PLC Module Firmware Anomaly Detection via Identification Cable
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Solution Overview
Problem
Current methods for detecting anomalies in the manufacturer program of programmable logic controller (PLC) modules are inefficient, requiring hardware modification and excessive memory usage, and lack a simple, rapid, and non-invasive approach.
Innovation Solution
A system utilizing a connecting cable with an identification device that connects the module to a computer station, allowing the module's software to launch an anomaly search mode without modifying hardware or volatile memory, using a software component that dialogues with the computer station to execute the manufacturer program and detect anomalies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the microprocessor is unsoldered and replaced with a microprocessor emulator to search for anomalies, then anomaly detection capability is improved, but device complexity and ease of operation deteriorate due to hardware modification requirements
Solution Approach 1:
A connection cable with an identification device (loop) serves as an intermediary between the computer station and the module. When connected, the loop establishes an electrical connection that automatically triggers anomaly detection mode, eliminating the need for hardware modification while enabling reliable anomaly detection through software-based emulation.
Solution Approach 2:
The patent replaces the mechanical hardware modification approach (unsoldering and replacing microprocessor) with an electrical/software-based solution. The identification device uses electrical connection through a loop to trigger software-based anomaly detection, substituting mechanical intervention with electronic signaling.
2Reliability
If the anomaly search tool is permanently active and fully embedded in the programmable automaton, then anomaly detection capability is improved, but memory usage and device complexity worsen
Solution Approach 1:
The anomaly detection system transitions from a static, permanently active embedded tool to a dynamic, on-demand system. The detection mode is activated only when the identification device is connected, allowing the system to switch between normal operation and anomaly detection mode, thereby reducing continuous memory usage while maintaining detection capability.
Solution Approach 2:
The software component for anomaly detection is pre-loaded in the module's memory but remains dormant until activated by the identification device. This preliminary preparation allows rapid activation when needed without requiring the system to continuously allocate full memory resources for active anomaly detection.
3Reliability
If the module structure is modified to enable anomaly search, then anomaly detection capability is improved, but ease of manufacture and adaptability worsen
Solution Approach 1:
The anomaly detection functionality is segmented into a separate, removable identification device that connects via cable rather than being integrated into the module's core structure. This segmentation allows the module to be manufactured without built-in anomaly detection hardware, maintaining ease of manufacture while enabling detection capability when needed.
Solution Approach 2:
The connection cable with identification device serves multiple functions: it acts as a communication interface between the computer station and the module, and simultaneously serves as an activation trigger for anomaly detection mode. This multi-functionality eliminates the need for dedicated anomaly detection hardware modifications to the module structure.
Data Source
Figure 1~2
AI summary
The system has a connecting cable (3) including a hardware identification part (300) i.e. strap, and connecting a specific input/output module (1) of a programmable logic controller with a computer terminal (2) e.g. personal computer. The module has software identification units to identify the cable when the cable is connected on a connector (13) of the module. A non-volatile memory (12) e.g. electrically EPROM, of the module stores a software component (121) i.e. ROM monitor, co-operating with software tools (220) of the terminal to search anomalies in a firmware (120) stored in the module. An independent claim is also included for a method of searching an anomaly in a firmware stored in a non-volatile memory of a module of a programmable logic controller.