SFA-5000 • SFA-10000 CANopen®
NOTE
Please refer to the “7 - Setting-up” section on page 79 for an example of how
the states are to be set.
6.3 Communication objects
Four different kinds of communication messages are used in a CANopen®
network:
Network management NMT protocol: NMT protocols are used by the Master
to manage the nodes and the network, issue the state machine change
commands (i.e. to start and stop the devices), detect the remote device
boot-ups and the 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 the Master to enable the Slaves
devices to transmit process data (encoder position and velocity).
- Emergency: the error messages are triggered by each error event.
- Node Guarding: used to request the state of the Slave: the NMT Master
polls each NMT Slave at regular time intervals.
Relation between the device states and the 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 Guarding
X
X
X
MAN SFA_5000_10000_CB E 1.0.odt
6 - CANopen® interface
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