Eaton easy800

2 Installation
2.7 NET network
Control Relay easy800 11/11 MN04902001Z-EN www.eaton.com 59
2.7.2 Cable length with cross-sections
For correct operation of the easyNet network the cable lengths, cross-
sections and cable resistances must match those listed in the following
table.
The impedance of the cables used must be 120 Ω.
The maximum transmission speed depends on the total length of the
network cables, (￫ section 12.3.7, “NET network”, page 359).
Calculating the cable length for a known cable resistance
If the resistance of the cable per unit of length is known (resistance per unit
length R’ in Ω/m), the entire cable resistance R
L
must not exceed the
following values. R
L
depends on the selected baud rates:
l
max
= Maximum cable length in m.
R
L
= Total cable resistance in Ω.
R’ = Cable resistance per unit length in Ω/m.
Cable length
Cable resistance Cross section
m
mΩ/m mm
2
AWG
- 40  140 0.13 26
- 175
 70 0.25 - 0.34 23, 22
- 250
 60 0.34 - 0.5 22, 21, 20
- 400
 40 0.5 - 0.6 20, 19
- 600
 26 0.75 - 0.8 18
- 1000
 16 1.5 16
￫
The installation of an expensive fibre optic link is recommended
with cable lengths > 500 m.
Baud Rate
Cable resistance R
L
Kbit/s
Ω
10 - 125  30
250
 25
500, 1000
 12
l
max
=
R
L
R’