CRC Error Correction Layer for Industrial Safety Messages
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Solution Overview
Problem
Existing industrial automation systems face frequent downtime and safety risks due to CRC alarms caused by erroneous safety messages and safety-relevant data, especially in communication networks with poor transmission quality and high susceptibility to interference, leading to increased productivity issues and safety problems.
Innovation Solution
An Error correction layer is inserted between the Safety communication layer and underlying communication layers, performing error detection and correction using Cyclic Redundancy Check (CRC) with a logical operation and Guessing Random Additive Noise Decoding (GRAND) to reduce CRC alarms and improve data integrity, without modifying existing layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If CRC check is applied to safety messages in communication networks with poor transmission quality, then error detection capability is improved, but CRC alarm frequency increases causing system downtime
Solution Approach 1:
The patent applies GRAND decoding as a preliminary error correction action before CRC verification. By guessing and correcting potential error patterns in advance, the system prevents CRC alarms that would otherwise occur due to transmission errors in poor quality networks, thus maintaining system availability while preserving error detection capability
Solution Approach 2:
The patent converts the harmful effect of transmission errors into a benefit by using GRAND decoding to guess and correct error patterns. Instead of letting errors cause CRC alarms and downtime, the system actively identifies and corrects them, transforming the potential harm into improved reliability
2Reliability
If error correction layer is inserted between Safety communication layer and underlying communication layers, then error correction capability is improved, but device complexity increases
Solution Approach 1:
The patent segments the communication system by inserting a dedicated Error Correction Layer between the Safety communication layer and underlying communication layers. This segmentation isolates the complex GRAND decoding functionality in a separate layer, maintaining modularity while providing enhanced error correction capabilities without overwhelming the existing system architecture
Data Source
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AI summary
The present invention relates to a method and a system for detecting and correcting errors in safety messages and/or safety-relevant data received by an automation component (A1, A2) of an industrial automation system via a digital communication network, especially a fieldbus communication system, wherein a safety protocol, which is implemented by means of a Safety communication layer (SCL), is used for data transmission of the safety messages and/or safety-relevant data, wherein Cyclic Redundancy Checks are applied to the safety messages and/or safety-relevant data, and wherein the safety messages and/or safety-relevant data are transmitted in the form of data packets (DP, DP1, DP2). An Error correction layer (ECL), which is inserted on the receiver's (A1, A2) side between the Safety communication layer (SCL) and underlying communication layers (CL) of the communication network, is designed to carry out the following steps to detect and correct errors in the safety messages and/or safety-relevant data. First a data packet (DP, DP1, DP2), which is received by the automation component (A1, A2) via the communication network, is retrieved from a receiving part (REC) of communication layers (CL) of the communication network (101). Then an error pattern (EP) is generated by an Error pattern generator unit (EPG) (102). Then a logical operation is applied to the received data packet (DP, DP1, DP2) and the generated error pattern (EP) by a Bit string calculator unit (BSC), wherein an updated data packet (DP') is determined as result (103). Then the updated data packet (DP') is checked for errors using Cyclic Redundancy Check according to a given CRC polynomial (CP) by an Error detector unit (ED) and an error signal (CRC_E) is set to a value, whether there is at least one error in the updated data packet (DP') or not (104). The value of the error signal (CRC_E) is evaluated and a number of repetitions of the steps of error pattern generation, determining an updated data packet (DP'), checking the updated data packet (DP') for errors and evaluating the error signal (CRC_E) is monitored by an Error correction control unit (ECC). These steps are repeated, until either the value of the error signal (CRC_E) indicates that the updated data packet (DP') is error-free or the number of repetitions of these steps reaches a predefined maximum number of repetitions.