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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)

302 questions
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Multiple Servers pymodbus connection issues Modbus TCP

I have an issue when I try to read holding registers using pymodbus and a raspberry pi. I can't seem to get two servers/slaves connected at the same time (either one or another will work, but together, I cannot read registers from both devices).…
Emerson
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Convert collection of 32 bool values to 32-bit integer

So I'm new to C# and I've searched but I just don't know what I'm searching for. I have a boolean variable called inputs that has saved 32 true/false bits from a ModBus interface library. Here's an image explaining my 32 true/false values. Basically…
Bidaum92
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Exception while trying to read out holding registers from device via Modbus/TCP

im trying to read values from holding registers of a device (PowerMonitor made by Weidmüller) using Modbus/TCP. I use java and a modbus library called "jamod". My code: public class Master1 { public static void main(String[] args) { …
lksk
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Pymodbus/Twisted Asynchronous Client Reconnecting

I have written a test code which reads some coils/registers from a PLC's modbus server. When I call one request the code works. I unplugged the cable then Twisted calls clientConnectionLost function so my client will reconnected, when I plugged back…
Poseidon
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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
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Convert register values to float 32 big endian

I have two signed register values 17147 and -27394. They are in order of High-Low bits. I want to get the value float 32 big endian value using these value. I have used following code to convert to value. My code int intValue = 17147; intValue <<=…
Alexander Raymak
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How to create modbus master/server tcp in flutter?

I want to create desktop app to communicate with PLC using modbus. I found modbus package, but I can not implement modbus server. There is only client implementation. I've read modbus source code and found that modbus client was created using Socket…
Miftakhul Arzak
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Facing an SocketTimeoutException while reading a register value using Modbus client

The exception looks like this: Exception in thread "main" java.net.SocketTimeoutException: Read timed out at java.base/sun.nio.ch.NioSocketImpl.timedRead(NioSocketImpl.java:283) at…
sdbibon
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Pymodbus read and decode register value

I am new to modbus comunication, i have to read from an inverter a single value from one register using modbus protocol (i use python with pymodbus for this): From the inverter documentation i read about register documentation: Register ADR:…
Manuel Santi
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Changing the configuration of TF6250-Modbus-TCP when used in TwinCAT/BSD

I have a device running TwinCAT/BSD. Following section 5 the manual for TwinCAT/BSD I have successfully managed to install the TF6250 package. After updating the firewall rules I have confirmed that I am able connect and issue modbus tcp requests…
Lachlan Wright
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Cannot locate rosdep definition for [rospy] - robotiq ros driver dependencies

I am going to install ros driver for robotiq gripper as indicated in http://wiki.ros.org/robotiq But for installing Modbus TCP dependencies (rosdep install robotiq_modbus_tcp), I have the following issue: ERROR: the following packages/stacks could…
Ali Roshanbin
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Modbus TCPIP flutter/dart exception error

I want to develop an app for requesting some datas from a device with modbus TCP /IP. I used flutter in order to create it but I have an error: E/flutter ( 7330): [ERROR:flutter/lib/ui/ui_dart_state.cc(166)] Unhandled Exception: NoSuchMethodError:…
Salvatore Ercole
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Why do we need Input Registers, Coil Bits and Input Bits in Modbus

In modbus there are 4 object types which are Input registers (R), Holding registers (R/W), Input Bits (R) and Coil Bits (R/W). What's stopping someone just using holding registers? Why are the other three data types needed?
tyleax
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Why QModbusClient does not read data after open statement?

I am trying to get a simple Modbus running and I am getting trouble with the sequense of commands. I have figured first, that I can't run multiple functions in a function. If I do this, then it looks like a connection was made, but it fails. If I…
RavenMujitsuNo
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pymodbus Modbus Server implementation with multiple slave devices context - writing to a register overwrites to all slaves

I have an issue with a simple pymodbus server implementation. From what I have read in the docs, this implementation should have unique slave contexts for each slave device, i.e. writing to device 0x01, register address 1, should be a different…
Crashtastic
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