Bus Node Circuit Encoding Emergency Switch States
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Solution Overview
Problem
Existing bus systems, such as the AS-interface, face challenges in efficiently networking multiple safety-relevant devices, particularly in identifying which device has triggered an emergency state when connected in series, leading to impracticalities in installations and potential safety hazards.
Innovation Solution
A bus node circuit that encodes binary input signals into collective and individual state representations, using a series circuit and optocouplers for electrical insulation, allowing for communication of a collective state during cyclic communication and individual states during acyclic communication, enhancing reliability and specificity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiple safety-relevant devices are connected in series via AS-interface, then the number of secure slaves is reduced, but the ability to identify which device triggered an emergency state is lost
Solution Approach 1:
The patent segments the emergency information into two distinct parts: a collective emergency state signal and individual device identification signals. The collective signal indicates whether an emergency occurred, while the individual signals (communicated via parameter codes) identify which specific device triggered it. This segmentation allows the system to use fewer secure slaves while maintaining full identification capability.
Solution Approach 2:
The patent employs periodic communication cycles where cyclic communication handles the collective emergency state and acyclic communication between cycles transmits the individual device identification information. This periodic structure allows the system to efficiently convey both types of information without requiring each device to be a separate secure slave.
2Loss of information
If each safety-relevant device is connected as a separate secure slave, then individual device identification is possible, but installation complexity and component quantity increase
Solution Approach 1:
The patent merges multiple safety devices into a single secure slave that can handle multiple inputs. This single secure slave processes collective emergency information through cyclic communication and individual device identification through acyclic communication, thereby reducing the total number of secure slaves needed while maintaining identification capability.
Solution Approach 2:
The secure slave is designed with multi-functionality to handle both collective emergency state communication and individual device identification. It can process multiple input signals from different safety devices and communicate both the emergency state and the specific device identity through the AS-interface protocol, making one secure slave serve multiple purposes.
3Productivity
If safety-relevant devices are connected in series, then installation time is reduced, but the safety monitor cannot determine which device activated
Solution Approach 1:
The patent introduces an intermediary communication mechanism where the single secure slave acts as a mediator between multiple safety devices and the safety monitor. It collects individual device states and transmits both the collective emergency information and the specific device identification through the AS-interface, enabling the safety monitor to identify the triggering device without requiring direct connections from each 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
Enables efficient networking of multiple safety devices with reduced components, improving installation efficiency and safety by clearly identifying the source of an emergency condition, thus enhancing safety and reducing installation time and fire hazards.
Implementation Method 1
using a series circuit and optocouplers for electrical insulation
Data Source
Figure 1
Figure 1a
Figure 2
AI summary
The present invention relates to an apparatus for connection to a communication bus for encoding the status of several emergency switches for communication across a bus interface (Fig.1).