Adaptive Pulse Frequency Measurement With Low-Speed MCU Counters

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Solution Overview

Problem

Current pulse frequency measurement methods in the process automation industry are costly due to the use of high-speed MCUs and FPGAs, especially for high-frequency pulse sequences, which increases implementation costs and resource requirements.

Innovation Solution

A pulse frequency measurement device and method utilizing a low-speed MCU in conjunction with an external hardware counter to measure pulse frequencies, employing a frequency calculation module that adapts measurement strategies based on pulse sequence characteristics, including time division strategies for multi-channel sampling and adaptive frequency recognition.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If FPGAs are used to implement frequency measurement logical function, then measurement precision and speed are improved, but device cost and complexity increase

Engineering Contradiction:
Improvefrequency measurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The frequency measurement function is segmented into two parts: the hardware counter handles pulse counting at high speed, while the low-speed processing unit handles frequency calculation and control. This segmentation allows each component to operate at its optimal speed, eliminating the need for expensive high-speed FPGAs while maintaining measurement precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediary mechanism where the hardware counter acts as a bridge between the high-frequency pulse signal and the low-speed processing unit. The counter captures pulse information and transfers it to the processing unit, which then calculates frequency, thereby mediating between high-speed signal acquisition and low-speed computation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If high-speed MCUs are used for frequency measurement, then productivity and measurement speed are improved, but device cost increases

Engineering Contradiction:
Improvemeasurement speedVSAvoiddevice cost
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system segments the measurement task so that the hardware counter (operating at high speed) handles pulse capture while the low-speed processing unit handles calculation. This allows using inexpensive low-speed MCUs instead of expensive high-speed MCUs, maintaining measurement speed through the high-speed counter interface.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent replaces the need for high-speed processing electronics with a combination of simple hardware counting and software-based frequency calculation. Instead of relying on high-speed MCU hardware, the system uses a hardware counter with a low-speed processor, substituting complex high-speed electronics with a simpler hybrid approach.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Measurement precision

If hardware counter with high counting speed is used, then measurement precision for high frequency pulses is improved, but device cost increases

Engineering Contradiction:
Improvehigh frequency pulse measurement precisionVSAvoiddevice cost
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system segments the high-frequency measurement task: the hardware counter captures high-frequency pulses at full speed, while the low-speed processing unit calculates frequency from the captured data. This segmentation enables accurate high-frequency measurement using inexpensive low-speed processors.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2912773B1Pulse frequency measurement device and method and control system
Publication Date: 2019.12.04 ABB (SCHWEIZ) AG
  • EP2912773B1 patent drawingFigure 1
  • EP2912773B1 patent drawingFigure 2~3
  • EP2912773B1 patent drawingFigure 4

AI summary

The present invention discloses a pulse frequency measurement device and method and a control system, the device including: a hardware counter configured to perform a counting operation on an input pulse sequence to output a counting result; and a processing unit configured to obtain number of pulses from the counting result outputted by the hardware counter and measure a first time period during which the obtained number of pulses occupy, in which the processing unit includes a frequency calculation module configured to calculate a frequency of the input pulse sequence based on the obtained number of pulses and the first time period. According to the invention, it is possible to achieve adaptive pulse frequency measurement and multi-channel sampling for multiple input pulse sequences with a relatively low cost while ensuring the accuracy of the measurement result.