CAN-8123/CAN-8223/CAN-8423 user’s manual (Revision 3.00, May/22/2009) ------
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5.4.2 Error Control Protocol
Error Control Protocol is a kind of the solution to check whether the
CANopen device is still alive or not. And its related objects include 0x100C and
0x100D. The 0x100C is the guard time, and the 0x100D is the life time factor.
The node life time is the guard time multiplied by the life time factor. The Node
Guarding timer of the CAN-8123/CAN-8223/CAN-8423 will start to count after
receiving the first RTR message for the guarding identifier. The communication
set of the Error Control protocol is displayed below.
t
: toggle bit
The value of this bit will be alternatively changed between two
consecutive responses from the NMT slave. After the node
Guarding protocol becomes active, the value of the toggle-bit of
the first response will be 0.
s
: the state of the NMT Slave
4: STOPPED
5: OPERATIONAL
127: PRE-OPERATIONAL