NMT State machine

The NMT state machine defines the communication status for CANopen devices.

NMT state initialization

The initialization state could be divided into three sub-states that are executed in a sequential way: Initializing (performs the basic CANopen initializations), Reset application (in where all manufacturer-specific and standardized profile area parameters are set) and Reset communication (where the communication profile and parameters are set). 
At the end of initialization state the device sends a boot-up message and goes directly to Pre-Operational state.

NMT state pre-operational

In Pre-Operational state, the communication using SDO messages is possible. PDO message are not yet defined and therefore communication using these message is not allowed. The device will pass to Operational message after receiving a NMT start node command.
Normally the master puts a node in Pre-Operational state during the set-up and configuration of device parameters.

NMT state operational

In Operational state all kind of messages are active, even PDO messages.

NMT state stopped

When entering in Stopped state, the device is forced to stop all communications with the exception of the NMT commands. (Node Guarding & Life Guarding).

NMT states and communication object relation

Following table shows the relation between communication states and communication objects. Services on the listed communication objects may only be executed if the devices involved in the communication are in the appropriate communication states