CAN-8123/CAN-8223/CAN-8423 user’s manual (Revision 3.00, May/22/2009) ------
156
Step 5. Users can send the node guarding protocol to start the mechanism of
the node guard. The life time here is equal to 1000 ms (guard time * life time
factor =250*4=1000),
11-bit COB-ID (bit)
Func Code
Node ID
8-byte Data (byte)
10 9 8 7 6 5 4 3 2 1 0
RTR
Data
Length
0
1
2
3 4 5 6 7
1 1 1 0 0 0 0 0 0 0 1
1
0
00 00 00
00
00 00 00
00
NMT master
NMT slaver
(CAN-8123/CAN-8223/
CAN-8423)
COB-ID
: 0x701
Step 5. Then, users will receive the message, recording the NMT state of the
CAN-8423. For the reason that life time is equal to 1000 ms (guard time * life
time factor =250*4=1000), users will transmit the node guarding protocol
again.
11-bit COB-ID (bit)
Func Code
Node ID
8-byte Data (byte)
10 9 8 7 6 5 4 3 2 1 0
RTR
Data
Length
0
1
2
3 4 5 6 7
1 1 1 0 0 0 0 0 0 0 1
0
8
7F 00 00
00
00 00 00
00
NMT master
NMT slaver
(CAN-8123/CAN-8223/
CAN-8423)
COB-ID
: 0x701
t
: 1
s
7F
The value 7F means that the CAN-8423 is in the NMT pre_operational
state.
Step 6. Since the life time is equal to 1000 ms (guard time * life time factor
=250*4=1000), users will transmit the node guarding protocol again.
Step 7. If the transmission is not available, an error event will be triggered, and
an EMCY message for guarding failure will be received. Moreover, all values
from the output channels will be changed according to index 0x6206, index
0x6207, index 0x6443, and index 0x6444.