On Apr 30, 9:41*pm, robgraham wrote:
On Apr 30, 9:03*pm, YAPH wrote:









On Sat, 30 Apr 2011 15:37:40 +0000, mick wrote:
You could use an "intelligent relay" here. You can get them with 4 n.o.
mains-rated contacts and 6 or 8 digital inputs. They include built-in
time switching, timers, logic etc. unfortunately the programming
software and lead is usually charged for, but not as much as for a
proper PLC! Most manufacturers do their own flavour of these. Have a
look at the Crouzet Millenium 3 range. This is a complete kit:
http://uk.rs-online.com/web/search/s...seAction.html?
method=getProduct&R=5368979

Interesting. Probably overkill for this application but not enough for
something like the wood-burner + boiler controller I built recently which
more than half a dozen outputs to pumps & motorised valves.

Presumably the programming s/w is proprietary, closed-source and windoze-
only?

Of course, a real tech-head would build a board with a PIC and relays on
it and program it using LDmicro ladder logic for free! *http://cq.cx/
ladder.pl

I thought Arduinos were current flavour of the month? :-)

But even if I were au fait with stuff like that it wouldn't be doing any
favours to my clients, who would have to find someone else to maintain
the system if I got run over by a bus.

--
John Stumbles *-- *http://yaph.co.uk

DEATH TO FANATICS!

Ahh - wood-burner/CH boiler interface. Two pumps, one motorised valve,
3 relays and some resistor-diode logic. *Simples. - that is until you
try plumbing in the Dunsley neutraliser.

Rob

I forgot to add that I have an aquaintance who lives in an ancient
pile and has a two boiler system. I've never asked him how it works,
but he is a microwave engineer and his solution to one piping problem
was to run the return concentric with the feed. I perhaps would
really want to know how the system as a whole works - I saw the boiler
room once and it was like something out of Para Handy's puffer.

Rob