I/O Unit Power Discontinuity Detection via Unique Communication Packets

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Solution Overview

Problem

Existing methods for detecting power discontinuity and communication line disconnection in I/O units connected to a numerical controller fail to distinguish between the two conditions, leading to unnecessary costs due to the requirement for large-capacity capacitors to maintain power supply voltage and inefficient communication processes.

Innovation Solution

A method that detects power discontinuity in I/O units by transmitting a unique communication packet to the front I/O unit, allowing for discrimination between power discontinuity and communication line disconnection, and acquiring alarm information from I/O units closer to the numerical controller, thereby eliminating the need for large-capacity capacitors and reducing communication interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a large-capacity capacitor is provided to hold the power supply voltage for internal circuits of each I/O unit until the right of a communication line is guaranteed, then the power discontinuity detection reliability is improved, but the cost increases

Engineering Contradiction:
Improvepower discontinuity detection reliabilityVSAvoidcost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent extracts the power discontinuity detection function from the conventional approach that requires capacitors. Instead of holding power supply voltage with capacitors, the system detects power discontinuity by monitoring communication signals, thereby eliminating the need for large-capacity capacitors and reducing cost while maintaining detection reliability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the electrical/physical approach of using capacitors to hold voltage with a communication-based detection method. The system uses signal transmission and reception between I/O units to detect power discontinuity, substituting the mechanical/electrical capacitor system with an information-based detection system

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

2Difficulty of detecting and measuring

If an auto-scanning scheme is used to detect communication failure by checking if no reply is received, then the detection capability is improved, but the ability to discriminate between power discontinuity and communication line disconnection deteriorates

Engineering Contradiction:
Improvecommunication failure detection capabilityVSAvoidfailure type discrimination accuracy
Core Design Contradiction:
Difficulty of detecting and measuringVSMeasurement precision

Solution Approach 1:

The patent segments the detection process into distinct phases: normal communication phase and power discontinuity detection phase. During the detection phase, the system transmits specific detection signals and monitors responses to determine whether failure is due to power discontinuity or communication line disconnection, enabling precise discrimination between failure types

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements a feedback mechanism where I/O units transmit response signals back to indicate their status. By analyzing the presence or absence of these feedback signals in response to detection transmissions, the system can accurately determine whether a failure is caused by power discontinuity or communication line disconnection

Inventive Principle:
Principle #23Feedback

3Device complexity

If communication packets are transmitted at the same timing as ordinary communication, then the communication process is simplified, but the detection accuracy deteriorates due to communication interference

Engineering Contradiction:
Improvecommunication process complexityVSAvoidpower discontinuity detection accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent implements periodic action by transmitting power discontinuity detection packets at specific, predetermined timings that are distinct from ordinary communication timings. This periodic detection transmission allows the system to monitor for power discontinuity without interfering with regular communication operations, maintaining both simplicity and accuracy

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP2028571B1Method of detecting disconnection and power discontinuity of I/O unit connected to numerical controller
Publication Date: 2013.12.11 FANUC LTD
  • EP2028571B1 patent drawingFigure 1~2
  • EP2028571B1 patent drawingFigure 3~4
  • EP2028571B1 patent drawingFigure 5

AI summary

A power discontinuity occurring in any one of a plurality of I/O units connected to a numerical controller is detected. When the power discontinuity occurs in any one of the I/O units, the I/O unit detects the power discontinuity, and transmits the detection of the power discontinuity to an I/O unit in front of the I/O unit, at a timing different from a timing of an ordinary communication, in the form of a communication packet having a data pattern different from an ordinary data pattern. When the front I/O unit receives the communication packet, the communication packet is stored in a memory as power discontinuity detection information.