Control Head Monitor Circuit for Internal Wire Break Detection
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Solution Overview
Problem
Existing control head monitors (CHMs) face challenges in differentiating between broken and short circuits due to undetectable internal wire breakages within their housing, necessitating improved methods for determining operational integrity.
Innovation Solution
A system and method utilizing a single pole double throw (SPDT) switch with a load element and a detection circuit to generate output signals during ON and OFF modes, allowing for comparison and identification of undamaged or damaged internal lines through a controller that generates visual, audio, or haptic notifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a standard supervisory circuit with end of line resistor is used, then circuit integrity can be monitored for broken circuits, but internal wire breakage cannot be differentiated from open-switch system
Solution Approach 1:
The supervisory circuit is segmented into multiple detection paths by introducing an SPDT switch with two distinct switching positions. The first position connects the supervisory circuit through a first path, while the second position connects it through a second path. This segmentation allows the system to differentiate between internal wire breakage and open-switch conditions by comparing signals from different circuit configurations.
Solution Approach 2:
The circuit transitions from a static configuration to a dynamic one by incorporating an SPDT switch that can change connection states. The switch dynamically reconfigures the circuit path based on its position, enabling the detection circuit to receive different signal configurations that reveal the true state of internal wiring versus switch status.
2Reliability
If internal wires are monitored for breakage, then operational integrity can be verified, but the system complexity increases due to additional detection requirements
Solution Approach 1:
The SPDT switch serves multiple functions: it acts as a normal switching element for alarm operations and simultaneously functions as a circuit configuration selector for integrity verification. The same switch mechanism enables both operational control and diagnostic capability, eliminating the need for separate verification hardware and reducing overall system complexity.
Solution Approach 2:
The existing SPDT switch within the alarm system is utilized for dual purposes - its primary alarm function and an additional integrity verification function. The switch's own operational states are leveraged to provide self-diagnosis capability, allowing the system to verify its own internal wire integrity without external intervention or additional components.
Data Source
AI summary
A control head monitor including a single pole double throw (SPDT) switch, is disclosed. The SPDT switch includes a first terminal, a second terminal, a third terminal, and a switching element. The load element is connected between an input line and the second terminal. The input line of a detection circuit is connected to the first terminal and an output line of the detection circuit is connected to the third terminal. The switching element is adapted to connect the first terminal and the third terminal during an OFF mode. The switching element is adapted to connect the second terminal and the third terminal, to generate at least one of an output signal and an absence of an output signal.