3 Protocol Description of the MD38CAN2
- 7 -
3 Protocol Description of the MD38CAN2
3.1 Software Feature
MD38CAN2 supports five protocols, described as follows:
■
NodeGuarding: The master can query the device state with this function.
■
Heartbeat: The slave reports its current state periodically to the master.
■
Service data object (SDO):
Only
expedited transfer is supported. Two bytes of a
parameter is transferred each time.
■
Three transmit process data objects (TPDOs) and three receive process data objects
(RPDOs)
■
Emergency (EMCY) objects
3.2 COB-ID
CANopen provides many types of communication objects (COBs), each having different
features (for details, see the description of the CANopen standard protocol). Different
communication objects are used based on the actual application scenarios. MD38CAN2
adopts the pre-defined communication object identifiers (COB-IDs), as follows:
1) Network management (NMT) object: 0x000
2) Synchronization (SYNC) object: 0x080
3) SDO:
■
Transmit SDO: 0x600+Node-Id
■
Receive SDO: 0x580+Node-Id
4) PDO:
■
RPDO1:
0x200+Node-Id
■
RPDO2:
0x300+Node-Id
■
RPDO3:
0x400+Node-Id
■
TPDO1:
0x180+Node-Id
■
TPDO2:
0x280+Node-Id
■
TPDO3:
0x380+Node-Id
5) EMCY object: 0x80+Node-Id
■
Node-Id: Indicates the device ID (node address), and it is set by the DIP switch.
■
COB-ID is fixedly allocated and cannot be changed.
