Post by andrej on Creating, using an external Function. ^{CODESYS Forge talk (Post)}
Hello all, I would like to create a simple which runs directly on Control WinV3 x64 3.5.21.0 For this purpose I created a simple dll myAdder.dll in Cpp // MyAdder.cpp // cl /LD /EHsc MyAdder.cpp /Fe:MyAdder.dll #include <windows.h> extern "C" __declspec(dllexport) int __cdecl CmpMyAdder_Add(int a, int b) { return a + b; } I added the dll in the respective folder. Furthermore I "registred" the dll in the CODESYSControl.cfg. However, when I want to use the library I get the error message: Uresolved reference: *'CMPMYADDERADD' * Can you give me a hint what step I missed or where I need to declare the dll, such that the dll resp. the reference can be resolved. Many thanks and kind regards
Last updated: 2025-04-18

Post by bruceae on Special Characters ^{CODESYS Forge talk (Post)}
Hello, I am fairly new to the codesys environment. Is there a reference chart that I can look at in order to write special character in a string? The Special characters that I need to inclue inside the string are as follows; Null Bell Carriage Return I have a TCP_Write command that I am sending to an external device. In order for that device to function properly it needs to see the string with the null and bell characters as the header, followed by the desired command, terminated with the carriage return. Any reference sheet or how to write this in the actual string would be greatly appreciated.
Last updated: 2025-08-26

Post by macros8 on Translation - How to get text as reference in Frames translated? ^{CODESYS Forge talk (Post)}
Hi, thanks for the link. Maybe I create elements in incorrect way. I always use Interface Editor to create variables which are used inside element (see pics). After that I place element in my visu and use Reference property to link variable or set the value. In that case the value of string is not transferred to general text list for translation as I mentioned before. Do I have to all properties which influence behavior of my element create in Frame configuration instead? What´s the difference to the Interface editor? Thanks a lot. M.
Last updated: 2024-01-02

Post by struccc on Release SP20 - Changes in behaviour? ^{CODESYS Forge talk (Post)}
This... is not very practical for me - as I have a bunch of different classes - it's just doesn't seems to be very practical to define a NULL for each of them... Something like this I use in parameter definitions. For example: VAR_INPUT refVFD_Drive : REFERENCE TO FB_VFD_Drive := GVL_DUMMY.Dummy_VFD; END_VAR I use this to prepare objects for code I don't control: Typycally visualizations - had many troubles with references set on the fly, right before opening a corresponding visualization... And yes, the instance in GVL_Dummy reports itself as "Fake", so it does not influence the actual application at all. Actually this way I could invalidate a reference, just to set it to a "Dummy" instance.
Last updated: 2024-03-25

Post by ranadheer on Assistance for MQTT configure with external broker (Mosquitto) ^{CODESYS Forge talk (Post)}
Hi everyone Am trying to make establish MQTT connection , where am using IIOT example for this as a demo mode. where i had given IP-address of of local Linux application as a 172.31.239.67 and port number as 1883 in the PLC_PRG itself, and preparing the publish message by manually as " this is from published message", and this should receive at the subscriber side. Aim: To make communicate external publisher to the CODESYS by using MQTT protocol. By any chance having reference documents about this implementation please share here. and suggest the process to make it possible. I had uploaded reference project file after updating address in th PLG_PRG, kindly assist to configure with the broker
Last updated: 2025-12-03

Post by chirag on About byte swap and convert into 16 bits ^{CODESYS Forge talk (Post)}
Hello, I have %QB0 8 high bits and %QB1 8 low bits . How can i swap bits %QB0 and %QB1 for requirment positions in a 16-bit value ? after that i need %QB0 and %QB1 in to 16bits . For that, i need help. Please see attached pictures for your reference. Thanks in advance.
Last updated: 2023-12-04

