Subject: From: Date:

Re: [ECS] Sprinkler Automation Gerry Duprey Wed, 7 Apr 1999 12:33:35 -0400 (EDT)

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On Wed, 7 Apr 1999 herronf@us.ibm.com wrote:

One thing to be wary of is the valves being stuck/left on.  If the PC
crashes (or the HA controller) while a valve is open and you are away,
it's going to get plenty muddy.

There are X10 based relay control boards that have "deadman" switches
that, if set, will cut the ciruit out after a predefined period to
specifically handle that (i.e. you know you never water any zone more than
30 minutes, so set a limit of 1 hour and if the valve isn't told to turn
off by then, the relay board will do it anyway).  

Another way is to add a bit of electronics between the digital outs and
the relays.  Specifically, something like a basic stamp.  These things are
cake to program and could be setup to accept digitally driven zone
controls for up to 4 (or 8 zones, with the basic stamp 2) and relay them
back out, but with timers to close them after a certain period in case the
controlling unit dies/forgets/evaporates.  I'd recommend putting the
controller in close proximity to the valve control relays and perhaps
backing them up with a battery.  While most power outages are short, you
could get one that was short enough that the relay didn't open, but the
controller freaked.  I'll admit, that might be closing in on over kill
though... :-)

Either way, you probably want to make sure you have some sort of "dumber"
backup to shut things off when ECS, the computer it's on or the controller
interface to the PC croak.

> 
> 
> I got Lawn and Garden (drip) Irrigation installed.  I got tired of the
> Clock timer in the garage so decided this was a task for ECS.  Built a box
> with a relay for each zone.  Even added a LED so I can see which zone is on
> etc.  I would appreciate any helpful programming tips examples from those
> of you who have done this task with ECS.  It is more complex than I
> realized.  The Clock/Timer would alow skip a day, every third day etc.
> Right now I'm just Time and Timer Driven.
> I would welcome code snippets or examples to list or offline.   Thanks,
> Frank
> 
> 

Gerry Duprey                     EMAIL: gerry@msage.com 
Micro Sage Software Systems      VOICE: (734) 663-0444
130 South First Street             WWW: http://www.msage.com/~gerry
Ann Arbor, MI 48104 USA

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