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

Post by struccc on Application failing to boot after system reboot ^{CODESYS Forge talk (Post)}
I started to experience the same issue, after upgrading to 3.5.19 , and still persists with 3.5.20.3 , using CodesysControlWinV3 x64 on Windows. Unfortunately, this is a live application, normally it is running for months without interruption - so it was a surprise at the last cold start... It was not possible to go online with the original version, so I couldn't see the application, or system status, just the log message. First time I manually clean the Application from the PlcLogic directory (there was no coredump file in there), then I could start the runtime service, and do a fresh download, and set the bootproject. I could not try a cold system reboot - it's in a 24/7 production environment, and I was under heavy pressure to start... What I did, I have created a backup from the * complete * runtime directory, from the failed, and fixed version - before and after download. This directory in my case C:\ProgramData\CODESYS\CODESYSControlWinV3x64\55096128 - At the next shutdown, it was sufficient to copy back this backup completely, and could start the runtime service afterwards. Ugly, but local staff with some skills can do it without programming tool... I don't store any live data, configuration, log files, persistent data in this directory - the only reason I need this is to edit the CodesysControl... .cfg file.... And to see the logfiles in emergencies like this. The application concerned doesn't use any retain area. - exactly for these reasons - Maybe that is causing the problem with the newer runtime versions As far as I see, this problem occurs only if the power of the Windows PLC is interrupted without a proper shutdown. Unfortunately, this can happen sometimes. The newer versions, seems tp modify CodesysControl.cfg on the fly, and register the applications, and bootproject information after download. (I don't really see CodesysControl.cfg a proper location for this... but that's just my feeling) So now I had a look at CodesysCotrol.cfg on my laptop and I found: [CmpRetain] ;Retain.SRAM.Size=0x200200 ;Retain.SRAM.Address=0xFA3C5776 ;SimulateSRAM=1 [CmpApp] ;Bootproject.CreateOnDownload=0 ;Bootproject.StoreOnlyOnDownload=0 ;Bootproject.InvalidateByRename=1 ;Bootproject.InvalidateBySetting=1 ;Bootproject.InvalidateNever=0 ;PersistentForce=0 ;RetainType.Applications=InSRAM ;RetainType.Applications=OnPowerfail ;RetainType.Applications=None ;Exception.Hardware.GlobalStop=1 Application.1=MyTestAppNoRetain The last line appeared after download and boot project creation. Maybe... Should set RetainType.Applications=None? I wonder about all these settings, but... Will write separately about it. I hope this helps a little...
Last updated: 2024-11-21

Post by clarenced on ERROR: Calling the program "AlarmStorage_Prg" is not allowed from multiple tasks ^{CODESYS Forge talk (Post)}
Using codesys v3.5 SP21 Patch 1. We are using Visualization to display alarms. Other then the automatically created AlarmManagerTask, there is no code written to call AlarmStorage_Prg. Any ideas why we would be seeing this error in the log? The runtime actually shutdown. Not sure if that was caused by this error or not. 2025-08-03T02:45:35.444Z, 0x00001012, 4, 0, 0, * ERROR: Calling the program "AlarmStorage_Prg" is not allowed from multiple tasks. 2025-08-03T03:48:15.294Z, 0x00001012, 4, 0, 0, * ERROR: Calling the program "AlarmStorage_Prg" is not allowed from multiple tasks. 2025-08-03T04:38:11.557Z, 0x00000103, 65544, 1, 0, runtime received SIGABRT - system may be in an inconsistent state * We recommend a reboot of the controller now! * 2025-08-03T04:38:11.576Z, 0x0000010f, 8, 1, 0, #### Exception: SysSemEnter - Semaphore deadlock detected - owner thread died [tid:726740] - system may be in an inconsistent state. 2025-08-03T04:38:11.576Z, 0x00000103, 65544, 1, 0, runtime received SIGABRT - system may be in an inconsistent state * We recommend a reboot of the controller now! 2025-08-03T04:38:11.576Z, 0x00000001, 8, 260, 3, #### Exception: HANDLED EXCPT* <excpt>NonContinuable</excpt> in CH_COMM_CYCLE 2025-08-03T04:40:12.308Z, 0x00000001, 1, 0, 35, CODESYS Control shutdown... 2025-08-03T04:40:13.436Z, 0x00000071, 1, 0, 13, Webserver stopped 2025-08-03T04:40:13.437Z, 0x00000114, 2, 1, 0, !!!! Warning: task_signalhandler_exit [MainTask] lost cycles: 14809 2025-08-03T04:40:13.497Z, 0x00000001, 1, 0, 10, [UNLOADED] IEC|Dynamic: <cmp>IecVarAccess</cmp>, <id>0x00001007</id> <ver>3.5.3.64</ver> 2025-08-03T04:40:13.506Z, 0x00000001, 1, 0, 10, [UNLOADED] IEC|Dynamic: <cmp>AlarmMgr</cmp>, <id>0x00001012</id> <ver>4.7.0.0</ver> 2025-08-03T04:40:13.513Z, 0x00000071, 2, 0, 14, !!!! Warning: Unbalanced calls to WebServerRequestRunning/WebServerReleaseRunning 2025-08-03T04:40:13.513Z, 0x00000001, 1, 0, 10, [UNLOADED] IEC|Dynamic: <cmp>IECVisualization</cmp>, <id>0x0000100c</id> <ver>4.7.0.0</ver> 2025-08-03T04:40:13.611Z, 0x00000124, 1, 0, 0, Provider 'AddressSpaceFragment Provider' (version 0x3051500) unregisterd at the OPC UA server. 2025-08-03T04:40:13.611Z, 0x00000124, 1, 0, 0, Provider 'OPC UA for IEC-61131-3' (version 0x3051500) unregisterd at the OPC UA server. 2025-08-03T04:50:17.708Z, 0x00000001, 1, 0, 36, CODESYS Control shutdown done
Last updated: 2025-08-04

