Two-Wire Hazard Warning Assembly Voltage Modulation
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Solution Overview
Problem
In existing two-wire line-based alarm systems, the voltage swing decreases significantly towards the end of the line due to ohmic resistance, leading to communication errors and incorrect pulse detection, especially when participants draw additional current, causing sudden drops in supply voltage that can be mistaken for pulse edges.
Innovation Solution
The supply voltage in each participant is reduced to an internal voltage lower than the original supply voltage by at least the amplitude of communication pulses, and a voltage converter, such as a linear regulator with a zener diode and RC elements, ensures current is drawn during pulse durations, maintaining consistent voltage modulation independent of line length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If participants draw current from the supply voltage during pulse intervals, then the supply voltage can be maintained at higher levels, but the voltage swing for communication pulses decreases due to ohmic resistance in the two-wire line
Solution Approach 1:
The patent changes the operating parameters by reducing the internal supply voltage in participants to at least the amplitude of communication pulses below the actual supply voltage. This parameter change ensures that participants draw current during pulse durations, maintaining symmetric loading and consistent voltage modulation independent of line length, thereby resolving the contradiction between maintaining supply voltage and preserving communication pulse detection accuracy
2Area of stationary object
If the two-wire line length is increased to cover more areas, then the system coverage is improved, but the voltage swing decreases significantly towards the end of the line due to ohmic resistance
Solution Approach 1:
The patent applies parameter changes by reducing the internal supply voltage in participants to at least the amplitude of communication pulses below the actual supply voltage. This ensures that the voltage modulation remains consistent throughout the entire two-wire line length, enabling extended system coverage without loss of communication signal amplitude
3Use of energy by moving object
If additional current is drawn by participants during operation, then the power consumption is satisfied, but sudden drops in supply voltage occur that can be mistaken for pulse edges
Solution Approach 1:
The patent changes the internal supply voltage parameter in participants to be at least the amplitude of communication pulses below the actual supply voltage. This ensures that current is drawn during pulse durations, maintaining symmetric loading and preventing sudden voltage drops that could be mistaken for pulse edges, thereby maintaining communication reliability while satisfying power consumption requirements
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 symmetric loading of the supply voltage, reducing communication errors and allowing longer two-wire lines or more participants without impairing security, by maintaining consistent voltage levels during pulse durations and preventing sudden voltage changes.
Implementation Method 1
a voltage regulator is connected, which generates an internal operating voltage... the supply voltage in each participant is reduced to an internal voltage which is at least by the amplitude of the pulses of the communication telegrams smaller than the supply voltage
Implementation Method 2
a storage capacitor is charged via a constant current circuit... the supply or line voltage does not drop significantly during initialization of the alarm line or due to high current draw by a single device during operation
Implementation Method 3
a constant current circuit connected to the two-wire line, via which a storage capacitor is charged... which regulates the current to, for example, several hundred μA
Data Source
Figure 1
Figure 2a~2b
Figure 3
AI summary
The method involves transmitting a communication message in form of supply voltage by voltage reduction embossed pulse sequences. The supply voltage is reduced in a subscriber on an internal excitation voltage. The internal excitation voltage is smaller than the supply voltage around amplitude of pulse of the communication message. An internal operating voltage of the subscriber is generated from the internal excitation voltage. An independent claim is also included for a danger detection system, which has a control center.