Python implements CAN communication

Detailed introduction of CAN communication and CAN communication using Python

What is CAN communication?

CAN (Controller Area Network) is a serial communication protocol for real-time applications, originally developed by the German Bosch company in 1986. It is a high-reliability, high-efficiency communication protocol, mainly used in automotive, industrial control and other applications.

Features of CAN communication

1. Strong anti-interference ability: CAN communication adopts differential signal transmission, which makes it have high anti-interference ability against electromagnetic interference, and can work stably in harsh working environments.
2. High reliability: CAN communication uses an error detection and correction mechanism, which can automatically detect and correct errors in data transmission, improving the reliability of communication.
3. High efficiency: CAN communication adopts an event-based communication method, and only communicates when data needs to be transmitted, avoiding the transmission of invalid data and improving communication efficiency.
4. Support multi-node: CAN communication supports multiple nodes to communicate at the same time, each node has a unique identifier, and can choose to receive and send data according to the identifier, realizing a flexible communication network.

Application of CAN communication

1. Automotive field: CAN communication is widely used in the automotive field for internal communication of vehicles, such as engine control, dashboard display, and in-vehicle entertainment systems.
2. Industrial control: CAN communication is widely used in the field of industrial control for the control and monitoring of various equipment, such as robot control, automatic production line control, etc.
3. Aerospace: CAN communication is widely used in the aerospace field for data transmission and control of aircraft, such as aircraft flight control systems and navigation systems.
4. Medical equipment: CAN communication is widely used in the field of medical equipment for data transmission and control of medical equipment, such as monitoring and control systems for medical instruments.

The basic principle of CAN communication

CAN communication adopts the master-slave communication mode, one of the nodes is the master node, and the other nodes are slave nodes. The master node is responsible for sending data, and the slave node is responsible for receiving data. The basic principle of CAN communication is as follows:

1. Data frame: CAN communication uses data frame for data transmission, and the data frame is composed of identifier, data, control bits, etc.
2. Identifier: Each data frame has a unique identifier, which is used to distinguish different data frames.
3. Data length: The data length of each data frame can be 0 to 8 bytes, determined according to actual needs.
4. Bit timing: CAN communication uses bit timing to determine the data transmission rate, usually several standard bit timing rates can be selected.
5. Differential signal transmission: CAN communication uses differential signals to transmit data, one of the lines is positive and the other is negative, and the data is transmitted by comparing the voltage difference between the two lines.

Summarize

CAN communication is a high-reliability, high-efficiency communication protocol, which has the characteristics of strong anti-interference ability, high reliability, high efficiency and multi-node support. It is widely used in the fields of automobile, industrial control, aerospace and medical equipment, and becomes an important technology for real-time application communication.

Python implements CAN communication

Python-can provides a powerful set of tools and methods for sending and receiving CAN messages, as well as parsing and processing CAN data. It supports many different CAN interfaces, including SocketCAN, PEAK, Kvaser, etc., so it can communicate with many different hardware devices.

Install and configure

To install python-can, you can use the pip package manager by running the following command on the command line:

pip install python-can

Once installed, you can canstart using python-can by importing the module:

import can

Before using python-can, the CAN interface needs to be configured. This can be done by editing a can.rcconfiguration file called , which should be located in the user's home directory. In this file, it is possible to specify the CAN interface to be used and other relevant parameters. For example, to use the SocketCAN interface, add the following to can.rcthe file:

[default]
interface = socketcan
channel = can0

Send and receive CAN messages

With python-can it is easy to send and receive CAN messages. First, a CAN bus object needs to be created:

bus = can.interface.Bus()

Then, you can use bus.send()the method to send the message:

msg = can.Message(arbitration_id=0x123, data=[0x01, 0x02, 0x03])
bus.send(msg)

To receive messages, you can use bus.recv()the method:

msg = bus.recv()
print(msg.arbitration_id)
print(msg.data)

Parse and process CAN data

Python-can also provides some useful tools and methods for parsing and processing CAN data. For example, you can use can.Messagethe object's properties to access the message's ID and data:

msg = can.Message(arbitration_id=0x123, data=[0x01, 0x02, 0x03])
print(msg.arbitration_id)
print(msg.data)

Additionally, can.Messagemethods of the object can be used to parse and format data:

msg = can.Message(arbitration_id=0x123, data=[0x01, 0x02, 0x03])
print(msg.data.hex())  # 将数据转换为十六进制字符串
print(msg.data.decode())  # 将数据解码为字符串

You can use can.Notifierthe class to register callback functions to perform specific actions when a message is received:

def handle_message(msg):
    print("Received message:", msg)

notifier = can.Notifier(bus, [handle_message])

Summarize

Python-can is a powerful Python library for controlling and communicating automotive networks. It provides a set of easy-to-use interfaces and tools for sending and receiving CAN messages, as well as parsing and processing CAN data. It allows easy communication with the CAN bus and interaction with electronic control units in the automotive and industrial fields. Whether it is car diagnostics, data acquisition, or car network simulation and testing, python-can is a very useful tool.