Stack Overflow
Stack Overflow

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
1
vote
1 answer

Multi-master in Modbus TCP

I have a weird problem with multi-master in Modbus TCP/IP. I know that Modbus Serial doesn't support multi master. But when I saw some documents, they said Modbus TCP supports multi master. I composed three tcp clients as Modbus TCP master and a…
chatgray
  • 33
  • 1
  • 6
1
vote
1 answer

How does port numbering works for receiving MODBUS TCP packets?

I am running an application on my microcontroller(MSP432), which writes data to an Ethernet cable to send it over to PC. I am using Packet sender to view the data received on the port(502) on PC from MC. Data received on PC As we can see in the…
JKV
  • 13
  • 5
1
vote
0 answers

Understanding modbus tcp output (reading temperature from thermocouple)

Upon reading an input register, I get the following output: 0x0 0x1 0x0 0x0 0x0 0x5 0x1 0x4 0x2 0x4 0xf3 I'm trying to convert the data portion (0x4 0xf3) into a recognizable temperature. Any help? I'm using a T type thermocouple. I have…
climbx5
  • 85
  • 1
  • 8
1
vote
1 answer

Trouble reading from PLC with pymodbus

I'm having some trouble reading registers from my WAGO 750-881 PLC using pymodbus, python 2.7, and Windows. I can read just fine with the Modbus Poll utility so I think the problem is in my python code. Using the following code I get the error:…
Mike C.
  • 1,761
  • 2
  • 22
  • 46
1
vote
2 answers

trying to build a MODBUS packet with scapy

i'm trying to build a MODBUS packet with scapy, but Wireshark can't recognize it. i mean, the MODBUS interpreted as the TCP data. here is the python code of Scapy: from scapy.all import * class Modbus(Packet): name = "Modbus/tcp" …
Amit_A
  • 11
  • 1
  • 2
1
vote
1 answer

Pymodbus Failed to Connect with PLC Slave and Raspberry Pi Master

I am trying to use a Raspberry Pi 3 Model B to read values from an Allen Bradly PLC. I'm using the Pymodbus Modbus TCP protocol to communicate between them. When I run a test client I get the following error: pi@raspberrypi:/var $ python…
LongCount
  • 13
  • 1
  • 5
1
vote
1 answer

How do you implement Modbus Function 20 using C#?

I've just been working on a project using this Modbus TCP library (https://github.com/stephanstricker/modbusTCP/tree/master/ModbusTCP/ModbusTCP) and this documentation for a reference to Function 20…
Mark
  • 768
  • 3
  • 8
  • 26
1
vote
2 answers

Modbus TCP - Arduino

I have to implement a Modbus TCP using a TI Launchpad board which is similar to Arduino. I have the following snippet. MbmByteArray[0] = 0x00; MbmByteArray[1] = 0x01; MbmByteArray[2] = 0x00; MbmByteArray[3] = 0x00; MbmByteArray[4] =…
Pr_123
  • 31
  • 5
1
vote
3 answers

LABVIEW - Show Modbus data on a historical trend

I've made a VI using modbus API and managed to connect to an HMI and read some data. I want to save this data in a file, also show this data on a historical trend even after a reset due to power failure. Which component should I use?
Ahmad Mansouri
  • 71
  • 1
  • 6
1
vote
2 answers

The right way, to continuously query a Modbus in Java (JAMOD)

I wanted to ask how to query every second Modbus, using the JAMOD library. Decided to make a preliminary connection to Modbus and then, within a loop while(true) query the Modbus. After interrogating the device, use a Thread.sleep (1000); is the…
JoeJoe
  • 83
  • 1
  • 12
1
vote
1 answer

Modbus TCP Slave Thread - set & get registers values

According to this howToModbusSlave I am trying to build my own modbus slave with registers of chosen value (later I wanna fill these values with data from monitored device using python/jython) and send them away using Predix (cloud platform). Since…
Dlike
  • 73
  • 1
  • 1
  • 8
1
vote
0 answers

Modbus TCP Python Server not working

I am trying to use asynchronous modbus server based to stream multiple values of data but I simply see zeros. Please help. My code is based on https://pymodbus.readthedocs.io/en/latest/examples/asynchronous-server.html #!/usr/bin/env python ''' #…
newadays
  • 11
  • 4
1
vote
2 answers

Modbus TCP/IP on Arduino

I am trying to implement Modbus TCP on arduino uno + ethernet shield using the following code. I am using a modbus slave simulator on a pc to check the following code. However, the code doesn't seem to be working. I have downloaded the code & the…
hs7624
  • 693
  • 2
  • 10
  • 20
1
vote
1 answer

Can I specify endianness when reinterpreting as a float?

I am writing a C program that communicates over modbus TCP. I send the float 3.14 on my modbus client, with a hexadecimal representation of 0x4048F5C3. My C code is correctly receiving the modbus packet, and now I just need to reinterpret the…
DJMcMayhem
  • 7,285
  • 4
  • 41
  • 61
1
vote
1 answer

Modbuspal slave and Jamod as tcp master

I'm using Modbuspal simulator as slave and Jamod tcp master code as master. The following is my Jamod tcp master code to read data from registers: import java.net.InetAddress; import net.wimpi.modbus.io.ModbusTCPTransaction; import…
user2782405
  • 393
  • 1
  • 6
  • 20
1 2 3
…
19 20