Access Point Bus Synchronization for Collision-Free Safety Signals
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Solution Overview
Problem
Existing control systems for access point devices, such as gates and doors, suffer from reduced reliability and speed due to excessive bus traffic and interference, particularly when peripheral devices communicate only in response to requests from a master, leading to potential failures in critical safety signals.
Innovation Solution
Implementing a communication system where peripheral units have independent clock devices to set characteristic time windows for signal transmission, allowing them to send data in broadcast mode without waiting for a master request, synchronized by an asynchronous synchronism signal, ensuring each unit has a unique absolute time reference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If peripheral devices communicate only in response to requests from the master controller, then the bus traffic is controlled and device addressing is simplified, but the communication speed and reliability deteriorate due to excessive bus traffic and potential failure of critical safety signals
Solution Approach 1:
The patent applies preliminary action by having peripheral devices calculate and prepare their response time delays in advance based on their addresses, rather than waiting for the master controller to query each device. This allows devices to be ready to transmit immediately when the broadcast request is received, improving communication speed while maintaining structured bus traffic control
Solution Approach 2:
The patent implements periodic action through the use of time windows organized in cycles. The master controller sends periodic broadcast requests, and peripheral devices respond in their assigned time windows within each cycle. This periodic structure maintains bus traffic control while enabling faster response compared to sequential querying, as all devices can respond within a single broadcast cycle rather than requiring individual queries
2Loss of information
If the master controller sends requests to all peripheral devices, then status information can be collected from all devices, but bus traffic increases and creates interference and collisions
Solution Approach 1:
The patent applies segmentation by dividing the bus communication into distinct time windows, with each peripheral device assigned a specific time window based on its address. This segmentation allows all devices to transmit status information simultaneously without interference, as each device has its dedicated transmission slot within the periodic cycle
Solution Approach 2:
The patent uses periodic action to structure bus communication into regular cycles where the master controller broadcasts a request and peripheral devices respond in their assigned time windows. This periodic structure enables efficient collection of status information from all devices while minimizing bus traffic interference through organized time-multiplexed access
3Device complexity
If peripheral devices wait for master requests to transmit data, then the communication protocol is simplified, but critical safety signals may be delayed or lost when the master is not communicating
Solution Approach 1:
The patent implements self-service by enabling peripheral devices to autonomously determine when to transmit data based on their assigned time windows and addresses. Devices can independently calculate their response timing and transmit critical safety signals without waiting for master controller requests, ensuring reliability even when the master is not actively communicating
Solution Approach 2:
The patent applies preliminary action by having peripheral devices pre-calculate their response time delays based on their addresses during system initialization. This allows devices to be ready to transmit immediately when needed, ensuring critical safety signals are not delayed or lost while maintaining a relatively simple communication protocol structure
4Adaptability or versatility
If multiple peripheral devices are connected to the bus, then the system functionality is enhanced, but the bus traffic and potential for collisions increase
Solution Approach 1:
The patent applies segmentation by assigning each peripheral device a unique address that determines its specific time window on the bus. This segmentation allows multiple devices to be connected and communicate simultaneously without collisions, as each device has its dedicated transmission slot within the periodic cycle
Solution Approach 2:
The patent uses periodic action to organize bus communication into regular cycles where all peripheral devices can transmit their data in assigned time windows. This periodic structure supports enhanced system functionality with multiple devices while maintaining high reliability through organized time-multiplexed access that prevents bus collisions
Data Source
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AI summary
A control system for access point devices, such as gates, doors, mobile barriers, and the like, comprising a communication bus, a control unit interfaced with the communication bus for transmitting/receiving digital information, which control unit comprises a clock device capable of measuring time; a plurality of peripheral units interfaced with the communication bus to transmit/receive digital information to/from the control unit. The peripheral units each comprise a clock device capable of independently measuring the time starting from an initial time reference to define characteristic time windows for each peripheral unit to be used to send signals on the bus and/or enable commands, the control unit being configured to send a synchronism signal to the peripheral units so that all the peripheral units have the same initial time reference, said synchronism signal being asynchronous and not connected to the intervals defined for the transmission on the bus.