{"id":126369,"date":"2022-07-08T12:19:09","date_gmt":"2022-07-08T12:19:09","guid":{"rendered":"https:\/\/blog.finxter.com\/?p=461066"},"modified":"2022-07-08T12:19:09","modified_gmt":"2022-07-08T12:19:09","slug":"how-to-convert-blf-can-to-csv-in-python","status":"publish","type":"post","link":"https:\/\/sickgaming.net\/blog\/2022\/07\/08\/how-to-convert-blf-can-to-csv-in-python\/","title":{"rendered":"How to Convert .blf (CAN) to .csv in Python"},"content":{"rendered":"\n
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5\/5 – (1 vote) <\/div>\n<\/div>\n

Problem Formulation<\/h2>\n

\"\ud83d\udcac\" How to convert .blf<\/code> from a CAN bus to .csv<\/code> in Python?<\/strong><\/p>\n

\"\ud83d\udca1\" What is BLF?<\/strong> The Binary Logging Format (BLF<\/a>) is a proprietary
CAN log format from the automative company Vector Informatik GmbH.<\/p>\n

\"\ud83d\udca1\" What is CAN?<\/strong> The Controller Area Network (CAN bus<\/a>) is a message-based protocol standard for microcontrollers in vehicles to communicate without a host computer.<\/p>\n

Method 1: Using BLF Reader and CSV Writer<\/h2>\n

To convert the BLF file 'my_file.blf'<\/code> to the CSV file 'my_file.csv'<\/code>, you can first iterate over the bus messages using can.BLFReader('my_file.csv')<\/code> and add the data to a list of lists<\/a>. Then, you can use the csv.writer()<\/a><\/code> approach to write the list of lists to a CSV file.<\/p>\n

Here’s an example that improves upon this<\/a> SO thread:<\/p>\n

import can\nimport csv log = [] for msg in list(can.BLFReader(\"my_file.blf\")): msg = str(msg) row = [msg[18:26], msg[38:40], msg[40:42], msg[46], msg[62], msg[67:90]] log.append(row) with open(\"my_file.csv\", \"w\", newline='') as f: writer = csv.writer(f, delimiter=',', quotechar='\\\"', quoting=csv.QUOTE_ALL) writer.writerows(log)\n<\/pre>\n
A more sophisticated version of this code is provided in this<\/a> Github repository. Here’s a screenshot of the code — notice the more advanced processing of a single message compared to our solution:<\/p>\n
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source<\/a><\/figcaption><\/figure>\n<\/div>\n
Method 2: Using the candas Library<\/h2>\n
The candas<\/code><\/a> library provides utility functions to work with .blf<\/code> files and the CAN bus. Among other things, it helps you with the conversion from BLF to CSV as outlined here<\/a>.<\/p>\n
This is the provided example:<\/p>\n
import candas as cd db = cd.load_dbc(\"dbc_folder\") # This is the BLF file 'my_file.blf':\nlog = cd.from_file(\"my_file\") # This prints a signal from the messages in the BLF:\nprint(log[\"AVGcellTemperature\"])<\/pre>\n
Method 3: Using Custom Solution from python-can Library<\/h2>\n
You can use your tailor-made solutions by combining the Readers and Writers provided in the python-can<\/a><\/code> library.<\/p>\n
It provides multiple utility functions such as:<\/p>\n