"Geo" wrote in message
...
On Sat, 29 Mar 2008 13:26:00 -0000, "Mike Lewis"
wrote:


However, the spikes are narrow - perhaps just one or two a day. I am
therefore assuming the problem lies with EMI. I've attached a number of
ferrite cores on the various cables as well as the serial leads and now
just
have to wait and see if this solves the problem.

OK - I had a quick look at their site and see that the basic sytem is
supplied
with 25 metre screened cabled from the analogue sensors. Also noted that a
12v
90mA supply would power the kit. If you have a charged battery available
it
might be worth running the system for a day with no mains connected to
eliminate
a power feed problem.
Is there any time pattern to the spikes (lighting up time for instance)?
I suppose you could miss some if you are only sampling every 5 minutes...

Geo

Thanks. The timing of the spikes varies but is generally at some point
through the afternoon. However, rainfall tends to spike overnight - but only
when it has been raining! I'm hopeful that the ferrite and increased
sensitivity of the UPS should do the trick, so I'll wait and see.

Mike