CANopen for Python
A Python implementation of the CANopen standard. The aim of the project is to support the most common parts of the CiA 301 standard in a simple Pythonic interface. It is mainly targeted for testing and automation tasks rather than a standard compliant master implementation.
The library supports Python 3.6+.
Features
The library is mainly meant to be used as a master.
- NMT master
- SDO client
- PDO producer/consumer
- SYNC producer
- EMCY consumer
- TIME producer
- LSS master
- Object Dictionary from EDS
- 402 profile support
Incomplete support for creating slave nodes also exists.
- SDO server
- PDO producer/consumer
- NMT slave
- EMCY producer
- Object Dictionary from EDS
Installation
Install from PyPI using pip:
$ pip install canopen
Install from latest master on GitHub:
$ pip install https://github.com/christiansandberg/canopen/archive/master.zip
If you want to be able to change the code while using it, clone it then install it in develop mode:
$ git clone https://github.com/christiansandberg/canopen.git $ cd canopen $ pip install -e .
Unit tests can be run using the pytest framework:
$ pip install pytest $ pytest -v
Documentation
Documentation can be found on Read the Docs:
http://canopen.readthedocs.io/en/latest/
It can also be generated from a local clone using Sphinx:
$ python setup.py build_sphinx
Hardware support
This library supports multiple hardware and drivers through the python-can package. See the list of supported devices.
It is also possible to integrate this library with a custom backend.
Quick start
Here are some quick examples of what you can do:
The PDOs can be access by three forms:
1st: node.tpdo[n] or node.rpdo[n]
2nd: node.pdo.tx[n] or node.pdo.rx[n]
3rd: node.pdo[0x1A00] or node.pdo[0x1600]
The n is the PDO index (normally 1 to 4). The second form of access is for backward compatibility.
import canopen
# Start with creating a network representing one CAN bus
network = canopen.Network()
# Add some nodes with corresponding Object Dictionaries
node = canopen.RemoteNode(6, '/path/to/object_dictionary.eds')
network.add_node(node)
# Connect to the CAN bus
# Arguments are passed to python-can's can.Bus() constructor
# (see https://python-can.readthedocs.io/en/latest/bus.html).
network.connect()
# network.connect(bustype='socketcan', channel='can0')
# network.connect(bustype='kvaser', channel=0, bitrate=250000)
# network.connect(bustype='pcan', channel='PCAN_USBBUS1', bitrate=250000)
# network.connect(bustype='ixxat', channel=0, bitrate=250000)
# network.connect(bustype='vector', app_name='CANalyzer', channel=0, bitrate=250000)
# network.connect(bustype='nican', channel='CAN0', bitrate=250000)
# Read a variable using SDO
device_name = node.sdo['Manufacturer device name'].raw
vendor_id = node.sdo[0x1018][1].raw
# Write a variable using SDO
node.sdo['Producer heartbeat time'].raw = 1000
# Read PDO configuration from node
node.tpdo.read()
node.rpdo.read()
# Re-map TPDO[1]
node.tpdo[1].clear()
node.tpdo[1].add_variable('Statusword')
node.tpdo[1].add_variable('Velocity actual value')
node.tpdo[1].add_variable('Some group', 'Some subindex')
node.tpdo[1].trans_type = 254
node.tpdo[1].event_timer = 10
node.tpdo[1].enabled = True
# Save new PDO configuration to node
node.tpdo[1].save()
# Transmit SYNC every 100 ms
network.sync.start(0.1)
# Change state to operational (NMT start)
node.nmt.state = 'OPERATIONAL'
# Read a value from TPDO[1]
node.tpdo[1].wait_for_reception()
speed = node.tpdo[1]['Velocity actual value'].phys
val = node.tpdo['Some group.Some subindex'].raw
# Disconnect from CAN bus
network.sync.stop()
network.disconnect()Debugging
If you need to see what's going on in better detail, you can increase the logging level:
import logging
logging.basicConfig(level=logging.DEBUG)