Post by hhermsen on Codesys v3.5.22.10 - Internal error:System.AggregateException...Value cannot be null...Parameter name: expLValue ^{CODESYS Forge talk (Post)}
I pinpointed down 4 possible causes for this compiler error: Bare/empty statements (;) standing alone inside an IF/CASE branch — just removed two instances. The optimizer that tries to inline/replace expression statements may choke when a statement has no actual assignment to extract. A VAR_IN_OUT parameter used directly as a FOR loop's own control variable (FOR X := X TO Y DO) General deep-nesting complexity — every one of my decode routines has the same shape (IF busy THEN ... FOR loop containing nested CASE/IF chains ... END_IF), and the crash trace consistently shows for loop → sequence → ifst → sequence → ifst → sequence regardless of the code change. This raises the possibility that it's not one specific statement but a structural depth/complexity limit in SP22.x's compiler optimizer — which would mean no small code change fixes the issue. Only restructuring to reduce nesting depth, or downgrading the compiler will. Something entirely outside my library files — which cannot not ruled out since the exact stack trace was triggered by a Visualization object, in a totally different codebase. This means the same crash signature can come from unrelated causes. IMHO cause 3 seems the most probable one..
Last updated: 2026-07-11

Post by ahuckphin on Issues with Modbus Slave with Raspberry Pi ^{CODESYS Forge talk (Post)}
I have a DFRobot RS485 temperature & humidity sensor (SEN0438) connected to my Raspberry Pi via a USB to RS485 adapter. I am able to connect and read the sensor data when running a python code locally. However in Codesys, I encounter this error "A bus error has occurred." and "There was no response in time". Could this be because of Modbus Server Channel and Modbus Server Init configuration on my part? Admittedly I am new to Codesys. To get to this stage, I: 1. added some lines to CODESYSControl_User.cfg 2. added "Modbus_COM" in Codesys and set "Serial Port Configuration" under "General" 3. added "Modbus_Master_COM_Port" in Codesys and checked transmission mode is set to "RTU" 4. added "Modbus_Slave_COM_Port" in Codesys and checked server address is set to 1 (also set 1 in my sensor) 5. added 1 channel and 1 init for "Modbus_Slave_COM_Port" under "Modbus Server Channel" and "Modbus Server Init"
Last updated: 2024-07-10

Post by jakubmphoenix on EtherCAT Master on RaspberryPi with EtherCAT Slave on Beckhoff ^{CODESYS Forge talk (Post)}
Hello everyone, I’m currently working on setting up an EtherCAT Master using CODESYS on a Raspberry Pi, and I’ve run into some issues I could use help with. Project Setup: EtherCAT Master: Raspberry Pi with CODESYS Control for Raspberry Pi 64 SL installed EtherCAT Slave: Beckhoff CX5130 with EK1200 coupler I/O Module: EL2008 License Module: EL6070-0033 I’ve installed the required CODESYS packages and the Linux gateway on the Raspberry Pi. In my project, I added the EtherCAT Master with the appropriate port settings and scanned for devices. The CX5130 shows up as a slave, but communication fails—I'm getting error messages and can't access the outputs. Specifically: The EL2008 output module isn’t recognized properly in CODESYS. There’s no option to communicate with it through the CX5130. I’ve tried connecting via both the Raspberry Pi’s built-in Ethernet port and an external network card. I've attached screenshots showing the errors I get in CODESYS and the devices detected via TwinCAT for reference. Any help or suggestions would be greatly appreciated! Thanks in advance! EMERGENCY FROM DEVICE 1001 ERROR CODE 16#A000 Error register 16#02 Error field: 16#02 Error field : 16#0E 16#04 16#00 16#04 16#00
Last updated: 2025-07-16

