Wiring Notes
CAN-CBX-COM2
Manual • Doc.-No.: C.3055.21 / Rev. 1.1
Page 37 of 125
6. 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.
6.1 Standards concerning CAN Wiring
The flexibility in CAN network design is one of the key strengths of the various extensions and
additional standards like e.g. CANopen, ARINC825, DeviceNet and NMEA2000 that have been built
on the original ISO 11898-2 CAN standard. In using this flexibility comes the responsibility of good
network design and balancing these tradeoffs.
Many CAN organizations and standards have scaled the use of CAN for applications outside the
original ISO 11898. They have made system level tradeoffs for data rate, cable length, and parasitic
loading of the bus.
However for CAN network design margin must be given for signal loss across the complete system and
cabling, parasitic loadings, network imbalances, ground offsets against earth potential and signal
integrity. Therefore the practical maximum number of nodes, bus length and stub length are
typically much lower.
esd has concentrated her recommendations concerning CAN wiring on the specifications of the
ISO 11898-2. Thus this wiring hints forgoes to describe the special features of the derived standards
CANopen, ARINC825, DeviceNet and NMEA2000.
The consistent compliance to ISO 11898-2 offers significant advantages:
1
Durable operation due to well proven design specifications
1
Minimizing potential failures due to sufficient margin to physical limits
1
Trouble-free maintenance during future network modifications or during fault diagnostics due to
lack of exceptions
Of course reliable networks can be designed according to the specifications of CANopen, ARINC825,
DeviceNet and NMEA2000, however it must be observed that it is strictly not recommended to mix
the wiring guidelines of the various specifications!
