"Andy Cap" wrote in message
...
On Wed, 16 Apr 2008 08:09:43 +0100, "Mr Sandman"
wrote:


Just to clarify then...or try to! I have two sets of terminals one on
each
powersupply, these are called P and B. The keypad shorts P & B together
to
switch the power on to the mag locks. So i have a wire coming from the
keypad to both terminals. Both power suppys are set up the same. Then i
have two wires coming from the smoke alarm activated relay. these two
wires
go short curuit when the alarm sounds. if i conect these two wires to one
of the power supplys P&B terminals, it all works as planed, ie the door
unlocks, but the electrition has put a wire from the terminals on that
power
supplys P&B terminals to the new power supplys P&B terminals. this causes
both power supplys to cut power to the maglocks when the smoke alarm
sounds,
but also when one keypad operates it also causes the other doors maglock
to
yurn off. So where do i put the diodes so that the smoke alarm relay
operates both power supplys P&B terminals, but dosent allow one power
supplys keypad to short the other keypads power supply P&B?


Just try and get one working first.
Remove the wire from the Smoke Alarm that connects to the lock P terminal
and
connect the diode. Reconnect the wire to the other end of the diode.
Test to see if the SA still operated the lock. If not reverse it.
If neither way works, as dennis@home says, the relay route is probably
easiest.
If just one direction works, then connect the other diode in EXACTLY the
same
place and orientation.

HTH
Andy



Cheers Andy, that's what I was thinking too, will have a go and let you know
how I get one.

cheers

Steve