Multi-layer PCB Shielding for Automation Component EMI
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Solution Overview
Problem
Existing automation components in decentralized periphery devices face issues with electromagnetic interference (EMI) affecting process signals and voltages, leading to errors in controlling technical processes due to lack of effective shielding for process voltage cables.
Innovation Solution
The implementation of a multi-layer printed circuit board with shielded outer layers and a connection block design that positions process voltage connection elements at the outer end, combined with a retaining clip and cable shield support to minimize interference, and the addition of filter and damping means downstream of process voltage connections to enhance electromagnetic compatibility (EMC) behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If process voltage cables are not shielded, then the device complexity is reduced and manufacturing cost is lowered, but electromagnetic interference affects process signals and voltages leading to control errors
Solution Approach 1:
The connection block is divided into functionally separate connection zones: process signal connection elements are isolated from process voltage connection elements through spatial segmentation and shielding structures. This segmentation prevents electromagnetic interference from voltage lines affecting signal lines while maintaining a unified connection block structure.
Solution Approach 2:
Shielding measures are applied locally only where needed - specifically around process signal connection elements and between signal and voltage zones - rather than shielding the entire connection block uniformly. This localized approach reduces material usage and complexity while maintaining reliability where it matters most.
2Object-affected harmful factors
If process voltage connection elements are placed at the outer end of the connection block, then interference coupling is reduced, but the connection block design becomes more complex
Solution Approach 1:
The connection block utilizes three-dimensional spatial arrangement to separate functions: process voltage connection elements are positioned at the outer end along one dimension, while process signal connection elements are positioned at inner ends or intermediate positions along the same dimension. This dimensional separation reduces interference coupling while maintaining a compact design.
Solution Approach 2:
Shielding structures and carrier elements with conductive outer layers act as intermediaries between process voltage connection elements and process signal connection elements. These intermediary structures redirect or block electromagnetic fields, preventing direct interference coupling while integrating seamlessly into the connection block geometry.
3Object-affected harmful factors
If cable shield support directly contacts the multi-layer printed circuit board, then the unshielded area is minimized reducing interference voltage, but manufacturing precision requirements increase
Solution Approach 1:
The cable shield support is designed to make substantial contact with the outer layers of the multi-layer printed circuit board, which are provided for shielding and connected to reference potential. This creates an equipotential connection that minimizes the unshielded area and reduces interference voltage coupling, while the substantial contact area provides manufacturing tolerance.
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
This configuration significantly reduces interference-induced errors, allowing for reliable and error-free control of technical processes by minimizing the coupling of interference into process signal lines and enabling the transmission of faster or higher-frequency signals.
Implementation Method 1
the outer layers of which are provided for shielding. Such a carrier element also shields the process signals in the area of the carrier element and the carrier element acts like an extended cable shield or like a continuation of the cable shield up to the connection elements of the electronic module
Implementation Method 2
the cable shield support therefore covers the connection elements for connecting the process voltage lines, as a result of which the interference caused by the process voltage is even better suppressed or prevented from being coupled into the process signal lines
Implementation Method 3
A retaining clip provided with a contact spring is fastened to one side of the multi-layer printed circuit board in such a way that the contact spring and a side wall form a recess at the outer end of the terminal block for receiving a lug of a cable shield support
Implementation Method 4
the multi-layer printed circuit board is provided with filter and damping means, which are connected downstream of the connection elements for connecting the process voltage lines
Data Source
Figure 1~2
AI summary
The automation component has a securing unit for securing base module on a mounting rail (2). A terminal block (3) having connecting elements (4,5) is formed on a multi-layer printed circuit board (1). A contact spring (10) is attached with a support bracket (11) that is attached to one side of the multilayer circuit board. A recess is formed at the outer end of the terminal block for receiving a lug (7) of a cable shield (8). The multi-layer printed circuit board is secured with mounting rail via additional contact springs (13,14). An independent claim is included for modular automation device.