ABB AC 800M

Network Wiring Section 3 Installation
60 9ARD000015-600
• The trunk line must be terminated at each end using a terminating resistor. For
more information, refer to Terminating Resistors on page 46.
• Trunk designing using thin cable has a significant impact on network power
design. For more information, refer to Table 14.
Table 54 lists the data rates for trunk distance and drop length.
Calculating the total cable length
1. The distance between any two points must not exceed the maximum cable
length allowed for the baud rate. Always use the longest distance between two
nodes in the network. For the cable length, refer to Figure 20.
For the respective cable type topology, refer to Table 12, Table 22, Table 32,
Table 42.
The cable length allowed is calculated using the following formulas:
ThickL + 5 * ThinL < 500 m for 125 kb
ThickL + 5 * ThinL < 250 m for 250 kb
ThickL + 5 * ThinL < 125 m for 500 kb
where ThickL is the length of the thick cable and ThinL is the length of the thin
cable.
2. The maximum trunk line distance is measured between the two terminating
resistors.
Table 54. Data Rates for Trunk Distance and Drop Length
Data Rate Trunk Distance
Drop Length
Maximum
Cumulative
125 KB 500 m (1640 ft)
6 m (20 ft)
156 m (512 ft)
250 KB 250 m (820 ft) 78 m (256 ft)
500 KB 125 m (410 ft) 39 m (128 ft)