Bus coupler

Can any one tell me the effects of putting a longer cable on the switch side of the bus coupler - I thought that it was just a volt free contact so why should there be a limit on the cable length?

 

If it was volt free, how could it detect a contact closure?
I think it has something to do with capacitance and reliable operation of the bus coupler. I'm sure you could run longer cables but maybe at the price of reliability.
Regards,
Michael.

 

The Bus coupler input contacts are referenced to C-Bus. Running long wires to the Bus Coupler contacts can inbalance the C-Bus network and make comms unreliable if you're not careful.

The solution is to use the DIN Auxiliary input unit, L5504AUX. Those inputs are connected through a decoupling transformer and can consequently be much longer.

The bus coupler is intentionally small so that it can be jammed in nooks and crannies near where the mechanical switches are, but this comes at the expense of the level of isolation from C-Bus.

 

Newman is correct. I have tried up to several metres in a noisy environment. I think I was pushing the limit as I began to get errors on a bus scan. Maybe coincedence, maybe not.