5-6 Network Cabling and System Performance
Table 5.3
Free Topology Specifications
The
maximum total wire length
is the total amount of wire connected per network segment.
This means the sum of all wire lengths used, not simply the wire in the path between two
devices. The maximum
device-to-device
distance is only limited by the maximum total wire
length.
Power Specifications, Simplified Form
A link power network allows for multiple branches, e.g., a star topology. A
branch
is defined as
any length of twisted pair cable that extends from the LPI-10 module. Loop topologies can be
formed by joining the ends of branches.
Whereas system and transmission distance specifications involve the entire network, power
specifications apply to individual branches. The closer the devices on a branch are to the LPI-10
module, the more devices that can be on that branch. Similarly, the fewer the devices on a branch,
the longer that branch can be.
Both nominal and worst case power specifications for the performance of the link power system,
with both lumped and distributed loads, are shown in tables 5.4 through 5.7.
The following section, “Power Specifications for Extended Performance,” may be used as an
alternative to tables 5.4 through 5.7. It is more complex, but will allow better performance for
certain topologies.
Multiple link power segments may be interconnected via physical layer repeaters or L
ON
W
ORKS
routers to extend distance, number of devices, and total available application current.
Maximum total wire length per
network segment
Units
Belden 85102
500
meters
Belden 8471
400
Level 4/22AWG
400
JY (St) Y 2x2x0.8
320
Category 5
400