How to read the status of one Modbus Slave in the codesys program ^{CODESYS Forge talk (Thread)}
How to read the status of one Modbus Slave in the codesys program
Last updated: 2021-08-15

Post by joshuav on Modbus TCP Codesys V3.5 SP19 + (64-bit) ^{CODESYS Forge talk (Post)}
Last updated: 2023-12-06

Post by ulvis on Modbus TCP Security ^{CODESYS Forge talk (Post)}
Anyone?
Last updated: 2025-02-06

Post by ulvis on Modbus TCP Security ^{CODESYS Forge talk (Post)}
Anyone?
Last updated: 2025-02-06

Post by dkugler on Modbus RTU Slave ^{CODESYS Forge talk (Post)}
Variablen aktualisieren aktiviert?
Last updated: 2023-12-06

Post by schorge on Modbus RTU Slave ^{CODESYS Forge talk (Post)}
ja
Last updated: 2023-12-10

Post by husarz17 on How change Unity-ID in TCP Modbus Slave ^{CODESYS Forge talk (Post)}
I need the same issue. In my application TCP server on raspberry (codesys) should have UnitID 1. But it only works when I am requesting with UnitID 255. And my application can't work with this parameters...
Last updated: 2026-03-31

Post by banialuk on Modbus TCP Server ^{CODESYS Forge talk (Post)}
I created Modbus Server TCP, but when I try started i have a error "TCP socet error" "Error on open/close/read/write TCP socket."
Last updated: 2024-10-21

Post by laazik2 on v3.5 SP19 - Modbus TCP Devices - Channel Limit? ^{CODESYS Forge talk (Post)}
I am actually wondering as well if there are plans to fix it or not? As adding two modbus devices creates it's own problems with connection limits and other issues, which some slave devices have.
Last updated: 2023-09-05

Post by squiggleypuff on Can't Add New Version of Modbus TCP Master ^{CODESYS Forge talk (Post)}
Turns out Modbus was working despite the pre-compiler errors; I was reading the wrong addresses of the slave device, which was why I was seeing all 0s. Thanks for ignoring me.
Last updated: 2024-04-09

MODBUS: ^{CODESYS Forge talk (Thread)}
MODBUS:
Last updated: 2023-08-14

MODBUS: ^{CODESYS Forge talk (Thread)}
MODBUS:
Last updated: 2023-08-08

MODBUS: ^{CODESYS Forge talk (Thread)}
MODBUS:
Last updated: 2021-02-09

MODBUS: ^{CODESYS Forge talk (Thread)}
MODBUS:
Last updated: 2021-02-09

Post by xnoop on MBTCP Slave configuration ^{CODESYS Forge talk (Post)}
Hello, I use Codesys 3.5 SP18 Patch 4 (64 bit) My Codesys project is composed of several dozen of Modbus TCP Slaves. I want to configure each of them by define : - Modbus TCP Slave Configuration : Name, IPAddress, port - Channels - Mapping I can't afford to configure manually and I need to find automatic way What possibilities does the Codesys offer? 1. I know it possible to use python script to create Modbus TCP Master and Slave. But I don't find anyway to create Channels and Mapping through the API 2. I 've tested to set mapping with file.csv on a Modbus Tcp Slave, but no way to import channels definition from file 3. I 've tried to use PLCOpenXml file. For example I 've create a project with an Ethernet device. I've exported it in PlcOpenXml file. After delete the Ethernet device, I've imported the PlcOpenXml file without success. I've tried the same by creating Modbus TCP Slave. Could you help me to find to good way ? Thanks
Last updated: 2024-06-19

Post by timvh on Modbus TCP Client ^{CODESYS Forge talk (Post)}
The Modbus Master example must work. We have used this several times on multiple projects. See https://forge.codesys.com/prj/codesys-example/modbus/home/Home/
Last updated: 2024-11-05

CODESYS Modbus 4.4.0.0 - Modbus network redundancy ^{CODESYS Forge talk (Thread)}
CODESYS Modbus 4.4.0.0 - Modbus network redundancy
Last updated: 2024-10-08

Post by nulltrace on Modbus TCP Server connection is ESTABLISHED but all holding registers are value 0? ^{CODESYS Forge talk (Post)}
your case looks different, the first one was an codesys modbus tcp-slave, your's an Master-Application with gateway. I dont know this Unit, but i would say, from Point of Codesys it looks wrong configured. Just give us more detailed configuration and the please make a sketch of the topology you're trying to realise.
Last updated: 2026-04-08

Post by joanm on Programmatically change the IP addresses of the Modbus TCP slave devices ^{CODESYS Forge talk (Post)}
Hello all, I am working in a project in which there are multiple Modbus TCP slaves. I need to be able to change the IP addresses of those devices from the HMI and I was planning to use the process depicted here: https://faq.codesys.com/display/CDSFAQ/Modbus+TCP+Slave%3A+Dynamic+Setting+of+the+IP+Address I can see the port number is what is used to specify which slave device we want to modify the IP address of. This said, can I freely set arbitrary port numbers to each device? I mean, can I set the first device to be at port 502, the second one at port 503... Any drawback or restriction? Is there any other way to reference to the device without having to change the port numbers? Thank you all in advance.
Last updated: 2024-01-04

Post by tokamk on Dynamic setting of the modbus tcp/ip slave ip address ^{CODESYS Forge talk (Post)}
Hello, I'm working on a project which includes Panel-PC which communicates with a PLC through Modbus TCP/IP. On the PLC I have a CODESYS code which has Modbus slave objects. The Modbus slave objects have to have manually set IP address in order for them to work properly and the Ip address has to be the PC-Panels's IP. This project is going to a customer and they're using their own IP address realm. So, my question is that is it possible to configure these slaves in some other way, so that the customer doesn't need to modify the CODESYS project? I was thinking that would it be possible to set the IP address of these slaves from external source?
Last updated: 2024-02-15

