Pre-assembled Switching Device with Segmented Safety and Control Circuits
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Solution Overview
Problem
Existing switching devices are either complex and costly or lack the ability to safely and operationally switch multiple drives simultaneously, failing to provide a simple and inexpensive solution for both safe and unsafe switching operations.
Innovation Solution
A prefabricated switching device with a housing containing a first input connection connected to output connections via single-channel safe switches and parallel signal paths, featuring a safety-related circuit for safe switching and a separate control circuit for operational switching, allowing independent control of switches and isolation upon receiving a safety-related switch-off signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple switches are integrated into a single switching device to enable both safe and operational switching of multiple drives, then the versatility and functionality are improved, but the device complexity and cost increase
Solution Approach 1:
The switching device is segmented into independent functional modules: safe switches for safety-critical paths, additional switches for operational paths, a safety-related circuit for safety functions, and a separate control circuit for operational control. This modular segmentation allows each component to perform its specific function independently, reducing overall system complexity while maintaining versatility.
Solution Approach 2:
The switching device integrates multiple switching functions into a single housing, enabling both safe switching (for emergency stop and safety-critical operations) and operational switching (for normal control operations) of multiple drives. This multi-functionality eliminates the need for separate switching devices, reducing system complexity and cost.
2Ease of manufacture
If a safety-related circuit and control circuit are integrated into the same housing to enable both safe and operational switching, then the compactness and cost-effectiveness are improved, but the risk of interference and reliability may worsen
Solution Approach 1:
The circuitry is segmented into distinct safety-related and control circuits, each with separate signal paths and control logic. This segmentation prevents electrical and logical interference between safety functions and operational functions, maintaining reliability while allowing integration in a single housing.
Solution Approach 2:
The patent introduces separate signal paths and isolation mechanisms as intermediaries between the safety-related circuit and control circuit. These intermediaries ensure that safety signals are not affected by control circuit operations, and vice versa, thereby maintaining system reliability in an integrated design.
3Device complexity
If single-channel safe switches are used instead of multi-channel switches, then the device complexity and cost are reduced, but the ability to provide redundant safe switching paths is limited
Solution Approach 1:
Multiple single-channel safe switches are combined in parallel within the same housing to provide redundant safe switching paths. This merging approach maintains the simplicity and cost-effectiveness of individual single-channel switches while achieving the redundancy needed for reliable safety-critical operations.
Data Source
Figure 1
AI summary
The device has a housing (1) with an input terminal (2), and a safety-related circuit (10) arranged within the housing and supplying a safety-relevant switching signal (S) outside the housing. The safety-related circuit controls a safety switch (3) in case of supplying of the switching signal such that the switch is opened. A control circuit (14) is separated from the safety-related circuit and arranged within the housing. An additional switch (12) is arranged in a signal path (4) and controlled by the control circuit independent of the switching signal.