Como usar o Python canopen de forma fácil?

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TUTORIAL: Introducing Python CANopen Library

Introduction

Python CANopen is a powerful library that provides tools for working with the Controller Area Network (CAN) protocol in Python. It allows users to communicate with CANopen devices, such as controllers, sensors, and actuators, using a simple and intuitive interface.

In this tutorial, we will explore the capabilities of the Python CANopen library and learn how to use it effectively. We will cover the installation process, basic usage, and advanced features of the library.

Installation

To install the Python CANopen library, follow these steps:

1. Open a terminal or command prompt.
2. Run the following command to install the library using pip:

pip install python-canopen

3. Wait for the installation process to complete.

Basic Usage

Once you have installed the library, you can start using it by following these steps:

1. Import the canopen module into your Python script:

import canopen

2. Create a new instance of the Network class:

network = canopen.Network()

3. Connect to a CANopen device using the connect() method:

network.connect(channel='can0', bustype='socketcan')

4. Initialize the network using the initialize() method:

network.initialize()

5. You are now ready to communicate with the CANopen device. For example, you can read the value of an object dictionary entry using the Network instance and the read() method:

value =  network.read(0x1000, 0x01).raw
print("Value:", value)

Advanced Features

The Python CANopen library also provides several advanced features that allow for more complex interactions with CANopen devices. Some of these features include:

Syncing the Network

To ensure that all devices on the network are synchronized, you can use the sync() method:

network.sync.start(0.1)

This will synchronize the network at a rate of 10 Hz.

Sending PDO Messages

You can send Process Data Object (PDO) messages to a CANopen device using the send() method:

network.send(0x200, [0x12, 0x34, 0x56, 0x78], 2)

This will send a PDO message with the data [0x12, 0x34, 0x56, 0x78] to object 0x200 on sub-index 2.

Interacting with Object Dictionaries

The Python CANopen library provides several methods for interacting with the object dictionaries of CANopen devices. For example, you can read the value of an object dictionary entry using the read() method:

value = network.read(0x1000, 0x01).raw
print("Value:", value)

You can also write a value to an object dictionary entry using the write() method:

network.write(0x1001, 0x01, 0xABCD)

Monitoring CAN Traffic

You can monitor the CAN traffic on the network using the Scanner class:

scanner = canopen.Scanner()
device_list = scanner.scan(channel='can0', bustype='socketcan')
print("Devices found:", device_list)

This will print out a list of devices found on the network.

Conclusion

The Python CANopen library provides a powerful and versatile toolset for working with CANopen devices in Python. In this tutorial, we have explored the basic usage and advanced features of the library, including network initialization, object dictionary interactions, and CAN traffic monitoring.

By following the steps outlined in this tutorial, you can start working with CANopen devices using the Python CANopen library and leverage its capabilities to build powerful and sophisticated applications.