SENSITRON
A Halma Company
MT2276E
GALILEO 32
Manual (EN)
P. 7/14
2.3
LAYOUT OF THE CONTROL UNIT MAIN BOARD
All connections of the GALILEO 32 control panel are to be performed on the
main board. See below the layout.
Figure 2.3
Main board layout
2.4
SYSTEM WIRING
Communication between the GALILEO 32 and the detectors is by a closed
RS485 loop. The control panel constantly monitors the detectors. A break in the
communication from any one of the detectors generates a Fault status in the
control panel.
2.6
GAS DETECTORS CONNECTION
Wirings between the control panel and the remote devices should be made by a
closed loop and by 4 wires: 2 wires for the RS485 communication and 2 wires for
the power supply. The cable for the RS485 communication must an EIA RS485: 2
core wires with section 0.22 / 0.35 mm
2
and shield (twisted pair). Nominal capac-
ity between the wires < 50pF/m, nominal impedance 120 ohm. These features
can be found in BELDEN cable 9842 or similar (data transmission cable in EIA
RS485). By this wiring, the line total length should not exceed 1000m.
Detectors are to be daisy chained. Absolutely avoid any star or tree mode con-
nection to prevent interference or wrong communication.
Make sure that each multi-polar wire includes just one RS485.
For the detectors’ power supply connection use a 2-wire cable with suitable sec-
tion as a function of the distance and the number of detectors.
Once the installation has been completed and the system is powered-on, make
sure that each detector gets at least 12 or 24 Vdc (it depends in the used power
supply.
