Digital Signal Processing Unit Operability Checking via Segmented Test Instructions
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Solution Overview
Problem
Existing systems for monitoring the operability of digital signal processing units in position sensors, such as those used in rotating systems, face challenges in ensuring continuous functionality and reliability, particularly in maintaining Safety Integrity Levels (SIL) without adequate internal diagnostic features.
Innovation Solution
The method involves executing additional instructions, such as test instructions, from a separate storage unit independent of the primary memory, allowing for continuous checking of the digital signal processing unit's operability during runtime by comparing results with expected outcomes using an external microcomputer, thereby isolating the check from memory malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional instructions are executed from the primary memory during each sequence, then the digital signal processing unit can be checked for operability, but the check becomes dependent on memory functionality and cannot isolate memory malfunctions
Solution Approach 1:
The patent divides the instruction storage into two separate segments: the primary memory containing the main instruction queue of N instructions, and a second storage unit containing additional test instructions. This segmentation allows the test instructions to be executed independently of the primary memory, enabling isolation of memory malfunctions while maintaining operability checking capability.
Solution Approach 2:
The patent extracts the test instructions from the primary memory and places them in a separate second storage unit. This extraction allows the operational check to be performed independently of the primary memory's functionality, solving the problem of being unable to isolate memory malfunctions when using the same memory for both main instructions and test instructions.
2Reliability
If the digital signal processing unit continuously executes instruction sequences for operational checking, then reliability monitoring is improved, but system time and processing efficiency are reduced
Solution Approach 1:
The patent implements partial action by executing only a small number of additional test instructions (x instructions) from the second storage unit during each sequence, rather than performing comprehensive tests. This partial checking approach provides continuous reliability monitoring while minimizing the time loss and maintaining processing efficiency.
Solution Approach 2:
The operational checking is performed periodically during each instruction sequence execution rather than continuously between sequences. The digital signal processing unit executes the additional test instructions at regular intervals (once per sequence), achieving continuous monitoring capability while avoiding constant time loss that would occur with more frequent checking.
3Reliability
If comprehensive diagnostic features are implemented to achieve necessary Safety Integrity Levels, then system safety is improved, but device complexity and cost increase
Solution Approach 1:
The digital signal processing unit performs self-diagnosis by executing additional test instructions and comparing the results against expected values stored in the second storage unit. This self-service approach enables comprehensive diagnostic capability for achieving Safety Integrity Levels without requiring external diagnostic equipment or complex additional hardware, thus improving safety while controlling device complexity.
Data Source
AI summary
A method for checking the operability of a digital signal processing unit of a position sensor, wherein the digital signal processing unit executes an instruction queue of N instructions one after another in sequences, wherein an additional number of x instructions is executed by the digital signal processing unit during each sequence, wherein the additional instructions are provided in a unit different from the memory, and that the results of the additional instructions are stored. The results of the additional instructions are read by a microcomputer. The results of the additional instructions are compared by the microcomputer with the expected results achieved by execution of identical additional instructions by the microcomputer or with expected results stored in the microcomputer. This includes a position encoder comprising a digital signal processing unit for calculating position information.