Manual R600V.DAE0 (EN)
Page 22 of 29
R600V.DAE0_manual_1.5 (EN).docm
3.4 Exemplary Decoding of a CAN message frame
Exemplary decoding
the “ground & canopy” message (PGN 0xC000)
Based on a line from a CAN log (6339707, 18C0FF80, Rx, 8, 8C, AB, 27, C, 34, C, 0, 0)
Tab 11
Decoding a CAN SAE J1939 message frame
SO
F
11 bit CAN ID
SRR
IDE
18 bit CAN ID
RTR
6
b
it
c
o
n
-
tro
l f
ie
ld
0
…8 byte
data field
1
6
b
it
CR
C
2
b
it
ACK
7
b
it
EO
F
0x
18 C0 FF 80
[
1 1000 1100 0000 1111 1111 1000 0000]
2
(11+18bit = 29bit)
0x
8C AB 27
0C 34 0C 00
00
Tab 12
Example for decoding the CAN ID (29bit, PDU1 format)
3
b
it
p
ri
o
ri
ty
PRIO
1
b
it
re
s
e
rv
e
d
R
1
b
it
d
a
ta
p
a
g
e
DP
8 bit PDU format (<240)
8 bit PDU specific
(group extension)
8 bit source
address
0x
06
[110]
2
0x
00
[0]
2
0x
00
[0]
2
0x
C0
[1100 0000]
2
FF
0x
[1111 1111]
2
0x
80
[1000 0000]
2
PDU1 format
Global destination address
PGN (parameter group number)
Tab 13
Example for decoding the 8 byte data field
0x
8C AB
27 0C
34 0C
00 00
[
1000 11
00
1010 101
1
0010 0111 0000 1100 0011 0100 0000 1100 0000 0000 0000 0000]
2
Sensor
status
(bit 1-2)
Canopy con-
fidence
(bit 3-9)
Ground
confidence
(bit 10-16)
Canopy distance
(bit 17-32)
Ground distance
(bit 33-48)
Reserved
(bit 49-64)
[
00
]
2
[
1100011
]
2
[
1010101
]
2
0x
0C 27
0x
0C 34
0x
00 00
0
99%
85%
3’111mm
3’124mm
N/A
Notes: little endian format, bit 1 underlined; colours indicate correspondences
