web Access

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Solution Overview

Problem

Conventional control systems require dedicated communication protocols and commands, leading to cumbersome system design and increased load on Programmable Logic Controllers (PLCs), compromising usability and security.

Innovation Solution

A control system with a control unit and an AI computation unit, each having network ports, where the control unit performs forwarding processing to transfer data between a client interface and the AI computation unit, maintaining separate network segments for enhanced security, using port forwarding and dedicated communication commands.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If dedicated communication protocols and commands are used for data exchange between PLC and general-purpose PC, then communication reliability is improved, but system design complexity increases and PLC processing load increases

Engineering Contradiction:
Improvecommunication reliabilityVSAvoidsystem design complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies universality by enabling the control unit to handle multiple functions: it acts as both a PLC for industrial control and a Web server for data exchange. By integrating Web server functionality into the control unit, the system eliminates the need for separate dedicated communication protocols between PLC and PC, reducing system design complexity while maintaining communication reliability through standardized Web protocols.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces a Web server as an intermediary layer between the control unit and the interface unit. This mediator translates industrial control data into standard Web formats, allowing communication without requiring the control unit to process dedicated communication protocols directly, thereby reducing its processing load while maintaining reliable data exchange.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If dedicated communication protocols are implemented, then data exchange precision is improved, but PLC processing load increases

Engineering Contradiction:
Improvedata exchange precisionVSAvoidPLC processing load
Core Design Contradiction:
Measurement precisionVSPower

Solution Approach 1:

The Web server acts as an intermediary that handles the complexity of data translation and protocol conversion. It receives data from the control unit in industrial formats, converts it to standard Web formats, and transmits it to the interface unit. This preserves data exchange precision while offloading processing tasks from the control unit, reducing its processing load.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent extracts the communication protocol processing function from the control unit and places it in the Web server. By separating these functions, the control unit focuses only on data collection and transmission, while the Web server handles the complex protocol conversion, thereby reducing the control unit's processing load while maintaining data exchange precision.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If network segments are separated for security, then system security is improved, but network complexity increases

Engineering Contradiction:
Improvesystem securityVSAvoidnetwork complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the network into two distinct network segments: one connecting the control unit and AI computation unit, and another connecting the control unit and interface unit. This physical or logical separation enhances security by isolating the industrial control network from the user interface network, while the control unit's routing functionality manages the complexity of inter-segment communication.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP4597934A1Control system
Publication Date: 2025.08.06 HITACHI IND EQUIP SYST CO LTD
  • EP4597934A1 patent drawingFigure 1
  • EP4597934A1 patent drawingFigure 2
  • EP4597934A1 patent drawingFigure 3

AI summary

A control system includes a control unit that has a Web server and two or more network ports, and a computation unit that has a Web server and a network port. The two or more network ports of the control unit include first and second network ports. The first network port of the control unit and the network port of the computation unit are coupled to a first network segment that is a closed network segment to which no elements other than the control unit and the computation unit are coupled. The control unit transfers data received from the interface unit to the computation unit, and also displays a Web server screen of the computation unit on a Web server screen of the control unit.