Re: Field Mills (fwd)

[Steven Roys <sroys@xxxxxxxx>]

---------- Forwarded message ----------
Date: Sat, 10 Jul 2004 08:20:51 +0930
From: Matthew Smith <matt@xxxxxxxxxx>
To: High Voltage list <hvlist@xxxxxxxxxx>
Subject: Re: Field Mills (fwd)

Tom Luttrell wrote:
> Having an alarm o/p for a (user) set field strength would be a good idea
> too.
> The ones I've seen installed in Malaysia to warn School kiddies to get
> inside worked that way.

Easy done - I'll have a good few spare i/o pins left on the microcontroller.

Further thought on the nature of this instrument makes me wonder whether we
should not run the serial and alarm signals through optical fibre.  Run the mill
from gel cells with a trickle charger.  The charger could be powered through a
relay stuck in a can of SF6 (or a proper HV relay) which could
disconnect/reconnect dependant on the state of the alarm signal.

Even in an indoor lab setting, I think it would be a good idea to isolate from
your (expensive) equipment using internal opto-isolators.  I think Antonio's
problem shows a good example of this.  Those meter terminals should have been
via an opto-isolator.  When you connect the wrong thing to them, you burn out
the opto-isolator.  Unplug and put in a new one for $1...

Cheers

M

-- 
Matthew Smith
Kadina Business Consultancy
South Australia