Post by timl on BacNet "Unaufgelöste Referenz" ^{CODESYS Forge talk (Post)}
Hallo, ich habe Probleme beim nachbauen des BacNet2 Tutorials "Erste Schritte" aus der CODESYS Online Help. https://content.helpme-codesys.com/de/CODESYS%20BACnet/_bacnet_first_steps.html Das Anlegen des BacNet2 Servers und der danach folgenden BacNet Datenpunkte erfolgt ohne Probleme. Der Code lässt sich mit F11 auch Fehlerfrei generieren. Beim Download auf die SPS tritt dann der Fehler auf dem Bild auf. Anbei auch ein Bild des Logs nach dem Download. CODESYS BACnet 2.0.0.0 ist über den Installer runtergeladen. Device: CODESYS Control Win V3 x64 Version 3.5.19.40 CODESYS 3.5.19.40 Im Bibliotheksverwalter ist BACnet2 2.0.0.0 aufgeführt Die Konfigurationsdatei habe ich mit folgenden anpassungen abgespeichert: [ComponentManager] Component.1=CmpTargetVisuStub Component.2=CmpWebServer Component.3=CmpWebServerHandlerV3 Component.4=SysCpuMultiCore Component.5=SysReadWriteLock Component.6=SysCpuBreakpoints Component.7=SysPipeWindows ;Component.8=CmpHilscherCIFX ;Component.9=CmpPCANBasicDrv ;Component.10=CmpCANFoxDrv ;Component.11=CmpIxxatCANDrv ;Component.12=CmpBlkDrvCanServer ;Component.13=CmpBACnet Component.14=CmpBACnet2 [CmpBACnet2] ;configuration file of the BACnet stack IniFile=$PlcLogic$/bacstac2.ini ;task priority of the BACstack process task, default: TASKPRIO_NORMAL_END (159) TaskPrio=128 ;name of the named pipe for the communication with the BACstack AppName=/tmp/BACnetServer Habe ich etwas vergessen?
Last updated: 2024-02-16

Post by jmorit on CAM Table - Quadratic velocity ramp with jerk limitation ^{CODESYS Forge talk (Post)}
Hello, I'm working on setup a CAM table by using the Codesys CAM Editor. My purpouse is to obtain a quadratic velocity ramp with jerk limitation motion profile, for which i define the accel/decel phases with Poly5 segment type, but the problem is that due to the fact i can "only" adjust until the acceleration, and the jerk is always setup to 0, and i cannot change the jerk values, i cannot achieve the desired results, as i need to generate jerk steps. Is there any way it can be achieved with the editor, or maybe by using PLC runtime code? Thank you in advance for your help BR, Jordi Morito
Last updated: 2023-12-02

Post by mubeta on Reset problem with CMZ SD/SVM drive ^{CODESYS Forge talk (Post)}
In a recent project with SoftMotion 4.15.0.0, where I integrated two SD drives from CMZ (from catalogue EDS and not imported), on CANopen bus, I found that the SoftMotion MC_Reset function does not reset the drive faults. Even if the drive is in fault, either on the device or on the drive at the CoDeSys level, the function does not reset, instead reporting the error code: no error to reset. Finally, I had to connect the reset bit of the ControlWord directly to a tag in my program. Something I never had to do on other drives: Lexium, etc. all reset simply with MC_Reset.
Last updated: 2024-07-24

Post by timvh on Clarifications regarding the appropriate runtime system to use ^{CODESYS Forge talk (Post)}
If you are not using any specific Raspberry Pi functionality, then probably the "universal" Control Linux ARM SL is the approriate runtime to run on the Pi. For the license it doesn't matter which runtime version you choose, because this is not hardware based anymore, but application based. Best is to use the latest version of CODESYS. To determine which license you need, double click on your device, go to the tab License metrics.... Generate the code for your application and see which license you need based on the metrics of your application.
Last updated: 2024-09-24

Post by timvh on Visuutils FbOpenDialog(Extended) not open Dialog from POUs ^{CODESYS Forge talk (Post)}
I had a similar situation recently where this didn't work, but read to the end to see the solution. The reason is that CODESYS only downloads visualisations (dialogs) if they are part of the project or linked to the project. In your case the dialog is not loaded onto the controller. But the solution is pretty simple: Double click on the Visualization Manager in your application. Select the Tab "Visualizations". Here you can see that your dialog is not "checked". Do this manually and load your project on the controller. Then your code should be able to open the dialog, because now it exists on the controller.
Last updated: 2024-09-28

Post by timvh on FB string and naming ^{CODESYS Forge talk (Post)}
I see, you want to initialize the FB. To be able to initialise it like you described, you need to add the FB_Init method to your FB. (right click on the FB, select add object --> method). Then press the arrow down, to select the FB_Init (overwrite default implementation). In the VAR_INPUT section of this method, add the variable --> Tag : STRING; Then in the code section of this method add: THIS^.Tag := Tag; // copy initial value to local variable in FB Search Google if you want to know more about FB_Init. PS, reflection + instance path, is also an option if you want to get the full name of the instance (path) of the Function Block. See: https://content.helpme-codesys.com/en/CODESYS%20Development%20System/_cds_pragma_attribute_instance_path.html
Last updated: 2024-09-30

