Chapter 15 CANopen Overview│CP2000
15-4
CANopen Communication Protocol
It has services as follows:
NMT (Network Management Object)
SDO (Service Data Objects)
PDO (Process Data Object)
EMCY (Emergency Object)
NMT (Network Management Object)
The Network Management (NMT) follows a Master/Slave structure for executing NMT service. A
network has only one NMT master, and the other nodes are slaves. All CANopen nodes have a
present NMT state, and NMT master can control the state of the slave nodes. Following shows the
state diagram of a node:
(1) After power is applied, start in the auto-initialization state
(2) Automatically enter the pre-operational state
(3) (6) Start remote node
(4) (7) Enter pre-operational state
(5) (8) Stop remote node
(9) (10) (11) Reset node
(12) (13) (14) Reset communication
(15) Automatically enter the reset application state
(16) Automatically enter the reset communication state
A: NMT
B: Node Guard
C: SDO
D: Emergency
E: PDO
F: Boot-up
Initializing Pre-Operational Operational Stopped
PDO ○
SDO ○ ○
SYNC ○ ○
Time Stamp ○ ○
EMCY ○ ○
Boot-up ○
NMT ○ ○ ○