Modbus Connect package for Python

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Modbus Connect is a Python package that provides a configurable Modbus TCP data adquisition library from Modbus TCP devices. It is designed to be used as a library for a data acquisition application, managing the connection to the devices and the data exchange with them. The data is returned in a format that can be easily used for sending to a database or MQTT broker.

The Modbus data table can be supplied as a csv file or as a Python dictionary. A dictionary is used to configure the Modbus Gateway. The dictionary can be created manually or by using the importer module from a csv file.

It is based on the PyModbus for the Modbus TCP communication.

The modbus-mqtt-digital-twin package provides a data acquisition application that uses the Modbus Gateway library. (Under development)

Installation

The package can be installed from PyPI:

pip install modbus-connect

Usage

For a complete example of the usage of the package, check the examples folder.

Here is a simple example of the usage of the package:

TODO: Non working example, UPDATE

from modbus_gateway import ModbusGateway

# Create a dictionary with the configuration of the Modbus Gateway

config = [
    {
        "name": "var1",
        "address": 0,
        "memory_bank": utils.MemoryBanks.HOLDING_REGISTERS,
        "datatype": "float32",
    },
    {
        "name": "var2",
        "address": 2,
        "memory_bank": utils.MemoryBanks.HOLDING_REGISTERS,
        "datatype": "float32",
    },
]

gateway = ModbusGateway(
    host=<host>,
    port=<port>,
    tags_list=config,
)

# Read the values from the modbus server

values = gateway.read_tags()
print(values)

This behaviour can be easly used for continuous data adquisition using rocktry or any other scheduler and fastly deploied using docker.

License

MIT

Contributing

Pull requests are welcome. For major changes, please open an issue first to discuss what you would like to change.

Please make sure to update tests as appropriate.

Framework

This project uses Poetry for dependency management and packaging. To install the dependencies, run:

poetry install

Add -without dev to the command to install only build and production dependencies.

To format and tests the code, use:

poetry run black ./modbus_connect/* ./tests/*

poetry run pytest tests/

Pre-commit hooks are used to ensure that the code is properly formated and tested before commiting. To install the pre-commit hooks, run:

poetry run pre-commit install

# Check hooks before commit
poetry run pre-commit

The pre-commit hooks can be skipped using the --no-verify flag on commit (NOT RECOMMENDED, use black before creating any commit) or the env variable SKIP with the hook id (for temporal commit which don't pass all tests).

# Skip tests on commit
SKIP=tests poetry run git commit -m "Commit message"

Coverage, reports and badges can also be built, check lint-test action for more details about the commands to use. Reports are generated in the reports folder, use:

poetry run pytest --junitxml=reports/tests/tests.xml --html=reports/tests/tests.html --cov-report xml:reports/coverage/coverage.xml --cov-report html:reports/coverage/coverage --cov=modbus_connect tests/

TODO

• Create docs
• Implement TDD importer for csv at least
• Create examples folder
• Right now the only examples available are inside the tests.

Authors

• Ángel Fernández Sobrino - AngelFernandezSobrino