Two-Wire Control Device Communication via Charge Period Modulation
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Solution Overview
Problem
In AC installations with multiple two-wire control devices connected in parallel and series with a consumer, existing technologies face challenges in enabling seamless communication and control between devices to ensure that only one device can turn the consumer on or off, while minimizing the need for additional wiring and avoiding self-short circuiting issues.
Innovation Solution
A method where two-wire control devices communicate by shortening their charge period during a predetermined AC cycle, allowing other devices to detect this change and take control, using existing wires for signaling and power supply, with a solid state switch and voltage detector to interpret voltage drops as instructions for control actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple two-wire control devices are connected in parallel to control a single consumer, then the consumer can be controlled from multiple locations, but the control devices cannot communicate effectively because the active device short circuits itself during operation
Solution Approach 1:
The patent introduces a mediator mechanism using the existing two-wire connection itself as the communication channel. By modulating the charging current characteristics during the brief non-short-circuit periods, the active control device can transmit signals to other devices without requiring separate communication wires. This resolves the contradiction by making the power supply wires serve dual functions: power delivery and information transmission.
Solution Approach 2:
The invention changes the parameters of the charging current (amplitude, duration, or waveform characteristics) during the brief periods when the solid state switch is non-conducting. These parameter variations encode communication signals that can be detected by other control devices, enabling information transmission through the power supply wires without affecting the primary switching function.
2Reliability
If two-wire electronic switches are used with self-contained electronics and solid state switches, then device complexity is reduced and reliability is improved, but communication between devices becomes difficult because the solid state switch short circuits the device most of the time
Solution Approach 1:
The patent utilizes the periodic nature of the solid state switch operation (conducting and non-conducting phases within each AC cycle) to create communication opportunities. During the brief non-conducting periods, the device can transmit signals by modulating the charging current, while maintaining high reliability through the robust solid state switch design. This periodic action transforms the limitation into a communication opportunity without adding complex communication hardware.
3Reliability
If separate signaling lines are used for communication between control devices, then reliable communication is achieved, but the number of wires increases and installation complexity increases
Solution Approach 1:
The patent makes the existing two-wire connection universal by enabling it to perform multiple functions simultaneously: power supply to the control devices and communication between them. By modulating the charging current characteristics during switch-off periods, the same wires that deliver power also carry communication signals, eliminating the need for separate signaling lines and reducing installation complexity while maintaining communication reliability.
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
Enables any two-wire control device to take control of the consumer's supply and instruct others to switch off, using existing wires for communication and power, ensuring robust signaling and efficient control without requiring additional wiring or wireless communication.
Implementation Method 1
a power supply adapted to be charged during a predetermined charging period via a charging circuit by a current flowing from said phase to the supply lead and through the consumer to neutral or vice versa
Implementation Method 2
a voltage detector adapted to detect a reduction in the voltage drop between said phase and said supply lead
Data Source
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AI summary
A method for communicating among a plurality of two-wire control devices (1, 1') in an AC installation, in which said two-wire control devices (1, 1') are arranged in parallel with each other and in series with a consumer (2), and in which said two-wire control devices (1, 1') are power supplied via said two wires during a predetermined charge period of each AC cycle in said AC installation. Communication is effected by shortening the duration of said charge period of one of the two-wire control devices (1, 1') with respect to said predetermined charge period when that specific control device is activated, and detecting in the other control devices (1, 1') said shortened charge period.