Table 9: Network Engine to Level Converter connection rules (M-Bus only)
Category
Rules and Maximums
General
Use either an RS-232 or RS-485 connected level converter or a network
connected level converter.
Number Devices
Use either one serial level converter or five network level converters per
trunk.
RS-232: Level converter maximum length on 15 m (50 ft)
RS-485: Level converter maximum length on 1,500 m (5,000 ft)
Line Length and
Type
Network level converter: maximum length of 2,000 m (6,600 ft) for plastic/
glass fiber optic with external adapter
10/100 BaseT: 100 m (330 ft) CAT5 cable
1000 BaseT: 100 m (330 ft) CAT5E cable
Termination
No termination
Table 10: Guidelines for LonWorks network bus topology
Cable Type
Maximum Segment Length
with FTT10 Devices Only
Maximum Segment Length
with FTT10 and/or LPT10/11
Devices
Belden 85102 Cable
2,700 m (8,850 ft)
2,200 m (7,200 ft)
Belden 8471 Cable
2,700 m (8,850 ft)
2,200 m (7,200 ft)
Level IV 22 AWG
1,400 m (4,600 ft)
1,150 m (3,770 ft)
JY (St.) Y 2 x 2 x 0.8
900 m (2,950 ft)
750 m (2,460 ft)
Note:
For the bus topology, the maximum length stub cable is 3 m (10 ft), and the stub lengths
must be calculated into the overall segment length.
Table 11: Guidelines for LonWorks network free topology
Cable Type
Maximum Node-to-Node
Distance
Maximum Segment Length
with FTT10 and/or LPT10/11
Devices
Belden 85102 Cable
500 m (1,640 ft)
500 m (1,640 ft)
Belden 8471 Cable
500 m (1,640 ft)
500 m (1,640 ft)
Level IV 22 AWG
400 m (1,300 ft)
500 m (1,640 ft)
JY (St.) Y 2 x 2 x 0.8
320 m (1,050 ft)
500 m (1,640 ft)
Table 12: Maximum number of devices per LonWorks network segment
Device Type
Maximum Allowed
FTT10 Nodes Only
64 nodes if repeaters are not used; 255 nodes if
repeaters are used
Mixed FTT10 and LPT-10/11 Nodes
([FTT10 x 2] + LPT10/11) < 128
Physical Layer Repeaters
Maximum of 1 per segment
Terminators
NAE55/NIE55 Installation Guide
26
