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46 Fieldbus interface
3 Basics IL•1F CANopen DS301
0198441113586, V2.01, 11.2008
3.6 Network management services
Network management (NMT) is part of the CANopen communication
profile; it is used to initialize the network and the network devices and to
start, stop and monitor the network devices in network mode.
NMT services are executed in a master-slave relationship. The NMT
master addresses individual NMT slaves via their node address. A mes-
sage with node address "0" is directed to all NMT slaves simultaneously.
Figure 3.28 NMT services via the master-slave relationship
The device can only take on the function of an NMT slave.
NMT services NMT services can be divided into two groups:
• Services for device control, to initialize devices for CANopen com-
munication and to control the behavior of devices in network mode
• Services:for connection monitoring
3.6.1 NMT services for device control
NMT state machine The NMT state machine describes the initialization and states of an
NMT slave in mains operation.
Figure 3.29 NMT state machine and available communication objects
To the right, the graphic shows all communication objects that can be
used in the specific network state.
NMT-
Slave
NMT-
Slave
NMT-
Slave
NMT-
Slave
NMT-
Slave
NMT-
Master
CAN
COB-ID
data
Operational
Pre-Operational
Stopped
Reset
Application
Reset
Communication
Initialization
Power on
C
A
D
E
B
NMT
SDO, EMCY
NMT
PDO, SDO, SYNC
EMCY, NMT