SMAR DFI302, Руководство пользователя

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DFI302 – Adding Power Supplies
7.11
DF47 – Intrinsic Safety Barrier for Fieldbus
Description
The Intrinsically Safe (IS) technology incorporated in the DF47 totally isolates the control network on
the hazardous side of the barrier. It also supplies up to 100 mA to field devices located in hazardous
area. The IS values of the power supply are designed for Fieldbus devices, which are according to
the FISCO model.
The incorporation of a Fieldbus repeater in accordance with IEC 1158-2, 31.25 Kbits/s will improve
the communication signal transmitted to hazardous areas without compromising the explosion proof
safety requirements. The networks in the hazardous and safe areas of the DF47 are completely
independent of each other.
In addition the bus termination for the hazardous network is incorporated into the DF47, which
means that only a single far terminator is required.
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H1 Isolated Barrier and IS Power Supply in accordance with the FISCO Model;
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Built-in H1 Fieldbus Signal Repeater;
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Provides up to 100 mA at 14 V to the hazardous network (for field devices);
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According to the IEC 1158-2, 31.25 Kbits/s standard for Fieldbus (Foundation Fieldbus and
PROFIBUS PA);
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FM & CENELEC Intrinsic Safety standards certified;
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Based on PTB Report W-53, “Investigations into Intrinsic Safety of Fieldbus Systems”;
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Bus termination on hazardous area;
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Installation can be done in safe area, Div. 2/Zone 2 or Div. 1/ Zone 1.
Installation
The specification and installation of the devices, including the DF47, must the executed by qualified
technicians. Please contact SMAR or our local representative if further information is required.
It is mandatory the installation of the intrinsically safe system fulfils the requirements of the local
authoritative organizations. In the United States, the system must fulfil the requirements of Article
504 of the National Electrical Code, the ISA RP 12.6 and SMAR’s control drawing.
Installation Principles
(according to ISA)
1. Ensure that the intrinsically safe and non-intrinsically safe circuits are separated to guarantee
that the ignition of non-intrinsically safe circuit does not intrude into the intrinsically safe circuit.
2. Ensure that the limiting parameters of system design, such as total inductance and capacitance,
for example, that determine the system approval, are not exceeded.
3. Verify if the power system faults and grounding differences do not generate an ignition.
Location
The barrier is normally installed in a dust-free and moisture-free NEMA 4 or 12 enclosure located in
the non-hazardous area. The enclosure should be as close as possible to the hazardous area to
reduce cable runs and increased capacitance. If the barrier is installed in a hazardous area, it must
be in a proper enclosure suited for that area. Only intrinsically safe terminals are located in the
barrier output.
Wiring
Intrinsically safe circuits may be wired in the same manner as conventional circuits installed for
unclassified locations with two exceptions summarized as separation and identification. The
intrinsically safe conductors must be separated from all other wiring by placing them in separate
conduits or by a separation of 2 inches of air space. The raceways, cable trays, open wiring, and
terminal boxes must be labeled “Intrinsically Safe Wiring” to prevent interference with the other
circuits.