Post by struccc on HTML5 Controls - string(>80) values ^{CODESYS Forge talk (Post)}
Dear all, does anyone have experience with HTML5 controls recently? CODESYS 3.5.20.30 / Visualization 4.6.0.0 I'd like to create a simple lightweight text editor, with proper multiline handling, cut & paste, scrolling, etc. And it seems to work fine, just have problems with strings longer than 80 bytes.... Declaring a variable sText1 : STRING(8000) and referencing it in the HTML5 Controls corresponding value property works perfectly one way: the code receive the data as a string (See log1)... (Note TypeID 1000...) Also sending back the data (seems to work (See log2) except it doesn't change the value of the bound variable. Probably the issue is with using SendSimpleValue method... Naturally, I could do a workaround, but maybe there is a more standard way to implement this... Please let me know if you have any suggestions.
Last updated: 2024-10-23

Post by kevinrn on Github Actions CI/CD tasks - development topic ^{CODESYS Forge talk (Post)}
Hi @steven-schalm, Thank you for your inquiry, and I apologize for the delayed response! We use GitHub Actions cloud runners for this purpose, as it eliminates the need to maintain our own build runners. You can get started by creating a free GitHub account, which includes complimentary minutes for running actions on Windows runners. You can find an example implementation in our repository: https://github.com/powerIO-GmbH/action-codesys-setup I'm currently working on making additional features public, including: Git checkout functionality, Code signing, Custom script execution However, these additions require some preparation before release. Feel free to contribute to the project! BTW: You can also execute this locally, even the yml files with nektos/act on your windows dev machine.
Last updated: 2024-11-27

Post by itsthefabs on (no subject) ^{CODESYS Forge talk (Post)}
Hallo zusammen, ich nutze eine Wago 8212 als Modbus Client (in früheren Codesys Versionen hieß der Modbus Master) und habe einen weitere Wago 8212 als Modbus Server (früher Modbus Slave). Bisher habe ich für den Client den Funktionsblock FbMbMasterTcp aus der WagoAppPlcModbus-Library genutzt. Zukünftig würde ich das allerdings gerne über das Anhängen eines Modbus-Geräts am Ethernet-Knoten im Projektbaum realisieren. Zum besseren Verständnis habe ich ein Bild beigefügt. Der Modbus mit dem Server läuft auch. Kommt es allerdings zum Fehler des Modbus, z.B. kurzzeitig keine Verbindung oder timeout, wird der Fehler nicht automatisch quittiert. Ich muss dann manuell über den Status des Server-Knotens einen Button mit "Bestätigen" drücken. Im Betrieb kann ich mich aber nicht jedes Mal einloggen um einen Fehler zu quittieren. Gibt es hier irgend einen Trick, wie ich das aus dem Programm-Code quittieren kann? Vielen Dank schon einmal.
Last updated: 2025-02-26

Post by imdatatas on Programmatically change Tappet on a cam ^{CODESYS Forge talk (Post)}
Yes, There is. As explained "Manual creation of CAM structure" on below section. Likewise tappet structure also can be create manual and value of the switching point can be change during IEC program running. https://content.helpme-codesys.com/en/CODESYS%20SoftMotion/_sm_basic_cam_programmatic_creation.html Just create a cam table and define some tapped points as sample for your project. Then on project compile, the created cam tapped data is converted internally into a global variable list. By clicking "Display generated code" in the "cam editor", you can display the automatically created global variables for both cam & tappets. Regards, Imdat
Last updated: 2025-04-02

Post by levih on FbHTTPs_Get how to get data from a website and use it in codesys ^{CODESYS Forge talk (Post)}
You get an array of DWORD into your receive buffer. You need to process this into usable data, before you can fit it into your DUT. I've made it work using FbWrite_ToIEC_ByRule in stead of Fb_JSON_ParseAndModify. I've attached images of the code. You receive the data into ARRAY[0..1023] OF DWORD. Then you use that array as the input for fbWrite_ToIEC_ByRule. To get the output from this you define a rule to fit the expected data structure including nesting levels. The you feed the rule into FbWrite_ToIEC_ByRule and then you can set the output to be of your DUT type.
Last updated: 2025-06-16

