Lenze ECSEE040 - Page 54

Electrical installation
Connection of system bus (CAN)
5
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54
EDBCSXE040 EN 6.0
Specification of the transmission cable
We recommend the use of CAN cables according to ISO 11898−2:
CAN cable according to ISO 11898−2
Cable type Twisted pair with shielding
Impedance 120 W (95 ... 140 W)
Cable resistance
Cable length £ 300 m £ 70 mW/m
Cable length £ 1000 m £ 40 mW/m
Signal propagation delay £ 5 ns/m
Bus cable length
 Note!
The permissible cable lengths must be observed.
1. Check the compliance with the total cable length in Tab. 5−1.
The baud rate determines the total cable length.
CAN baud rate [kbit/s] Max. bus length [m]
50 1500
125 630
250 290
500 120
1000 25
Tab. 5−1 Total cable length
2. Check the compliance with the segment cable length in Tab. 5−2.
The segment cable length is determined by the cable cross−section used and the number
of nodes. Without a repeater, the segment cable length corresponds to the total cable
length.
Number of nodes
Cable cross−section
0.25 mm
2
0.5 mm
2
0.75 mm
2
1.0 mm
2
2 240 m 430 m 650 m 940 m
5 230 m 420 m 640 m 920 m
10 230 m 410 m 620 m 900 m
20 210 m 390 m 580 m 850 m
32 200 m 360 m 550 m 800 m
63 170 m 310 m 470 m 690 m
Tab. 5−2 Segment cable length
3. Compare the two values detected.
If the value detected from Tab. 5−2 is smaller than the total cable length to be provided
from Tab. 5−1 , repeaters must be used. Repeaters divide the total cable length into
segments.
 Observe...
the information on the use of a repeater in the CAN Communication Manual.