How to Decode Message from a Canbus (Iptronik)
I Retrieve from a Canbus the Following Message and Signal Data (From an Iptronik Sim Stg Machine). I Coded It with Python, I Use the Python-Can Library and I...
I retrieve from a canbus the following message and signal data (from an Iptronik sim stg machine). I coded it with python, I use the python-can library and I have ubuntu 18.04
The message /signal retrieved :
Timestamp: 1570622811.311113 ID: 0060 S DLC: 8 e4 7f 55 55 55 55 04 00 Channel: can0
Timestamp: 1570622811.811173 ID: 0060 S DLC: 8 e4 7f 55 55 55 55 0f 06 Channel: can0
Timestamp: 1570622812.311224 ID: 0060 S DLC: 8 e4 7f 55 55 55 55 65 1a Channel: can0
Timestamp: 1570622812.811266 ID: 0060 S DLC: 8 e4 7f 55 55 55 55 47 0c Channel: can0
Timestamp: 1570622813.311266 ID: 0060 S DLC: 8 e4 7f 55 55 55 55 2c 58 Channel: can0
Timestamp: 1570622813.811316 ID: 0060 S DLC: 8 e4 7f 55 55 55 55 20 36 Channel: can0
from the dbc file I have this information.
BO_ 96 DEVICE_51900450_0: 8 C_51900450
SG_ Beschleunigung : 0|16@1+ (0.000152590218966964,-5) [-5|5] "V" IPETRONIK_CAN_1
SG_ Pos : 48|16@1+ (0.000152590218966964,0) [0|10] "V" IPETRONIK_CAN_1
when I convert to the 4 first bits and the four last one I get this number that does not correspond to the dbc file .
(228, 127, 3, 0)
(228, 127, 3, 0)
(228, 127, 62, 3)
(228, 127, 162, 16)
(228, 127, 143, 28)
(228, 127, 252, 93)
Can you help me or give me some advice to convert properly the signal according to the dbc instructions. Thank you in advance :)
3 Answers
this might help you...
import cantools
import can
from pprint import pprint
db = cantools.database.load_file('******_dbc.dbc') #path of .dbc file
print( db.messages)
can_bus = can.interface.Bus('can0', bustype='socketcan')
message = can_bus.recv()
for msg in can_bus:
print ( db.decode_message(msg.arbitration_id, msg.data))
You may use CAN BUS tools () to load your .DBC file and properly decode your CAN messages:
pip install cantools
Here's the sample code:
>>> import cantools
>>> from pprint import pprint
>>> db = cantools.database.load_file('tests/files/dbc/motohawk.dbc')
>>> db.messages
[message('ExampleMessage', 0x1f0, False, 8, 'Example message used as template in MotoHawk models.')]
>>> example_message = db.get_message_by_name('ExampleMessage')
>>> pprint(example_message.signals)
[signal('Enable', 7, 1, 'big_endian', False, 1.0, 0, 0.0, 0.0, '-', False, None, {0: 'Disabled', 1: 'Enabled'}, None),
signal('AverageRadius', 6, 6, 'big_endian', False, 0.1, 0, 0.0, 5.0, 'm', False, None, None, ''),
signal('Temperature', 0, 12, 'big_endian', True, 0.01, 250, 229.53, 270.47, 'degK', False, None, None, None)]
In python there is this awesome library
You can go through the source code of it to find the fields you need to extract :
All relevant fields for messages and signals can be found out in cantools/database/can/message.py and /database/can/signal.py in this github link
For eg: if you need names and unit of signals you could use signal.name and signal.unit
Sample code to extract these fields:
#**dbc_file** is the full path of dbc
db = cantools.database.load_file(dbc_file)
for msg in db.messages:
msg_name = msg.name
msg_id = msg.frame_id
msg_length = msg.length
sender = msg.senders
msg_group = db.get_message_by_name(msg_name)
for signal in msg_group.signals:
#name of signal
sig_name = signal.name
#unit of signal
sig_unit = signal.unit
Hope this might help some one!!!
Marcus Vance is a cybersecurity auditor and technology writer dedicated to educating the public about online safety, data privacy regulations, enterprise security, and emerging cyber threats.
