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Questions tagged [pymodbus3]

48 questions
11
votes
2 answers

Modbus Error: [Invalid Message] Incomplete message received, expected at least 2 bytes (0 received)

Problem pymodbus master/client can send a request to the slave/server. The slave/server make the things to return ready and is waiting for the master/client to pick them up. Despite the readiness of the server/slave, the master/client just returns…
Andreas
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4
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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
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4
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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
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4
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1 answer

Pymodbus RTU connection troubles

I am a beginner with both python and modbus and I'm trying to control a fan connected to a serial port with pymodbus for hours now. Using a proprietary software from the manufacturer I was able to control the fan, so the connection itself works. …
Till K.
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3
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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
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2
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2 answers

Passing from manual Docker host network to Docker Compose bridge

I have 2 docker images a modbus server and a client which I run manually with docker run --network host server and the same with the client and work perfectly. But now I need to add them to a docker-compose file where the network is bridge, what I…
19mike95
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2
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1 answer

Is it possible to use pyModbusTCP as modbus slave?

I'm perusing the pyModbusTCP with the intent of writing a Modbus slave running on Linux. [begin rant]: pyModbusTCP uses the terms "client" and "server" instead of "slave/master", so the docs are a bit confusing. [end rant] It seems all they do in…
Ryan Griggs
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2
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0 answers

Pymodbus Server TCP read/write

Currently with the example of the pymodbus document I was able to create a server, from another PC I can read the variables that I want to monitor remotely. But when I change one of the variables in remote access, I do not know how to obtain it from…
MM87
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2
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1 answer

Pymodbus: how do I read the individual bits of this input register?

I have a solar power project and real-time monitor which uses an EpSolar Tracer charge controller, and a Raspberry Pi to read the energy data via MODBUS. I'm reading the input registers easily when they are simple integers, like this - # Request…
Matt Hubbert
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1 answer

What is difference between pymodbus and pymodbus3 modules?

Hope you are doing great! I recently started using python for modbus communication. I want to clear my few doubts. What module is better for modbus implementation using Python - minimalmodbus, pymodbus, pymodbus3 or else. I am using python3.4 but…
Ravi C
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1
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minimalmodbus: No communication with the instrument (no answer) ModBus RTU

I try to establish connection between a Mass flow controller and pc using minimalmodbus python library. Based on device document I have to set the communication port as: Communication speed: 9600 Baud Start bit: 1 Data bits: 8 Stop bits:…
Soprano
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1
vote
0 answers

Reading coil and holding registers concurrently using pymodbus3

I have a working code that can reads the coil status continuously using pymodbus3 library. The code is something like below. This is adapted from a basic sample and serves the purpose of looking for the coil status(address 0x01) change to "1" and…
Arun
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How can i communicate between delta plc with Ethernet support and python pymodbustcp

please help me My first test is with a Delta DVP-12SE11R PLC and the connection is with the Modbus TCP/IP protocol. I have a python code written using pymodbustcp module. I have tested that code with a modbus slave simulator and it is working…
Akash Banaulikar
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1
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0 answers

ModbusTCP: Reverse engineering without having any documents of client(master)

Concept we have a ship simulator(client) and Modbus controller(Server). Our goal is to develop an emulator(like controller) on my PC. But we have no information about the client(simulator). Progress Firstly we checked the actual outputs from the…
Seong Su Byeon
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1
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2 answers

Pymodbus read holding registers

I was assigned to perform the task without any documentation. I have a problem with reading data from MODBUS. This is the script that I was able to create: from pymodbus.constants import Endian from pymodbus.payload import BinaryPayloadDecoder from…
miesiu
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