Post by nano on Dynamic setting of the modbus tcp/ip slave ip address
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habe a look to this faq, this should work for u https://faq.codesys.com/plugins/servlet/mobile?contentId=24510471#content/view/24510471
Last updated: 2024-02-17
Post by ph0010421 on Sending Sequential Modbus TCP Packets
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Hello You'll need to write a proper sequence to send, then wait for confirmation, and then move on to the next step. Use the CASE statement in ST. It's perfect for creating a sequence.
Last updated: 2024-03-08
Post by vincentger on v3.5 SP19 - Modbus TCP Devices - Channel Limit?
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Any resolution on this? I have currently 75 channels in my project that i brought up from SP18, which means i am 65 Channels above the new limitation?
Last updated: 2024-04-09
Post by nulltrace on How change Unity-ID in TCP Modbus Slave
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Hey Husarz. i don't forget you, the Thing is, to give you my answer, i have to wait for Answer from Codesys/E. Schwellinger. i suspect Mr. Schwellinger is on in Vacations that week. so please, be patient at moment
Last updated: 2026-04-10
Post by nulltrace on How change Unity-ID in TCP Modbus Slave
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Hey Husarz, thanks for your Message, now i understand your Problem, also able to reproduce that. Pls. give me a Short Time to Check some stuff on this, i'll come back to this Topic with news ASAP. Greetings
Last updated: 2026-04-03
Post by nulltrace on How change Unity-ID in TCP Modbus Slave
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Hey, I also waiting for feedback from Mr. Schwellinger @eschwellinger, please send me an answer, i would appreciate it. The clue is, i know the solution, but have to check if it's allowed to share.
Last updated: 2026-04-14
Post by husarz17 on How change Unity-ID in TCP Modbus Slave
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Good to know there's a solution to this problem. I hope you'll be able to share it with me. I can't wait to hear about it.
Last updated: 2026-04-20
Post by timvh on Modbus TCP & RTU with Control for Linux SL
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RS485 doesn't seem very logical to use in VPLC's in my opinion. I also don't know if this is supported.... But for TCP/IP, I think you still need to configure the Nic settings. See the attached png. In my case enp6s0. When changing this setting, restart the VPLC. What is really nice, is that you don't have to configure the IP address setting in Linux. By setting the Nic to a certain IP address in the CODESYS instance configuration, this is automatically done for you. I only tested this with EtherCAT, but I guess this works the same for Modbus TCP/IP.
Last updated: 2024-10-23
Post by ofey on Modbus TCP communication
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Hi! I tried setting up the PLC I'm working with (Beijer GN-9373) to connect to a modbus master running on a laptop. I have an ethernet connection (via USB-C to ethernet) between the laptop and the controller. I have tried following tutorial on how to set this up. I have added an ethernet device with the IP-address of the PLC. Further I added a ModbusTCP_Slave_Device with default settings. I get the error "Failed to open TCP Port: 1" when I try to go online with the PLC. Earlier I tested the exact same set up with the soft PLC from codesys. I can then read/write values correctly with the Modbus master i have running on the laptop. Hope anybody can help me with this, thanks in advance!
Last updated: 2023-10-06
Post by jens on Modbus tcp - channel
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Help wanted This is the first time i'm doing a Modbus Tcp project. I have some VLT with a extension module MCA-122. i'm currently unable to write to the VLT slave, but i can read from status word parameter=1603 and address := 16029 where the address is calculated from parameter is ((id x 10)-1). in the manual the functions that are supported are 3 hex, 6 hex, 10 hex, b hex and 11 hex. read holdin registers, write single register, write multiple registers, get comm. event counter, report slave id. i'm only using the Modbus Slave Channel is this wrong when trying to write to the vlt ?
Last updated: 2024-06-13
Post by kislov on CODESYS Modbus 4.4.0.0 - Modbus network redundancy
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Hi. There is next information in CODESYS Modbus 4.4.0.0 Release Notes: "Modbus network redundancy" How to use this feature? As I understand, new fields in STUCT ModbusTCPComSettings are associated with it, but more detailed information is needed.
