Powering expanders from the auxiliary power terminals

To calculate the number of expanders/keypads that can safely be powered from the auxiliary 12V DC power terminals, add the total maximum current draw from all of the expanders/keypads to be powered and determine if this total is less than the specified 12V DC auxiliary power.

See the technical data for the specific auxiliary current and the corresponding installation instruction or data sheet of modules, keypads and expanders for current consumption.

 

Expander 1 Current (mA) + Expander 2 Current (mA) + ….. <Auxiliary Power

If the electronic or relay outputs are already powering external devices, the power supplied to these devices must be subtracted from the 12V DC auxiliary power supply to determine the amount of available power from the auxiliary power terminals (0V 12V).

If the total maximum current draw from the expanders exceeds the auxiliary power, a PSU expander should be used to provide additional power.

Powering expanders from the auxiliary power terminals

1	SPC controller
2	Battery
3	Auxiliary 12V power terminals
4	Keypad
5	Keypad
6	I/O expander