Technical Manual
WDGA with CANopen-Interface
5 - General information about CAN
© Wachendorff Automation GmbH & Co. KG
16
Rev.1.24
5.4 Network management (NMT)
A CANopen network always needs a network management master. The NMT master
controls the NMT states of all connected nodes.
A node can be switched into three different states:
Pre-Operational
Operational
Stopped
After a CANopen node is switched on and the communication
and the internal application is initialised, the node switches into
pre-operational state. From this state the NMT-Master can
switch the node into the other states. To show that a node is
ready after boot up, it sends a "boot-up message". These
messages uses the CAN-ID of the Emergency service (EMCY).
The message is permanently associated with the node ID.
Description of the NMT-states:
Pre-Operational
Object
Communication enabled
SDO
yes
PDO
no
NMT
yes
SYNC
no
EMCY
yes
Heartbeat
yes
SDO communication is enabled.
PDO communication is disabled.
Table 5.4: Available communication – Pre-Operational
Содержание WDGA CANopen
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