Freeing up a 4 Channel Relay

Hi everyone..I am in the process of re-jigging my c-bus lighting system and want to free up a
4 Channel relay for other lighting applications.
I hope to do this by combining toilet and bathroom lights and exhaust fans
on 2 channels, rather than the 4 channels they each currently occupy.
If I do this for two toilets and two bathrooms, I then free up a 4 channel relay.

Currently, input units combine the light and exhaust so that whichever key is pressed, both light and exhaust turns on.
Would connecting (combining) the relevant exhaust channel with the light channel
on the relay terminal block, do the trick ?
Do I have to consider anything else - addresses etc ??
Cheers
Ian

 

What I think you are saying is this:

• You have 2 bathrooms and 2 toilets
• Each room has both a light and a fan (8 circuits in total)
• The key input units have been programmed to turn on both fan and light when either button on the switch in that room is pressed, effectively making the two circuits behave as one.
• You're looking to combine these two circuits electrically into 1, so each room is wired to a single relay channel, thus freeing up 4 relay channels for other purposes.

Is that right?

Assuming the above is correct then of course you can combine both circuits together on a single relay channel. Since your installation is already wired, the easiest way for your electrician to do this would be to combine the switched active circuits within the switchboard.

Once this is done you can simplify your programming. You'll only need 1 group address for each room now, not 2, so you can put both buttons on the switch to the same group address. You'll also need to move the group addresses of your newly-free 4-channel relay unit to new addresses, otherwise they may continue to operate.

I'm a little suprised to see that you have all your rooms configured this way. A very typical and very practical configuration for bathrooms/toilets with C-Bus is for the system to keep the fan on for a little while after the light goes out. With your proposed configuration you'll lose the ability to do this entirely, whereas with your current configuration the only thing stopping you from doing it is a little programming time.

 

Thanks Newman for taking the time to respond...you have summarised it much better than I did, and, yes, that's exacty what I am trying to achieve!

One point though.. when you say "combine the switched active circuits within the switchboard", I take it by 'switchboard' you mean the terminal block on the Relay unit itself. ??

Thanks again
Ian

 

The switchboard is one of the names given to the enclosure that houses all the C-Bus (and other) electrical equipment. Inside the switchboard are the C-Bus relay units and the electrical wiring enters the switchboard to make connection with the relay units via the terminal blocks on those units.

The most practical way "to combine the switched active circuits within the switchboard" would be to insert the active wires for the light and the relay into the same terminal block on the relay unit.

 

ok.. thanks for that. But seeing as I want to combine light with fan I am guessing you mean - insert the active wires (channels) for the light and the fan into the same terminal block on the relay unit - not "insert the active wires for the light and the relay into the same terminal block on the relay unit." ??

Cheers
Ian

 

Yes, that's right. Just a typo on my part.

 

Thanks a lot, Newman.. Booked sparky in for this week and then I will program as suggested!
Cheers
Ian