User Manual

12/06 AWB2724-1584GB
99
Appendix
CAN/easy-NET network
Accessories
• RJ45 plug, Type: EASY-NT-RJ45 (8-pole)
Table 25: Prefabricated cables
• User-assembled cable, Type: EASY-NT-CAB (100 m 4 x 0.18
mm2)
• Crimping tool for RJ45 plug, Type: EASY-RJ45-TOOL.
• Bus terminating resistor, Type: EASY-NT-R RJ45 plug with
integrated bus terminating resistor 120 O
Cable length with cross-sections
For correct operation of the network the cable lengths, cross-
sections and cable resistances must match thoses listed in the
following table.
The impedance of the cables used must be 120 O.
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 O/m), the entire cable resistance R
L
must not
exceed the following values. R
L
depends on the selected baud rate:
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
Smin = minimum cable cross-section in mm2
rcu = specific resistance of copper if not stated otherwise 0.018 Omm2/m
Calculating length with known cable cross-section
The maximum cable length for a known cable cross-section is
calculated as follows:
l
max
= cable length in m
S = minimum cable cross-section in mm
2
rcu = specific resistance of copper if not stated otherwise 0.018 Omm2/m
h
Pre-assembled cables have RJ45 plugs at both ends.
Cable length Part no.
cm
30 EASY-NT-30
80 EASY-NT-80
150 EASY-NT-150
Cable length
Cable
resistance
Cross-section
m
mO/m mm
2
AWG
up to 40 F 140 0.13 26
Up to 175
F 70 0.25 … 0.34 23, 22
Up to 5 x 240 F 60 0.34 … 0.5 22, 21, 20
Up to 400 F 40 0.5 … 0.6 20, 19
Up to 600
F 26 0.75 … 0.8 18
up to 1000 F 16 1.5 16
h
Further information on the CAN cable lengths and
terminals can be obtained from the ISO standard 11898.
Baud rate Cable resistance RL
Kbaud O
10 … 125 F 30
250 F 25
500 F 12
lma
x
=
RL
R’
Smi
n
=
l x rcu
12.4
h
If the calculation result does not correspond to a standard
cross section, take the next higher cross section.
lmax
=
S x 12.4
rcu