Echelon LonPoint Module - Manual (Page 28)

3-6 Network Cabling and Connections
Doubly Terminated Bus Topology Segment
If a doubly-terminated bus topology is used, then two Model 44101 terminators are
required, one at each end of the bus, as shown in figure 3.7. The Model 44100
Terminator's orange wires should be connected to the twisted pair network. The
Terminator's green wire must be connected to earth ground. The green wire must
never be connected to the shield of a twisted pair cable.
orange
Network
green
44100
Terminator
Termination Termination
orange
Network
green
44101
Terminator
Figure 3.7 Double Termination for Bus Topology (Two Model 44101 Terminators)
Terminating Shielded Cables for the TP/FT-10 Channel
Model 44100 and 44101 Terminators are intended for use exclusively with unshielded
twisted pair cables and must NOT be used as terminators for shielded cables. If a
shielded cable is to be used then special Terminators must be fabricated for both free
topology and bus cabling architectures. These special Terminators will ensure the
effectiveness of the shield in providing noise immunity in electromagnetically harsh
environments. Figure 3.8 presents the schematic for a Free Topology Shielded Cable
termination.
Network
Cable
Network
Cable
Ground
Cable
Shield
C1 R2 R4
R1
C2 R3
R1, R2, R3
R4
C1, C2 78.7 ž, 1%, 1/8W
150 ž , 1%, 1/8W
100 µ F ± 10%, 50V minimum aluminum-
electrolytic type (observe polarity)
+
+
Figure 3.8 Free Topology Network Terminator for use with Shielded Cables
(Use only one Terminator.)
Figure 3.9 presents the schematic for a Bus Topology Shielded Cable termination.