User`s guide

DeviceNet Physical Layer and Media

Adept SmartController User’s Guide, Rev. K 89

B.4 DeviceNet Physical Layer and Media

The DeviceNet physical layer and media specifications are published in the ODVA

manual, chapter 9, volume 1. It describes possible topologies and components of the

physical layer of the DeviceNet.

Figure B-1 on page 89 shows several possible topologies. The DeviceNet specifications

also specify system grounding, mixing of thick and thin cable media, termination, and

power distribution.

The basic topology is the trunkline-dropline topology. This topology uses separate

twisted-pair buses for the distribution of signals and power. The specifications allow

trunklines and droplines made of thick or thin cable. The baud rate, maximum distance

from end-to-end of the network, and cable size are dependent on each other. See Tab le B-2

on page 91 for further details.

Figure B-1. Trunklines and Droplines Made of Thick and Thin Cable

WARNING: The DeviceNet specification requires that the

CAN_H and CAN_L signal lines tolerate voltages up to

18 V. Since the supply voltage exceeds 18 V, improperly

wiring the supply voltage to these signal lines may cause

equipment damage.

Node

Multiple

Node

Branching

Drop Line

Multi-Port

Ta p

Trunk Line

Terminating

Resistor

Multiple Node

Daisy Chain

Drop Line

Zero Length Drop Line

Terminating

Resistor

Short Drop Lines (6 m/20 ft)

Tap

Multi-Port

Ta p

Drop Line

Node Node