Passing in a device_id to read_holding_registers causes error got an unexpected keyword argument 'device_id'

[8none1]

I'm using version 3.8.6 from pip and talking to an EW11 modbus TCP adapter.

According to the docs I can pass in a device_id.

However, when I do this I get the error:

TypeError: ModbusClientMixin.read_holding_registers() got an unexpected keyword argument 'device_id'

When ommiting device_id altogether things work as expected.

Example code

from pymodbus.client import ModbusTcpClient
c = ModbusTcpClient(host="hostname")
c.connect()
r = c.read_holding_registers(47, count=7, device_id=1)

Error

Traceback (most recent call last):
  File "<python-input-4>", line 1, in <module>
    r = c.read_holding_registers(47, count=7, device_id=1)
TypeError: ModbusClientMixin.read_holding_registers() got an unexpected keyword argument 'device_id'

[janiversen]

Looks a lot like the pymodbus version is NOT v3.8.6

look at the code:

def read_holding_registers(self,
                               address: int,
                               *,
                               count: int = 1,
                               device_id: int = 1,
                               no_response_expected: bool = False) -> T:
        """Read holding registers (code 0x03).

        :param address: Start address to read from
        :param count: (optional) Number of registers to read
        :param device_id: (optional) Modbus device ID
        :param no_response_expected: (optional) The client will not expect a response to the request
        :raises ModbusException:

        This function is used to read the contents of a contiguous block
        of holding registers in a remote device. The Request specifies the
        starting register address and the number of registers.

        Registers are addressed starting at zero.
        Therefore devices that specify 1-16 are addressed as 0-15.
        """
       

[janiversen]

Are you sure you do not another version installed e.g. globally that that precedence.

Did you verify with pip that v3.8.6 is actually installed?

[8none1]

I thought the same thing, but everything I've tried says it's 3.8.6:

$ pip3 show pymodbus
Name: pymodbus
Version: 3.8.6
Summary: A fully featured modbus protocol stack in python
Home-page: https://github.com/pymodbus-dev/pymodbus/
Author: Galen Collins, Jan Iversen
Author-email: 
License: BSD-3-Clause
Location: /home/will/source/growatt_modbus/.venv/lib/python3.13/site-packages
Requires: 
Required-by: 

$ python3
Python 3.13.2 (main, Feb  5 2025, 01:23:35) [GCC 14.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import pymodbus
>>> print(pymodbus.__version__)
3.8.6
>>> 

🤷

[8none1]

... and yet, when I go in to site_packages and look in mixin.py:

    def read_holding_registers(self,
                               address: int,
                               *,
                               count: int = 1,
                               slave: int = 1,
                               no_response_expected: bool = False) -> T:
        """Read holding registers (code 0x03).

        :param address: Start address to read from
        :param count: (optional) Number of registers to read
        :param slave: (optional) Modbus slave ID
        :param no_response_expected: (optional) The client will not expect a response to the request
        :raises ModbusException:

        This function is used to read the contents of a contiguous block
        of holding registers in a remote device. The Request specifies the
        starting register address and the number of registers.

        Registers are addressed starting at zero.
        Therefore devices that specify 1-16 are addressed as 0-15.
        """

I'm clearly not running the actual 3.8.6.

So I dunno. Something funky happened. I'll delete the venv and start again. If I can recreate this issue I will re-open the issue but otherwise this is something at my end. Sorry for the noise.