NORD Drivesystems BU0260 - Manual (Page 98)

Supplementary Manual CANopen for NORDAC SK 20E
98 Subject to technical amendments BU 0260 GB
8 Additional information
8.1 Bus configuration
In an industrial environment the correct installation of the bus system is particularly
important in order to reduce potential interference. The following points are designed to
help prevent interference and problems right from the start. The installation guidelines are
not complete and applicable safety and accident prevention guidelines must be complied
with.
8.1.1 Laying of the CAN/CANopen bus cables
A CAN network consists of a maximum of 128 subscribers (nodes) and is based on a linear topology. The
number of subscribers is dependent on the driver modules (standard approx. 100 nodes). Repeaters must be
used for a high number of nodes.
With NORDAC frequency inverters, a twisted two-wire cable (with connected shield) is used for data transfer.
8.1.2 Cable material
The frequency inverter is usually connected to the CANopen system by a twisted, shielded two-wire cable. .
The guaranteed transfer speeds or transfer distances can only be achieved without errors if the specific cable
parameters are complied with.
The following relationship exists between the individual cable parameters:
Bus cable length Resistance Cable cross-section Possible transfer rates
0 - 25m 70 m /m  0.25 mm 2 , AWG23 1 Mbit/s
25 - 50m 70 m /m  0.25 mm 2 , AWG23 800 kBits/s
50 - 80m < 60 m /m  0.34 mm 2 , AWG23 500 kBits/s
80m - 230m < 40 m /m  0.5 mm 2 , AWG21 250 kBits/s
230m – 480m < 26 m /m  0.75 mm 2 , AWG18 125 kBits/s
480m – 1km < 20 m /-  1 mm 2 , AWG… 50 kBits/s
The interface is compliant with ISO 11898. The maximum permissible voltage on the CAN_L and CAN_H
cables is -8V … +18V.
NOTE
The lower the shielding resistance of the CANopen cable, the better the EMC quality. The
electromagnetic compatibility (EMC) describes the normally required state, that technical
devices do not interfere with each other due to electrical or electromagnetic effects.