Serial Slave Addressing via PWM Signal Encoding
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Solution Overview
Problem
Traditional methods for addressing RS-485 slave devices require complex and costly wiring, especially as the number of devices increases, often necessitating multiple hardwired address lines and external devices for manual configuration, which complicates and costs the system.
Innovation Solution
A system utilizing a master device and multiple slave devices with serial communication transceivers, address input/output ports, and controllers in a daisy chain arrangement, where pulse-width modulation (PWM) or pulse-frequency modulation (PFM) signals are used to automatically determine and assign unique addresses to each slave device, eliminating the need for external devices and complex wiring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If hardwired address lines are used to address slave devices, then addressing capability is provided, but wiring complexity and cost increase with the number of devices
Solution Approach 1:
The patent combines multiple address lines into a single serial communication bus, allowing multiple address bits to be transmitted sequentially over one wire rather than requiring separate physical wires for each address bit. This merging approach maintains full addressing capability while dramatically reducing wiring complexity.
Solution Approach 2:
The single serial bus serves multiple functions: it transmits both data and address information, and can dynamically reconfigure its role based on the communication phase. This multi-functionality eliminates the need for dedicated address lines while preserving complete addressing capability.
2Quantity of substance
If more slave devices are connected to the system, then system capability increases, but the number of hardwired address lines must increase
Solution Approach 1:
The patent merges all address line functions into a single serial communication channel, allowing the system to scale to any number of slave devices without increasing the physical number of wires. Address information is encoded in the serial data stream rather than requiring additional physical conductors.
3Extent of automation
If external devices are used to initiate automatic addressing process, then addressing automation is provided, but system complexity and cost increase
Solution Approach 1:
The patent enables slave devices to automatically receive and process their own address assignments through the serial bus without requiring external addressing devices or manual configuration. Each slave device autonomously reads its address from the serial data stream and configures itself, eliminating the need for external addressing hardware.
4Loss of information
If handshaking and bus disconnection are used for address transmission, then address data can be transmitted, but the approach becomes complex and costly
Solution Approach 1:
The patent maintains continuous serial communication throughout the addressing process without requiring bus disconnection or complex handshaking sequences. Address data is transmitted seamlessly as part of the normal serial data stream, allowing uninterrupted communication while ensuring reliable address delivery to each slave device.
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 solution simplifies and reduces the cost of addressing by allowing each slave device to autonomously determine its address through PWM/PFM signals, reducing wiring complexity and eliminating the need for handshaking or external triggers, thus enhancing productivity and reducing errors in field installations.
Implementation Method 1
receive a pulse-width modulation (PWM) or pulse-frequency modulation (PFM) signal from a previous one of the multiple slave devices
Implementation Method 2
receive a pulse-width modulation (PWM) or pulse-frequency modulation (PFM) signal from a previous one of the multiple slave devices
Data Source
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AI summary
A system for automatically addressing serially connected slave devices includes a master device and multiple slave devices each including a serial communication transceiver, an address input port, an address output port, and a controller. The system also includes a serial communication wiring bus connected between the serial communication transceivers of the master and slave devices, and at least one digital address line connected between the address input ports and the address output ports. Each controller is configured to receive a PWM or PFM signal from a previous one of the multiple slave devices, determine an address for the slave device including the controller according to the received PWM or PFM signal, and transmit a PWM or PFM signal indicative of the determined address to a subsequent one of the multiple slave devices.