Stack Overflow
Stack Overflow

Questions tagged [pymodbus]

Pymodbus is a python implementation of modbus protocol providing both client and slave features.

PYMODBUS is a full modbus implementation of modbus protocol using python. It provides both client and server features and supports Modbus over RTU, ASCII, TCP, UDP protocols. The library also supports both synchronous and asynchronous variants of both client and server features.

Pymodbus is supported on both on python 2.7 and python 3.x

For more info refer

290 questions
5
votes
1 answer

What does the pymodbus "unit" parameter mean?

I have some modbus TCP code written under pymodbus 1.2 the relevent code was result = modbus_client.read_holding_registers(40093, 3) After updating to pymodbus 1.4.0 it wouldn't work until I cargo culted the new unit parameter into the function call…
Joshua Clayton
  • 1,669
  • 18
  • 29
5
votes
2 answers

pymodbus Exception Response(131, 3, IllegalAddress)

I'm trying to run this piece of code: from pymodbus.client.sync import ModbusSerialClient as ModbusClient import logging logging.basicConfig() log = logging.getLogger() log.setLevel(logging.DEBUG) client = ModbusClient(method='rtu', baudrate=9600,…
Dmitry Misharov
  • 101
  • 2
  • 10
4
votes
2 answers

What is the pymodbus syntax to assign values to TCP server registers?

I am trying to implement a simple synchronous TCP server using the Synchronous Server Example. However, I do not understand the syntax explanations in the documentation. The example includes the following code block: store = ModbusSlaveContext( …
JLEM
  • 45
  • 1
  • 5
4
votes
2 answers

The pymodbus connection sometimes doesn't respond?

I'm use "pymodbus" lib to connect PLC devices. The device is used Modbus RTU over TCP that devices will return the temperature and humidity of the environment. map address list 0001: temperature 0002: humidity I performed once to get value and…
frank
  • 101
  • 1
  • 2
  • 6
4
votes
1 answer

Error in connecting 2 modbus slave pymodbus

I am working on pymodbus. Trying to read the data from multiple units (multiple slaves) it gives me data but when the 1 of the slaves did not respond or is off the other slaves also shows the error after some time. please help. Thank you from…
Eng
  • 41
  • 4
4
votes
2 answers

Auto Discovery of the slave id of modbus device in a network

How to determine whether device connected to the network is modbus device after getting valid ip range through broadcasting mechanism or How to Auto Discover the slave id of modbus device connected to the gateway ?
Ayushi Gupta
  • 173
  • 1
  • 2
  • 13
4
votes
4 answers

Modbus Error: [Input/Output] No Response received from the remote unit

I' trying to connect from my Mac laptop to a Modbus device (MR-SI4) using a serial connection using a USB RS485 converter that gets "mounted" to /dev/cu.SLAB_USBtoUART. This is my code: import logging logging.basicConfig() log =…
otmezger
  • 10,410
  • 21
  • 64
  • 90
3
votes
3 answers

How to request Ebox wifi with modbus

I've never used modbus before. I have an eBox-Wifi Epever connected to an MPPT charge controller TRIRON for solar power. I was able to make it connect to my wifi and now has an accessible IP : 192.168.39.149 I just want to extract some data from it,…
bob dylan
  • 989
  • 2
  • 10
  • 26
3
votes
0 answers

Pymodbus RTU [Errno 25] Inappropriate ioctl for device

I'm trying to have a modbus RTU client on my Raspberry Pi 4 talking to the modbus synchronous server available in the pymodbus examples (https://pymodbus.readthedocs.io/en/latest/source/example/synchronous_client.html). I set up the server like…
Federico
  • 43
  • 7
3
votes
1 answer

Accessing Raw Bytes in pyModbus Transactions

I have a python script which can handle Modbus transactions using the pymodbus library. For troubleshooting purposes I would like to print the raw bytes sent and received to the device, preferably in hex format. Here is simplified code, see the…
Dave1551
  • 323
  • 2
  • 13
3
votes
0 answers

How to find out if a client is connected to a pymodbus tcp server

I have a pymodbus server running and I'd like to know if a client is connected to it that it is serving. Is there any way to do that? I can't see an obvious way. I'm using the synchronous server: pymodbus.server.sync.ModbusTcpServer
Mr. Fegur
  • 797
  • 1
  • 6
  • 18
3
votes
3 answers

How to stop a pymodbus async ModbusTcpServer?

I want to stop a pymodbus async ModbusTcpServer then start a new server. Therefore, I've tried with the following simplified code snippet, but I got an error: from pymodbus.server.async import StartTcpServer, StopServer from pymodbus.device import…
Benyamin Jafari
  • 27,880
  • 26
  • 135
  • 150
3
votes
0 answers

How to implement a message with a custom function code in pymodbus?

I'm currently trying to implement a modbus request that has a custom function code. The implementation is based on this example: custom_message.py import struct from pymodbus.pdu import ModbusRequest, ModbusResponse from pymodbus.client.sync import…
laberning
  • 769
  • 7
  • 19
3
votes
1 answer

Pymodbus TCP `read_holding_registers` returns stale/old data

I've started using pymodbus to read values from modbus to store in a database off site. I've been struggling with an issue that the value received in the response is not the same as the value I can see on the Jace. I've tried modbus-tk as well and…
Pieter Hamman
  • 1,532
  • 18
  • 18
3
votes
2 answers

pymodbus: request creation and response receiving

Can anyone explain how to create the request and get the response in right way using pymodbus via Modbus TCP/IP? I have the PLC which I want to use as slave and PC - as master. I trying to do it in such way: from pymodbus.client.sync import…
user2739393
  • 33
  • 1
  • 6
1
2 3
…
19 20