Wireless Adapter EMI Shielding via Metallic Housing

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Solution Overview

Problem

Industrial process plants with numerous field devices often fail to utilize advanced data capabilities due to high costs, resulting in a need for a wireless adapter that can transmit data from these devices to control systems or monitoring systems via a wireless network, while also addressing electromagnetic interference and environmental constraints.

Innovation Solution

A wireless adapter with a metallic housing and antenna, featuring a wireless communications module that forms a continuous conductive surface with a metallic shield to reduce electromagnetic interference, and an antenna positioned outside the conductive surface for effective wireless communication, along with improved form factors to fit various environments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a wireless adapter is installed in confined spaces near field devices, then wireless communication capability is improved, but electromagnetic interference from process control loops deteriorates signal reliability

Engineering Contradiction:
Improvewireless communication capabilityVSAvoidelectromagnetic interference
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

A metallic shield acts as an intermediary barrier between the wireless adapter's antenna and the process control loop wires. The shield intercepts electromagnetic fields from the control loops before they can interfere with the antenna, while still allowing the adapter to be installed in confined spaces near field devices.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The metallic shield converts harmful electromagnetic interference into a beneficial shielding effect. By positioning the shield between the antenna and control loop wires, the electromagnetic fields that would normally cause interference are instead reflected or absorbed by the shield, protecting the wireless communication.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Volume of moving object

If the antenna is positioned close to the wireless communications module for compact design, then device size is reduced, but electromagnetic interference increases

Engineering Contradiction:
Improveadapter sizeVSAvoidelectromagnetic interference
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The metallic shield serves as a mediator that allows the antenna to be positioned close to the wireless communications module for compact design, while simultaneously protecting the antenna from electromagnetic interference generated by the module's circuitry.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If traditional hardwired connections are used for field devices, then electromagnetic interference protection is improved, but installation complexity and cost increase

Engineering Contradiction:
Improveelectromagnetic interference protectionVSAvoidwiring complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The metallic shield provides electromagnetic interference protection similar to hardwired connections, but enables wireless communication instead. The shield acts as an intermediary that allows wireless operation while maintaining the EMI protection characteristics of hardwired systems.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 reliable wireless communication between field devices and control systems, reduces electromagnetic interference, and allows attachment to devices in confined spaces, enhancing data transmission and operational efficiency.

Implementation Method 1

the antenna is separated from the wireless communications module by a metallic shield

Methodology Applied
Scientific EffectElectromagnetic shielding: Faraday Cage

Data Source

PatentEP2291716B1Improved form factor and electromagnetic interference protection for process device wireless adapters
Publication Date: 2018.08.08 ROSEMOUNT INC
  • EP2291716B1 patent drawingFigure 1
  • EP2291716B1 patent drawingFigure 2
  • EP2291716B1 patent drawingFigure 3

AI summary

A process device wireless adapter (300, 600, 700, 800) includes a wireless communications module (310, 602, 702), a metallic housing (302, 606), and an antenna (320, 604, 826). The wireless communications module (310, 602, 702) is configured to communicatively couple to a process device (350) and to a wireless receiver (502). The metallic housing (302, 606) surrounds the wireless communication module (310, 602, 702) and has a first end and a second end. The first end is configured to attach to the process device (350). In one embodiment, a metallic shield (608, 708) contacts the housing (302, 606) second end such that the metallic shield (608, 708) and the housing (302, 606) form a substantially continuous conductive surface. The antenna (320, 604, 826) is communicatively coupled to the wireless communication module (310, 602, 702) and separated from the wireless communication module (310, 602, 702) by the metallic shield (608, 708). Preferably, the wireless communications module (310, 602, 702) illustratively includes a printed circuit board that has a length that is greater than its width.