Post by askjong on Update variables when OPC UA Client updates. Error ID: 268468277 BadAttributeIdInvalid ^{CODESYS Forge talk (Post)}
Hi, I'm connecting to a OPC UA Server using the Data Soruce Manager OPC UA Client. This works well until the OPC UA Server updates and the OPC UA list doesn't match up when i did last clicked the "Update variables" to add variables. All the variables are still the exists and none are removed from the server, but more are added during the engineering process. The error message i get in CODESYS is "Error in OPC UA call BadAttributeIdInvalid, Error ID: 268468277". The issues is fixed when i press the "Update variables" button and just press ok without adding or removing any variables in the list. Is there a way to either automatically update the browsepath if it fails or on startup, or to trigger it by code?
Last updated: 2024-01-08

Post by timvh on Is it possible to use debug functions such as Step Execution while the PLC ladder is in Running? ^{CODESYS Forge talk (Post)}
Yes, it is possible to set breakpoints and use step into / step over (also in Ladder diagram). Yes, the PLC will actually stop, so be carefull with this. How a PLC works is that at the start of the execution of the Task, the Inputs are read, then the code is being executed and then the outputs are written. So if you set a breakpoint, you will not see your analog inputs changing, because the task cycle is interrupted and the inputs and outputs are not refreshed. For detailed information, see: https://content.helpme-codesys.com/en/CODESYS%20Development%20System/_cds_using_breakpoints.html
Last updated: 2024-01-16

Post by dhumphries on No source code available ^{CODESYS Forge talk (Post)}
Try using an Ethernet/IP scanner instead of an adapter, I'm guessing the 2 devices you're trying to communicate with are adapters, you have to have a scanner somewhere and Codesys should be a scanner. I don't know why you're getting the error, you should be able to use your Ethernet port as an EthernetIP adapter (although I've never had a reason to try,) but it's probably not what you wanted to do, unless you're connecting to another PLC that is a scanner. Good luck configuring the devices you're trying to connect to, it will be a lot easier if you have an .EDS file instead of starting with a generic module, even with an .EDS it can be tricky getting the communication working.
Last updated: 2024-02-03

Post by enginear on auf Feldbusvariablen über Array zugreifen ^{CODESYS Forge talk (Post)}
Hallo, ich würde gerne die Variablen, die ich mit Ethernet/IP übertrage gerne in meinem Programm möglichst einfach ansprechen. Ist es möglich die übertragenen Variablen über ein Array direkt anzusprechen? Ich kann zwar die Variablen alle händisch benennen und dann im Programm auf diese zugreifen, aber wenn es viele Variablen sind und ich diese alle der Reihe nach in einer Schleife durchgehen möchte, so ist das schon viel Code der dafür notwendig ist. Bei mir werden die Variablen in Codesys unter dem Ordner (kann man aufklappen) 'Exclusive Owner' angezeigt. Da klingt es doch naheliegend, dass man direkt über den Ordnernamen die Variablen per Indexierung oder ähnliches ansprechen kann. vielen Dank und viele Grüße enginear
Last updated: 2024-02-23

Post by sachem on Problem retain values Weidmuller UC20-WL2000 ^{CODESYS Forge talk (Post)}
Good afternoon. I am working with a weidmuller uc20-wl2000 controller, using a codesys license. We made a ladder code to control a process, and it works well, but we want some variables to remain stored even when the controller is turned off. We tried to use retain variables, but at the time of loading the program, when we went offline from the controller, the program was deleted, it did not remain in the controller, and in the same way if we turned off the controller. In addition to this, when we tried to program it again, the program would not stay loaded and began to present errors with the opc-ua communication. What could be causing this problem? How can we maintain the values of the variables without damaging the program or affecting the controller? thank you
Last updated: 2024-04-10

Post by wiresplus on How to Connect / Go Online without re-downloading the project ^{CODESYS Forge talk (Post)}
Hello, I have a PLC in a remote location. I can connect to it, but when I use a different PC, it asks me to re-download to the PLC - which will a) interrupt production and b) cause version issues. Codesys being open-source, if someone else has made changes, I need to be able to connect, upload the current project, compare it with mine and then decide what next. Every time I connect, it says Warning: An application 'Application' is currently in RUN mode on the PLC. As there is no matching compile information, this existing application needs to be replaced. Click 'Yes' to download the latest code or 'No' to abort. What am I doing wrong?
Last updated: 2024-04-13

