Microcontroller shielding questions

[dzorde at aesprodata.com.au]

     Get hold of the European EMC standards, they have a section 
     specifically on automotives.  ie, the levels you have to test too for 
     compliance.  I guess that if you can design to pass these levels, 
     you'll be OK.  Give someone like the UK consulate a call, they should 
     be able to help you with the relevant section of the standards and any 
     other info you want.
     
     
     Dan        dzorde at aesprodata.com.au


______________________________ Reply Separator _________________________________
Subject: Microcontroller shielding questions
Author:  diy_efi at coulomb.eng.ohio-state.edu at INTERNET
Date:    9/17/96 9:14 AM


Hi All,
     
I am designing a small (2"x2") controller board for use in the automotive 
and robotics industries.  The board is based on the MC68HC16Z1 
microcontroller.  Since the engine compartment of a car is filled with EMI 
we are attempting to make the board as resistant as possible to the effects 
of the EMI.
     
Since I don't know the specifics of the sources of EMI a an automobile I 
would appreciate anyone who could help me with the following questions and 
maybe give some extra advice on things I have not asked about but are of 
concern in this type of design.
     
What are the frequency and voltage levels of noise present in the typical 
automobile (EFI, and carburettor type)?
     
What is the strength of the magnetic waves created by spark plugs and/or 
distributors?  What is currently done to protect against it?
     
What type of wire is used to connect a controller to the rest of the system 
(shielded, unshielded, twisted pair)?
     
Can anyone give me some information on how to determined the type of 
shielding to use (box type and thickness, feed through type and value)? 
What is necessary?  What is commonly used and what is affordable?
     
Thanks in advance,
     
Wade Barnes, Electronics Tech.
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