ENGLISH
Pag. 28
³
Please remember that the shield is to be grounded from the control panel side only.
Also remember never to connect the shield to the detectors.
³
Ensure the wire connections, either clutching or crimping type, are properly carried
out with terminals that do not oxidise or loosen. We recommend having them sol-
dered.
³
The SMART S-IS gas detectors can be connected to control panels available on the
market having 4-20 mA input signals.
³
Please make sure the panels are certified according to the standards EN /IEC60079-29-
1:2016.
Figure 3 shows the connection of a SMART S-IS detector to a control panel. Control panels
accepting 4-20 mA input signals allow the connection of only one detector per input.
Figure 3) Connection scheme for the 4-20 mA output
5.7 RS485 serial output connection
To connect SMART S-IS gas detectors to RS485 bus lines, it is necessary to use a 4-wire cable,
1 pair for the RS485 bus and 1 for the power supply. It is also necessary that:
³
Wiring between the detectors and the control panel should be made by using con-
nection cable EIA RS485: 2 core wires with section 0.22 / 0.35 mm2 and shield (twisted
pair). Nominal capacity between the wires <50pF/m, nominal impedance 120 Ω. These
features can be found in BELDEN cable 9842 or similar (data transmission cable in EIA
RS485).
³
Using this wiring, the total length of the line should not exceed 1000 m.
³
Detectors and output modules are to be wired in daisy chain mode. We recommend
avoiding star or tree mode connection as interference immunity would be reduced.
³
Make sure that each multi-polar wire includes just one RS485.
³
Make sure that a 120 Ω end line resistor is placed at the beginning and at the end (on
the last detector or output module) of the bus line.
shield connected to the
earth (just at one side)
DL1
DL2
DL3
JP1
JP6
JP5
Power supply: Vcc-
Power supply: Vcc+
RS485:
A
RS485: B
4-20 mA
output
JP3
4
5
6
1
2
3
Not used
+
S
Summary of Contents for SMART S-IS
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