AM58K CANopen®
6.3 Communication objects
Four different kinds of communication messages are used in a CANopen®
network:
Network management NMT protocol: NMT protocols are used to issue state
machine change commands (i.e. to start and stop the devices), detect
remote device boot-ups and error conditions.
Process Data Objects PDO protocol: used to process real time data
(transmission of process data in real time).
Service Data Objects SDO protocol: used to set and read values from the
object dictionary of a remote device.
Special Function Objects:
- SYNC: synchronization message used by master to enable slaves devices
to transmit process data (encoder position and velocity).
- Emergency: error messages are triggered by each error event.
- Nodeguard: used to request the state of the slave.
Relation between device states and communication objects:
Initial.
Pre-oper.
Operat.
Stopped
NMT
X
X
X
PDO
X
SDO
X
X
SYNC
X
EMCY
X
X
Boot-up
X
Node guard
X
X
X
6.3.1 Pre-defined connection set
Master
Slave broadcast
Type of COB
(Object)
Function code
(binary)
COB-ID (hex)
NMT
0000
000
SYNC
0001
080
peer-to-peer transmission
EMERGENCY
0001
081 - 0FF
PDO 1 (tx)
0011
181 - 1FF
PDO 2 (tx)
0101
281 - 2FF
PDO 3 (tx)
0111
381 - 3FF
PDO4 (tx)
1001
481 - 4FF
SDO (tx)
1011
581 - 5FF
SDO (rx)
1100
601 - 67F
Node guard
1110
701 - 77F
Boot-up
1110
701 - 77F
The type of COB (tx or rx) is viewed from the slave device.
MAN AM58K CB E 1.1.odt
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6 - CANopen® interface
