Device Identification on Common Bus Using Collision Detection

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Solution Overview

Problem

Current methods for identifying and configuring multiple electrical devices with identical default settings on a common communications bus line are impractical, as they require significant time and resources, often leading to device redundancy and increased complexity due to the need for extensive serial number scanning and hardware modifications.

Innovation Solution

A method that reduces the time required to identify serial numbers by using a scanning technique that modifies the number of bits scanned based on collision detection, allowing for efficient association of devices with unique addresses without needing to scan all possible serial numbers, thereby minimizing user intervention and hardware requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If scanning is performed for all possible serial numbers from the known totality or range, then complete identification of all devices is achieved, but the scanning time becomes unacceptable due to the very large number of possible serial numbers

Engineering Contradiction:
Improveidentification completenessVSAvoidscanning time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent segments the serial number scanning process into multiple stages. Instead of scanning all possible serial numbers sequentially, the system divides the search space by sending queries with different bit patterns (e.g., scanning devices with address bits 0-7 set to specific values, then 8-15, etc.). This segmentation reduces the time required for complete identification while ensuring all devices are found.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a new dimension to the scanning process by using multiple scanning passes with different bit positions. Rather than linearly incrementing through all serial numbers, the system varies which bits are scanned in each pass, effectively adding a dimensional aspect to the search strategy that reduces total scanning time while maintaining completeness.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If the serial number is used as the identifying value for mass produced devices, then each device can be uniquely identified over the product life cycle, but the serial number becomes very long requiring significant overhead to future proof the product

Engineering Contradiction:
Improvedevice identification reliabilityVSAvoidserial number length
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts only the necessary portion of the serial number for identification purposes. Instead of using the complete long serial number, the system scans and identifies devices using a subset of bits (e.g., 8 bits at a time), extracting just enough information to uniquely identify each device without requiring the full serial number length.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent applies partial action by scanning only the necessary number of bits required to identify devices in the current system. Rather than future-proofing for all possible serial numbers, the system scans enough bits to handle the current device population, performing a partial scan that is sufficient for present needs without the overhead of complete serial number handling.

Inventive Principle:
Principle #16Partial or excessive action

3Measurement precision

If devices are arranged to break and reattach the communications link for identification, then serial numbers can be identified sequentially, but hardware specifically for this purpose is required resulting in additional expense and design complication

Engineering Contradiction:
Improveserial number identificationVSAvoidhardware requirements
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces the mechanical approach of breaking and reattaching communication links with an electronic/software-based scanning method. The control panel electronically queries devices on the communication bus using different bit patterns, identifying devices through software logic rather than physical link manipulation, thereby eliminating the need for special hardware.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent enables devices to respond to identification queries using their existing communication capabilities without requiring special identification hardware. Devices self-identify by responding to scanned queries with their address information, using their normal communication interface rather than dedicated identification hardware.

Inventive Principle:
Principle #25Self-service

4Measurement precision

If individual electronic interrogation of devices is performed separate from the central control station, then serial numbers can be identified and associated with devices, but the process requires significant time and user intervention

Engineering Contradiction:
Improvedevice association accuracyVSAvoididentification time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent merges the identification process with the existing communication bus infrastructure. Instead of separate individual interrogation, the system combines device identification with the normal communication protocol, allowing the control panel to scan and identify multiple devices simultaneously through the shared bus without requiring separate communication channels or significant user intervention.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent enables devices to automatically respond to identification scans without requiring user intervention. When the control panel sends scan queries, devices automatically respond with their address information, performing self-identification that reduces manual involvement and accelerates the process.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP2168319B1Identifying a plurality of devices
Publication Date: 2023.01.18 JOHNSON CONTROLS FIRE PROTECTION LP
  • EP2168319B1 patent drawingFigure 1
  • EP2168319B1 patent drawingFigure 2
  • EP2168319B1 patent drawingFigure 2

AI summary

A method of identifying a plurality of devices connected along a common communications link is disclosed. Each device bears a unique identification. number belonging to a defined range of such numbers. A control station (P) scans the devices by sending a succession of interrogation signals, the interrogation signals comprising a representation of the identification numbers of the devices. A first scan is carried out with interrogation signals identifying a first lrange of identification numbers, and each device sends to the control station, a response signal that comprises its complete identification number and a checksum, upon a match of the identification numbers. If two or more of the devices generate a response signal, the response signals will be deemed to be invalid by the control station, and the first scan is paused. Upon pausing of the first scan, the control station initiates a second scan comprising interrogation signals identifying a more limited range of identification numbers. Successive scans are carried out until, only a single response is returned whereby the control station associates a unique identification number with each of the devices.