Wiring Notes
CAN-CBX-AO412
Manual • Doc.-No.: C.3040.21 / Rev. 1.2
Page 31 of 92
5. Correct Wiring of Electrically Isolated CAN Networks
For the CAN wiring all applicable rules and regulations (EC, DIN), e.g. regarding electromagnetic
compatibility, security distances, cable cross-section or material, have to be met.
5.1 Light Industrial Environment (Single Twisted Pair Cable)
5.1.1 General Rules
Note:
esd grants the EU Conformity of the product, if the CAN wiring is carried out with at least
single shielded single twisted pair cables that match the requirements of ISO 118982-2.
Single shielded double twisted pair cable wiring as described in chapter 5.2 ensures the
EU Conformity as well.
The following general rules for CAN wiring with single shielded single twisted pair cable must be
followed:
1
A cable type with a wave impedance of about 120
ü
±10% with an adequate wire cross-section
(0.22 mm²) has to be used. The voltage drop over the wire has to be considered!
2
For light industrial environment use at least a two-wire CAN cable.
Connect
ý
the two twisted wires to the data signals (CAN_H, CAN_L) and
ý
the cable shield to the reference potential (CAN_GND)!
3
The reference potential CAN_GND has to be connected to the functional earth (FE) at
exactly one point.
4
A CAN net must not branch (exception: short cable stubs) and has to be terminated with the
characteristic impedance of the line (generally 120
ü
±10%) at both ends (between the signals
CAN_L and CAN_H and not at GND)!
5
Keep cable stubs as short as possible (l < 0.3 m)!
6
Select a working combination of bit rate and cable length.
7
Keep away cables from disturbing sources. If this cannot be avoided, double shielded wires are
recommended.
