DeviceNet

DeviceNet is a network system used in the automation industry to interconnect control devices for data exchange. It utilizes the over a Controller Area Network media layer and defines an application layer to cover a range of device profiles. Typical applications include information exchange, safety devices, and large I/O control networks.

DeviceNet was originally developed by American company Allen-Bradley (now owned by Rockwell Automation). It is an application layer protocol on top of the CAN (Controller Area Network) technology, developed by Bosch. DeviceNet adapts the technology from the and takes advantage of CAN, making it low-cost and robust compared to the traditional RS-485 based protocols.

In order to promote the use of DeviceNet worldwide, Rockwell Automation has adopted the "open" concept and decided to share the technology to third party vendors. Hence it is now managed by ODVA, an independent organization located in North America. ODVA maintains specifications of DeviceNet and oversees advances to DeviceNet. In addition, ODVA ensures compliance to DeviceNet standards by providing conformance testing and vendor conformity.

ODVA later decided to bring DeviceNet back to its predecessor's umbrella and collectively refer to the technology as the Common Industrial Protocol or CIP, which includes the following technologies:

ODVA claims high integrity between the three technologies due to the common protocol adaptation, which makes industrial controls much simpler compared to other technologies.

DeviceNet has been standardized as IEC 62026-3.

Technical Overview Define the OSI seven-layer architecture model the physical layer, data link layer and application layer

Nodes are distributed along a DeviceNet network by the means of a trunkline-dropline topology. This topology allows for ease in wiring and access to the network from multiple taps. In addition, nodes can be easily removed and added to reduce production downtime, increase network flexibility, and decrease troubleshooting time. Since the physical layer is optically isolated from the device, communication power and device power can share the same bus (further reducing the complexity of the network and components within). (Introduction)

DeviceNet supports 125 kbit/s, 250 kbit/s and 500 kbit/s data rates. Depending on the chosen cable type, DeviceNet can support communication up to 500 meters (using round, large diameter cable). Typical round cable supports up to 100 meters, while flat-style cable supports up to 380 meters at 125 kbit/s and 75 meters at 500 kbit/s. (Physical Layer )

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