Post by tvm on VisuFbFrameBase.SetInputPositionData: The element id for the input position cannot be determined ^{CODESYS Forge talk (Post)}
This came up again today, so I'll post the fix for future reference. Happens with Schneider Machine Expert 2.2 and M262 controllers. Add this bit of code to a program called from the visu task //disable "VisuFbFrameBase.SetInputPositionData" log messages, which fill up the logs IF VisuElems.Private_Visu_Globals.g_ValueChangedListenerManager.GetListenerCount() > 0 THEN VisuElems.Private_Visu_Globals.g_ValueChangedListenerManager.RemoveValueChangedListener(VisuElems.Private_Visu_Globals.g_ValueChangedListenerManager.listenerForOnValueChanged); END_IF
Last updated: 2025-03-06

Post by trusty-squire on SysProcessCreate2 on Linux runtime ^{CODESYS Forge talk (Post)}
Hi, I'm trying to launch a continuously running python script from Codesys and monitor the script status inside the Codesys runtime (running on a Linux enviroment). For now I'm testing with the below to emulate a continuously running Python script: #test.py i = 0 while True: i += 1 I'm able to successfully run the script using SysProcessExecuteCommand2 (I can see the Python process running in the task manager). However, this "freezes" the Codesys execution of the task - it sits on that command and will not continue until the Python script ends. I've proven this works by using the task monitor to kill the process, then Codesys continues on happily through the task. What I want to do is use SysProcessCreate2 to set up the Python script as a background task and monitor the process using SysProcessGetState. This always results in the error "ERR_OPERATION_DENIED". I know that I'm able to execute commands (as above), so my config should be correct. Is SysProcessCreate2 functional on a Linux environment? Is there something in the config file I'm missing? Here's my "working" code that uses SysProcessExecuteCommand2: VAR bTest : BOOL; sCommand : STRING := '/usr/bin/python3 /var/opt/codesys/PlcLogic/Application/test.py'; refCommand : REFERENCE TO STRING REF= sCommand; sOutput : STRING; refOutput : REFERENCE TO STRING REF= sOutput; result : RTS_IEC_RESULT; END_VAR IF bTest THEN SysProcessExecuteCommand2( pszCommand:= refCommand, pszStdOut:= refOutput, udiStdOutLen:= SIZEOF(sOutput), pResult:= ADR(result) ); bTest:= FALSE; END_IF And here's the code that always results in the ERR_OPERATION_DENIED error: VAR bTest : BOOL; sApp : STRING := '/usr/bin/python3'; sCommand : STRING := '/var/opt/codesys/PlcLogic/Application/test.py'; refApp : REFERENCE TO STRING REF= sApp; refCommand : REFERENCE TO STRING REF= sCommand; hResult : SysProcess.RTS_IEC_RESULT; hHandle : SysProcess.RTS_IEC_HANDLE; END_VAR IF bTest THEN hHandle := SysProcessCreate2( pszApplication:= refApp, pszCommandLine:= refCommand, ulFlags:=SYSPROCESS_CREATEFLAG_HIDDEN, pResult:= ADR(hResult) ); bTest:= FALSE; END_IF Here's the relevant section from the config file at /etc/codesyscontrol/CODESYSControl.cfg: [SysProcess] Command=AllowAll Appreciate any support or ideas. Thanks!
Last updated: 2025-03-16

Post by onstage on Unable to add EL6751 to Control RTE V3 on W11 IoT LTSC using Eng. V3.5 SP21 ^{CODESYS Forge talk (Post)}
For reference, it was just me being unfamiliar with EtherCAT in CoDeSys. Anyone with knowledge who would have opened the ScanResult screenshot would have identified that the preceding EK1100 was the device missing in the library. Bottom line - Do something else for a while and then get back at it with fresh eyes!
Last updated: 2025-09-08

Post by nz-dave on Bool turning on in case stament in wrong state? ^{CODESYS Forge talk (Post)}
pretty sure its not. ive done a cross reference and only have one write that sets it to true. Only way i can stop it is to remove the function block call from the main pou that is running said case. its got me stumped:/
Last updated: 2023-12-16

Post by tvm on Cannot pass array of constant size to a function as a reference ^{CODESYS Forge talk (Post)}
maybe this would be a better approach, then you don't have to pass the constant at all. FUNCTION fun : INT VAR_IN_OUT arr: ARRAY[*] OF INT; END_VAR VAR lower: DINT; upper: DINT; END_VAR lower:= LOWER_BOUND(arr, 1); upper:= UPPER_BOUND(arr, 1); see here as well https://help.codesys.com/api-content/2/codesys/3.5.12.0/en/_cds_datatype_array/
Last updated: 2024-01-08

