C-Bus power supply

Newby question...... New system to be installed.

DIN mounted modules with C-Bus power supply Vs DIN mounted modules without C-Bus power supply .

• Do I need all modules to have a power supply?
• Is a built in supply to get the current rating of the outputs?
• Will one modules power supply be enough if i have a few?

Thanks

 

Each output units with a power supply will supply 200mA to the network. You need to calculate the total current requirements of your network to decide on the number of power supplies. This depends on the number and type of units. If you enter you configuration in Toolkit, it will work out the current required and you can then determine how many power supplies you need. You can have excess current available (in fact and extra 200mA is recommended as then a power supply failure won't take out the whole system). The maximum current allowed is 2A (10 output units with power supplies).

You can also get seperate power supplies with a higher current, and some other devices may included a power supply, so you need to take these into the total.

 

Due to a piss poor decision made by an inexperienced sparky during my house build (the boss sent the wrong guy to my site). I had to have a separate power supply module installed in my network breakout cupboard some 70m by cable from the cbus output units to compensate for the dramatic voltage drop caused by having a ctouch at the end of that run.

The output units will say something like “200ma power supply included” screen printed on the blue fascia if they have them.

 

Cbus cable has a loop resistance of about 0.2 ohms per metre per pair, so 70 metres of cable gives you a total resistance of 70 * 0.2 / 2 = 7 ohms. The highest current touch screen is the color spectrum at 85mA which gives you a voltage drop of under 0.6V. Touch screens with a power supply draw only 20mA from Cbus.

You either had a very marginal network supply, or there is a cabling problem.

 

I am suspecting a cabling issue, the screen is flicking a little while I am typing