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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

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Is it possible to use "read_holding_registers" with unitid greater than 255 in TCP mode?

I am using thingsboard gateway to connect to a modbus slave with unitid greater than 255, the pymodbus throws error like below: tb-gateway-py_1 | struct.error: ubyte format requires 0 <= number <= 255 tb-gateway-py_1 | ''2020-04-23 08:43:46' -…
Chad Cai
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Unable to read holding register PLC usign Pymodbus serial

I am trying to read a holding register on my PLC suning pymodbus I connected to my PLC using serial RS232 through com port 5 client = ModbusClient(method='rtu', port='com5', timeout=1,baudrate=9600) client.connect() Out[8]:…
Dylan Devotta
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Read Counter value From CLICK PLC to python using pymodbus with RS232 port

Very New to this but I would essentially like to read my counter value from my CLICK PLC into my python. My Click Series PLC only has a RS232 Port with Modbus protocal . Can I use pymodbus for this? Is there another way to do this? Any help would be…
Dylan Devotta
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How do I interpert the output of registers using pymodbus?

I am using pymodbus to get the values of a few registers via modbus. I have a connection and results, but I am confused on how to interpret the results. My code is: from pymodbus.client.sync import ModbusTCPClient client = ModbusTcpClient(host…
peter_wx
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is there a way to read the data coming from a connected device within pymodbus?

I have an asynchronous server of pymodbus below as example #!/usr/bin/env python """ Pymodbus Asynchronous Server Example -------------------------------------------------------------------------- The asynchronous server is a high performance…
sasori
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How to shape a CALL in PYMODBUS (Modicon?)

i am in a serius battle with a solar inverter right know (INGETEAM 3play) i am connected by TCP / IP. I need to understand how to shape my call becouse i am not having the answer i want, and also i dont' know how many bits i am waiting for an…
Cristobal Rencoret
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How to write to holding registers in pymodbus?

I want to write to the holding registers an actuator of mine has, but I've only recently started using pymodbus and I'm a little uncertain about some of its commands. As far as I've understand the primary write command looks like…
OverDemon
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Getting Integer Value from a Modbus RTU Slave using Python Code

I am reading the values in the registers of a modbus slave. But the values stored in the registers is combination of two registers. That is if register 3 has 72, and register 4 has 489. The actual value is 72489. I was able to do this. But the…
Hari
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Pymodbus-read-input-registers CRC invalid, discarding header

I am working with PZEM-004T 3.0 Version I have the unit now responding with errors. import pymodbus import serial from pymodbus.pdu import ModbusRequest from pymodbus.client.sync import ModbusSerialClient as ModbusClient #initialize a serial RTU…
Kevin Roberts
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pyModbus - TCPServer in/out traffic monitor

I am a newbie in python. Sorry if the question may sound silly. I'm using pyModbus to implement an asynchronous Modbus TCP server on a BeagleBone Black. It works well, I'm able to connect with clients and retrieve values from the registers. I start…
marcorto
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Pymodbus Register Custom Format with Serial Client

I have a Serial Client, which uses a custom format on top of the Modbus protocol, so I have to decode the answers accordingly. However, I don't seem to be able to register my function with the Serial Client, as I get an Error: AttributeError:…
TheKaltur
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pymodbus tcp synchronous client unable to trap error when connection fails

Using the pymodbus example from https://github.com/riptideio/pymodbus It is working fine and connecting to the PLC and reading the holding registers. But I have one issue. When the PLC is switched off, the code is not able to trap the disconnected…
suresh
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rtu Pymodbus trouble reading slave device

I have been trying to connect to a device using a serial port and RTU Modbus. The device is a variable frequency controller: Which is connected to my laptop via the following RS485 to USB…
Hayden Eastwood
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Get data from SMA Cluster Controller using Pymodbus

I am trying to get data from a SMA Cluster Controller using pymodbus, but I don't get any response. In example, the documentation says that request in address 30005 with 2 registers and to the unit 1 I'll get the Serial Number for the Cluster…
Sebastián Olhaberry
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Pymodbus : TypeError: string indices must be integers

I am trying to use the modbus_mapper in pymodbus and I'm facing the following issue Traceback (most recent call last): File "C:\Users\AppData\Local\Programs\Python\Python37-32\lap.py", line 311, in mapping_decoder mapping['addr'] =…
krcyn
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