Joe wrote:
-----Original Message-----
From: [email protected] [SMTP:[email protected]]
Sent: Tuesday, September 07, 1999 2:04 PM
To: [email protected]
Cc: [email protected]
Subject: Immunity Problems ??
>EMC Professionals,
>We have 42 of the same instruments installed in one laboratory.
What are they? What type of power feeds and I/O lines or sensors?
What about physical separation?
>They are each installed on their own dedicated line.
Powerline?
>On a regular basis
The toughest problems are unpredictable, intermittent failures. This
is your first ray of hope; you should try to associate the problem with
external conditions; i.e., a step in your process, the plant elevator, the
air conditioning, every 107 minutes, something.
>an instrument will shut down during a run.
A bit more description about the "shutdown."
>The instrument that shuts down is different each time.
Really, NEVER the same instrument? Or do you just mean it strikes
randomly?
>These instruments are laboratory equipment that meet Class A
radiated limits of
>EN 55011 and meet the immunity requirements of EN 50082-1.
So, then you really don't have a problem? (Sorry, grin!)
>Any ideas as to the potential cause of the problem and possible
ways to resolve
>the problem would be greatly appreciated.
Well, you can start right away with the correlation effort. You
could also put a powerline monitor on the power buss. If you operated one
instrument without I/O or data or control leads, you might start to get an
idea about the problem if that one instrument NEVER shutdown. That might say
the problem is not coupled through the power bus. OTOH, if it failed just as
the others, that may lend weight toward the power bus as the path.
Can you operate an instrument in another building? Do you get zero
shutdowns, or the same probability? Can you operate a cluster of your
instruments in a remote location, and do they exhibit shutdown problems too?
>Regards
>Joe Martin
>EMC/Product Safety Engineer
>P.E. Biosystems
>[email protected]
That's enough for now! Organize your info and get back to the list.
Regards,
Ed
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Ed Price
[email protected]
Electromagnetic Compatibility Lab
Cubic Defense Systems
San Diego, CA. USA
619-505-2780 (Voice)
619-505-1502 (Fax)
Military & Avionics EMC Services Is Our Specialty
Shake-Bake-Shock - Metrology - Reliability Analysis
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