Post by danp1406 on Question about Demo License limitations for Modbus TCP communication and Fieldbus Instances ^{CODESYS Forge talk (Post)}
Hello everyone, I am currently working with CODESYS Virtual Control for Linux running in Docker on a Debian virtual machine. I am deploying my application using Deploy Control SL, and in my project I am using the ModbusFB library to implement Modbus TCP communication. My setup is the following: I am trying to establish a Modbus TCP connection between a virtual PLC (CODESYS acting as Modbus TCP Client/Master) and a Siemens S7-1200 PLC acting as a Modbus TCP Server. From the Debian VM, I can successfully ping the S7-1200 and verify that port 502 is open using tools like nc. Network-wise, everything appears to be correct. However, when running the application in CODESYS, I receive messages such as “Demo mode for Modbus/TCP Master started. Will expire and stop!” and socket errors like “ClientSocket.UpdateStatus socket error 111 disconnecting.” The ClientTCP block from the ModbusFB library attempts to connect, but the connection does not remain stable. My main question is whether the CODESYS demo license explicitly limits or interrupts Modbus TCP Master communication. Is it expected that in demo mode the runtime will automatically close sockets after some time or prevent stable Modbus TCP connections? I would like to confirm whether this behavior is normal when using ModbusFB in demo mode, or if I should continue troubleshooting the configuration. Additionally, I would like clarification regarding the “fieldbus instances” mentioned in CODESYS licensing options (for example, 2, 4, or 16 instances). What exactly is considered one fieldbus instance? Does one Modbus TCP Client block count as one instance? Does each active connection to a different device count separately? Do Modbus TCP Master and Server count independently toward the total number of instances? Finally, I would appreciate clarification on any other practical limitations of demo mode when using industrial communication libraries such as ModbusFB. Are there limits on the number of connections, number of requests, or communication duration? I am trying to determine whether demo mode is sufficient for testing a virtual PLC communicating with a Siemens S7-1200 over Modbus TCP, or whether a full license is required even for this kind of validation scenario. Thank you in advance for any guidance.
Last updated: 2026-02-25

Post by viksym on How to get the motor scaling value from code ^{CODESYS Forge talk (Post)}
If anybody finds this in the future, I managed to do it like this: scalingValue := EncoderPulseCountPerRev / ABS(AxisName.fScaleFactor); No need to use MC_ReadParameter as I am able to read this value directly from the axis object. Using an absolute value of the fScaleFactor is there in case the axis is set as inverted, in which case it would be a negative value. I was not able to figure out how to get EncoderPulseCountPerRev programatically, but since all my servos use an encoder with pulse count per revolution of 16#800000, the final equation looks like this: scalingValue := 16#800000 / ABS(AxisName.fScaleFactor);
Last updated: 2025-08-19

Post by ophelia on Phantom Test Slot Preventing Suite Completion ^{CODESYS Forge talk (Post)}
Hi all, I'm working with a CODESYS 3.5 unit test framework on an embedded Linux PLC and running into an issue where a phantom test slot appears in the results that never completes, preventing the full test suite from ever finishing. The symptom: A blank-named test entry appears in the results table with an ever-increasing action count. It stays as "Testing" or "Failing" indefinitely. Because it never closes, bAllFinished never goes TRUE and the final report is never generated. Question: Has anyone seen this kind of phantom slot issue in a CODESYS unit testing setup? Thanks
Last updated: 2026-07-09

