Shielding And Routing Of The Bus Cables; Bus Termination - SEW-Eurodrive MOVIDYN DeviceNet AFD11A Manual

The DeviceNet option card is opto-decoupled on the driver side in accordance with the DeviceNet
specification (Volume I, Chapter 9). This means the CAN bus driver must be powered with 24 V via
the bus cable.
The required cable is also described in the DeviceNet specification (Volume I, Appendix B). The
connection must be made according to the color code specified in Table 1.
2.4

Shielding and routing of the bus cables

Having the bus cable correctly shielded cuts out electrical interference which can occur in an
industrial environment. The following measures ensure the best possible shielding:
• Fasten the retaining screws of plugs, modules and potential compensating cables until finger-
tight.
• Apply the bus cable shielding on both ends.
• Do not route the signal and bus cables in parallel to the power cables (motor leads); use sepa-
rate cable ducts if at all possible.
• Only use metal, grounded cable racks in industrial environments.
• Route the signal cables and the associated potential compensation closely to each other at the
shortest distance.
• Avoid using plug connections to extend bus cables.
• Route the bus cables in close proximity to available grounding surfaces.
• Use bus connectors with a metal-plated or metal housing.
IMPORTANT!
In the event of fluctuations in the ground potential, a compensating current may flow along the
shield which is connected at both ends and to the ground potential (PE). In this case, make ade-
quate provision for potential compensation in accordance with the relevant VDE regulations.
2.5 Bus term ination
In order to avoid disruptions in the bus system due to reflections etc., each DeviceNet segment
must be terminated with 120 Ω bus terminating resistors at the first and last physical participant.
The bus terminating resistor must be wired between terminals 2 and 4 of the bus connector.
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M OVIDYN DeviceNet AFD11A
Installation 2
7