Post by egr99 on Modbus TCP Server connection is ESTABLISHED but all holding registers are value 0?
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Hi there, Read the above description and experienced the same: Reading coil/discrete input/input register/holding register doesn't fill the mapped I/O variable. Any suggestions? Defined (see attachment): - Ethernet (with parameters according to the used Ethernet adapter of my Windows 11 laptop) - -Modbus TCP Client - - -LOGO231 as Modbus TCP Server - - -WS242 as Modbus TCP Server (WaveShare Modbus TCP <-> RTU converter) - - - -WS242_01 as Modbus Server, COM port (slave-id 1 RTU) - - - -WS242_03 idem (slave-id 3 RTU) - - - -WS242_11 idem (slave-id 11 RTU) Writing coil/holding register works from a mapped I/O variable works fine. Verification of Modbus traffic with WireShark: QUERY to and the RESPONSE of all slave-ids are correct Status of all defined is CONNECTED, RESPONSE_SUCCESS, RUNNING etc. Request counters increase with expected frequency. Error counter = 0. (To have all counters works fine I had to change Modbus TCP Client's parameter OptimizationON to FALSE). LOGO231 works fine: values in mapped I/O conform expectation WS242 without Modbus Server, COM port and with defined channels (for only 1 slave-id possible) works fine. PLC Settings: Update I/O while in stop: I see xBusy changing from FALSE to TRUE and vice versa. Always update variables: Enabled 1
Last updated: 2026-04-05
Post by darwin03 on Mismatch between coordinate monitor and actual motion using SMC_GroupJog2, MC_MoveLinearAbsolute (6DOF)
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Hi Guys!!! I am experiencing an issue when trying to move 6DOF using SMC_GroupJog2 and MC_MoveLinearAbsolute, but I don't understand why, when I jog only X or Y, the coordinate I monitor just changes the X or Y value. It's true, but in reality, Joint6 is still running like the video. Am I wrong somewhere? Many thanks for considering my request.! Video: https://drive.google.com/drive/folders/1vRHQ3AtTO3mijptqZgn5OcP9pyi527Jm?usp=sharing
Last updated: 2026-04-06
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
Fuzzy Logic PID Controller
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Fuzzy Logic PID Controller
Last updated: 2025-11-18
Post by nulltrace on Modbus TCP Server connection is ESTABLISHED but all holding registers are value 0?
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it works pretty well on codesys-version using device-tree and channels. heres the twist: each uid should be represented as a device, which in your case, it isn't. on the other hand, you found a solution which already works fine. Happy Modbus'ing
Last updated: 2026-04-09
Modbus TCP Server connection is ESTABLISHED but all holding registers are value 0?
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Modbus TCP Server connection is ESTABLISHED but all holding registers are value 0?
Last updated: 2026-04-09
Post by tomstix on JSON_Utilities_SL JSONFileWriter error NULL_POINTER
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Hi, did you ever find an answer to this?
Last updated: 2026-04-09
Combo box drop-down invisible
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Combo box drop-down invisible
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JSON_Utilities_SL JSONFileWriter error NULL_POINTER
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JSON_Utilities_SL JSONFileWriter error NULL_POINTER
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Post by confre on Combo box drop-down invisible
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Hi, I created a combo box and I need to know when the drop‑down menu is open, in order to avoid hiding the combo box while the drop‑down is visible. Alternatively, if it’s not possible to detect whether the drop‑down is open, I would like to know how to close or hide the drop‑down programmatically when the combo box is made invisible. I'm using Codesys 3.5 SP19 on IFM CR1074 without touch screen (with standard keyboard handling) Thanks.
Last updated: 2026-04-09
Post by buczekj on ERROR: Calling the program "AlarmStorage_Prg" is not allowed from multiple tasks
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Many issues with the alarmmanager and alarmstorage can be solved by deleting the configuration, rebooting, and redownloading. I've found that the configurator doesn't always update when you make chanegs. For linux installations it is typically located in /var/opt/codesys/PlcLogic/alarms/ look for file Application.AlarmConfiguration.xml cd /var/opt/codesys/PlcLogic sudo rm -r alarms sudo reboot
Last updated: 2026-04-09
ERROR: Calling the program "AlarmStorage_Prg" is not allowed from multiple tasks
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ERROR: Calling the program "AlarmStorage_Prg" is not allowed from multiple tasks
Last updated: 2026-04-09
Post by automa on Best practice to reduce CPU load
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I am experiencing quite high CPU load on My Schneider M241 PLC with WebVisu. I would like to know what is best practice and how you create your application with pages, frames, tags, dialogs and settings to make an efficient HMI with low CPU load. Thanks
Last updated: 2026-04-10
Post by transcend on Movesuperimposed Command Aborted Error
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Hello everyone, I am building a 3-axis packaging machine. First, I created a virtual axis and connected the knife to the virtual axis using a CAM. I also linked the conveyor system to the virtual axis with GearIn. However, I’m facing the following issue: when I use SUPERIMPOSED to change the conveyor’s motion, I get a COMMAND ABORTED error. The exact error is: SMC_ERROR.SMC_FB_WASNT_CALLED_DURING_MOTION. Why am I getting this error?
