Isolated Logic Controller Architecture for Networked Control Systems
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Solution Overview
Problem
Industrial control systems (ICSs) at the basic control level are vulnerable to network attacks, as control logic and process inputs reside in the same controller, making them exposed to network exploits, which can lead to unauthorized commands and physical impacts, such as equipment damage or process excursions.
Innovation Solution
Implementing an isolated logic controller (ILC) with a bridge interface that separates the control logic from the network interface, using unidirectional communication channels to protect the control logic and process logic from network attacks, and physically securing programming ports with robust passwords to prevent local tampering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If control logic and network interface are integrated in the same controller, then device complexity is reduced and ease of operation is improved, but vulnerability to network attacks increases
Solution Approach 1:
The controller is divided into separate functional modules: a network interface controller for handling network communications and a logic controller for executing control logic. This segmentation isolates the control logic from direct network exposure, reducing vulnerability to network attacks while maintaining operational simplicity through modular design.
Solution Approach 2:
A bridge interface acts as an intermediary between the network interface controller and the logic controller. This mediator component receives commands from the network interface, validates and conditions them, then transfers approved commands to the logic controller, thereby protecting the control logic from direct network threats.
2Reliability
If control logic is isolated from the network interface using a bridge interface, then reliability against network attacks is improved, but device complexity increases
Solution Approach 1:
The controller architecture is segmented into distinct functional units connected through a bridge interface. This segmentation, while increasing structural complexity, enhances reliability by creating isolation barriers that prevent network attacks from directly affecting control logic, trading manageable complexity for significant security improvement.
Solution Approach 2:
The bridge interface serves as a mediating component that manages communication between the network interface controller and logic controller. Although this intermediary adds to device complexity, it fundamentally improves reliability by filtering, validating, and conditioning commands before they reach the control logic, thereby blocking malicious network inputs.
3Object-affected harmful factors
If unidirectional communication channels are used in the bridge interface, then protection from network attacks is enhanced, but loss of information increases due to restricted communication
Solution Approach 1:
The bridge interface acts as an intelligent intermediary that uses unidirectional communication channels to protect the logic controller from network attacks. It conditions commands by validating their authenticity and appropriateness before forwarding them unidirectionally to the logic controller, thereby maintaining protection while preserving essential control information through careful filtering rather than blanket blocking.
Data Source
AI summary
An architecture for a control system in a network, and devices and techniques for implementing the same. The architecture may comprise a logic controller isolated from the network by an interface controller and a bridge interface between the interface controller and the logic controller.