Use on Linux

[axgrinder]

This is not a pymodbus issue... maybe.

I have a some code based on and using this library. I can execute the code on windows and everything is perfect. When attempting to use on ubuntu 22.04, I can see using netstat -t the server is established. Using Modbus poll on another pc,

I can connect but get timeout errors.

Same issue using mbpoll on the same linux machine

Error the linux system running the server shows:

".../async_io.py, line 69, in callback_connected
self.framer = self.server.framer(
Type error: 'str' object is not callable"

This is the exact same code that is flawless on windows. What am I missing? is it some permissions to allow the data out of the linux machine?

[janiversen]

Without seeing the code it's impossible to tell what the problem is.

Are you sure both systems use v3.7.4 the error looks like an old server.

[axgrinder]

Thank you for your response. Again, the codes works perfectly on windows 11 both with python3 and pycharm. Only on linux do I have an issue. here are the 2 scripts:
Server.py:
import asyncio

from pymodbus.datastore import (
ModbusServerContext,
ModbusSlaveContext,
ModbusSparseDataBlock,
)
from pymodbus.server import (
StartAsyncTcpServer,
)

import constants as c
import helper

def setup_server(context=None):
"""Run server setup."""
args = helper.get_commandline(server=True)
if context:
args.context = context
if not args.context:
# setup registers FOR TOP LEVEL INFORMATION
network_info = ModbusSparseDataBlock(c.NETWORK_REGS, mutable=True)
system_info = ModbusSparseDataBlock(c.SYSTEM_REGS, mutable=True)

    #  Set the slave ids
    context = {
        0x01: ModbusSlaveContext(hr=network_info, ir=system_info)
    }

    # Build data storage
    args.context = ModbusServerContext(slaves=context, single=False)

network_info = ModbusSparseDataBlock(c.NETWORK_REGS)
system_info = ModbusSparseDataBlock(c.SYSTEM_REGS)

context = {
    0x01: ModbusSlaveContext(hr=network_info, ir=system_info)
}
args.context = ModbusServerContext(slaves=context, single=False)
return args

async def run_async_server(args):
"""Run server."""
address = (args.host if args.host else "", args.port if args.port else None)
server = await StartAsyncTcpServer(
context=args.context, # Data storage
address=address, # listen address
framer=args.framer, # The framer strategy to use
ignore_missing_slaves=True, # ignore request to a missing slave
)

return server

async def async_helper():
"""Combine setup and run."""
run_args = setup_server()
await run_async_server(run_args)

if name == "main":
asyncio.run(async_helper(), debug=False)

updater.py:
#!/usr/bin/env python3

import asyncio
import logging
from datetime import datetime

from pymodbus.datastore import (
ModbusServerContext,
ModbusSlaveContext,
ModbusSparseDataBlock,
)

import server
import constants as c

update_path = c.UPDATE_PATH

r1_volt_path = c.R1_VOL_PATH
r1_volt_data = [c.TEST] * (c.CELL_COUNT + 1)

_logger = logging.getLogger(name)

async def updating_task(context):
input_registers = 0x04
holding_registers = 0x03

incrementing loop

while True:
    await asyncio.sleep(1)

    # setup time for first registers
    time_info = [datetime.now().year, datetime.now().month, datetime.now().day, datetime.now().hour,
                 datetime.now().minute, datetime.now().second]
    # Update time in Modbus
    context[0x01].setValues(holding_registers, 0x03, time_info)

    # setup system info
    system_info = [15, 16, 17, 18, 17, 16, 15]
    # update system info
    context[0x01].setValues(input_registers, 0x1007, system_info)

def setup_updating_server():
"""Run server setup."""
network_info = ModbusSparseDataBlock(c.NETWORK_REGS, mutable=True)
system_info = ModbusSparseDataBlock(c.SYSTEM_REGS, mutable=True)

context = {
    0x01: ModbusSlaveContext(hr=network_info, ir=system_info)
}
context = ModbusServerContext(slaves=context, single=True)
return server.setup_server(context=context)

async def run_updating_server(args):
"""Start updating_task concurrently with the current task."""
task = asyncio.create_task(updating_task(args.context))
task.set_name("Update Server")
await server.run_async_server(args) # start the server
task.cancel()

async def main():
"""Combine setup and run."""
run_args = setup_updating_server()
await run_updating_server(run_args)

def get_in():
asyncio.run(main(), debug=True)

get_in()

The script runs no issue on windows. connects with Modbus poll and updates the date in sl:1, reg:3, count 6.

not sure if that pic will show but it is Modbus poll on windows reading 3-8 with no errors.

The same script on Ubuntu 22.04 connects but gives a time out error

I think this is more a Linux issue but I have not figured it out. using netstat -t, I can see the server established but just get time out.

Thank you again for any help you can provide.

[axgrinder]

was using 3.6.8, updated to 3.7.4 a got more errors

[axgrinder]

However, 3.7.4 does still work on windows through pycharm.

[janiversen]

Updating from 3.6.8 to 3.7.4 requires changes in the app code !

the "KeyError: '127.0.0.1'" in the traceback suggest you are using 2 different versions of pymodbus !!!

Our CI runs on ubuntu and tests with python 3.9 ... 3.13 so I am sure StartAsyncServer works on Ubuntu / MacOS and Windows.

[janiversen]

please check with pip, with versions are installed on your windows and your ubuntu system.

the type error is because you have not specified framer= correctly, and exactly that have changed with 3.7.0