Post by rmaas on Direct Pointers in IOMapping for EtherCAT with IoDrvEthercatLib.ETCSlave_Dia ^{CODESYS Forge talk (Post)}
Hi, Im not sure if this is what you mean, but i do succesfully use the IoDrvEthercatLib.ETCSlave.InputData and IoDrvEthercatLib.ETCSlave.OutputData to read from and write to beckhoff DI and DO cards. Very convenient as you can make an FB with an VAR_IN_OUT of type IoDrvEthercatLib.ETCSlave and only have to pass the slave reference... So i am not using .ETCSlave_Diag but .ETCSlave...
Last updated: 2024-02-13

Post by struccc on Release SP20 - Changes in behaviour? ^{CODESYS Forge talk (Post)}
Wow.... I missed this one in the manual - so there is a special syntax to invalidate a reference... Great :) Seems to work. (it's just mentionned in the examples line)... I've always assigned 0 to the variable, with := 0 - like setting a pointer to 0. In theory, that should work as well. Thanks!
Last updated: 2024-03-25

Post by wb16 on Visualisation generates "Unresolved reference" ^{CODESYS Forge talk (Post)}
Hello Zol6, Have you solved this issue? I use Festo PLC CPX-E-CEC-C1 to create alarm monitoring project. In CODESYS V3.5-SP18 I used the Alarm Storage object and have the same problem. Is it the PLC that is not compatible or the version of the library is not match? Best, wb16
Last updated: 2024-06-10

Post by denizerm on Deploy Control SL cant find Podman ^{CODESYS Forge talk (Post)}
I found something that might be the main cause for this: /etc/os-release features the ID=debian entry on my reference system; When i temporarily override my DUTs os-release to feature ID=debian or similar its able to detect Podman. Is there a way to fix this behaviour?
Last updated: 2025-10-24

Post by kaotic2499 on Upgraded Raspberry 2b to Raspberry 5, Trends Broken? ^{CODESYS Forge talk (Post)}
There is currently a bug with the Raspberry Pi 64 SL where it is unable to Trend Global Retain or PersistantVars. The work around is to use standard Global Variables for Trend Data. This will be patched by Codesys in the near future reference "VIS-6170"
Last updated: 2025-11-13

Post by pernockham on Pointer/reference to Codesys trend recording object? ^{CODESYS Forge talk (Post)}
I have a Hmi that acts as an interface for many (mostly identical) units. This is managed by a sort of "mux" where you select which unit that should be presented on the HMI. Backbone is solved by a HMI-gvl defined as reference/pointer to "unit-data", which then can be set to the individual units. While this works for most data I still have not sorted how to solve this for the trend recordings. One solution would be to have already "mux:ed" data values as source for the/one trend. However then the trend would contain data from different units/sources which could/will cause confusion. If its possible to "clear" this can be mitigated. Possibly let the trend have its own "mux-selector" (ie, the hmi are focusing on unit#3 however trend data is locked on unit#5), that could also work.. Or, let each unit have its own trend recording, which is focused if the unit is "selected". Can I reach the trend recording objects programmatically (those defined in the device tree)? Ie, can I use a "reference/pointer to these trend recording objects"? There is a field "data source" in the trend properties dialog which seems to resemble what Im looking for? But Im not sure if I can use it in some way, I cannot change anything in this field it only says <local application="">. </local>
Last updated: 2025-09-16

Post by timvh on Specify Input Configuration "OnDialogClosed" Action to only react to certain Dialogs ^{CODESYS Forge talk (Post)}
What maybe helps is the Visu Dialog ST demo project: https://store.codesys.com/en/visu-dialog-st.html This has an application IECOpenDialog where dialogs are opened using the VU.FbOpenDialogExtended function blocks. The fbOpenConfigurationDialog call has a reference (interface) to the "close listener" FB of which it's method is automatically called when the dialog is closed. This way you can create specific function blocks for each dialog when it is closed and do what you want with the data that might have been changed.
Last updated: 2023-09-28

