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