By "box of tricks", I assume you mean my original device. No, there is
no AC power available. DC power is fed to the device via its data
communications cable. All that's available is as I've stated - a set of
n/o relay contacts.
However, there will obviously be a mains power point somewhere between
this device and the switching device that I'm looking for, since the
whole point is to switch 240VAC to a bell that may or may not be
physically close to my original device.
The device you want MAY be available off the shelf as a module
intended for use with either a PLC system or lighting control
interface unit. (IE: someting like a clipsal C bus, but of the type
that you can interface to, rather than only being able to work with
their control unit). I would also try Haymans, Turks, Clipsal, HPM,
PDL etc, as if there is an approved item thats suitable, they would
likely have it or be able to get it, as there must be a need for this
sort of thing.
The other thing you could look at is commercial lighting controllers
for stage use etc, as these things must be run by a computer at some
stage, therefore needing to be switched by a logic level signal at
some point.
If the bell(s) are a fixed installation in a building, get the end
user to arrange a licensed electrician to install an approved DIN or
panel mount relay and transformer to power the relay if you cant
supply a voltage from your circuit) in the building to switch the 240v
bell circuit, then switch this arrangement via your contacts.
Consulting with a licensed electrician may solve this problem for you.
Personally, I would consider a Solid State Relay that is approved and
isolated sufficiently to protect your electronics, take the voltage
(+5v, +12V etc) that you have in your existing circuit - and use it to
activate the SSR. A solid state relay should only need 10s of MA to
achieve this.
If your customer doesnt want to go to this expense or trouble, they
may have to consider replacing the bell(s)
with the 24vac bell you specify for use with your product.
-0-----------------------------------------------
Pointers to this "HOST of readily available solutions" would be welcome.
I'm not sure how a "$5 fucking plug pack" changes much, but I'm
willing to find out.
Remember, I'm looking for something that is type-approved - I realise
that a $5 plug pack and a mains-rated relay would *easily* do the job,
but that's not a neat and tidy solution and it's not energy authority
approved, and the end users would likely electrocute themselves hooking
it up.
if its mounted in a proper housing, with a mains lead and socket on it
- I dont see how it could electrocute anyone, if its just a plug-in
device (like bobs link to the DSE switch box).
If you are worried about that though, throw an RCD plug on it, or
better still, make them get a licensed electrician to do the install
if its that risky for the end user.
it might be a lot cheaper to design and build something like this than
pay $380 for that fancy switch box mentioned elsewhere.