Post by tehthoams on Find Function: Object reference not set to an instance of an object. ^{CODESYS Forge talk (Post)}
Hey, Sorry this isn't super helpful, but i had this problem once and was able to resolve it. I can't recall how I solved it and whether it was a problem with my codesys installation or the project itself. If it is the codesys installation, make sure all your required libraries and plugins are installed and available. compare with a colleagues installation if possible. I vaguely recall saving a copy of my project and deleting things one by one until the error went away...
Last updated: 2023-10-30

Post by tehthoams on Find Function: Object reference not set to an instance of an object. ^{CODESYS Forge talk (Post)}
Hey, Sorry this isn't super helpful, but i had this problem once and was able to resolve it. I can't recall how I solved it and whether it was a problem with my codesys installation or the project itself. If it is the codesys installation, make sure all your required libraries and plugins are installed and available. compare with a colleagues installation if possible. I vaguely recall saving a copy of my project and deleting things one by one until the error went away...
Last updated: 2023-10-30

Post by timvh on Management of a PLC network from a remote station ^{CODESYS Forge talk (Post)}
Maybe the CODESYS HMI is a good solution. https://store.codesys.com/en/codesys-hmi-sl-bundle.html Run this on the remote main control station. In the HMI application you can add the data source manager and to this manager you can add Data sources. A data source has a reference to the PLC you want to connect to and can get access to the variables of the PLC application. You can then use these variables in the visualization of the HMI application.
Last updated: 2023-12-04

Post by konradkmiller on Variable assignments ^{CODESYS Forge talk (Post)}
I have a snippet of code that I was given as a reference in ST. ** ModbusMasterRTU( xConnect:= TRUE, IPort:= IoConfigGlobals.COM1, // IoConfigGlobals.RS232485Interface, // COM1=Front Port / Serial module = Name of module in Devices structure I/O list udiBaudrate:= 19200, usiDataBits:= 8 , eParity:= WagoTypesCom.eTTYParity.None , eStopBits:= WagoTypesCom.eTTYStopBits.One , eHandshake:= WagoTypesCom.eTTYHandshake.None , ePhysical:= WagoTypesCom.eTTYPhysicalLayer.RS485HalfDuplex, xIsConnected=> xIsConnected , xError=> , oStatus=> , eFrameType:= WagoAppPlcModbus.eMbFrameType.RTU , tTimeOut:= T#1S, utQuery:= utQuery , xTrigger:= SEND, utResponse:= utResponse)** What is the meaning of => in this context?
Last updated: 2024-07-20

Post by mikek10 on Error IoDrvEthernetIP: Connection Failure. (16#1) How to solve ^{CODESYS Forge talk (Post)}
Your connection configuration should look something like the attachment. Consuming assembly O->T will be the hex of the assembly you want to reference for output data - I want 102 (DO Data Only) shown in the Wago web page 102 = 16#66. Producing assembly (T->O) is the assembly you require for input data - again shown in the Wago web page - I want 108 (DI Data Only) or 16#6C Then set the number of bytes as per the data in the Wago web page too (both 2 in my case)
Last updated: 2024-07-22

Post by installwhat on Initialization of POUs (FB_Init) ^{CODESYS Forge talk (Post)}
Hi I was wondering if there's a pattern I can employ to acheive what you're doing but with a "reference to" and also allowing for online changes? Someone told me that the new beckhoff keeps references safe during online changes but all the documentation I've found suggests that's not the case. The easiest thing is to use fb_init for normal vars and pointers and references can be added in the function body every cycle and this allows for method calls after so far as I can tell.
Last updated: 2024-07-29

Post by warrumungi on Opening a Dialog on a specific Client from ST ^{CODESYS Forge talk (Post)}
Hi Thanks, Manuel, for providing this solution and insight. I too had exactly the same problem as you did. While I did implement a custom filter, I'd also like to point out what jinlee mentioned above...I see no reference to VU.PublicVariables.Clients.Current anywhere?? In my case I only needed to show a dialog on a "master" client, not all the clients, so I filtered by IP address to do this.
Last updated: 2024-11-05

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