Post by wbj0t on What the right way to update TCP/COM slave device holding registers ^{CODESYS Forge talk (Post)}
Hi all :) I have an plc. This plc has option to be as slave device. There are TCP -> Serial Slave Device and COM -> Serial Slave Device. There are 4096 ModBus holding registers with mark "internal modify" for the both devices above. So, COM Slave has 4096 registers and TCP Slave has 4096 registers. And, finally, I have an ARRAY[0..4095] OF WORD. This array glued with COM Slave and TCP slave. Yes, I need plc's opportunity to be communication both TCP and COM ways for the same registers. For example, the next task structure: * TASK_0: 1. pou_READ_Registers 2. pou_0 3. pou_1 4. ... 5. pou_N 6. pou_WRITE_Registers At the first pou I read registers for the other pous, after job we have sort of state of the plc. At the last pou (6) we write modified registers. It is a good scenario: some one wrote registers for the job, after job we save these (modified) registers. But, what if registers wrote between 1 and 6 pou by operator, for example, at the 3 pou -> the last pou 'pou_WRITE' will rewrite this request from operator. What the right way to work with this logic? Thanks you.
Last updated: 2024-07-01

Post by jens on Modbus tcp - channel ^{CODESYS Forge talk (Post)}
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 thysonfury on OPTO22 Groov Epic PR2 Modbus Comms Dropping out every 2 hours and 4 Mins ^{CODESYS Forge talk (Post)}
Hi after some assistance with an error on a Groov PR2 PLC. We have a few different communications set up as shown below: One Modbus TCP Slave Connection - ( Sending / Receiving Data from a PC ) Two Modbus TCP Master Connection - ( Reading Data from a UPS Panel and Reading Data Gas Chromatograph) One Modbus RTU Slave Connection 485 - (Reading Data from a fire and gas panel) One Modbus RTU Master Connection 485 - (Sending Data to a Telemetry Unit) All Licenses have been installed as per OPTO22 suggestions of the order below: Modbus TCP Master Modbus TCP Slave Modbus RTU Master Modbus RTU Slave When I check on License manager the RTU Master license seems to disappear on installing the RTU. (What ever reason I’ve been told this is “normal”). If I use Device License Read It will successfully read all the licenses correctly. Now the issue is every 2 hours and between 4. For what ever reason the communications seems to end and lock up for about 20 seconds. During this time even if I was logged into the PLC it would kick me off and I’d have to re type the password to enter. Most of the devices can handle this however the RTU flags up a communications failure at the SCADA and is raising alarms every 2 hours and 4 mins. We’ve had multiple people go through the code to check for anything obvious. Does anyone have any ideas?
Last updated: 2024-04-15

Post by thysonfury on OPTO22 Groov Epic PR2 Modbus Comms Dropping out every 2 hours and 4 Mins ^{CODESYS Forge talk (Post)}
Hi after some assistance with an error on a Groov PR2 PLC. We have a few different communications set up as shown below: One Modbus TCP Slave Connection - ( Sending / Receiving Data from a PC ) Two Modbus TCP Master Connection - ( Reading Data from a UPS Panel and Reading Data Gas Chromatograph) One Modbus RTU Slave Connection 485 - (Reading Data from a fire and gas panel) One Modbus RTU Master Connection 485 - (Sending Data to a Telemetry Unit) All Licenses have been installed as per OPTO22 suggestions of the order below: Modbus TCP Master Modbus TCP Slave Modbus RTU Master Modbus RTU Slave When I check on License manager the RTU Master license seems to disappear on installing the RTU. (What ever reason I’ve been told this is “normal”). If I use Device License Read It will successfully read all the licenses correctly. Now the issue is every 2 hours and between 4. For what ever reason the communications seems to end and lock up for about 20 seconds. During this time even if I was logged into the PLC it would kick me off and I’d have to re type the password to enter. Most of the devices can handle this however the RTU flags up a communications failure at the SCADA and is raising alarms every 2 hours and 4 mins. We’ve had multiple people go through the code to check for anything obvious. Does anyone have any ideas?
Last updated: 2024-04-15

Post by thysonfury on OPTO22 Groov Epic PR2 Modbus Comms Dropping out every 2 hours and 4 Mins ^{CODESYS Forge talk (Post)}
Hi after some assistance with an error on a Groov PR2 PLC. We have a few different communications set up as shown below: One Modbus TCP Slave Connection - ( Sending / Receiving Data from a PC ) Two Modbus TCP Master Connection - ( Reading Data from a UPS Panel and Reading Data Gas Chromatograph) One Modbus RTU Slave Connection 485 - (Reading Data from a fire and gas panel) One Modbus RTU Master Connection 485 - (Sending Data to a Telemetry Unit) All Licenses have been installed as per OPTO22 suggestions of the order below: Modbus TCP Master Modbus TCP Slave Modbus RTU Master Modbus RTU Slave When I check on License manager the RTU Master license seems to disappear on installing the RTU. (What ever reason I’ve been told this is “normal”). If I use Device License Read It will successfully read all the licenses correctly. Now the issue is every 2 hours and between 4. For what ever reason the communications seems to end and lock up for about 20 seconds. During this time even if I was logged into the PLC it would kick me off and I’d have to re type the password to enter. Most of the devices can handle this however the RTU flags up a communications failure at the SCADA and is raising alarms every 2 hours and 4 mins. We’ve had multiple people go through the code to check for anything obvious. Does anyone have any ideas?
Last updated: 2024-04-15

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