End Module for Hazard Alarm Line Testing
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Solution Overview
Problem
Existing hazard alarm systems struggle to comply with DIN EN 54 Part 13 standards, which require testing for impermissibly high resistance on signaling lines under load conditions, as traditional methods cannot reverse polarity or apply changing voltages and currents on signaling lines without compromising system functionality.
Innovation Solution
The method involves an end module that limits voltage and increases quiescent current on the signaling line, ensuring the voltage remains sufficient for the last detector while allowing the detection of impermissibly high resistance, using a non-linear circuit with a resistor and Zener diodes to maintain functionality during testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional quiescent current monitoring is used with a terminating resistance of 10kΩ, then the system can detect interruptions and short circuits, but it cannot detect impermissibly high series resistance under load conditions as required by DIN EN 54 Part 13
Solution Approach 1:
The end module dynamically adjusts the quiescent current on the signaling line to a higher test current value that enables detection of impermissibly high resistance while maintaining compatibility with detector operation. This dynamic current adjustment allows the system to meet DIN EN 54 Part 13 requirements without compromising existing detector functionality.
Solution Approach 2:
The invention changes the quiescent current parameter from traditional low values to a higher test current value that is still compatible with detector minimum operating voltages. This parameter change enables the detection of high resistance faults while maintaining system compatibility with standard detectors.
2Measurement precision
If the quiescent current is increased to detect high resistance, then the detection sensitivity improves, but the voltage at the end of the signaling line may drop below the minimum detector operating voltage
Solution Approach 1:
The end module applies a partially excessive quiescent current that exceeds traditional values needed for basic fault detection, but remains within limits that preserve sufficient voltage for detector operation. This controlled excessive current enables high resistance detection while maintaining detector compatibility.
Solution Approach 2:
The system uses feedback from the measured quiescent current to determine line resistance, while the end module ensures the current is set at a level that provides both detection sensitivity and sufficient voltage headroom for detector operation under the specific line conditions.
3Reliability
If the quiescent current is set too high, then high resistance detection is improved, but false alarms may occur when current exceeds the alarm current threshold of detectors
Solution Approach 1:
The quiescent current is set to a partially excessive level that enables high resistance detection but remains below the alarm current threshold of detectors. This controlled current level provides detection sensitivity without triggering false alarms from detector misinterpretation.
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 ensures the signaling line remains functional during testing, meeting the standards by maintaining sufficient voltage and current for detectors, even under alarm conditions, and allows for the detection of high resistance without causing false alarms or system impairment.
Implementation Method 1
The voltage at the end of the signaling line is limited by means of the end module to a value that is greater than the minimum detector operating voltage
Implementation Method 2
the quiescent current is limited by means of the end module a value is set that is greater than the sum of the quiescent currents of the n detectors (n ≥ 1)
Data Source
Figure 1~2
AI summary
The method involves measuring a standby-current of a detection line (U E) enclosed with end modules (D1, D2, R2). Reference value is compared with generation of error message during undercut of the value. A voltage in end of the detection line is limited by the modules to be equal to the value, where voltage is larger than a minimal detection operating voltage. A standby-current is adjusted using the modules to be equal to the value, which is larger than the sum of the standby-current of a detector (M) and smaller than an alarm current of an individual detector with minimal operating voltage. An independent claim is also included for a hazard detection system, comprising an end module.