Post by paulorb on STRUCT AT %MW1000 ^{CODESYS Forge talk (Post)}
Hi I am trying to use STRUCT to parse commands from Modbus/TCP, Modbus client will fill the bytes related to a specific command (type, parameters), then PLC (Codesys) will access the command parameters. A STRUCT will simplify a lot the process of parsing the data, so I don't need to parse byte per byte, address will be mapped to a struct and I can use it for parsing the data. From what I understood, the compiler does not allow me to specify the location of the struct for a %MW register. VAR_COMMAND AT %MW1002: structGenericModbusCommand; This will throw: Bad declaration, use '%ML' for 'structGenericModbusCommand' variable But If I change it to %ML, when you go online you see that it is actually allocating the struct in another memory address. When we go online, on GVL we can see: VAR_COMMAND. structGenericModbusCommand %ML1002 commandType COMMANDTYPE %MB8016 ... %MB8020 I am not specifying a pointer or a reference it is a struct type, why is it mapping to a %MW location (random one). How can I control where it is mapping to? I need a consistent way to map STRUCT to specific modbus address. Is it possible? Thanks, Paulo Note I am using a Codesys OEM: Schneider Machine Expert Logic Builder (M241)
Last updated: 2024-08-13

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

How to use more 4 instances of CANopen/Profibus/Modbus with The application-based license CODESYS Control ^{CODESYS Forge talk (Thread)}
How to use more 4 instances of CANopen/Profibus/Modbus with The application-based license CODESYS Control
Last updated: 2023-11-02

Post by gorditron on Modbus Slave RTU in der Applikation abschalten ^{CODESYS Forge talk (Post)}
Hallo, gibt es eine Möglichkeit die Modbus Slaves (ModbusSlaveComPort) innerhalb der Applikation über ein Variable zu aktivieren oder zu deaktivieren? Bilder als Datei Danke!
Last updated: 2023-11-09

Post by brzozka100 on Change modbus server parameters from program ^{CODESYS Forge talk (Post)}
Hello, is there a possibility to change modbus server parameters (baud rate, parity, etc.) configured in devices tree from PRG? I need to be able to change them, for example, from HMI.
Last updated: 2024-07-16

Post by brzozka100 on Change modbus server parameters from program ^{CODESYS Forge talk (Post)}
Hello, is there a possibility to change modbus server parameters (baud rate, parity, etc.) configured in devices tree from PRG? I need to be able to change them, for example, from HMI.
Last updated: 2024-07-16

Post by wagomikep on Number of Connections to Modbus TCP Slave ^{CODESYS Forge talk (Post)}
Hello, Is there a maximum number of Masters that can connect to a Modbus Slave that is configured in the device tree? Is this limited by the CODESYS IDE, or the manufactures hardware and CPU load? Thank you,
Last updated: 2024-08-01

Post by wagomikep on Number of Connections to Modbus TCP Slave ^{CODESYS Forge talk (Post)}
Hello, Is there a maximum number of Masters that can connect to a Modbus Slave that is configured in the device tree? Is this limited by the CODESYS IDE, or the manufactures hardware and CPU load? Thank you,
Last updated: 2024-08-01

Post by wagomikep on Number of Connections to Modbus TCP Slave ^{CODESYS Forge talk (Post)}
Hello, Is there a maximum number of Masters that can connect to a Modbus Slave that is configured in the device tree? Is this limited by the CODESYS IDE, or the manufactures hardware and CPU load? Thank you,
Last updated: 2024-08-01

Post by wagomikep on Number of Connections to Modbus TCP Slave ^{CODESYS Forge talk (Post)}
Hello, Is there a maximum number of Masters that can connect to a Modbus TCP Slave that is configured in the device tree? Is this limited by the CODESYS IDE, or the manufactures hardware and CPU load? Thank you,
Last updated: 2024-08-01

Post by jacobwago on v3.5 SP19 - Modbus TCP Devices - Channel Limit? ^{CODESYS Forge talk (Post)}
Hello All, The solution is updating SP19 Modbus version from 4.3.0.0 to 4.4.0.0 (see attached image for bug fix). Thank you,
Last updated: 2024-09-30

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 timvh on Modbus TCP & RTU with Control for Linux SL ^{CODESYS Forge talk (Post)}
Most likely your IP address is set to 172.... because you use a VPN connection to your device. Probably best to use the other Ethernet interface for your modbus communication.
Last updated: 2024-10-24

Post by gatto on Application-based license Modbus Channels ^{CODESYS Forge talk (Post)}
Hi Sandro, did you find any solution? I'm in version 3.5.20.40 and i have only one modbus channel. I don't want the problem to happen to me if I do an update one day.
Last updated: 2025-09-01

Post by cmason on v3.5 SP19 - Modbus TCP Devices - Channel Limit? ^{CODESYS Forge talk (Post)}
There still is no solution to this. I am running Modbus version 4.4.0.0 and it still wont let me add more than 10 channels. Does anyone have a solution for this?
Last updated: 2025-09-05

