Optoelectronic Sensor Voltage Monitoring and Short Circuit Prevention

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Solution Overview

Problem

Optoelectronic sensors, such as light barriers, often indicate operational readiness even when the supply voltage is insufficient, leading to potential short circuits and undetectable malfunctions due to incorrect wiring, resulting in downtimes and tedious troubleshooting.

Innovation Solution

Incorporating a supply voltage monitoring unit that ensures the operating display only lights up when the voltage is sufficient for safe operation, with the controller activating the switching output only when operational readiness is confirmed, and monitoring both voltage and current to prevent short circuits.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the sensor uses conventional voltage monitoring with reset thresholds of 1-5 volts, then the basic ASIC supply is monitored, but the full sensor function cannot be guaranteed and operational readiness is falsely indicated

Engineering Contradiction:
Improveoperational readiness indicationVSAvoidvoltage monitoring accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent changes the voltage monitoring parameter from conventional reset thresholds of 1-5 volts to a minimum supply voltage of 10-30 volts that matches the sensor's actual operating requirements. This parameter change ensures that the monitoring accurately reflects the true operational readiness of the complete sensor system, not just the basic ASIC supply.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the sensor operates with insufficient voltage, then the operating display may light up, but the switching output can be destroyed by overload due to short circuits from incorrect wiring

Engineering Contradiction:
Improveoperating display indicationVSAvoidswitching output safety
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent implements preliminary voltage verification before enabling the switching output. The controller only activates the switching output after confirming that the minimum supply voltage is present, preventing overload destruction from incorrect wiring before it can occur.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent establishes a feedback loop where the controller continuously monitors the supply voltage and uses this information to control the switching output activation. This feedback mechanism ensures the switching output is only activated when voltage conditions are safe, preventing destruction while maintaining accurate operational indication.

Inventive Principle:
Principle #23Feedback

3Productivity

If the sensor does not monitor the specified supply voltage, then the operating display lights up even with insufficient voltage, but troubleshooting becomes tedious and downtimes increase

Engineering Contradiction:
Improvesystem uptimeVSAvoidtroubleshooting time
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent performs preliminary detection of cabling errors and insufficient voltage before they cause system failures. By checking voltage conditions in advance and preventing operation when voltage is insufficient, the system avoids malfunctions that would require tedious troubleshooting and cause downtimes.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP2161592B1Optoelectronic sensor
Publication Date: 2011.05.18 SICK AG
  • EP2161592B1 patent drawingFigure 1~2
  • EP2161592B1 patent drawingFigure 3

AI summary

The sensor (10) has a supply voltage monitoring unit (34) checking a supply voltage (30) by comparison with an internally produced reference voltage (32), which is a measurement for a preset minimum voltage supply of the sensor. The minimum voltage supply is in range of 10 to 30 Volts. A control unit e.g. microcontroller, determines whether the supply voltage is available as a function of the status of the sensor. A display (36) e.g. green LED, displays whether the control unit detects the status or not. The reference voltage is balanced by laser-trimming of the control unit. An independent claim is also included for a method for monitoring a supply voltage of an optoelectronic sensor.