A2C-SG2-M12
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6
Protocol
It is important to understand the simple protocol before reading further. The first CAN byte is always the command. The second CAN
byte is a sub-command. The remaining 6 CAN bytes are Data.
6.1
Protocol format
Communication takes place over a CAN bus Interface
The communication can use both 11-bit or 29bit frame format – CAN 2.0A / 2.0B.
R
TR
D
LC
C
om
m
an
d
Su
b
co
m
m
an
d
D
at
a
0
D
at
a
1
D
at
a
2
D
at
a
3
D
at
a
4
D
at
a
5
Bit length
1
4
8
8
8
8
8
8
8
8
Range
0
Al
w
ay
s
0
1
- 8
0x
00
–
0
xf
f
0x
00
–
0
xf
f
0x
00
–
0
xf
f
0x
00
–
0
xf
f
0x
00
–
0
xf
f
0x
00
–
0
xf
f
0x
00
–
0
xf
f
0x
00
–
0
xf
f
Identifier
: Default Identifier is set to 0x125 from factory, but can be changed as shown in 7.1.1
RTR
: RTR is not used, so it must always be 0.
DLC
: DLC should be between 1 and 8. There is always at least one data byte as they are used as a commando word.
Command
: Command byte
Sub Command
: Sub command byte
When data bytes are combined to form 16 or 32bit variables the big endian system is used.