Post by cmason on v3.5 SP19 - Modbus TCP Devices - Channel Limit? ^{CODESYS Forge talk (Post)}
There still is no solution to this. I am running Modbus version 4.4.0.0 and it still wont let me add more than 10 channels. Does anyone have a solution for this?
Last updated: 2025-09-05

Controlling PM564-eth PLC using Weintek HMI with MODBUS TCP/I. I keep getting communication errors. ^{CODESYS Forge talk (Thread)}
Controlling PM564-eth PLC using Weintek HMI with MODBUS TCP/I. I keep getting communication errors.
Last updated: 2021-02-15

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

Post by tobifenny on Modbus TLS Kommunikation ^{CODESYS Forge talk (Post)}
Hier ist das handbuch: https://www.kostal-solar-electric.com/fileadmin/downloadcenter/kse/BA_KOSTAL_Interface_KSEM_DE.pdf Im Kapitel 1.3.2 ist das mit dem TLS beschrieben und in Kapitel 3.6.2 sind die Modbus-Register beschrieben.
Last updated: 2025-11-06

Post by ggaida on runtime dynamic modbus devices ^{CODESYS Forge talk (Post)}
Kurtk, I am working through a very similar scenario. I am curious if you have had any success since your post in implementing dynamic modbus configurations? Thx!
Last updated: 2025-11-20

Post by ggaida on runtime dynamic modbus devices ^{CODESYS Forge talk (Post)}
Kurtk, I am working through a very similar scenario. I am curious if you have had any success since your post in implementing dynamic modbus configurations? Thx!
Last updated: 2025-11-20

Post by jp23 on Unable to Connect to Modbus RTU Device ^{CODESYS Forge talk (Post)}
Hi all, I am attempting to use the Control Win V3 soft PLC to control a WAGO 750-315 remote I/O system via modbus RTU communication. I am struggling to connect to the device. I have been following this tutorial: https://www.youtube.com/watch?v=YlRfkESaNds I have setup my devices as shown in the images below. I have verified that my com port settings are correct as I am able to connect/control using modbus simulator software with these settings. I have also connected to a modbus master simulator program as instructed in the video, but the orange triangles will not go away. Additionally, I have updated my settings to 485 using the PLC shell. I have also set "always update variables" to enabled (1). Serial port, PCI-Bus, and modbus serial device status all show as "Not Running."
Last updated: 2024-08-26

Post by jp23 on Unable to Connect to Modbus RTU Device ^{CODESYS Forge talk (Post)}
Hi all, I am attempting to use the Control Win V3 soft PLC to control a WAGO 750-315 remote I/O system via modbus RTU communication. I am struggling to connect to the device. I have been following this tutorial: https://www.youtube.com/watch?v=YlRfkESaNds I have setup my devices as shown in the images below. I have verified that my com port settings are correct as I am able to connect/control using modbus simulator software with these settings. I have also connected to a modbus master simulator program as instructed in the video, but the orange triangles will not go away. Additionally, I have updated my settings to 485 using the PLC shell. I have also set "always update variables" to enabled (1). Serial port, PCI-Bus, and modbus serial device status all show as "Not Running."
Last updated: 2024-08-26

Post by jp23 on Unable to Connect to Modbus RTU Device ^{CODESYS Forge talk (Post)}
Hi all, I am attempting to use the Control Win V3 soft PLC to control a WAGO 750-315 remote I/O system via modbus RTU communication. I am struggling to connect to the device. I have been following this tutorial: https://www.youtube.com/watch?v=YlRfkESaNds I have setup my devices as shown in the images below. I have verified that my com port settings are correct as I am able to connect/control using modbus simulator software with these settings. I have also connected to a modbus master simulator program as instructed in the video, but the orange triangles will not go away. Additionally, I have updated my settings to 485 using the PLC shell. I have also set "always update variables" to enabled (1). Serial port, PCI-Bus, and modbus serial device status all show as "Not Running."
Last updated: 2024-08-26

Post by jp23 on Unable to Connect to Modbus RTU Device ^{CODESYS Forge talk (Post)}
Hi all, I am attempting to use the Control Win V3 soft PLC to control a WAGO 750-315 remote I/O system via modbus RTU communication. I am struggling to connect to the device. I have been following this tutorial: https://www.youtube.com/watch?v=YlRfkESaNds I have setup my devices as shown in the images below. I have verified that my com port settings are correct as I am able to connect/control using modbus simulator software with these settings. I have also connected to a modbus master simulator program as instructed in the video, but the orange triangles will not go away. Additionally, I have updated my settings to 485 using the PLC shell. I have also set "always update variables" to enabled (1). Serial port, PCI-Bus, and modbus serial device status all show as "Not Running."
Last updated: 2024-08-26

Sort by relevance or date