Field Device Connecting Apparatus With Isolated Power And Signal Paths
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Solution Overview
Problem
Existing connecting apparatuses for field devices on a bus network, such as Profibus PA, face issues where a bus cable failure or disturbance signals affect all connected field devices, and extending the fieldbus during operation can disrupt communication, leading to voltage dips and potential device failures.
Innovation Solution
A connecting apparatus with parallel power supply and signal paths, isolated by coupling units, includes a measurement device to detect current changes and control a switching element to prevent disturbances, along with a delay circuit, current rise limiting circuit, energy store, and monitoring device to ensure seamless connections during telegram pauses, minimizing disruptions and maintaining communication integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If field devices are connected to the bus during operation, then the fieldbus can be extended dynamically, but voltage dips occur causing communication disturbances and device resets
Solution Approach 1:
The connecting apparatus divides the power supply and signal paths into separate parallel channels with independent coupling units. This segmentation allows the power supply path to be isolated from signal path disturbances, enabling hot-swapping of field devices without causing voltage dips that would affect communication on the bus.
Solution Approach 2:
Coupling units are introduced as intermediary components between the bus and field device connections. These coupling units act as mediators that transfer power and signals while isolating disturbances, allowing dynamic connection of field devices without directly exposing the bus to connection-induced voltage dips and noise.
2Device complexity
If power supply and signal paths are shared on the bus, then device complexity is reduced, but disturbances from one path affect the other
Solution Approach 1:
The connecting apparatus segments the previously shared power supply and signal paths into separate parallel channels. Each path has its own coupling unit, which maintains the simplicity of the overall structure while preventing cross-path interference through electrical isolation at the coupling points.
Solution Approach 2:
Coupling units serve as intermediary elements that connect the bus to both power supply and signal paths independently. These intermediaries provide galvanic isolation, blocking disturbance signals from crossing between paths while still allowing normal operation of both paths.
3Ease of operation
If manual connection of field devices is allowed, then ease of operation is improved, but contact bouncing causes voltage drops and telegram interference
Solution Approach 1:
The coupling units act as intermediaries between the manual connection interface and the bus. They absorb and isolate contact bouncing effects, preventing these mechanical connection disturbances from causing voltage drops or interfering with telegram transmission on the bus.
Solution Approach 2:
The coupling units provide beforehand cushioning by preparing isolated connection paths that can absorb connection disturbances. This prior protection mechanism ensures that even if contact bouncing occurs during manual connection, the bus and other field devices remain unaffected.
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
The solution allows for disturbance-free bus extensions and connections, preventing noticeable reactions on the bus, ensuring stable communication and preventing field device resets or communication collapses by isolating power and signal paths and managing current changes effectively.
Implementation Method 1
a supply voltage carried on the bus is isolated from a signal, which is likewise carried on the bus, by a first coupling unit arranged in the power supply path
Implementation Method 2
a second coupling unit arranged in the signal path
Data Source
AI summary
A connecting apparatus for connection of field devices comprising a bus connection for connection to a bus, a field device connection for connection for a field device, a power supply path and a signal path, wherein the power supply path and the signal path are arranged in parallel with one another between the bus connection and the field device connection such that a supply voltage carried on the bus is isolated from a signal, which is likewise carried on the bus, by a first coupling unit arranged in the power supply path and a second coupling unit arranged in the signal path.