Last updated: 2024-10-07
Post by hanpekel on Reading request counter value from modbus server in application
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Any way I can read the value of the 'request counter' (see screenshot) in my application. Amount of client connections is easily found using ModbusTCP_Slave_Device.uiClientConnections; But for request counter it does not seem to be that simple.
Last updated: 2024-10-16
OPC UA Client unable to connect to CeDeSys OPC UA Server but able to connect to other OPC UA Server
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OPC UA Client unable to connect to CeDeSys OPC UA Server but able to connect to other OPC UA Server
Last updated: 2018-10-30
Post by jeroenaero on Difference between using OPCUA symbol configuration and OPCUA Server object
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Hi, What is exactly the difference between using symbol configuration as OPCUA server or using the Codesys object OPCUA server? What are the advantages and disadvantages of using symbol configuration and OPCUA server object. Please let me know
Last updated: 2025-10-30
Post by fmon on Modbus : dis- / re-connect cable: modbus does not re-start
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Problem solved The client modbus cycle time was linked to a task at 500ms. Whereas the channel modbus was at 200ms. Certainly problem of packages synchronisation. I let the client modbus cycle time to be handled by itself (See attachement) --> "Use the bus cyle time parameters" (traduce from french) See attachement
Last updated: 2025-03-18
Post by rh-pk on v3.5 SP19 - Modbus TCP Devices - Channel Limit?
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Hi, i found a solution for me. I had installed a 'old' version of CoDeSys (3.5.18 P5). I tried to add channels there, which works fine. I created a new project, added an Ethernet-Port, added a Modbus-Master and then I copied the ModBus-Slave from my working project to the new project. Now I could add more channels. I add the channels 10 and 11. Then I deleted (please make a backup before :-) the original ModBus-Slave in my working project and copied the extended Slave back to my working project. Surprisingly it is now possible to add new channels. Maybe this will help you.
Last updated: 2024-02-14
Post by egr99 on Modbus TCP Server connection is ESTABLISHED but all holding registers are value 0?
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You're absolutely right. Sorry for that. In the meantime I wrote a Function block to handle the reads and writes to the different attached RTU-devices. It processes the parameter like (str_Modbus:=(usiSlave:=1, uiFC:=5, uiLEN:=1, uiOFFSET:=0, uiInterval:=500)) and the corresponding output, waits for the response and processes next request in a 5-state procedure. It's working for 2 gateways (stable without errors, although error recovery is included). But nevertheless it should be possible with the Channel definitions of Codesys. Much easier to maintain :)
Last updated: 2026-04-08
What the right way to update TCP/COM slave device holding registers
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What the right way to update TCP/COM slave device holding registers
Last updated: 2024-07-01
Post by sinameshksar on TCP Socket Client
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Hello I'm looking for a TCP socket client project example. Can you assist?
Last updated: 2024-09-11
How can i program a TCP/IP communication on softlinkARM?
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How can i program a TCP/IP communication on softlinkARM?
Last updated: 2011-06-28
Yellow triangle and bus not running error in Modbsu TCP master and Slave.
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Yellow triangle and bus not running error in Modbsu TCP master and Slave.
Last updated: 2021-12-07
Yellow triangle and bus not running error in Modbsu TCP master and Slave.
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Yellow triangle and bus not running error in Modbsu TCP master and Slave.
Last updated: 2021-12-07
can I send data over udp/tcp in simulation mode?
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can I send data over udp/tcp in simulation mode?
Last updated: 2016-06-05
CAA net base TCP client cause PLC to crash - Kernel message : N0HZ_local_softirq_pending 80
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CAA net base TCP client cause PLC to crash - Kernel message : N0HZ_local_softirq_pending 80
Last updated: 2024-01-12
Post by simover on TCP/IP client
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I want to send a string to a tics TCP/IP server. I got i working with the Net Base lib. for communication good with this tcis i need to by array of byte I want to include a string in the third position of the array TCIS_Send[1] :=254; //this valus is fix for evry communication TCIS_Send[2] :=80; //this valus is fix for evry communication TCIS_Send[3] := ; here I put my and my string is lik this 5806509-DRAP10#AB#3452302073 TCIS_Send[4] :=252; //this valus is fix for evry communication
Last updated: 2023-12-18
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