5
To guarantee efficient operation of the SimpleHome system, it must be sized correctly. To do so, proceed as follows:
1) establish the number of power supply units required, on the basis of the number and type of devices installed;
2) establish the correct cable cross-sections for the Bus sections as well as the inputs (commands) and outputs (loads), on the
basis of the number of power supply units used and how they are installed within the system.
Establishing the number of power supply units required:
Each device connected to the Comelit home automation system is powered directly by the 3-wire bus; a single home automation
power supply unit is capable of supplying 2A continuously (2.2A peak). To guarantee efficient operation of a system, the number
of power supply units required must be determined; to calculate this number, simply add the nominal absorption of the connected
devices together.
The configurator available on the website
pro.comelitgroup.com
provides the information required to calculate the nominal
absorption. (Downloads_Home automation_Home automation system configurator)
N.B. It is always wise to add a little in reserve (e.g. 30%) in order to guarantee system continuity in the event that one of the
power supply units experiences a fault.
Establishing the required cross-sections:
To reduce the cross-section of the bus backbones in use, we recommend that power supply units are distributed as close
as possible to the device groups with the greatest power absorption instead of being concentrated in one area (especially for
modules on DIN bars).
In fact, the nearer the power supply to the electrical nodes with the greatest absorption, the lower the current running along the
bus backbone. According to Ohm's law (V = Rline x Iabsorbed), the lower the current circulating, the lower the drop in voltage.
In terms of voltage, to guarantee efficient operation of the SimpleHome system, the following rules should be observed:
1) power supply voltage of the devices on the bus = 24 Vdc +/- 5%
2) voltage, measured between the BUS DATA LINE wire and the BUS POWER SUPPLY NEGATIVE, should be greater than 4.7
V at every point in the system (5 V is the optimum value).
N.B. If a device on the bus fails to communicate, apart from the various tests, we recommend measuring the voltage
between the BUS DATA LINE wire and the POWER SUPPLY NEGATIVE on the terminal board and making sure it is over
4.7 V. If it is not, we recommend installing a power supply unit near the device.
POWER SUPPLY
UNIT
SIMPLEHOME BUS
MODULE WITH 9 INPUTS
AND 8 x 16A OUTPUTS
ADDITIONAL POWER
SUPPLY UNIT
MODULE
WITH 5
INPUTS
OTHER
DEVICES
green (bus)
red (+)
blue (-)
