CANopen • 119

Network Architecture

5.2 Network Architecture

5.2.1 Transmission Media

5.2.1.1 Type of Cable

A bus medium forms the basis for the physical connection of CAN.

With CAN, both the bus coupling and the bus medium are specified according to ISO 11898 (CAN High-Speed).

According to the cable specification, the Twisted-Pair medium (shielded cables twisted in pairs) with a wave resistance of 108...132 Ohm is recommended.

Twisted-Pair is low priced, convenient to use and permits simple bus type wiring.

The WAGO CANopen fieldbus nodes are intended for wiring using shielded copper wire (3x0.25 mm²).

Two important points have to be taken into consideration when designing the electrical bus medium:

•the maximum bus length and

•the required conductor cross section.

5.2.1.2Maximum Bus Length

The length of the bus is mainly limited by the signal running time and must, therefore, be adapted to the Baud rate:

Table 5-1: Maximum bus length dependent on the set Baud rate

WAGO-I/O-SYSTEM 750

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