Hi, I am new to this group so I forgive me if I do anything wrong!
I am an electronic design engineer with very phew knowledge and experience about EMC. Where I work we must connect together some OEM modules with our own modules. The whole must comply with EMC requirements of course. After this introduction here is my problem: We have on LCD that has the GND connected with the EARTH(protective). This LCD is power by 5v and can be disconnected / connected during operation. We also have another LCD smaller in our supervision module and here we have again the GND<->EARTH. All GNDS are the 5v GND. The problem is that when we switch on the exterior LCD some disturbances arise on the GND that triggers the voltage supervision chip on the Supervision board. We have solved this by making another connection GND-EARTH near the 5v Power source. We have done all the tests including security tests again and it seems ok but I do not know if this is correct since I believe we are increasing the electrical current on earth(probably not on the earth that comes outside the machine). So, I will really appreciate any comments on this matter. Thanks, Joao Martins ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