Post by thejesh on WebVisu: switch-frame destroys and rebuilds referenced visualization - is retention configurable? ^{CODESYS Forge talk (Post)}
Hi, HTML5 Conrtrol elements on CODESYS V3.5 SP22 Patch 2, WebVisu only (no TargetVisu). The client is Chromium 147 in kiosk mode on a Raspberry Pi CM5 panel; the runtime is CODESYS Control Win V3 x64/CODESYS Control RTE V3 x64 on a separate IPC. I have measured that changing a Frame element's switch-frame variable destroys the currently referenced visualization and fully rebuilds it on return, including all embedded HTML5 controls. We would like to know whether this lifecycle is configurable. Measurement 1: Curently, our production page contains a good number of custom HTML5 controls and will only increase , each of which the WebVisu client instantiates as a separate about:srcdoc iframe. I counted live targets via the Chromium remote debugging endpoint (curl http://localhost:9222/json/list) before and after switching. Production displayed (index 0) 108 iframes Switched to a light page (index 1) 46 iframes Switched back to Production 108 iframes 62 controls are destroyed on leaving the page and re-instantiated on return. Observed latency was approximately 2.5 -5s away from the heavy page and approximately 4.0 -5 s back to it. This was measured with the panel otherwise idle: 2.8% system CPU, 97.1% idle, 2 h 56 min uptime, no remote-desktop session running, hardware acceleration confirmed active in chrome://gpu. I had previously measured the same behaviour under a much higher CPU load and have since resolved that load separately (VISU_TASK cycle period), so I am confident the rebuild is the frame lifecycle itself and not CPU starvation. Measurement 2 — frame offset instead of switch index I then displayed the same overlay page by a different mechanism. Instead of using a switch-frame index, I placed the page in a fixed Frame parked off-screen below the visible canvas, and drive its Y offset from an INT in Structured Text to move it into view. With this approach the overlay appears immediately, the production page underneath is never torn down and keeps updating, and no visualization is destroyed or rebuilt in either direction. The iframe count does not change at any point. This is the same visualization, containing the same HTML5 controls, as in Measurement 1 — the only difference is how it is brought on screen. So the rebuild appears to be a property of the switch-frame mechanism specifically, not of the page or its control count. Questions: Is the destroy-and-rebuild behavior on switch-frame the intended and documented lifecycle for WebVisu? Is there any setting, property or client option that causes a referenced visualization to remain instantiated when it is not the active index — the equivalent of keeping it mounted but not displayed? Does the runtime or client offer any form of caching or pre-instantiation for referenced visualizations, so that a return switch does not pay the full construction cost? Is the cost specific to HTML5 controls, or would the same rebuild occur with an equivalent number of native visualization elements? We ask because it would inform whether reducing our HTML5 control count is a viable solution. Is there a recommended pattern for showing a full-screen page over a live production screen without tearing the production screen down? My current workaround is to keep every page permanently instantiated and move it on and off screen by driving a frame offset variable, which avoids the rebuild entirely but means every page stays live and consumes client resources for the life of the session. This works, but I would prefer to use the supported mechanism if one exists. Any help on this is greatly appreciated. Thank you!
Last updated: 2026-08-07

Post by jzhvymetal77 on IecVarAccessLibrary.IBaseTreeNode methon ^{CODESYS Forge talk (Post)}
I had this code working in a previous version of CoDeSys to read variables from a GVL that were added to the Symbol configuration. The problem now is that when I get the _IBaseTreeNode_Parent, it returns a valid interface, but none of the methods or properties work. If you monitor the _IBaseTreeNode in the watch window, it does show the correct child count. However, it fails at step 30, where the child count incorrectly returns zero. In the image, you can see that the watch window displays the correct value that the property should return. Attached is the full project code. FUNCTION_BLOCK Symbols_TO_STR VAR_INPUT i_sPath : STRING(255); i_diIndexChild : DINT; i_diIndexComponent : DINT; END_VAR VAR_OUTPUT q_diChildCount : DINT; q_diComponentCount : DINT; q_sName : STRING(255); q_sValue : STRING(255); q_sType : STRING(80); q_sErrorResult : STRING(80); END_VAR VAR uiStepCopy : UINT; uiStep : UINT; uiStepProcessCopy : UINT; uiStepProcess : UINT; _IBase : IecVarAccessLibrary.IBase; _pIIecVarAccess5 : POINTER TO IecVarAccessLibrary.IIecVarAccess5; _IIecVarAccess5 : IecVarAccessLibrary.IIecVarAccess5; _RTS_IEC_RESULT : IecVarAccessLibrary.RTS_IEC_RESULT; _udiResult : UDINT; _VariableInformationStruct : IecVarAccessLibrary.VariableInformationStruct; _IBaseTreeNode_Parent : IecVarAccessLibrary.IBaseTreeNode; _IBaseTreeNode_Child : IecVarAccessLibrary.IBaseTreeNode; _ITypeDesc_Child : IecVarAccessLibrary.ITypeDesc; _TypeDescAsUnion_Child : IecVarAccessLibrary.TypeDescAsUnion; _arIBaseTreeNode_Child : ARRAY[0..20] OF IecVarAccessLibrary.IBaseTreeNode; _TypeClass_Child : IecVarAccessLibrary.IBaseLibrary.TypeClass; _psSymbolName_Child : POINTER TO STRING; _sSymbolName_Child : STRING(255); _IBaseTreeNode_Component : REFERENCE TO IecVarAccessLibrary.IBaseTreeNode; _TypeClass_Component : IecVarAccessLibrary.IBaseLibrary.TypeClass; _ByteAddress_Component : __XWORD; _ByteOffset_Component : __XWORD; _sArrayIndexName_Component : STRING(20); _diArrayIndexCalc_Component : DINT; _diArrayIndexValue_Component: DINT; _psSymbolName_Component : POINTER TO STRING; _sSymbolName_Component : STRING(255); END_VAR uiStepCopy:=uiStep; uiStepProcessCopy:=uiStepProcess; CASE uiStep OF 10: // GET IBASE FROM CURRENT APP _IBase:= IecVarAccessLibrary.IecVarAccGetFirstInterface2(0); IF _IBase<>0 THEN uiStep:=20; ELSE q_sErrorResult:=CONCAT(UINT_TO_STRING(uiStep), ': IecVarAccGetFirstInterface2'); uiStep:=9000; END_IF 20: //QueryInterface IIecVarAccess5 from IBASE _pIIecVarAccess5 := _IBase.QueryInterface(IecVarAccessLibrary.ITFID_IIecVarAccess5, ADR(_RTS_IEC_RESULT)); IF _pIIecVarAccess5<>0 AND _RTS_IEC_RESULT=0 THEN _IIecVarAccess5 := _pIIecVarAccess5^; uiStep:=30; ELSE q_sErrorResult:=CONCAT(UINT_TO_STRING(uiStep), ': QueryInterface_IIecVarAccess5'); uiStep:=9000; END_IF 30: // Get IBaseTreeNode_Parent _IBaseTreeNode_Parent := _IIecVarAccess5.VarAccGetNode3(ADR(i_sPath), ADR(_VariableInformationStruct), ADR(_RTS_IEC_RESULT)); IF _IBaseTreeNode_Parent<>0 AND _RTS_IEC_RESULT=0 THEN q_diChildCount:=_IBaseTreeNode_Parent.ChildCount; uiStep:=40; ELSE q_sErrorResult:=CONCAT(UINT_TO_STRING(uiStep), ': IBaseTreeNode_Parent'); uiStep:=9000; END_IF 40: // Get IBaseTreeNod_Child IF(q_diChildCount-1>=i_diIndexChild AND i_diIndexChild >=0) THEN _IBaseTreeNode_Child := _IBaseTreeNode_Parent.GetChild(i_diIndexChild); IF _IBaseTreeNode_Child<>0 THEN uiStep:=50; ELSE q_sErrorResult:=CONCAT(UINT_TO_STRING(uiStep), ': IBaseTreeNode_Parent'); uiStep:=9000; END_IF ELSE q_sErrorResult:=CONCAT(UINT_TO_STRING(uiStep), ': i_diIndexChild OutBounds'); uiStep:=9000; END_IF
Last updated: 2025-08-20

