4 structure of the can data telegram, 1 identifier, Structure of the can data telegram – Lenze 8400 BaseLine C User Manual
Page 176: Identifier, 9system bus "can on board
9
System bus "CAN on board"
9.4
Structure of the CAN data telegram
176
Lenze · 8400 BaseLine C · Reference manual · DMS 1.6 EN · 01/2014 · TD05
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9.4
Structure of the CAN data telegram
[9-2]
Basic structure of the CAN telegram
The following subchapters provide a detailed description of the identifier and the user data. The
other signals refer to the transfer characteristics of the CAN telegram whose description is not in-
cluded in the scope of this documentation.
Tip!
Please visit the homepage of the CAN user organisation CiA (CAN in automation) for further
information:
9.4.1
Identifier
The principle of the CAN communication is based on a message-oriented data exchange between a
transmitter and many receivers. All nodes can transmit and receive quasi-simultaneously.
The identifier, also called COB-ID (abbr. for communication object identifier), is used to control
which node is to receive a transmitted message. In addition to the addressing, the identifier con-
tains information on the priority of the message and the type of user data.
The identifier consists of a basic identifier and the node address of the node to be addressed:
Identifier (COB-ID) = basic identifier + node address (node ID)
Exception: The identifier for process data/heartbeat/emergency objects as well as network ma-
nagement and sync telegrams is freely assigned by the user (either manually or automatically by the
network configurator), or is permanently assigned.
Node address (node ID)
Every node of the system bus network must be assigned to a node address (also called node ID)
within the valid address range (1 ... 63) for unambiguous identification.
• Assigning a node address more than once within a network is impermissible.
• The own node address is configured via code
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