A simple Modbus/TCP client library for Python.

Since version 0.1.0, a server is also available for test purpose only (don't use in project).

pyModbusTCP is pure Python code without any extension or external module dependency.

The module is currently test on Python 3.5, 3.6, 3.7, 3.8, 3.9 and 3.10.

You can install this package from:

PyPI, the easy way:

# install the last available release
sudo pip install pyModbusTCP

# install a specific version (here release v0.1.10)
sudo pip install pyModbusTCP==v0.1.10

From GitHub:

# install a specific version (here release v0.1.10) directly from github servers
sudo pip install git+https://github.com/sourceperl/[email protected]

GitHub:

git clone https://github.com/sourceperl/pyModbusTCP
cd pyModbusTCP
git ckeckout v0.1.10
sudo python setup.py install

Note on the use of versions:

Over time, some things can change. So, it's a good practice that you always use a specific version of a package for your project, instead of just relying on the default behavior. Without precision, the installation tools will always install the latest version available for a package, this may have some drawbacks. For example, in pyModbusTCP, the TCP automatic open mode will be active by default from version 0.2.0. It is not the case with previous versions and it just doesn't exist before the 0.0.12. This can lead to some strange behaviour of your application if you are not aware of the change.

See examples/ for full scripts.

from pyModbusTCP.client import ModbusClient

# TCP auto connect on first modbus request
c = ModbusClient(host="localhost", port=502, unit_id=1, auto_open=True)

# TCP auto connect on modbus request, close after it
c = ModbusClient(host="127.0.0.1", auto_open=True, auto_close=True)

regs = c.read_holding_registers(0, 2)
if regs:
    print(regs)
else:
    print("read error")

if c.write_multiple_registers(10, [44,55]):
    print("write ok")
else:
    print("write error")

Documentation available online at http://pymodbustcp.readthedocs.io/.

On windows OS with older Python version (<3), win_inet_pton module is require. This avoid exception "AttributeError: 'module' object has no attribute 'inet_pton'".

install win_inet_pton:

sudo pip install win_inet_pton

import win_inet_pton at beginning of your code:

import win_inet_pton
from pyModbusTCP.client import ModbusClient