Click on the following bookmarks for further details of a Design Guide for emc:
Shielding,
PCB, Signal Integrity and ESD Design Guides.
A flexible Design Review Check List generator,
which is fully user-editable.
Shielding Integrity
Design Guides
The diagram below highlights several areas in the design of a shielded
enclosure which can affect the emc performance of the equipment as a whole.
Clicking on a label such as 'Gasketted Interface' with the left
mouse button provides more information on the topic, whilst clicking with the right mouse
button launches the relevant analysis tool. In the case of the gasket, the tool which
analyses the gasket groove design is provided.
PCB Design Guide
The PCB Design guide highlights areas of the pcb layout which can
affect emc performance. These are highlighted in the diagram shown below, and as with the
Shielding Integrity guide, the left mouse button provides further information, and the
right mouse button launches the appropriate analysis tool.
In addition, a series of 'Golden Rules' for PCB design are provided, to further highlight some of the design principles.
The Golden Rule for PCB design describing the importance of reducing
loop area, formed by a clock signal and its return for instance. This reduces differential
mode radiated emissions.
Signal Integrity Design Guides
The Signal Integrity item in the Design Guides menu summarises the
tools which deal with the examination of sinusoidal signals. Thus a trapezoidal waveform
can be represented by a series of sinusoidal waveforms at odd harmonics of the fundamental
frequency, and a link to the Fourier analysis tool is provided.
As with the other design Guide items, the left mouse button can be
clicked for more information, and the right mouse button can be clicked to jump to the
indicated analysis tool. The signal integrity window is shown below.
Design Guide: ESD Protection
The ESD item on the Desgin Guides menu provides a number of tips for
dealing with electrostatic discharge. These include the problems of plastic panels with
openings for components, of pcbs with ground connections resulting in preferential
grounding paths, and the need to maintain continuity across cabinet seams.
Design Review
A Design Review facility is provided under the Design Guides menu, to
enable the emc aspects of a development project to be reviewed for emc considerations in a
structured manner.
A series of check lists is provided, which divide the project into a
number of logically separate areas. Each area, or module, contains a number of items which
the user can check as 'OK', 'X', 'N/A' or leave blank. OK is used to show that the item
requirement is met, X not met, and N/A to mean the item is not applicable.
The series of checks can be attached to a particular project, and the
item checking details saved with the project.
The user can edit and add to the list of items to check, and can even
create entirely new design review check lists, on subjects unrelated to electromagnetic
compatibility.
The Design Review form is shown below.
An item is checked by pointing at it on the check list, and using
the Check button to toggle between the four possible check states. The 'More Info' button
accesses further details of the check itself.
Checked lists can be printed from the File Menu, which also allows a
Project to be opened or created. This allows a series of checks to become a unique data
set. An analysis of the user's checks is available, and is described on the following
page.
The check items themselves are created and edited from the Edit Module
form, accessed with the Edit Module button.
The Edit Module form is shown below:
Each Check List contains a number of modules, created, edited
and removed using the New Module, Edit Module and Delete buttons at the top of the form. A
description can also be attached to the module, using the text box below the Module title.
The list of check items for each module is shown in the centre of the
form, and the check itself is entered in the box below the list. The item is added to the
list using the Add To List button, to add a new item to the end of the list, the Insert
button, to put the new item at the highlighted point in the list, or the Edit button, to
replace the highlighted item in the list.
Checks may be deleted using the Delete button. A description can also
be added to each check, which is subsequently accessible directly from the Design Review
Check List form. A graphic can also be attached to the description, using the Info Picture
button, to provide further guidance to the user of the check list.
A series of checks can be analysed from the Design Review Check List
form using the Analysis menu item, which displays the form shown below:
