Home

Awesome

Micropython Modbus library

Forked from Exo Sense Py, based on PyCom Modbus and extended with other functionalities to become a powerfull micropython library

Installation

The current implementation does only run on a board with external SPI RAM. As of now up to 300kB of RAM are required. This is more than an ESP32-D4 Pico provides by default.

esp32spiram-20220117-v1.18.bin is used as MicroPython firmware

This repo contains submodules (even sub-submodules), sorry for that. Perform the following steps to clone and update everything to gain the best usage experience:

# clone this repo with all submodules
git clone --recurse-submodules https://github.com/brainelectronics/micropython-modbus.git

# init and update all submodules
git submodules update --init --recursive

# enter micropython helper modules submodule
cd helpers
# check available tags
git tag --list
# checkout the latest non breaking tag, choose manually
git checkout x.y.z
# return to root of repo
cd ..

# enter python modules submodule
cd modules
# check available tags
git tag --list
# checkout the latest non breaking tag, choose manually
git checkout x.y.z
# return to root of repo
cd ..

# enter WiFi Manager submodule
cd wifi-manager
# check available tags
git tag --list
# checkout the latest non breaking tag, choose manually
git checkout x.y.z
# return to root of repo
cd ..

Install required tools

Python3 must be installed on your system. Check the current Python version with the following command

python --version
python3 --version

Depending on which command Python 3.x.y (with x.y as some numbers) is returned, use that command to proceed.

python3 -m venv .venv
source .venv/bin/activate

pip install -r requirements.txt

Copy files

For interaction with the filesystem of the device the Remote MicroPython shell can be used.

Open the remote shell with the following command. Additionally use -b 115200 in case no CP210x is used but a CH34x.

rshell -p /dev/tty.SLAB_USBtoUART --editor nano

Perform the following command to copy all files and folders to the device

mkdir /pyboard/helpers
mkdir /pyboard/lib
mkdir /pyboard/primitives
mkdir /pyboard/registers
mkdir /pyboard/static/
mkdir /pyboard/templates

cp helpers/*.py /pyboard/helpers
cp -r lib/* /pyboard/lib/
cp -r wifi-manager/lib/* /pyboard/lib
cp wifi-manager/primitives/*.py /pyboard/primitives
cp registers/modbusRegisters-MyEVSE.json /pyboard/register/
cp wifi-manager/simulation/static/css/*.gz /pyboard/static/
cp wifi-manager/templates/* /pyboard/templates

cp wifi-manager/wifi_manager.py /pyboard
cp modbus.py /pyboard
cp main.py /pyboard
cp boot.py /pyboard
<!-- #### uPIP Connect to the device, setup the WiFi connection as recommended and install this package with the following two lines ```python # WiFi connection must be established before of course import upip upip.install('micropython-modbus') ``` [Micropython lib README](https://github.com/micropython/micropython-lib/blob/3c383f6d2864a4b39bbe4ceb2ae8f29b519c9afe/README.md) For example, to add collections.defaultdict, copy collections/collections/__init__.py and collections.defaultdict/collections/defaultdict.py to a directory named lib/collections on your device. [Micropython PyPI packaging guidelines](https://github.com/micropython/micropython/issues/413) -->

Usage

Start a REPL (may perform a soft reboot), wait for network connection and start performing Modbus requests to the device.

For further details check the header comment of main.py.

<!-- ### Device configuration All configuration parameters are in the [config.py](config/config.py) file. To access this file on the module join its WiFi network or AccessPoint. A Web server will be enabled by default. Use a Web browser to connect to [`192.168.4.1`](http://192.168.4.1/) using the credentials specified in the [config.py](config/config.py) configuration file. Refer to [config_network.py](config/config_network.py) for the default WiFi and AccessPoint credentials. Download the configuration file, edit it and re-upload it. If using the Web interface, after the upload, the device will automatically restart using the new configuration, otherwise, on the next power-on, it will start with the new configuration. -->

Register configuration

The available registers are defined by a JSON file, placed inside the /pyboard/registers folder on the board and selected in main.py.

As an example the registers of a Brainelectronics MyEVSE, MyEVSE on Tindie board is provided with this repo.

<!-- Configure it to work as Modbus RTU slave **or** Modbus TCP server, by setting `MB_RTU_ADDRESS` **or** `MB_TCP_IP` to a valid value. If both are set, the TCP configuration will be ignored. If neither are, it will boot as *not configured* and endup in the REPL. When configured as Modbus TCP server, the configuration Web interface will be available at the configured IP address. --> <!-- ## Available webpages | URL | Description | |-----|-------------| | / | Config page of device | | /config | Config JSON of Modbus RTU/TCP | | /config-network | Config JSON of network | -->

Supported Modbus functions

Refer to the following table for the list of supported Modbus functions.

ID Description
1Read coils
2Read discrete inputs
3Read holding registers
4Read input registers
5Write single coil
6Write single register
15Write multiple coils
16Write multiple registers

Credits

Big thank you to giampiero7 for the initial implementation of this library.

<!-- Links -->