DeviceNet is designed to connect simple devices from multiple vendors that comply with the DeviceNet network standards. DeviceNet device profile standards provide interchangeability between device manufacturers.

Each DeviceNet segment can connect up to 64 devices. It is a four-wire system delivering 8 amps at 24VDC, sufficient for field devices such as solenoid valves. The four wires carry signal and power typically on a single cable. Multiple power supplies can be used for redundancy and additional power requirements.

DeviceNet uses a trunk (bus) line with drop cables connecting devices. The trunkline requires 121 ohm terminating resistors at each end of the trunk.

DeviceNet supports Master/Slave, Peer-to-Peer, and Multi-Master network models. Data can be transferred on a cyclic or change of state basis using a Producer/Consumer paradigm that conserves network bandwidth. DeviceNet is very commonly used for communications from host systems to motor control centers and variable speed drives.

DeviceNet Network Highlights

Type of Network	Device Bus
Physical Media	Two Shielded twisted pairs in one shielded thick, thin or flat cable (one pair for signal, one pair for power)
Network Topology	Bus with drops
Maximum Devices	62 devices per segment
Maximum Distance	(using Thick cable)
Maximum Distance with repeaters	6,000 meters
125Kbps	- 500m (1640 ft) - 6m (20 ft) individual drop cable length - 156m (512 ft) cumulative drop cable length
250Kbps	- 250m (820 ft) - 6m (20 ft) individual drop cable length - 78m (256 ft) cumulative drop cable length
500K bps	- 100m (328 ft) - 6m (20 ft) individual drop cable length - 39m (128 ft) cumulative drop cable length
* Thin cable may be used as trunk. Maximum distance is 100 meters, regardless of data rate
Communication Methods	Master/slave, multiple master, peer-to-peer, change of state or cyclic (uses Producer/Consumer Paradigm)
Primary usage	Motor Control Centers, Variable Speed Drives, Remote I/O applications
Power and Communications on same cable	24VDC power on power bus (multiple supplies may be used for additional power or as backup). A separate 24VDC power supply for communication bus is recommended.
Device Power Supply	24VDC on power bus
Wiring Types
Thick Cable	(ODVA Type II cable), generally used for trunk cable
Thin Cable	(ODVA Type I cable), commonly used for drop cables
Mid Cable	(ODVA Type III cable), used when more flexible drop cable is needed
Blue/White conductors for communications
Red/Black conductors for power
Grounding aspects	Ground only the power supply closest to the middle of the network
Terminators	121 ohm terminator at each trunk line end
Web Site	www.odva.org
Conventional I/O System	DeviceNet Network
Advantages	Advantages
Technology is already understood	Excellent support for motor control centers, variable frequency drives, and conventional I/O
Lower device cost	Moderate device cost adder
Independent wiring from devices to the control system means wiring problems with one device don’t affect other field devices	Lower installed cost
Drawbacks	I/O modules allow for conventional analog and discrete device integration
Higher installed cost	Relatively fast transmission speeds
Point-to-point wiring is expensive	Transmission Speed and cable lengths: 125kb @ 420m 250kb @ 200m 500kb @ 100m
Many wiring connections: - are labor intensive to install - create many points of failure - increase complexity when troubleshooting - require large amounts of cabinet or rack space for installation of terminal blocks - create time-consuming initial checkout and startup	Power and Signal on same cable
Expansion requires duplicating the entire wiring scheme for each additional point	Up to 64 addressable nodes
	Wide variety of topologies available, including Trunk, Line, Drop
	Duplicate node address detection
	Supports some device diagnostics
	Drawbacks
	Slaves can only be owned by one master
	Does not support Intrinsically Safe installations