Welcome. Another hint. Since you're paying big bucks to the guys doing the tests, get an in-depth explanation from them. You may have to hire them for an hour or two. It is much cheaper and much faster when you know everything before a new design than after. Ahem, as far as I was told, the new regulation require the tests to go to 3GHz now instead of the 1GHz before. This, because the customers want to operate convenient high power microwave devices in the close vicinity of other electronics. This means mobile phones. Plus there are numerous so called convenient low power microwave devices, aka bluetooth.
In the long run consider a spectrum analyzer for 20k$ up.
Rene
Tom Robinson wrote:
Thank you for your help it's very much appreciated.
Tom Robinson
-----Original Message----- From: Rene Tschaggelar [mailto:[EMAIL PROTECTED] Sent: Monday, October 25, 2004 3:57 PM To: Protel EDA Discussion List Subject: Re: [PEDA] Need some help...Conducted RF immunity test...
Tom Robinson wrote:
We are currently attempting to get all our products to meet the new requirements for the EN60601-1-2-2001 by the November 1st deadline. We
have
all our products updated to the new requirements except for one. We have been having some difficulty with the new Conducted RF immunity test EN61000-4-6 / ENV50141 on this product. This test basically takes an AM modulated signal with a 3V level in the range of 150k to 80 meg and
couples
it into all I/O and power cables using a bulk current injection probe
clamp.
Our system is detecting the induced interference and shutting down indicating a fault condition exists. Unfortunately this is considered a failure for this test. Has anyone had any experience trying to comply to this test. We have tried filtering several critical signals to prevent the faults, but the induced signal seems to everywhere. Any suggestions would
be
helpful at this point.
Yes, the conducted RF... Do you have a metal enclosure ? If so, it has to be grouded. Is your PCB also connected to the case ? Even a slow analog or digital pcb requires an RF layout, or at least partially.
To make it simple I tell you how to pass this test. 1)have a blank metal case with the pcb inside and the case connected to earth 2)the GND of the pcb is at least AC connected to the case, eg with 100nF every few cm. Better, if the GND and the case are conneted at one point, usually where the supply comes in, or the GND is connected to the case at the circumference. That depends whether the pcb is analog, digital or RF. 3)each wire coming into the case is connected to the case with a 100nF for slow signals and 10nF for faster signals. These caps short the RF. Consider the RF may go to 3GHz in the actual version, so keep the connections short. One inch is a lambda quarter antenna and the case may act as resonator.
Ah, you have a plastic case, that makes it more complicated. You are a bit late with a 1. Nov deadline...
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