SMAR FY302, Инструкция по установке, эксплуатации и обслуживанию

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Series 302 FIELDBUS FOUNDATION – Installation, Operation and Maintenance Manual
1.10
It works as low impedance for DC and high impedance for AC communication signal and may have
an additional internal terminator activated by a frontal key. The active impedance is fundamental for
the network correct operation.
The Foundation Fieldbus impedance is on a device of non-isolated, active impedance control,
complying with the IEC61158-2 standard. This device has an output impedance that works in
parallel with the two bus terminators (a resistor of 100
Ω in series with a capacitor of 1 µF) assisting
to the pattern and results in purely resistive line impedance for a wide frequency range. The Smar
DF49 module has two channels and the DF53 module four channels.
Repeaters H1
The passive repeater increases the H1 segment range of 1900 m by amplifying its signal. Up to 4
repeaters may be used with 8-bit preamble or a maximum of 8 repeaters with 16-bit preamble. A
maximum of 4 repeaters. It is usually allowed.
As the repeater isolates the communication signal and the power supply, it is possible to connect
devices that drain more current from the bus or even to create new segments starting from the same
main bus (Figure 1.12). Smar offers the RP302 repeater, as well as the DF47 model that works both
as repeater and intrinsic safety barrier.
Figure 1.12 - Isolation Provided by the Barrier
Intrinsic Safety Barrier
The intrinsic safety barrier has the primary function to limit the energy available in the bus that
circulates for the classified areas.
A classified area is that whose atmosphere is potentially explosive. The barrier usually isolates and
repeats the FF signal, allowing several segments on the dangerous side to be connected to the safe
side. See Figure 1.12. The Smar offers the model DF47, which works as repeater and intrinsic
safety barrier, as well as the SB302 model, which is an isolated barrier.
Derivation Box
It allows the connection and disconnection of devices without interrupting the continuity of the bus,
increasing the plant availability and simplifying maintenance. It reduces start-up time, stoppage time
and cabling costs.
In the Smar JM400 model, the weather-proof and explosion-proof housing prevents water, oil or dirt
from reaching the electric connections (IP66/68). Its cover lock mechanism doesn’t require specific
support. See Figure 1.13 and 1.14.