CAN-8123/CAN-8223/CAN-8423 user’s manual (Revision 3.00, May/22/2009) ------
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3.5 NMT Introduction
The Network Management (NMT) follows the node-oriented structure and
the master-slave relationship. In the same CAN bus network, only one
CANopen device is allowed to execute the function of NMT master. Each
CANopen node is regarded as a unique NMT slave identified by its node ID
from 1 to 127.
The NMT service supplies two protocols, the module control protocol and
the error control protocol. Through the module control protocol, the nodes can
be controlled to several kinds of status, such as installing, pre-operational,
operational, and stopped. According to the NMT slave can present in different
statuses, it has different privileges to carry out the communication protocol.
Through the error control protocol, users are enable to detect the remote error
in the network in order to confirm whether the node still works or not.