316 questions
1
vote
0
answers
31
views
PyModbus server returns wrong register values
I'm learning PyModbus and facing an issue with register values being read incorrectly by the client.
Server stores values [16689, 39322] in holding registers
Client reads [39322, 0] instead
The ...
1
vote
0
answers
46
views
Modbus TCP register returns unexpected value from EM Modbus Gateway IFS (Phoenix Contact)
I'm trying to read power consumption data (e.g., P_ALL, total active power) from a Phoenix Contact EMM 3-24DC/500AC-90-EXM-IFS device via a MODBUS-GATEWAY-IFS over Modbus TCP using Python (pymodbus).
...
- 11
0
votes
1
answer
68
views
SQL Function to Swap Words for 32-Bit Float Modbus Data
I have a Power Meter that communicates via Modbus TCP/IP. I'm using Kepware to retrieve the data and store it in a Microsoft SQL database. The Holding Register I'm pulling contains 32-bit float values,...
- 29
0
votes
0
answers
192
views
Modbus tcp communication issues while using Twincat
I am using C# application to read and write data from a beckhoff ipc running twincat3. I am writing data to holding registers based on some events acyclically. Sometimes the data is write is not ...
- 11
0
votes
1
answer
570
views
Resulting byte order for 2 Modbus register: low word, high word. Little endian
I have a requirement to encode 32bit signed integer in two consecutive modbus 16bit register.
The requirement say that the byte order should be little endian and the lower address register should be ...
- 5,519
1
vote
0
answers
183
views
Using Apache Nifi with Plc4xSourceProcessor to read modbus data
I'm using Apache Nifi 1.22.0 and Plc4xSourceProcessor 0.12.0 to read ModBus data.
Connection string: modbus-tcp://xx.xx.xx.xx:port seems to work fine.
I'm trying to read from 30001 (Read Input ...
2
votes
0
answers
125
views
Is there a way to use Modbus Function Code 23 from server to write data via DataBank() with pyModbusTCP?
I am using pyModbusTCP library to exchange data with a tool. The tool only supports Modbus Function Code 23 (Read Write Registers) and can only act as a Modbus Client and a TCP Master. I am able to ...
0
votes
1
answer
852
views
Waveshare POE TCP Modbus Relay configuration connecting but not reading or writing
I have a Waveshare 8-channel Modbus POE ETH Relay and I’m really struggling with getting it integrated into Home Assistant.
I have been able to connect in python using pymodbus TCP client, and I also ...
- 2,257
0
votes
0
answers
594
views
Modbus TCP request timeout
I'm using https://github.com/simonvetter/modbus. I'm able to open a connection with the device, but requests to read registers always timeout.
My first time using modbus. Can anyone tell me what the ...
- 191
0
votes
1
answer
373
views
PortNotOpenError while connecting to Modbus
I am trying to connect to Modbus TCP using the modbus-serial library for JavaScript. I have confirmed that I am using the correct IP address and port. My network doesn't have a firewall and if it does,...
1
vote
1
answer
237
views
PyModbusTCP reading different values than actual ModBus values?
I am trying to read from registers 40001 to 40004 through PyModbusTCP, when reading value 40001 on PyModbusTCP I am not reading the same value that is shown on the screen of the equipment and the one ...
- 11
0
votes
1
answer
104
views
Why can't read the correct data in python with modbus?
I am trying to get data from a power network meter (https://www.lumel.com.pl/resources/Pliki%20do%20pobrania/ND25/ND25_service_manual_Interface.pdf),
but the data I get isn't "understandable"...
- 3
1
vote
1
answer
172
views
modbus c++ library modbuspp with X20PS9400a B&R
I cannot set a digital output / coil on X20PS9400a B&R using modbuspp library
I tried, unsuccessfully, to run the following example to set up a digital output on the X20PS9400a B&R:
#include &...
- 45
0
votes
1
answer
206
views
insconsistent modbus server client relation
I am simulating a Modbus server client connection in VM (Ubuntu). The server is running and writing a random value on a register. The client is supposed to read the random written value from the ...
-2
votes
1
answer
2k
views
Modbus 485 Communication In Case of 2 or more Masters/Clients
I am curruntly working on building industrial application. I have a Slave - PCB device built on STM32 that gets data from the sensors. It transfers serial data in every 5 seconds through RS485 USB ...
1
vote
2
answers
549
views
modbus register conversion
I'm using the easy modbus library and reading the ambient temperature with a pt-100 and a plc fl055 0808n v2, when my temperature reaches 30 degrees celsius, it begins to show random negatives numbers ...
0
votes
1
answer
465
views
Efficient algorithm for modbusaddress scan on multiple connected devices in Python
I am trying to connect to multiple (20) separate devices using Modbus TCP. Since it is beforehand not known what the modbusaddresses are (devices are changed regularly), I want to implement a modbus ...
- 76
0
votes
1
answer
484
views
Problem establishing connection over Python Modbus TCP to a Mitsubishi Inverter
I am trying to establish a Modbus connection from a laptop to a Mitsubishi inverter (FR A-800 E series) (the manual for this connection can be found [here][1])
I am using pymodbus and I can establish ...
1
vote
0
answers
783
views
Write data ower Modbus tcp to HUAWEI SUN2000 KTL error
I would like to change the PV inverter settings via Modbus TCP.
the system reads correctly when I write I get an error!!!
I use Raspberry PI and Python.
Modbus address is 40125 and data is RW (...
- 15
0
votes
2
answers
4k
views
How do i make a modbus simulation?
I am trying to make a Modbus simulation in python and a Modbus client to read the values from the server.
But i keep getting this error:
Here is my server code:
import random
from pymodbus.datastore ...
0
votes
2
answers
893
views
ModbusTcpClient: How to read long integer values from Input registers in python
I am trying to get data from a sensor using ModbusTcpClient as below
client = ModbusTcpClient('xx.xx.xx.xx', port=502)
connection = client.connect()
request = client.read_input_registers(220,2, unit=...
- 797
1
vote
2
answers
913
views
Reading modbus registers
I have python script which reads registers from energy meter and saves values to database.
Script was working fine until today when i tried to run it and i got error:
AttributeError: '...
user13592259
-1
votes
1
answer
1k
views
Values received over Modbus TCP are much higher than expected
I have some measurements coming in from over Modbus TCP/IP and I have successfully identified the values that I'm trying to measure.
However the values all differ by some amount from the measurements.
...
- 55
0
votes
1
answer
883
views
How do I view raw memory addreses of MODBUS TCP/IP holding registers in CODESYS
For a work project, I have to read a bunch of holding registers from an IFM CR1203 PLC that is programmed using CODESYS 3.5.
The PLC will be running a slave instance and the device reading the holding ...
user19365766
1
vote
0
answers
230
views
Linux libmodbus multi thread free(): double free detected in tcache 2 Aborted (core dumped)
Hi all im working in linux libmodbus tcpip server client process I am reading the data from 3 different server, when all the server are connected then there is no issues but when i disconnect one ...
- 11