DeviceNet and the DeltaV System

The DeviceNet network

The port on the DeltaV DeviceNet card acts as the DeviceNet master and can support up to 61 devices. The port is the interface between the DeltaV system and the DeviceNet network. Device configuration is done through Electronic Data Sheet (EDS) files. These files are specially formatted ASCII files, provided by the device manufacturer, that are required for configuring a device with the DeltaV Explorer. The EDS file contains all the parameter information for a device.

The following table shows the recommended DeviceNet trunk lengths at various baud rates:

Baud Rate

Maximum Trunk Length for Series 1

Maximum Trunk Length for Series 2

125 k

500 m (1640 ft.)

500 m (1640 ft.)

250 k

250 m (820 ft.)

250 m (820 ft.)

500 k

61 m (200 ft.)(1)

100 m (328 ft.)

(1) ODVA specifications allow for a maximum trunk length of 100 m (328 ft.) at 500 k baud; however, testing indicates that a few device types experience unstable operation at these limits. Emerson recommends a maximum trunk length of 61 m (200 ft.) at 500 k baud to maintain a stable DeviceNet system with a wide variety of devices.