Baumer BA_DSRT_22DJ - Handbuch (Seite 18)

Manual_CANopen_StrainLink_EN_V3_05.doc 18/65 Baumer
22.07.11/dam Frauenfeld, Switzerland
4.4.3 Network Management (NMT)
In a CANopen network, there is one NMT master and between 1 and 127 NMT slaves.
The NMT master has complete control over all devices and may change the state of these devices.
The NMT messages have the highest priority in a CANopen network and have ID = 0. An NMT command
has only two data bytes. The NMT master can control the state of a single slave (e.g., ID = 2) or the entire
network (ID = 0).
The states in a CANopen network are usually shown using a state diagram. The following states are possible
in a CANopen network:
- Initialization
- Pre-Operational
- Operational
- Stopped
Initialization
The node is in the Initialization state following an NMT reset or a power-on. The device application and
communication are initialized in this state. After completing initialization, the node transmits a Boot-up
message and switches automatically to the Pre-Operational state.
Pre-Operational
In this state, it is possible to communicate with the node via SDOs. No PDO messages can be sent. This
state is primarily used for configuring the CANopen devices.
Operational
In this state, the node is completely ready for operation and can transmit messages on its own.
Stopped
With the exception of Node guarding and Heartbeat messages, the node can send no other messages in this
state. Only LSS configuration functions in this state.