Network Management Services

Overview

The network management (NMT) is used to start, stop, reset and initialize CANopen nodes. It process boot-up messages and error control events of the individual CANopen slave devices.

The error control mechanism monitors CANopen slave devices by Heartbeat or Node Guarding.

The behavior of the CANopen slave devices depends on the configuration of the following objects:

NMT startup object (1F80 hex)

This object specify the start-up state (OPERATIONAL, PRE-OPERATIONAL, or STOPPED) for every CANopen slave devices on the network.
Slave assignment object (1F81 hex)

The start-up states of the CANopen slave devices can be modified once the BMECXMCXM is in CONNECTED RUN state by sending NMT commands using explicit messages.

The NMT commands are accessible through a WRITE_SDO or READ_SDO in object 1F82 hex.

NOTE: NMT commands are accepted in both automatic and manual modes.

NMT State Machine

The following figure gives the NMT service commands to controlling the operating behavior of a CANopen node on the network:

(1)

Start remote node

(2)

Stop remote node

(3)

Enter pre-operational

(4

Reset communication

(5)

Reset node

NMT Commands Values

The following table gives the NMT commands available through CANopen SDO commands:

Value (hex)	READ_SDO command	WRITE_SDO command
00	NMT state unknown	Reserved
01	CANopen device missing	Reserved
02	Reserved
03	Reserved
04	NMT state STOPPED	NMT service Stop remote node
05	NMT state OPERATIONAL	NMT service Start remote node
06	Reserved	NMT service Reset node
07	Reserved	NMT service Reset communication
08	Reserved
–	–
7E	Reserved
7F	NMT state PRE-OPERATIONAL	NMT service Enter pre-operational
80	Reserved
–	–
83	Reserved
84	NMT state STOPPED	NMT service Stop remote node (excluding NMT master and requesting CANopen device)
85	NMT state OPERATIONAL	NMT service Start remote node (excluding NMT master and requesting CANopen device)
86	Reserved	NMT service Reset node (excluding NMT master and requesting CANopen device)
87	Reserved	NMT service Reset communication (excluding NMT master and requesting CANopen device)
88	Reserved
–	–
8E	Reserved
8F	NMT state PRE-OPERATIONAL	NMT service Enter pre-operational (excluding NMT master and requesting CANopen device)
90	Reserved
–	–
FF	Reserved

NMT Command Data Examples:

This table shows the command data for a Start remote node:

Value	Size	Parameter
0: PLC 1...5: DTM	SINT	Connect ID
127	SINT	Node ID
1F82 hex	INT	Index
Node ID: 1...7F hex: Node ID targeted 80 hex: all nodes (broadcast)	SINT	Subindex
[1]	INT	Length
05 hex 85 hex (excluding master)	SINT	Data

This table shows the command data for a Stop remote node:

Value	Size	Parameter
0: PLC 1...5: DTM	SINT	Connect ID
127	SINT	Node ID
1F82 hex	INT	Index
Node ID: 1...7F hex: Node ID targeted 80 hex: all nodes (broadcast)	SINT	Subindex
[1]	INT	Length
04 hex 84 hex (excluding master)	SINT	Data