파이썬 CANopen 사용 방법

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Python Canopen Tutorial

Introduction

In this tutorial, we will explore how to use the Python canopen library to communicate with CANopen devices. We will provide a step-by-step guide along with detailed explanations and executable sample codes.

Prerequisites

Before we begin, make sure you have the following:

• Python installed on your machine
• An understanding of the CANopen protocol and its basic concepts
• A CAN-to-USB adapter to connect your computer with the CAN bus

Installing the canopen Library

To get started, we need to install the canopen library. Open your terminal and run the following command:

pip install canopen

Make sure you have an active internet connection to fetch the required packages.

Connecting to a CANopen Device

1. Import the canopen module in your Python script:

import canopen

2. Create a network object to manage the CAN bus:

network = canopen.Network()

3. Initialize the network with the appropriate CAN bus driver:

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

Replace 'can0' with the corresponding CAN interface on your system. You can find this information using the ifconfig command.

Scanning for Devices

1. Discover all devices connected to the CAN bus:

devices = network.scanner.find()

2. Print the found devices:

for device in devices:
    print("Found device:", device)

Opening a CANopen Device

1. Create a device object to interact with a specific device:

device = canopen.RemoteNode(1, 'usr/canopen/object_dictionary.eds')

Replace 1 with the node ID of the device you want to communicate with. Make sure to provide the correct path to the object dictionary file (.eds).

2. Add the device object to the network:

network.add_node(device)

3. Initialize the device:

network.initialize()

Reading and Writing Data

1. Read an object dictionary variable from the device:

value = device.sdo[0x1000].raw
print("Value:", value)

Replace 0x1000 with the index of the object you want to read.

2. Write a value to an object dictionary variable:

device.sdo[0x1001].raw = 42

Replace 0x1001 with the index of the object you want to write to.

Closing the Connection

1. When you are done communicating with the device, close the network connection:

network.disconnect()

Conclusion

In this tutorial, we have covered the basics of using the Python canopen library to communicate with CANopen devices. We provided step-by-step instructions along with executable sample codes for connecting to a device, scanning for devices, opening a device, reading and writing data, and closing the connection.

You are now equipped with the knowledge to start interacting with CANopen devices in your Python projects. Happy coding!