Network Management Services - Altivar Process ATV900 Manual

Network Management Services

Description
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 during operation on
the network.
NMT services can be divided into two groups:
Services for device control, to initialize devices for CANopen communication and to control the behavior

of devices during operation on the network.
Services for connection monitoring to check the status of network devices.

Network Management State Machine
The CANopen NMT slave device implements a state machine, which brings automatically after power-on
and internal initialization every device in pre-Operational state. In this state the node may be configured
and parameterized using SDO, no PDO communication is allowed.
The NMT master device may switch all nodes or a single node to operational state and conversely. In
operational state PDO transfer is allowed. By switching a device into the stopped state, it is forced to stop
PDO and SDO communication. Furthermore, this state can be used to achieve certain application
behavior.
In the operational state, all communication objects are active. Object Dictionary access through SDO is
possible.
NMT Message Description
The NMT services for device control are transmitted as unconfirmed messages with COB ID 0. By default,
they have the highest priority on the CAN bus.
COB ID
0 (000 hex)
(1)
If Node ID is 0, the command specifier is broadcast to all CANopen slaves.
The following table provides the of command specifier used to manage the NMT state machine.
Command specifier (CS)
1 (01 hex)
2 (02 hex)
128 (80 hex)
129 (81 hex)
130 (82 hex)
NHA80945 04/2017
Byte 0
Command specifier (CS)
Meaning
Start_Remote_Node
Stop_Remote_Node
Enter_Pre-Operational_State
Reset_Node
Reset_Communication
Byte 1
(1)
Node ID
Basics
23