Rockwell Automation 1757-FFLD Linking Device Configuration Manual - Manual (Page 20)

Publication 1757-PM002A-EN-E - June 2006
2-10 Set Up A System
Figure 2.3 Rockwell linking device with a Simple Two-Port
Fieldbus Network
Tree Topology - Chicken Foot
This topology consists of a single fieldbus segment connected to a common
junction box to form a network. A tree topology is practical if the devices on
the same segment are well separated but in the general area of the junction
box. It allows maximum flexibility when configuring and assigning devices to
networks/segments, and it is the preferred topology for reuse of existing
wiring.
(1)
Figure 2.4 is an example of a junction box at the end of a trunk. Remember
that a trunk is the longest cable path between any two devices on the network.
Since it is at the end of the trunk, the terminator within the junction box is
activated. The spurs that are shown on the bottom of the junction box must be
taken into consideration using the maximum spur length table (Table 2.1 on
page 13).
Fieldbus Device
Power Supply
Fieldbus Device
Power
Conditioner Power
Conditioner
Two-
Port
Linking
Device
Wire Pair
Wire Pair
T T
T T
Terminator Terminator
Terminator Terminator
T
(1) FF Engineering Guide (6.1.2)