SMAR LD292, Operation, Maintenance & Instruction Manual

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LD292 - Operation and Maintenance Instruction Manual
1.10
The LD292 is powered via the bus. The limit for such devices is 16 for one bus for non-intrinsically
safe requirement.
The Figure 1.6 shows the correct installation of the conduit, in order to avoid penetration of water, or
other substance, which may cause malfunctioning of the equipment.
CORRECT
WIRES
INCORRECT
Figure 1.6 - Conduit Installation
NOTE
For more installation details please refer to the Fieldbus Installation Manual
Bus Topology and Network Configuration
Other types of cable may be used, other than for conformance testing. Cables with improved
specifications may enable longer trunk length or superior interface immunity. Conversely, cables
with inferior specifications may be used subject to length limitations for trunk and spurs plus possible
nonconformance to the RFI/EMI susceptibility requirements. For intrinsically safe applications, the
inductance/ resistance ratio (L/R) should be less than the limit specified by the local regulatory
agency for the particular implementation.
Bus topology (See Figure 1.7) and tree topology (See Figure 1.8) are supported. Both types have a
trunk cable with two terminations. The devices are connected to the trunk via spurs. The spurs may
be integrated in the device giving zero spur length. A spur may connect more than one device,
depending on the length. Active couplers may be used to extend spur length.
Active repeaters may be used to extend the trunk length.
The total cable length, including spurs, between any two devices in the Fieldbus should not exceed
1900 m.
The connection of couplers should be kept less than 15 per 250 m.
Terminator
Enable
Junction
Box
Shield
Spur
Spur
Spur
Phase
Neutral
Ground
Panel
Ground
Analog
Ground
Terminator
Figure 1.7 - Bus Topology