Dual-Clock Time Management for Automation Equipment

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Solution Overview

Problem

Existing time management systems in automation equipment face issues with slow access to external RTC components, limited resolution, high cost, and inability to resynchronize clocks after power interruptions, leading to inconsistencies and inefficiencies.

Innovation Solution

A dual-clock system is implemented, where a low-cost RTC hardware component with a second-time base is used in conjunction with a software-incremented clock with a millisecond time base, utilizing an auxiliary capacitor power supply to maintain time coherence during power outages, and periodic synchronization is performed to prevent clock drift.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an external RTC hardware component is used for time management, then time keeping function is provided, but access speed becomes particularly slow

Engineering Contradiction:
Improvetime keeping functionVSAvoidaccess speed
Core Design Contradiction:
ReliabilityVSSpeed

Solution Approach 1:

The time management function is segmented into two independent parts: a fast software-based clock for high-speed access and a hardware RTC for accurate time keeping. Each component operates independently and serves its specific purpose, resolving the contradiction between speed and reliability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A synchronization mechanism acts as an intermediary between the software clock and hardware RTC. This mediator periodically transfers time data from the RTC to the software clock, ensuring both components remain coherent while allowing the software clock to operate at high speed.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If a standard RTC component with one second resolution is used, then cost is reduced, but time resolution remains limited

Engineering Contradiction:
ImprovecostVSAvoidtime resolution
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The invention creates a virtual copy of the RTC functionality in software, running at a higher clock frequency than the hardware RTC. This software-based time base copies the time-keeping function but operates with millisecond or microsecond resolution, providing high precision without the cost of a high-resolution hardware RTC.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The system changes the time resolution parameter by using a software clock that counts at a higher frequency (milliseconds or microseconds) than the standard RTC (seconds). This parameter change is achieved through software manipulation rather than hardware modification, maintaining cost-effectiveness while improving precision.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If a battery is used to maintain time during power interruption, then time management is maintained, but the system cannot quickly resynchronize after power restoration

Engineering Contradiction:
Improvetime management continuityVSAvoidsynchronization recovery time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The software clock continuously maintains time counting even during power interruptions (when powered by capacitor or backup power), preparing the system for quick recovery. When main power is restored, the system immediately detects the power return and synchronizes the software clock with the RTC, achieving fast recovery without waiting for battery recharging or complex resynchronization procedures.

Inventive Principle:
Principle #10Preliminary action

4Reliability

If the RTC hardware component is external to the microprocessor, then time management is provided, but access becomes particularly slow

Engineering Contradiction:
Improvetime management functionVSAvoidsystem architecture
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The microprocessor is given multiple functions: it executes the application program and simultaneously maintains the software-based time base. This multi-functionality eliminates the need for frequent external RTC access, as the microprocessor can perform time-related operations using its own internal resources, reducing access delays and simplifying the interaction architecture.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This solution ensures coherent and high-resolution time management in automation equipment, allowing for quick recovery and synchronization after power cuts without damaging the system, maintaining operation integrity.

Implementation Method 1

an auxiliary power supply, in particular a capacitor, intended to maintain the time management in the event of an interruption of the main electrical power supply

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP1986071B1System and method for managing time in automatic control equipment
Publication Date: 2015.10.21 SCHNEIDER ELECTRIC IND SAS
  • EP1986071B1 patent drawingFigure 1

AI summary

The present invention relates to a time management method implemented in an automation equipment, from a system which comprises: - a first clock (H1) having a first counter (C1) operating on a first time base, - a second clock (H2) having a second counter (C2) operating on a second time base identical to the first time base and a third counter (C3) operating on a third time base lower than the second time base, said time management method being characterized in that it consists in particular of: - performing a resynchronization of the second clock (H2) after the restoration of the main power supply (G1), this resynchronization consisting, when a modification of the first counter (C1) is made, of loading the first counter (C1) into the second counter (C2) and of initializing the third counter (C3) to zero.