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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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Create a simple Client/Server using Modbus in C

I am currently working on a project which will allow different automates to communicate. To do so, I would like to create a client and a server that will talk using the modbus protocol. I am not sure if I want to be using ModBus/TCP, ModBus/RTU or…
PiggyGenius
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How can I convert negative binary number to int?

I want to read Data via node red modbus node from a data source. The range is -20000 to 20000, but the node cannot handle negative numbers, so I had to convert them to binary numbers (DWORD), split them in the lower and higher word and convert these…
c0nr3f
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Issue while writing ModbusClient and ModbusServer together

About the Code I am using EasyModbus Nuget in C# Window Form Application. I am trying to fetch the changed Holding Register's Address Value through RTU(Real Time Update) using ModbusServer. Below code connect to server. void Connect() { …
Pankaj
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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
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Home Assistant with MODBUS

Integrating a MODBUS installation with Home Assistant MODBUS controller in the Gavazzi SH2WEB24 Home Assistant Configiguration.yaml: modbus: name: SmartHouse type: tcp host: port: 502 # SmartHouse Functions switch: platform:…
Davy
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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
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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
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ModBus TCP communication using Ruby: failing to implement HelloWorld

I am able to communicate with a ventilation installation (Helios KWL EC 500 W which supports holding registers only, english description starts at 50% of the file) using the modpoll utility v3.4. But I failed to transfer the very first communication…
Twonky
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ModbusTCP Server/Slave Implementation in Python (pymodbus)

I try to write a ModbusTCP server software connected wıth a database. I used pyModbus library for that task. That library has an Updating Server Example. By using that code, I wrote my code as : ''' Pymodbus Server With Updating…
Şansal Birbaş
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How should I handle reconnections in twisted.application.internet.ClientService?

I am trying to make use of the recently introduced twisted.application.internet.ClientService class in a twisted application that does simple modbus-tcp polling using pymodbus. I feel my issues have nothing to do with the modbus Protocol that I am…
DanSut
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Combine and convert two 16 bit numbers into one 32 bit number (float) in JavaScript

I need to build a NodeJS server-based prototype that reads industrial modbus data. I am reading two consecutive 16bit decimal registers that provide me an array with two entries: // eg transaction = [ 17007, -2621 ] or // eg transaction = [ 17007,…
Tremendus Apps
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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
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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
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Modbus Registers beyond 255 cannot be accessed SimpleModbus

I'm french student and I have been playing with SimpleModbus for 1 week, and it worked fine... Until I tried to implement a slave with a large amount of registers (1000 needed). Registers beyond 255 using slave 1 cannot be accessed. Whatever I do I…
Gabriel
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libmodbus Unit ID altering

I am using the libmodbus libraries to communicate with a solar inverter with a Modbus interface (SMA). The Modbus specification document specifies that a certain Unit ID should be used to read registers on the device. The device offers a TCP…
Cornel Verster
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