Occupancy Sensor Output Timing to Reduce False-Off Delays
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Solution Overview
Problem
Occupancy sensors often experience time delays before signaling unoccupied status, leading to potential false-offs when spaces are still occupied, which can result in unnecessary power termination.
Innovation Solution
Implementing a reduction timer that overrides the internal time delay, allowing for a shorter time period before deactivating the power pack output, thereby reducing the time delay from 5-30 minutes to approximately 1 second, controlled by a switch or programmatically.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a time delay is built into the occupancy sensor to avoid false-off situations, then reliability is improved, but loss of time increases
Solution Approach 1:
The patent implements a dynamic time delay system where the sensor can operate in two modes: a first mode with a longer time delay (5-30 minutes) for high reliability, and a second mode with a shorter time delay (approximately 1 second) for faster response. A switch or programmable controller allows users to dynamically select between these modes based on their specific needs, resolving the contradiction by making the time delay parameter adjustable rather than fixed.
Solution Approach 2:
The patent changes the time delay parameter from a fixed value to an adjustable parameter. By providing multiple preset time delay values (longer delay for reliability, shorter delay for speed) and allowing user selection through a switch or programming interface, the system can adapt the time delay parameter to different operational requirements, thus resolving the contradiction between reliability and time loss.
2Reliability
If a longer time delay is used in the occupancy sensor, then false-off situations are avoided, but energy efficiency deteriorates due to unnecessary power termination
Solution Approach 1:
The system allows dynamic selection between a longer time delay mode (for avoiding false-offs) and a shorter time delay mode (for energy efficiency). When the shorter time delay mode is selected, devices remain powered longer when occupied, preventing unnecessary power termination and improving energy efficiency while maintaining acceptable reliability through the still-present time delay protection.
Solution Approach 2:
By making the time delay parameter adjustable, users can optimize the balance between reliability and energy efficiency. The shorter preset time delay option specifically addresses energy efficiency by minimizing unnecessary power termination, while the longer option maintains high reliability. This parameter adjustment capability resolves the contradiction by allowing users to select the optimal setting for their specific application requirements.
Data Source
AI summary
One or more switches in an occupancy sensor are enabled. When a switch is enabled, a reduction timer measuring a reduction time delay is initiated when an occupancy condition is detected by an occupancy sensor. In addition, one or more outputs controlled by the reduction timer are activated so that a signal is sent to a control system to notify the control systems of the occupancy condition. When the reduction time delay expires, the outputs of the occupancy sensor that are controlled by the reduction timer are deactivated, and so the outputs cease sending the signal to the control system. As a result, the control systems initiate their own internal time delays sooner.