Post by rossanoparis on Clarifications regarding the appropriate runtime system to use ^{CODESYS Forge talk (Post)}
Hallo all I would appreciate some clarifications regarding the appropriate runtime system to use. I've been using 'KUNBUS CPUs' and 'CODESYS Control for Raspberry Pi MC SL' for the last 4 years. Recently, there have been some changes in the CODESYS licensing policy. [ https://store.codesys.com/en/howto_applicationbasedlicenses ] My questions are mainly two: 1) If I need to start a new project using 'KUNBUS CPUs', which is the correct runtime system to use. 2) Old projects built using 'CODESYS Control for Raspberry Pi MC SL' should be updated to another RT system? Current RT systems ... a)CODESYS Control for Raspberry Pi MC SL b)CODESYS Control for Linux ARM SL c)CODESYS Virtual Control SL May I count on receiving an explanation to understand the differences among the runtime systems listed above? A detailed and well-organized answer would be greatly appreciated. Kind regards Rossano
Last updated: 2024-09-23

Post by rene-h on ClientFilter used the same Client ID 2 times - Bug? ^{CODESYS Forge talk (Post)}
Hello, like the topic name says, i have a problem on one Visu which i cannot reproduce on another Visu. We filter buttons with input locks and visible items with [CURRENTCLIENTID] on different WebVisu's with different ID's, and one time the itfClient used the same Client ID for 2 Clients, so the Visualization on the first ID was wrong, because that one which connected after did not have the same permissions like the first, so the first one was blocked. We read the Clients with the VisuClientIteration project: //count active clients gCli.iNumberOfClients:=gCli.iNumberOfClients+1; // if client is active write data to global struct IF gCli.iNumberOfClients > 0 THEN gCli.astClientInfo[gCli.iNumberOfClients-1].iClientID:=itfClient.ClientId ; gCli.astClientInfo[gCli.iNumberOfClients-1].stCurrentVisu:=itfClient.CurrentVisuName; gCli.astClientInfo[gCli.iNumberOfClients-1].wsUserName:=itfClient.UserName; gCli.astClientInfo[gCli.iNumberOfClients-1].sIpAddress:=itfClient.GetIPv4Address(); gCli.astClientInfo[gCli.iNumberOfClients-1].ClientType:=itfClient.ClientType; END_IF Runtime from the device: 3.5.19.20 Codesys we use: 3.5.20.10 I added a screenshot where the same ID exists 2 times. Thanks for your answers.
Last updated: 2025-05-14

