CAN-8x23 user’s manual (Revision 3.20, Ma r/08/2012) ------
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Devices will directly lead to the Pre-Operational state after finishing the
device initialization. Then, the nodes will be switched into different state by
receiving a specific indication. By the way, each different NMT state will
consider a specific communication method. For example, the PDO message
can only do the transmission and receiving in the operational state. In the
following table, the relationship among each NMT state and communication
objects is given.
Installing
Pre-operational Operational Stopped
PDO
O
SDO
O
O
SYNC Object
O
O
Time Stamp Object
O
O
EMCY Object
O
O
Boot-Up Object
O
NMT
O
O
O
3.5.2 Error Control Protocols
There are two kinds of protocols defined in the error control protocol.
According to the CANopen spec, one device is not allowed to use the following
error control mechanisms at the same time, Node Guarding Protocol and
Heartbeat Protocol. In addition, the CAN-8x23 provides the salve function of
the Node Guarding Protocol for practical applications. Therefore, only node
guarding protocols will be highlighted here, and described below.
