Current Limit for Thick Cable

For thick cable, the maximum current on the network is 16 Amps.  However, only 8 Amps is

permitted on a single network segment. 16 Amps can be drawn from a single power supply by

locating the power supply at the center point of two network segments, supplying 8 Amps to

each segment.

For thin cable, the maximum current permitted is 3 Amps.

The DeviceNet Master module consumes 450mA at 5VDC (typical) from the PLC backplane.

This power is used for module operation, The DeviceNet Master powers its network transceiver

from the 24VDC DeviceNet network power source. Linear power supplies are recommended for

the DeviceNet power source. The DeviceNet power source should not also be used for device

power. Transients caused by  I/O devices can cause communications errors and even create

bus-off conditions.

The DeviceNet specification recommends using a power tap to connect a power supply to the

network. The power tap should be appropriately fused for the current capacity of the bus cables.

The maximum current on the network depends on the cable type.

The DeviceNet network power supply must be grounded, but only at one point.  The V- signal

must be connected to protective earth ground at the power supply only.  If multiple power

supplies are used, only one power supply must have V- connected to earth ground.