DeviceNet™ information
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02/13/2017
4 DeviceNet
™ information
DeviceNet
was developed by Rockwell Automation and the ODVA
™ as an open
field bus standard, based on the CAN protocol and is standardized in the European
standard EN 50325. Specification and maintenance of the DeviceNet standard is
regulated by the ODVA
™. DeviceNet
, along with ControlNet
™ and EtherNet/IP™,
belongs to the family of CIP
™-based networks. The CIP™ (Common Industrial
Protocol) forms a common application layer for these 3 industrial networks.
DeviceNet
, ControlNet
™ and Ethernet/IP™ are therefore well matched to one
another and present the user with a graduated communication system for the physical
layer (Ethernet/IP
™), cell layer (ControlNet™) and field layer (DeviceNet
).
DeviceNet
is an object-oriented bus system and works according to the
producer/consumer model.
DeviceNet
Protocol
The DeviceNet
protocol is an object-oriented protocol. It is typically used for networking
sensors and actuators with the superordinate automation devices (PLC, IPC).
DeviceNet
Data Link Layer
Layer 2 (Data Link Layer) is based on the Controller Area Network (CAN), which was
originally designed for use in motor vehicles.
DeviceNet
Network and Data Transport Layer
The link is set up with the Group 2 Unconnected Port. Selected CAN identifiers are
used for the link set-up. A link, once set up, can be used for transmitting explicit
messages or for setting up additional I/O links. As soon as an I/O link has been set up,
I/O data can be exchanged between the DeviceNet
users. The 11 bit identifier is
used exclusively for coding I/O data. The 8-byte wide CAN data field is fully available
for user data.
DeviceNet
Application Layer
– CIP
™
Protocol
The CIP
™ (Common Industrial Protocol) forms the application layer for DeviceNet
.
The CIP
™ defines the exchange of I/O data in realtime via I/O messages (I/O
messaging or implicit messaging), as well as the exchange of data required for
configuration, diagnosis and management via explicit messages (explicit messaging).
The communication between two devices always takes place according to a
connection-oriented communication model, either via a point-to-point or a multicast-V1
connection. This allows both master/slave and multi-master systems to be realized.
Data are known as objects and are logged in the object directory of each device.
