Triangulation Sensor Self-Testing Reference Channel
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Solution Overview
Problem
Existing triangulation photoelectric proximity sensors lack a method to effectively test and monitor their own functionality without disrupting the signal flow through the monitoring area, making it difficult to detect errors in the transmitting and receiving blocks without a defined surveillance area, which can impact machine safety.
Innovation Solution
Incorporating a second reference light transmitter for safety-related self-testing, allowing the system to compare receiver output signals with reference signals and switch to a safe state if deviations are detected, while also using a reference light receiver to monitor ambient light and timing, ensuring the sensor's integrity and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a triangulation photoelectric proximity sensor is used for object detection in a surveillance area, then object detection capability is provided, but the system cannot perform self-testing without disrupting the signal flow through the monitoring area
Solution Approach 1:
The patent segments the light transmission path into two independent channels: a reference channel with a reference light transmitter and reference light receiver for self-testing, and a measurement channel with the main light transmitter and light receiver for object detection. This segmentation allows the reference channel to perform safety-related self-tests without disrupting the measurement channel's signal flow through the monitoring area, thus maintaining both reliability and productivity.
2Reliability
If the entire signal flow runs through the monitoring area for object detection, then object detection is enabled, but fault detection in transmitting and receiving blocks becomes difficult without a defined surveillance area
Solution Approach 1:
The patent introduces a reference light transmitter and reference light receiver as intermediary components that create a separate reference path for self-testing. The reference light transmitter emits reference light that is detected by the reference light receiver, providing a known reference signal for monitoring the functionality of transmitting and receiving blocks without requiring a defined external surveillance area. This intermediary testing path simplifies fault detection while maintaining system reliability.
3Reliability
If reference runs and reference measurements are performed cyclically to test system blocks, then self-monitoring capability is achieved, but machine throughput is reduced due to loss of productive time
Solution Approach 1:
The patent enables continuous self-monitoring by maintaining the reference light path as an always-active monitoring channel. Unlike cyclic reference runs that periodically interrupt productive operations, the reference light transmitter and reference light receiver continuously monitor the functionality of the sensor system without stopping or disrupting the main object detection operations. This continuous monitoring achieves high safety integrity levels while maintaining full machine throughput without loss of productive time.
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
The solution enhances machine safety by enabling self-monitoring and fault detection within the triangulation photoelectric proximity sensor, ensuring the highest possible safety integrity level and reducing the need for dedicated reference runs, thus improving machine throughput and reducing productive time lost to testing.
Implementation Method 1
The light transmitter (2), for example a light-emitting diode or a laser
Implementation Method 2
The light transmitter (2), for example a light-emitting diode or a laser
Implementation Method 3
The receiver elements are a plurality of photodiodes for the conversion of optical power into current
Data Source
AI summary
Triangulation photoelectric proximity sensor (1) having a first light emitter (2) for emitting transmitted light into a detection zone (3), a transmitting optical system (4), in particular a lens, being arranged upstream of the light emitter (2), a first light receiver (6) having an array of receiving elements (5) for receiving light from the detection zone (3), which is remitted by an object (7) to be detected, the receiving elements (5) generating respective received signals, a receiving optical system (8) arranged in the beam path between detection zone (3) and first light receiver (6) for generating a light spot from the remitted light on the first light receiver (6), wherein the position of the light spot in the triangulation direction on the first light receiver (6) results in dependence on the distance of the object (7), and a control and evaluation unit (9) for generating a detection signal from the received signals on the basis of the position of the light spot on the first light receiver (6), wherein a further second light transmitter (2) is provided as a reference light transmitter (12) for safety-oriented self-testing.