Post by timvh on USB Game Controller with Raspberry Pi ^{CODESYS Forge talk (Post)}
I'm not sure it will work, but you could try it with the CmpCharDevice library. You could create a function block that looks something like this: As input for the filename, you have to use your Linux device, e.g.: '/dev/input/event0' '/dev/input/by-path/platform-button@23-event' Off course you must also pass the pointer to the memory where the data can be written to and the size (count in number of bytes) of the buffer. FUNCTION_BLOCK FB_CharDevice VAR_INPUT szFilename: STRING; pbyBuffer : POINTER TO BYTE; udCount : UDINT; END_VAR VAR_OUTPUT iState : INT := 0; nrBytesRead : DINT; END_VAR VAR xInit : BOOL := TRUE; dFlags: DINT := CmpCharDevice.ACCESS_MODE.O_RDONLY + DINT#4000; // see details for flags: http://linux.die.net/man/2/open, + DINT#4000 is for non-blocking hDevice: CmpCharDevice.CmpCharDevice_Implementation.RTS_IEC_HANDLE := -1; Result : CmpCharDevice.CmpCharDevice_Implementation.RTS_IEC_RESULT; END_VAR IF xInit THEN hDevice := CmpCharDevice.CDOpen(szFilename, dFlags ,Result); // if it would not succeed, the result is -1 (Invalid handle) IF hDevice <> 16#FFFFFFFF AND Result = 0 THEN iState := 5; END_IF xInit := FALSE; END_IF IF iState = 5 THEN nrBytesRead := CmpCharDevice.CDRead(hDevice, pbyBuffer, udCount, Result); ELSE nrBytesRead := 0; END_IF Make sure you close the connection properly, maybe by overwriting the default FB_Exit method of the FB: // Clean up device IF hDevice <> 16#FFFFFFFF THEN __TRY CmpCharDevice.CDClose(hDevice,Result); __CATCH ; __ENDTRY iState := 0; END_IF
Last updated: 2026-05-01

Post by imdatatas on MC_CamIn did not work properly with SMC_FreeEncoder on SoftMotion 4.17.0.0 ^{CODESYS Forge talk (Post)}
Hello, I am facing a problem with the new Softmotion 4.17.0.0 version. Has anyone encountered a similar problem, what is the solution? I would be happy if you could share it. Problem description: -- "SMC_FreeEncoder" encoder axis is the master, -- The motor of the servo driver on the EtherCAT bus is the slave axis. -- When the MC_CamIn block executed, the InSync output is activated. However, although the master encoder axis position value changes, there is no movement in the slave servo axis! Test steps: 1-) EtherCAT servo axis installed, configured and motion test was performed with MC_Jog. No problem. 2-) Softmotion general axis pool > SMC_FreeEncoder was added and pulse amount configuration was performed. No problem. 3-) Incremental encoder actual count value was transferred to the "SMC_FreeEncoder.diEncoderPosition" variable as DINT under the ethercat task in every cycle and the encoder axis position value was observed. No problem. 4-) A simple CAM table with a 1:1 ratio was created under the project tree. (For example: Simply, when the encoder rotates 1 turn, the motor will rotate 1 turn.) 5-) The SMC_FreeEncoder axis enabled with MC_Power and brought to the StandStill state. 6-) The MC_CamTableSelect block was run with default input values ​​(all absolute) and only the Cam table name was specified. The Done output was seen successfully. No problem. 7-) The MC_CamIn block was activated with default input values ​​(absolute) and only the master encoder axis name, slave servo axis name, CamTableID input pins was specified and then "Execute" input set to TRUE. 8-) The InSync output information of the MC_CamIn block observed as TRUE. However, although the encoder axis value changed, the position value of the slave axis did not change at all, it did not move. It always remained at 0.0mm. 9-) When I repeated the same steps above, only changing the master axis to SM_Drive_Virtual instead of FreeEncoder and gave movement to the virtual axis, this time the slave axis moved successfully. However, when the same steps and operations are performed with the same IDE just downgrade SoftMotion version from 4.17.0.0 to 4.10.0.0, everything works normally and without problems as expected in MC_CamIn block with FreeEncoder master. (By the way, The used IDE version is Codesys V3.5 SP20patch3.) Best Regards Imdat
Last updated: 2024-11-11

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