Beckhoff CX-B510 Series, Руководство пользователя

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Connection and cabling
CXxxxx-M510/B510 25 Version: 1.0
3.2 Cabling
CAN is a 2-wire bus system, to which all participating devices are connected in parallel (i.e. using short drop
lines). The bus must be terminated at each end with a 120 (or 121) Ohm terminating resistor to prevent
reflections. This is also necessary even if the cable lengths are very short!
Since the CAN signals are represented on the bus as the difference between the two levels, the CAN leads
are not very sensitive to incoming interference (EMI): Both leads are affected, so the interference has very
little effect on the difference.
Additional shielding of the twisted wires can be used to further reduce EMI interference.