Dual-CPU Field Device Diagnosis Using Sequence Feedback

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Solution Overview

Problem

Existing field devices, such as pressure gauges and flowmeters, face challenges in efficiently diagnosing failures in their central processing units (CPUs) within a short time frame.

Innovation Solution

A field device configuration with a sensor, first CPU, and second CPU, where the first CPU performs arithmetic operations and fixed-cycle processing, voluntarily transmitting sequence information to the second CPU for failure diagnosis, allowing the second CPU to determine normal execution of fixed-cycle processing and self-diagnosis based on this information.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If the second CPU requests sequence information from the first CPU for failure diagnosis, then the diagnosis can be performed, but the processing time increases due to the request-response cycle

Engineering Contradiction:

ImproveCPU failure diagnosis timeVSAvoidCPU failure detection accuracy

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The first CPU performs fixed-cycle processing and voluntarily transmits sequence information to the second CPU before a failure diagnosis request is made. This preliminary action ensures that the sequence information is already available when needed, eliminating the request-response delay and enabling immediate failure diagnosis without sacrificing detection accuracy.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The first CPU voluntarily provides sequence information as feedback to the second CPU, allowing the second CPU to continuously monitor the first CPU's operation status. This feedback mechanism enables the second CPU to detect failures promptly by comparing received sequence information against expected values, resolving the contradiction between fast diagnosis and accurate detection.

Inventive Principle:

Principle #23Feedback

2Productivity

If the first CPU performs extensive fixed-cycle processing, then the processing capability is improved, but the transmission of sequence information increases the communication load

Engineering Contradiction:

ImproveFixed-cycle processing capabilityVSAvoidCommunication energy consumption

Core Design Contradiction:

ProductivityVSLoss of energy

Solution Approach 1:

The patent extracts only the essential sequence information (results of fixed-cycle processing) from the first CPU's extensive processing operations and transmits only this condensed data to the second CPU. This extraction approach maintains high processing capability while minimizing communication load and energy consumption by transmitting only necessary diagnostic data rather than all processing details.

Inventive Principle:

Principle #2Taking out (Extraction)

Data Source

PatentUS20250298682A1Field device and diagnosis method

Publication Date: 2025.09.25 YOKOGAWA ELECTRIC CORP

AI summary

In a field device 10, a sensor 101 measures a given physical quantity and outputs a sensor measurement value that is a value representing the measured physical quantity, a first CPU 102 performs a given arithmetic operation and given fixed-cycle processing on the sensor measurement value and voluntarily transmits sequence information containing a result of executing the fixed-cycle processing, and a second CPU 103 determines whether the first CPU 102 has a failure by determining whether the fixed-cycle processing is executed normally based on the sequence information.