MT4299E Rev.1
15/10/2019
Pagina 23 di 55
9841 or similar wire (EIA RS485 data transmission wire). Only connect detectors (and IN and
OUT modules) in cascade. Avoid tree or delta connection since they reduce interference
immunity.
-) Detector power supply (and IN and OUT modules on the bus) must be connected with a 2-
core wire with adequate section based on the number of connected devices, their distance from
the power supply and each device’s consumption (please see the technical manual enclosed
with gas detectors for this purpose).
Each device connected on the unit's RS485 bus must have its own univocal address. STG/IN8-
S and STG/OUT16-S address settings are described later in this manual. See the manual of
the detector for its address settings.
3.5.1)
Detectors connection
Gas detectors can be connected to the MU+PK control panel in two different
ways, based on the detector output signal.
1) 4-20 mA analogue proportional output.
The detector connected to the unit and ST.G/IN8 PK modules will send an average 4-20
mA signal referring to its range (i.e. 0-300 ppm, 0-30 ppm, 0-100% LEL etc.) and the
unit, suitably programmed, will display the relevant gas concentration indication
measured by the detector
(average value) and consequently activate the alarms when
the set values are reached.
2) RS485 digital proportional output (only Smart P)
The detector connected to the unit will send a data signal on the RS485 line. This signal
is an average (for CO and NO2 detectors referring to its range (i.e. 0-300 ppm, 0-300
ppm, etc.) and the unit, suitably programmed, will display the relevant gas concentration
indication measured by the detector
(average value) and consequently activate the
alarms when the set values are reached.
