https://github.com/semiversus/python-durand
Python CANopen library with focus on implementing server nodes
https://github.com/semiversus/python-durand
can canopen communication embedded python
Last synced: 5 months ago
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Python CANopen library with focus on implementing server nodes
- Host: GitHub
- URL: https://github.com/semiversus/python-durand
- Owner: semiversus
- Created: 2021-06-22T21:02:49.000Z (almost 5 years ago)
- Default Branch: main
- Last Pushed: 2025-05-12T11:49:45.000Z (about 1 year ago)
- Last Synced: 2025-12-14T15:19:30.473Z (6 months ago)
- Topics: can, canopen, communication, embedded, python
- Language: Python
- Homepage: https://github.com/semiversus/python-durand
- Size: 188 KB
- Stars: 7
- Watchers: 2
- Forks: 2
- Open Issues: 0
-
Metadata Files:
- Readme: README.rst
- Changelog: CHANGELOG.md
Awesome Lists containing this project
README
================================================
Python Durand - CANopen Responder Device Library
================================================
A CANopen library to implement responder nodes.
**Backends:**
- CAN interfaces via python-can_
.. header
Synopsis
========
- Pure Python implementation
- Licensed under MIT (2021 Günther Jena)
- Source code hosted on GitHub.com_
- Tested on Python 3.7, 3.8, 3.9, and 3.10
- Unit tested with pytest_, coding style enforced with Black_, static type checking with mypy_, static code analysis with Pylint_, documentation generated with Sphinx_
- Supports CiA301_ (EN 50325-4)
.. _pytest: https://docs.pytest.org/en/latest
.. _Black: https://black.readthedocs.io/en/stable/
.. _mypy: http://mypy-lang.org/
.. _Pylint: https://www.pylint.org/
.. _Sphinx: http://www.sphinx-doc.org
.. _GitHub.com: https://github.com/semiversus/python-durand
.. _CiA301: http://can-cia.org/standardization/technical-documents
Feature List
============
* **Object Dictionary:**
- Provides callbacks for validation, update, download, and read operations
- Supports records, arrays, and variables
* **EDS Support:**
- Dynamic generation of EDS files
- Automatically provided via object 0x1021 ("Store EDS")
* **SDO Servers:**
- Supports up to 128 SDO servers
- Expedited, segmented, and block transfer for upload and download
- Dynamically configurable COB-IDs
- Custom upload and download handlers supported
* **PDO Support:**
- Up to 512 TPDOs and 512 RPDOs
- Dynamically configurable
- Transmission types: synchronous (acyclic and every nth sync) and event-driven
- Supports inhibit time
* **EMCY Producer Service:**
- Dynamically configurable COB-ID
- Supports inhibit time
* **Heartbeat Producer Service:**
- Dynamically configurable
* **NMT Slave Service:**
- Boot-up service
- Callback for state change provided
* **SYNC Consumer Service:**
- Dynamically configurable COB-ID
- Callback for received sync provided
* **CiA305 Layer Setting Service:**
- Supports fast scan
- Configurable bitrate and node ID
- Identify remote responder supported
* **CAN Interface Abstraction:**
- Full support for python-can_
- Automatic CAN ID filtering by subscribed services
* **Scheduling:**
- Supports threaded and async operation
**TODO:**
- Build object dictionary via reading an EDS file
- Support MPDOs
- TIME consumer service
- Up- and download handler as I/O streams
Examples
========
**Creating a Node:**
.. code-block:: python
import can
from durand import CANBusNetwork, Node, Variable, Record, DatatypeEnum
bus = can.Bus(bustype='socketcan', channel='vcan0')
network = CANBusNetwork(bus)
node = Node(network, node_id=0x01)
Congratulations! You now have a CiA-301 compliant node running. The Layer Setting Service is also supported out of the box.
**Adding Objects:**
.. code-block:: python
od = node.object_dictionary
# Add variable at index 0x2000
od[0x2000] = Variable(DatatypeEnum.UNSIGNED16, access='rw', value=10, name='Parameter 1')
# Add record at index 0x2001
record = Record(name='Parameter Record')
record[1] = Variable(DatatypeEnum.UNSIGNED8, access='ro', value=0, name='Parameter 2a')
record[2] = Variable(DatatypeEnum.REAL32, access='rw', value=0, name='Parameter 2b')
od[0x2001] = record
**Accessing Values:**
The objects can be read and written directly by accessing the object dictionary:
.. code-block:: python
print(f'Value of Parameter 1: {od.read(0x2000, 0)}')
od.write(0x2001, 1, value=0xAA)
**Adding Callbacks:**
A more event-driven approach is to use callbacks. The following callbacks are available:
- `validate_callbacks`: Called before a value in the object dictionary is updated
- `update_callbacks`: Called when the value has been changed (via `od.write` or via CAN bus)
- `download_callbacks`: Called when the value has been changed via CAN bus
- `read_callback`: Called when an object is read (return value is used)
.. code-block:: python
od.validate_callbacks[(0x2000, 0)].add(lambda v: v % 2 == 0)
od.update_callbacks[(0x2001, 2)].add(lambda v: print(f'Update for Parameter 2b: {v}'))
od.download_callbacks[(0x2000, 0)].add(lambda v: print(f'Download for Parameter 1: {v}'))
od.set_read_callback(0x2001, 1, lambda: 17)
**PDO Mapping:**
PDOs can be dynamically mapped via the SDO server or programmatically. The PDO indices start at 0.
.. code-block:: python
node.tpdo[0].mapping = [(0x2001, 1), (0x2001, 2)]
node.tpdo[0].transmission_type = 1 # Transmit on every SYNC
node.rpdo[0].mapping = [(0x2000, 0)]
node.tpdo[0].transmission_type = 255 # Event-driven (processed when received)
Installation
============
.. code-block:: bash
pip install durand
Credits
=======
This library would not be possible without:
- python-canopen_: CANopen library (by Christian Sandberg)
- python-can_: CAN interface library (by Brian Thorne)
.. _python-canopen: https://github.com/christiansandberg/canopen
.. _python-can: https://github.com/hardbyte/python-can