User Manual

Connecting the NET network
59
08/04 AWB2528-1423GB
Calculating the cable length with known cable
resistance
If the resistance of the cable per unit of length is known
(resistance per unit length R’ in O/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 O
R’ = Cable resistance per unit length in O/m
Calculating cross-section with known cable lengths
The minimum cross-section is determined for the known
maximum extent of the network.
l = cable length in m
S
min
= minimum cable cross-section in mm
2
r
cu
= resistivity of copper, if not otherwise stated 0.018 Omm
2
/m
Baud rate
Cable resistance R
L
kBaud O
10 to 125 F 30
250 F 25
500
1000
F 12
l
max
=
R
L
R’
S
min
=
l x r
cu
12,4
h
If the result of the calculation does not yield a standard
cross-section, the next larger cross-section is used.