Magnetic Knob Assembly for Sealed Field Device Menu Navigation
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Solution Overview
Problem
Conventional field devices in process automation systems require opening the housing to access user interface controls, which is impractical and potentially hazardous in environments with explosive or corrosive conditions, necessitating a solution for navigating the UI without opening the device.
Innovation Solution
A device menu controls connector with a cylindrical hollow body, Hall effect sensors, and a knob assembly that allows for navigation and interaction with the field device's UI without physically opening the housing, using a locking mechanism and elastomer sealing to maintain environmental integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the field device housing is hermetically sealed to protect against hazardous environments, then the device's reliability and safety in explosive/corrosive conditions is improved, but the ease of operation for UI navigation deteriorates because the controls are enclosed and require opening the housing
Solution Approach 1:
The device is segmented into two functional parts: a hermetically sealed housing containing the electronics, and a separate removable knob assembly containing the UI controls. This allows the housing to remain sealed for explosion safety while the knob assembly can be attached for UI navigation.
Solution Approach 2:
A magnetic coupling mechanism acts as an intermediary between the sealed housing and the external knob assembly. The magnets in the housing interact with the magnetically coupled components in the knob assembly, enabling signal transmission and control functionality without physical penetration of the sealed housing, thus maintaining explosion safety while enabling UI operation.
2Ease of operation
If the field device housing is opened to access UI controls, then the ease of operation for menu navigation is improved, but the device's protection against hazardous environments deteriorates
Solution Approach 1:
The control functionality is segmented from the sealed housing and placed in a separate knob assembly. This allows menu navigation to be performed externally without opening the housing, thus avoiding environmental exposure while maintaining ease of operation.
Solution Approach 2:
The knob assembly creates a functional copy of the UI controls outside the sealed housing. By replicating the control interface in the removable knob assembly, users can interact with the device menus without needing to access the internal controls inside the sealed housing.
3Ease of operation
If a removable control assembly is added to enable external UI access, then the ease of operation is improved, but the device complexity increases
Solution Approach 1:
Multiple functions are merged into the removable knob assembly: mechanical coupling to the housing, magnetic coupling for signal transmission, sealing interface for maintaining protection, and UI control elements. This consolidation enables external UI access while managing complexity by integrating rather than multiplying separate systems.
Solution Approach 2:
The removable knob assembly serves multiple functions simultaneously: it provides the UI control interface, maintains the hermetic seal when attached, enables signal transmission through magnetic coupling, and can be easily removed for storage or replacement. This multi-functionality reduces the need for separate systems for each function.
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 safe and practical navigation of the field device's UI in hazardous environments by allowing the knob assembly to be removably attached and sealed, allowing for UI interaction without exposing the device to explosive or corrosive conditions.
Implementation Method 1
the flange contacts the cable gland and compresses the elastomer sealing ring to seal the cable gland
Implementation Method 2
a printed circuit board (PCB) having at least one Hall effect sensor
Data Source
AI summary
A device menu controls connector for a process automation field device include a field device part and a removable knob assembly. The field device part includes one or more Hall effect sensors, and the knob assembly includes one or more magnets. When the knob assembly is attached to the field device part, the knob may be rotated clockwise or counter-clockwise, or may be pushed or pulled. The interaction of the magnets and Hall effect sensors allow the field device to sense the rotation and the pushing and pulling of the knob. The programming of the field device allows the device menu controls connector to simulate <Up>, <Down>, <Right>, <Left>, <Enter>, and <Esc> key presses of a user interface. A field device having such a device menu controls connector is also disclosed.