Sensitron S3832R32, Инструкция по эксплуатации

Страница: 22 / 28

ENGLISH
Pag. 18
3.1 Connection relays outputs
To connect relays, see the board layout described in Figure 2. It’s important to consider these
explanations: NC stays for normally closed, NO indicates a contact normally open and COM
is the common contact. The gas detector has the relay 1 associated to the firs alarm thresh-
old and the relay 2 to the second threshold as default setting. The user can set different con-
nections, as described in Figure 2. It’s possible to connect both the alarm thresholds at the
same relay, the association of the same event to both relays is highly discouraged.
When correctly set, SMART3R LITE can be installed in systems with a functional safety SIL2.
In order to guarantee this capability the following settings must be implemented
• Relays must be set as normally energized (JP27 open)
• Connect to a relay only the fault event (close PIN 1-2 of JP26 or JP28)
• Duringt installation step, connect a 1.33A fuse to each relay’s output
• Check the relays functionality at least one time per year, by testing detector response
with gas application and checking the relays activation
The following table describes the safety parameters related to the relays outputs:
SFF PFD λsd [1/h] λsu [1/h] λdd [1/h] λdu [1/h] T1 MTTR
94,10% 2,09E-04 3,80E-10 2,94E-07 4,26E-07 4,52E-08 1 anno 24h
3.2 Connection serial line RS485 (optional)
The connection of SMART3R LITE to RS485 bus lines should be performed by using a 4-wire
cable, 1 pair for the RS485 bus and 1 for the power supply. It is also necessary that:
• 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).
• Using this wiring, the total length of the line should not exceed 1000 m.
• Detectors are to be wired in daisy chain mode. We recommend avoiding star or tree
mode connection as interference immunity would be reduced.
• Make sure that each multi-polar wire includes just one RS485.
• Make sure that a 120 Ω end line resistor is placed at the beginning and at the end (on
the last detector) of the bus line.
• For the detectors’ power supply connection, we recommend using a 2-wire cable with
suitable section according to the distance and number of detectors.
• Once the installation has been completed, verify that each detector reaches at least
12 Vdc.