Lenze E84DGFCC - Manual (Page 37)

EDS84DMOTCAN EN 3.0 - 11/2011
L
37
Communication manual 8400 motec CANopen
Data transfer
Structure of the CAN data telegram
7.1.1 Identifier
The principle of CAN communication is based on a message-oriented data exchange
between a transmitter and many receivers. All nodes can virtually transmit and receive
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 contains 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
management 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)
For unambiguous identification, a node address (also called node ID) within the valid
address range (1 ... 63) must be assigned to every node of the system bus network.
 A node address may not be assigned more than once within a network.
 The own node address can be configured via the DIP switches or via code
C00350 .
Setting the CAN node address
( 33)
Identifier assignment
The system bus is message-oriented instead of node-oriented. Every message has an
unambiguous identification, the identifier. For CANopen, node-oriented transfer is
achieved by the fact that every message has only one transmitter.
 The basic identifiers for network management (NMT) and sync as well as the basic SDO
channel (SDO1) are defined in the CANopen protocol and cannot be changed.
 In the Lenze setting, the basic identifiers of the PDOs are preset according to the
"Predefined connection set" of DS301, V4.02 and can be changed via parameters/
indexes, if required.
Identifiers of the process data objects
( 51)