Stumped

I was working on a project for one of most reputed banks. They were advised on the system from our system integrators. As I commissioned the system to run on it's own with the sensors online and placed schedules to run the lighting circuits. The cable that connects to the system has been connected properly but the cable coming from the sensors when connecting to the relay it cancels out the bus connection and the sensors come online. When the cable is unplugged from the relay the bus connections come online while the sensors go offline.

I have tried all possible scenarios to fix this problem but i never found one. Does anyone might have come across this kind of issue and might have an answer to this would be highly appreciated.

Thanks in Advance

 

Start with the basics.....
1 - Have you check that there are no shorts on the cable that runs from the board to the sensors (+ or - crossed at a sensor can also do this)
2 - What voltage to you have at the sensors when they are connectted. How many power supplies do you have the network and how many devices is connectted?

If you say that as soon as you connect the field cable the C-Bus light drops out then it's either a short on cable or not enough power supply.

Hope this points you in the right direction