Last updated: 2026-04-11
Post by wollvieh on Sysfile Konfiguration
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https://forge.codesys.com/forge/talk/Deutsch/thread/d2df08e587/#3d9c
Last updated: 2026-04-13
Movesuperimposed Command Aborted Error
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Movesuperimposed Command Aborted Error
Last updated: 2026-04-13
Sysfile Konfiguration
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Sysfile Konfiguration
Last updated: 2026-04-13
Post by struland on Sysfile Konfiguration
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Bei mir half: [SysFile] IecFilePath=/mnt/sdcard Allerdings ist es kein Raspi. Den Ordner, der gelesen werden soll mal auf korrekte Zugriffsrechte prüfen. Im Falle das SELinux aktiv ist mit ls -lZ, ansonsten ls -al
Last updated: 2026-04-13
Post by struland on Sysfile Konfiguration
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Bei mir half: [SysFile] IecFilePath=/mnt/sdcard Allerdings ist es kein Raspi. Den Ordner, der gelesen werden soll mal auf korrekte Zugriffsrechte prüfen. Im Falle das SELinux aktiv ist mit ls -lZ, ansonsten ls -al
Last updated: 2026-04-13
Post by msegon on Send HTML body with Mail Service SL
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I'm trying to send a mail using Mail service SL. I would like the body to be in HTML format for a nicer look. Which I managed to do, but only if I don't send an attachment. Can someone help me with the settings on how to send an HTML body and attachment? I used the Mail Service SL Example project, the only thing I added in the "Main_PRG" code in line 51 under "SendMailFB" is "mimeType := 1". I'm using Library: Mail Service SL Library Documentation Company: CODESYS Title: Mail Service SL Version: 1.13.0.0 Categories: Application|Utils Namespace: MAIL Author: CODESYS Development GmbH Placeholder: Mail_Service_SL
Last updated: 2026-04-14
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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Hi nulltrace, Thanks for the info. I'm waiting to hear back from you. Take care!
Last updated: 2026-04-13
Post by alexgooi on Modbus TCP interface get stuck
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Dear Forum, I'm currently experimenting with Modbus interfaces in combination with a virtual controller. I have the following setup (Modbus_Setup.png): I have an IPC with Debian installed on it (Debian 13). On this Debian machine I have installed a docker server and on this docker server a Codesys runtime container is deployed (Codesys_image.png). The Modbus scanner makes connection with and IO coupler and this works well. But when I physically disconnect the ethernet connection between the IPC and the IO coupler the Modbus interface gets stuck in a state where it gets stuck in the busy state (Modbus_Stuck.png). When I plug the cable back in, the IO coupler isn't communicating until the xBusy variable is manually set to False, after this action is performed the communication goes back to normal. I have tried to set the container network to host and bridge (Network.png), but both version gives the same result (stuck scanner). I would expect that the Modbus interface is generating a timeout after 1 sec, because this is how it is setup (Modbus_settings.png), but this is not what happens. I have thought to write a piece of code that writes xBusy to false when it is stuck but because it is an output I'm not able to write to it. I have tried this with another PC (different CPU/motherboard) but this gives the same outcome. I tried updating to the latest version of Virtual control (4.20) but this gives the same result. I also tried to do the same thing with an ethernet IP scanner, and this gives an error after the timeout is expired (so this works well). I have tried to connect to the IO coupler using the Modbus_FB lib (Modbus_FB.png) the FB's are giving the correct errors and behaving as expected. At last I have tried to use a Scanner on a Codesys controller (no IPC) and here the scanner behaves as expected (an alarm is triggered after the timeout has been expired). The version of the Codesys components are listed in the picture Versions.png Is there anyone that can give me a push in the right direction? Kind regards Alex
Last updated: 2026-04-14
Modbus TCP interface get stuck
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Modbus TCP interface get stuck
Last updated: 2026-04-14
Post by reinier-geers on Resize and position Numpad/Keypad
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HI, I download the scale dialog. But cant find were i can Set the size of the dialogs. only the position. I want the diolog bigger
Last updated: 2026-04-15
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