# pycomm3 **Repository Path**: hellolutar/pycomm3 ## Basic Information - **Project Name**: pycomm3 - **Description**: No description available - **Primary Language**: Unknown - **License**: MIT - **Default Branch**: master - **Homepage**: None - **GVP Project**: No ## Statistics - **Stars**: 0 - **Forks**: 0 - **Created**: 2026-07-27 - **Last Updated**: 2026-07-27 ## Categories & Tags **Categories**: Uncategorized **Tags**: None ## README ======= pycomm3 ======= .. <> .. image:: https://img.shields.io/pypi/v/pycomm3.svg?style=for-the-badge :target: https://pypi.python.org/pypi/pycomm3 :alt: PyPI Version .. image:: https://img.shields.io/pypi/l/pycomm3.svg?style=for-the-badge :target: https://pypi.python.org/pypi/pycomm3 :alt: License .. image:: https://img.shields.io/pypi/pyversions/pycomm3.svg?style=for-the-badge :target: https://pypi.python.org/pypi/pycomm3 :alt: Python Versions | .. image:: https://img.shields.io/pypi/dm/pycomm3?style=social :target: https://pypi.python.org/pypi/pycomm3 :alt: Downloads .. image:: https://img.shields.io/github/watchers/ottowayi/pycomm3?style=social :target: https://github.com/ottowayi/pycomm3 :alt: Watchers .. image:: https://img.shields.io/github/stars/ottowayi/pycomm3?style=social :target: https://github.com/ottowayi/pycomm3 :alt: Stars .. image:: https://img.shields.io/github/forks/ottowayi/pycomm3?style=social :target: https://github.com/ottowayi/pycomm3 :alt: Forks | **⚠️ NOTE:** ``pycomm3`` is no longer actively developed Introduction ============ ``pycomm3`` started as a Python 3 fork of `pycomm`_, which is a Python 2 library for communicating with Allen-Bradley PLCs using Ethernet/IP. The initial Python 3 port was done in this `fork`_ and was used as the base for ``pycomm3``. Since then, the library has been almost entirely rewritten and the API is no longer compatible with ``pycomm``. Without the hard work done by the original ``pycomm`` developers, ``pycomm3`` would not exist. This library seeks to expand upon their great work. .. _pycomm: https://github.com/ruscito/pycomm .. _fork: https://github.com/bpaterni/pycomm/tree/pycomm3 Drivers ======= ``pycomm3`` includes 3 drivers: - `CIPDriver`_ This driver is the base driver for the library, it handles common CIP services used by the other drivers. Things like opening/closing a connection, register/unregister sessions, forward open/close services, device discovery, and generic messaging. It can be used to connect to any Ethernet/IP device, like: drives, switches, meters, and other non-PLC devices. - `LogixDriver`_ This driver supports services specific to ControlLogix, CompactLogix, and Micro800 PLCs. Services like reading/writing tags, uploading the tag list, and getting/setting the PLC time. - `SLCDriver`_ This driver supports basic reading/writing data files in a SLC500 or MicroLogix PLCs. It is a port of the ``SlcDriver`` from ``pycomm`` with minimal changes to make the API similar to the other drivers. Currently this driver is considered legacy and it's development will be on a limited basis. .. _CIPDriver: https://docs.pycomm3.dev/en/latest/usage/cipdriver.html .. _LogixDriver: https://docs.pycomm3.dev/en/latest/usage/logixdriver.html .. _SLCDriver: https://docs.pycomm3.dev/en/latest/usage/slcdriver.html Disclaimer ========== PLCs can be used to control heavy or dangerous equipment, this library is provided "as is" and makes no guarantees on its reliability in a production environment. This library makes no promises in the completeness or correctness of the protocol implementations and should not be solely relied upon for critical systems. The development for this library is aimed at providing quick and convenient access for reading/writing data inside Allen-Bradley PLCs. Setup ===== The package can be installed from `PyPI`_ using ``pip``: ``pip install pycomm3`` or ``python -m pip install pycomm3``. .. _PyPI: https://pypi.org/project/pycomm3/ Optionally, you may configure logging using the Python standard `logging`_ library. A convenience method is provided to help configure basic logging, see the `Logging Section`_ in the docs for more information. .. _logging: https://docs.python.org/3/library/logging.html .. _Logging Section: https://docs.pycomm3.dev/en/latest/getting_started.html#logging Python and OS Support ===================== ``pycomm3`` is a Python 3-only library and is supported on Python versions from 3.6.1 up to 3.10. There should be no OS-specific requirements and should be able to run on any OS that Python is supported on. Development and testing is done primarily on Windows 10. If you encounter an OS-related problem, please open an issue in the `GitHub repository`_ and it will be investigated. .. attention:: Python 3.6.0 is not supported due to ``NamedTuple`` not supporting `default values and methods `_ until 3.6.1 .. _GitHub repository: https://github.com/ottowayi/pycomm3 .. <> Documentation ============= This README covers a basic overview of the library, full documentation can be found on `Read the Docs`_ or by visiting `https://pycomm3.dev `_. .. _Read the Docs: https://pycomm3.readthedocs.io/en/latest/ Contributions ============= If you'd like to contribute or are having an issue, please read the `Contributing`_ guidelines. .. _Contributing: CONTRIBUTING.md Highlighted Features ==================== - ``generic_message`` for extra functionality not directly implemented - working similar to the MSG instruction in Logix, arguments similar to the MESSAGE properties - See the examples section for things like getting/setting drive parameters, IP configuration, or uploading an EDS file - used internally to implement some of the other methods (get/set_plc_time, forward open/close, etc) - simplified data types - allows use of standard Python types by abstracting CIP implementation details away from the user - strings use normal Python ``str`` objects, does not require handling of the ``LEN`` and ``DATA`` attributes separately - custom string types are also identified automatically and not limited to just the builtin one - BOOL arrays use normal Python ``bool`` objects, does not require complicated bit shifting of the DWORD value - powerful type system to allow types to represent any CIP object and handle encoding/decoding the object LogixDriver ----------- - simple API, only 1 ``read`` method and 1 ``write`` method for tags. - does not require using different methods for different data types - requires the tag name only, no other information required from the user - automatically manages request/response size to pack as many requests into a single packet - automatically handles fragmented requests for large tags that can't fit in a single packet - both support full structure reading/writing (UDTs, AOIs, etc) - for ``read`` the ``Tag.value`` will be a ``dict`` of ``{attribute: value}`` - for ``write`` the value should be a dict of ``{attribute: value}`` , nesting as needed - does not do partial writes, the value must match the complete structure - not recommended for builtin type (TIMER, CONTROL, COUNTER, etc) - both require no attributes to have an External Access of None - uploads the tag list and data type definitions from the PLC - no requirement for user to determine tags available (like from an L5X export) - definitions are required for ``read``/``write`` methods - automatically enables/disables different features based on the target PLC - Extended Forward Open (EN2T or newer and v20+) - Symbol Instance Addressing (Logix v21+) - detection of Micro800 and disables unsupported features (CIP Path, Ex. Forward Open, Instance Addressing, etc) LogixDriver Overview ==================== Creating a driver is simple, only a ``path`` argument is required. The ``path`` can be the IP address, IP and slot, or a full CIP route, refer to the documentation for more details. The example below shows how to create a simple driver and print some of the information collected about the device. :: from pycomm3 import LogixDriver with LogixDriver('10.20.30.100/1') as plc: print(plc) # OUTPUT: # Program Name: PLCA, Device: 1756-L83E/B, Revision: 28.13 print(plc.info) # OUTPUT: # {'vendor': 'Rockwell Automation/Allen-Bradley', 'product_type': 'Programmable Logic Controller', # 'product_code': 166, 'version_major': 28, 'version_minor': 13, 'revision': '28.13', 'serial': 'FFFFFFFF', # 'device_type': '1756-L83E/B', 'keyswitch': 'REMOTE RUN', 'name': 'PLCA'} Reading/Writing Tags -------------------- Reading or writing tags is as simple as calling the ``read`` and ``write`` methods. Both methods accept any number of tags, and will automatically pack multiple tags into a *Multiple Service Packet Service (0x0A)* while making sure to stay below the connection size. If there is a tag value that cannot fit within the request/reply packet, it will automatically handle that tag independently using the *Read Tag Fragmented (0x52)* or *Write Tag Fragmented (0x53)* requests. Both methods will return ``Tag`` objects to reflect the success or failure of the operation. :: class Tag(NamedTuple): tag: str # the name of the tag, does not include ``{<# elements>}`` from request value: Any # value read or written, may be ``None`` if an error occurred type: Optional[str] = None # data type of tag, including ``[<# elements>]`` from request error: Optional[str] = None # ``None`` if successful, else the CIP error or exception thrown ``Tag`` objects are considered successful (truthy) if the ``value`` is not ``None`` and the ``error`` is ``None``. Examples:: with LogixDriver('10.20.30.100') as plc: plc.read('tag1', 'tag2', 'tag3') # read multiple tags plc.read('array{10}') # read 10 elements starting at 0 from an array plc.read('array[5]{20}) # read 20 elements starting at elements 5 from an array plc.read('string_tag') # read a string tag and get a string plc.read('a_udt_tag') # the response .value will be a dict like: {'attr1`: 1, 'attr2': 'a string', ...} # writes require a sequence of tuples of [(tag name, value), ... ] plc.write('tag1', 0) # single writes do not need to be passed as a tuple plc.write(('tag1', 0), ('tag2', 1), ('tag3', 2)) # write multiple tags plc.write(('array{5}', [1, 2, 3, 4, 5])) # write 5 elements to an array starting at the 0 element plc.write('array[10]{5}', [1, 2, 3, 4, 5]) # write 5 elements to an array starting at element 10 plc.write('string_tag', 'Hello World!') # write to a string tag with a string plc.write('string_array[2]{5}', 'Write an array of strings'.split()) # write an array of 5 strings starting at element 2 plc.write('a_udt_tag', {'attr1': 1, 'attr2': 'a string', ...}) # can also use a dict to write a struct # Check the results results = plc.read('tag1', 'tag2', 'tag3') if all(results): print('They all worked!') else: for result in results: if not result: print(f'Reading tag {result.tag} failed with error: {result.error}') .. Note:: Tag names for both ``read`` and ``write`` are case-sensitive and are required to be the same as they are named in the controller. This may change in the future. Unit Testing ============ ``pytest`` is used for unit testing. The ``tests`` directory contains an L5X export of the testing program that contains all tags necessary for testing. The only requirement for testing (besides a running PLC with the testing program) is the environment variable ``PLCPATH`` for the PLC defined. User Tests ---------- These tests are for users to run. There are a few tests that are specific to a demo plc, those are excluded. To run them you have the following options: with `tox`: - modify the ``PLCPATH`` variable in ``tox.ini`` - then run this command: ``tox -e user`` or with ``pytest``: .. code-block:: set PLCPATH=192.168.1.100 pytest --ignore tests/online/test_demo_plc.py *(or the equivalent in your shell)* .. Note:: Test coverage is not complete, pull requests are welcome to help improve coverage. License ======= ``pycomm3`` is distributed under the MIT License