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Questions tagged [modbus-tcp]

A messaging structure developed by Modicon. It is used to establish master-slave/client-server communication between intelligent devices.

A messaging structure developed by Modicon in 1979. It is used to establish master-slave/client-server communication between intelligent devices. (from http://www.modbus.org/faq.php)

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How can I determine the return function code being sent from a Modbus response using Python

For clarity I am using Python and pyModbusTCP to communicate via modbus. If I am using function code 1 to read coil status, how can I determine the function code of the message that was sent back? Below is an example of how I sent messages to a…
user21051037
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Python -> 'NoneType' object is not subscriptable when using pyModbusTCP to read_holding_registers() AFTER read_coils()

For clarity I am using Python3.10.9 with pyModbusTCP 0.2.0 to communicate with a PLC. I have several grouping of coils which I read using the read_coils() method from the package, and I use the read_holding_register() to read individual holding…
user21051037
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How to read Analog Output Holding Registers on Advantech ADAM 6717 through ModBus TCP

I've been exploring the ADAM 6717 from Advantech. This is the ModBus address table for said device: At first I wanted to modify the value of the Digital output channel 0(DO0), so, as can be seen from the picture above, such address is the 0x0017. I…
Juan_David
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Pymodbus write_registers : Working with bytes vs words

When writing to multiple registers using Pymodbus it seems that the encode method on the class WriteMultipleRegistersRequest creates a word to add to the packet from the list of values using this packet += struct.pack('>H', value) I have registers…
timoh
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How to get access to data in a QModbusDataUnitMap from Qt Modbus library?

I have already create a Modbus server program in my PC with the Modbus library from Qt, using as example the code that is provided for the platform (I don't want a program with graphical interface so my program is not totally like the example) and…
lidia la cal
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Modbus Server failure in combination with tkinter

I am currently trying to write data to a modbus server via the UI tkinter. To do this, I'm using tkinter to create the UI and implement a button that internally calls me a function called print_entry(), starts the Modbus and writes the entered…
Hotte
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Persistent communication failure via modbus with flutter

I try to communicate with a connected object via modbus. The problem is that just a few exchanges, the phone disconnects from the equipment due to an error. Also, the connected object does not provide internet access so by default, the android…
Roméo David AMEDOMEY
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Read measured values via Modbus TCP from Bender PEM353 meters which are connected with Bender Comtraxx465ip using Beckhoff PLC

I want to read measured values from different registers of three different Bender PEM353 meters which are connected with Bender comtraxx465 gateway. In this system, Modbus TCP/IP protocol is considered to transfer the data from gateway to Beckhoff…
Alok Nath
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Is it possible to write to multiple coils using pyModbusTCP library

There is a method from the documents that looks like client.write_coils(1, [True]*8) My assumption is that this will write True 8 times because how do I supply a list of addresses? I want to supply a list of 8 modbuss address and assign them all…
user8901723980173
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Execute async await task WriteMultipleCoilsAsync issue

I could us some help getting the WriteMultipleCoilsAsync task to run. I'm getting the error message Cannot assign void to an implicitly-typed variable on the Task.Run statement. I need to capture the response message from…
Paul
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Problem with kivyMD TCPModbus app not reading from the server

I created an app, based on a teacher's videoclass program. It turned out I had some issues, returning me the following exceptions and Id badly apreciate your attention: Error during data status reading. Error during data setpoint reading. Error…
caio_alBR
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Is it possible to get information from the PLC Citrino FX using Modbus TCP PHP?

I have a Citrino PLC at my company, and I would like to get the PLC's internal information. We currently use InduSoft Web Studio which obtains this information via Modbus TCP. https://prnt.sc/J7vq2zHhNUdp Using the InduSoft Web Studio i can get and…
Rafael Bernardo
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Read Analog Input via Modbus TCP

I want to read a Analog Input via Modbus TCP from a WAGO AI. The input I am trying to read is connected via a WAGO 753-483 Module. The Ethernet Connection is working via a WAGO Ethernet Controller 750-881. From the documentation I believe that the…
Markus
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Windows forms app which uses System.IO.Ports is crashing after some time

I have a C# WinForms application that uses EasyModbus library to pool data from several slaves on RS485 RTU. Application crashes in about 40 minutes of running. It crashes in System.IO.Ports .dll. This is what I…
Matej Blaško
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Python Modbus RTU over TCP

I am trying to read and write data over Modbus TCP with python. When I am using ModbusPoll with the following setup everything works. I try to read the data now with python and I am using the pymodbus library for this. My code looks like this: from…
maja95
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