Fire Alarm Pulse Voltage Noise Filtering
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Solution Overview
Problem
Fire alarm systems often experience erroneous detection due to noise interference when diagnosing failures in alarm devices, particularly in systems with elongated power supply wires, leading to incorrect identification of device failures.
Innovation Solution
A fire alarm system that applies pulse voltage consecutively to alarm devices multiple times, measuring power consumption to calculate statistical values such as averages, maximums, or minimums, and determining failure based on differences from a predetermined reference value, thereby reducing the likelihood of erroneous detection caused by noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a single pulse-shaped voltage is applied to the alarm device for failure diagnosis, then the diagnosis can be performed quickly, but noise superimposed on the current detection causes erroneous failure detection
Solution Approach 1:
The patent applies pulse voltage to the alarm device multiple times consecutively (e.g., 5 times) rather than once, creating a periodic measurement pattern. This allows the system to distinguish between transient noise and genuine failure conditions by observing consistent patterns across multiple cycles, thereby improving measurement precision while maintaining reasonable diagnosis time.
Solution Approach 2:
The system calculates the average current value from multiple pulse voltage applications and compares it against a threshold. This feedback mechanism allows the system to filter out noise by relying on the consistent pattern that emerges from repeated measurements, improving current detection accuracy without significantly increasing the overall diagnosis time.
2Measurement precision
If pulse voltage is applied multiple times consecutively to reduce noise impact, then measurement accuracy improves, but the time required for failure diagnosis increases
Solution Approach 1:
The patent applies pulse voltage a specific number of times (e.g., 5 times) which is more than once but not excessively many times. This partial repetition is sufficient to filter out noise through averaging while keeping the overall diagnosis time within acceptable limits, balancing measurement precision with time efficiency.
Solution Approach 2:
The system changes the measurement parameter from a single instantaneous current value to an average current value calculated from multiple pulse voltage applications. This parameter transformation allows the system to maintain high measurement precision while the multiple measurements can be performed rapidly in succession, minimizing time loss.
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 approach effectively minimizes erroneous failure detection in fire alarm systems by accounting for noise interference and transient power changes, ensuring accurate diagnosis of alarm device failures.
Implementation Method 1
The alarm controller applies pulse voltage to the alarm device a plurality of times consecutively, the pulse voltage having such a short time length that the alarm device does not issue a noticeable alarm. The alarm controller measures power consumption for each of the pulse voltages
Data Source
AI summary
Pulse voltage is applied to an alarm device a plurality of times consecutively, the pulse voltage having such a short time length that the alarm device does not issue a noticeable alarm. Power consumption for each of the pulse voltages is measured. Any of an average value of the plurality of power consumptions, a maximum value of the plurality of power consumptions, or a minimum value of the plurality of power consumptions, is calculated as a statistical value. When a difference between the statistical value and a predetermined reference value is greater than a predetermined threshold, it is determined that failure has occurred.