MT4412E Rev.3
15/10/2019
Page 12 of 30
Dip-switch 1: Baud Rate Bus RS485
Position
Bus communication speed
Detector and module compatibility
ON
115200
Smart “S” gas detectors; ST.G/IN8-S and
ST.G/OUT16-S modules
OFF
9600
Smart “3G” gas detectors; ST.G/IN8-S and
ST.G/OUT16-S modules
Dip-switches 2 and 3: RS485 bus communication protocol
Sw 2
Sw 3
Protocol
Detector and module
compatibility
Notes
ON
ON
Galileo
Smart “S” gas detectors;
ST.G/IN8-S and ST.G/OUT16-
S modules
Baud Rate 115200
OFF
ON
NU
NU
NU
ON
OFF
Modbus
Smart "G" gas detectors;
STG/IN8-S and STG/OUT16-S
modules
Baud rate 9600 (if they are
not connected to the Smart
"G" bus detectors, 115200
Bps can be set (switch 1)
OFF
OFF
Setting not used
Dip-switches 4 and 5: Communication (baud rate) of the RS232 serial port with
the PC
Sw 4
Sw 5
Baud Rate
ON
ON
9600 Bit/sec.
OFF
ON
19200 Bit/sec.
ON
OFF
38400 Bit/sec.
OFF
OFF
115200 Bit/sec. (default)
Dip-switches 6 and 7: not used
Dip-switch 8: restore default settings
Position
Function
ON
If set to ON, default data is restored when the central unit is switched on
OFF
Normal position
2.2)
Field device connections
The unit has 1 RS485 data bus to which 8 gas detectors can be connected
The gas detectors are connected through the serial bus (directly in the serial RS485 if equipped
with serial output or through 1 module with 8 STG/IN8 S inputs if of type 4-20 mA) and the
ST.G/OUT16-S output module
The maximum length of each serial data bus is 800 m.
To connect devices, 4 conductors are required (intended both as detectors with a serial output as
well as IN and OUT modules): 2 for the RS485 serial bus and two for powering the devices. For
this reason, two different wires must be used or a single wire that has suitable characteristics, as
described below.