Post by zer0g on Modbus Client Request Not Processed ^{CODESYS Forge talk (Post)}
I'm using the code bellow which is based on the Codesys example: FUNCTION_BLOCK MODBUS_master_example_ST VAR initDone : BOOL := FALSE; aIPAddress : ARRAY [0..3] OF BYTE := [127,0,0,1]; clientTcp: ModbusFB.ClientTcp; // buffer to read input registers aDataInputRegisters : ARRAY[0..9] OF UINT; // some client requests clientRequestReadInputRegisters: ModbusFB.ClientRequestReadInputRegisters; xExecute: BOOL; END_VAR IF NOT initDone THEN initDone := TRUE; // configure clientTcp clientTcp(aIPaddr:=aIPAddress, uiPort:=502, udiLogOptions := ModbusFB.LoggingOptions.All); // configure clientRequestReadInputRegisters clientRequestReadInputRegisters(rClient:=clientTcp, uiUnitId:=1, udiTimeout:=TO_UDINT(T#1000MS)); END_IF // call the client FB's clientTcp(); clientRequestReadInputRegisters(rClient:=clientTcp,xExecute := xExecute AND NOT clientRequestReadInputRegisters.xBusy ,uiStartItem:=2, uiQuantity:=3, pData:=ADR(aDataInputRegisters[0])); As you can see the clientTCP is called cyclically with the same result.
Last updated: 2024-05-30

Post by matt-purcell on Which Lib to use, connect to a socket with URL instead of IP address ^{CODESYS Forge talk (Post)}
Hello, I have a new project and I need to connect to a TCP socket using the URL instead of an explicit IP address, myendpoint@mydomain.com Which library is best suited for this? This is for a new enterprise project, the endpoint is a server in a datacenter running some real time application. We have big IP, it will automatically reassign the IP address to the backup server if a crash occurs so an explicit IP won't work for me. I've done this in RS logix, working now to migrate that code over to codesys. Thanks in advance!
Last updated: 2024-06-17

Post by mr-ege on Error: C0138: No matching 'FB_Init' method found for instantiation of VisuClientObjectMgr ^{CODESYS Forge talk (Post)}
Hi all! I'm trying to learn PLC Programing. Today I was making a simple PLC program, as you can see. When I compile the program without the visualization, there are no errors. However, when I add the visualization and then compile it, I get this error. I don’t know how to solve the problem. I have tried the following solutions: rebooting the PC and updating the software. Error Code: C0138: No matching 'FB_Init' method found for instantiation of VisuClientObjectMgr Compile complete -- 1 errors, 0 warnings Build complete -- 1 errors, 0 warnings : No download possible Version: CODESYS V3.5 SP21 Patch 3
Last updated: 2025-11-25

Post by mait-tim on Drive communication errors ^{CODESYS Forge talk (Post)}
With a machine I'm working with i get a communication error when I'm updating some softstop limits. As soon as I update the code the drives do not want to operate. Using the MC_readStatus I'm receiving errors as soon as i want to start a movement. Using MC_ReadAxisError i see that i receive error 131, no response. With a SMC3_ETC_ReadParameter_CoE i do not recieve any driver errors. Does anyone know how i can figure out what the error is and how to solve it. When i go back to the old software no errors occur. Im working with a legacy machine running a Beijer PLC with some Mitsubishi drives. running on Codesys 3.5 SP10. the runtime version is probably 3.5.3. The drives are all Ethercat Drives (CoE). All using the SM3_drive_ETC libary and the SM3_basic library.
Last updated: 2025-12-22

Post by sheberle on No Bootproject possible ^{CODESYS Forge talk (Post)}
Hello Alex, the message is generated by the CODESYS code generator based on the DevDesc settings of the memory areas available for the target. The problem arises when after too many online changes the area is full. Therefore no more boot project can be generated. Short-term remedy as described in the dialog: Clean and fresh download. This way the initial memory size will be "used" again After how many online changes did this error occur? There is no set limit on the number of online changes, but making too many changes could be a risk. br Simon
Last updated: 2026-03-31

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