Post by alexgooi on OPC-UA and other communication questions ^{CODESYS Forge talk (Post)}
Dear forum, I currently have a big question mark above my head, and maybe this forum can shine some light on the situation. I recently updated to Codesys 3.15 SP19 Patch 6. And now I’m trying to setup the OPC-UA server, besides that I’m trying to connect to the controller with the Codesys V3 (Ethernet) protocol. OPC-UA I have installed the correct licenses on my controller (Runtime and communication). I’m able to connect to the controller with an OPC-UA client, and I’m able to browse the tags, so far so good. Therefore I’m assuming that the OPC-UA server is running on the controller. But now the strange part, in the device security settings I have set the communication Policy to BASCI256SHA256 ( I also have tried the other ones) and the communication mode is set to secure if possible (I also have tried all the other ones) (see picture). With these settings I would assume that I would only be able to login with a Basic256SHA256 policy with a client. But the opposite is true, I am able to login using the no policy mode and when I set it to Basic256SHA256 the client (UA-Expert) notes that this policy is not available on the server. I then check the certificates and I noted that there is no certificate for the OPC-UA server, I tried to generate one but it gave the error that the certificate has not been created by the device (See picture). To summarize I have no clue what is going on, and the controller does the opposite of what I would expect. Codesys Ethernet V3 driver I have a HMI connected to the same controller using the Ethernet V3 driver. But this will not connect. I tried all the Protocols (see picture), with and without the username and password enabled. But it will not connect, when I scan the available servers I can see the controller with the port number that I am expecting, so I’m assuming that the Codesys V3 ethernet driver is up on the controller. Does anyone can give me some direction, because the stuff that I tried doesn’t make sense to me. Thank you in advance
Last updated: 2024-04-02

Post by axberry on CODESYS Control for Raspberry Pi 5 - "Hardware version or firmware version not supported" on Rev 1.1, persists across multiple runtime versions and OS images ^{CODESYS Forge talk (Post)}
Hi, I'm trying to run CODESYS Control for Raspberry Pi SL on a Raspberry Pi 5, and the runtime consistently fails to start with the following error when launched manually: ooops... this runtime was built for RASPBERRYPI. Hardware version or firmware version not supported! (-18, 0x00000BB8, 0xFFFFFFFB) Hardware: Raspberry Pi 5 Model B Rev 1.1 Revision code: d04171 CPU: aarch64, BCM2712 Serial number is correctly exposed via /proc/cpuinfo and /proc/device-tree/serial-number /proc/device-tree/model correctly reports "Raspberry Pi 5 Model B" What I've tried (all resulting in the same error): CODESYS Control for Raspberry Pi SL 4.11.0.0 (SDK 3.5.19.61) — the version that introduced Pi 5 support CODESYS Control for Raspberry Pi SL 4.21.0.0 (SDK 3.5.22.20) — latest available Raspberry Pi OS Bookworm (64-bit) with kernel 6.12.93+rpt-rpi-2712 (June 2026 build) Fresh install on Raspberry Pi OS Bookworm (64-bit) with an older image from November 24, 2025 — same error, ruling out a kernel-version regression Bootloader/EEPROM confirmed up to date (rpi-eeprom-update reports "up to date") Clean purge and reinstall of the codesyscontrol package each time (verified via dpkg -l, no leftover files) Verified /etc/codesyscontrol/3S.dat correctly symlinks to /etc/codesyscontrol/3S_aarch64.dat The service starts (systemctl status briefly shows active (running) with a real PID under /opt/codesys/bin/codesyscontrol.bin), but crashes shortly after and the process disappears — port 11740 never opens. Since this happens identically across two different runtime versions and two different OS images (5+ months apart), it doesn't seem to be a kernel/firmware timing issue. Could this be specific to the Rev 1.1 board revision, or is there a known issue with the hardware detection logic in the SL runtime that I should be aware of? Happy to provide full debug logs (-d flag output) or journalctl output if useful. Thanks in advance!
Last updated: 2026-08-10

Post by mariapaola on Port instantiation of serial interface in WAGO PLC using Modb_L05.lib in CoDeSys v2.3 ^{CODESYS Forge talk (Post)}
Hi, Would really appreciate your insights in this issue I have. I am currently using a WAGO 750-881 with multiple IO devices. For one of them I already occupied the MODBUS Master configuration tool so I cannot overwrite it for my other devices. I have a total of two serial interfaces WAGO 750-652. The first one is instantiated in COM2 and doesn't need any protocol since the information comes in an specific formatting that need little code to differentiate between needed info. This one is working just fine. The second one is where I have an issue. I have tried to instantiate the port using MODBUS library modb_L05.lib to properly receive the data from an ARDUINO and I am absolutely unable to open the port: Signal DEVICE2.fbModbus.MODBUS_EXT_MASTER.Interface.Com_Port_Ist_Offen is never TRUE, among with all other signals from that interface, while signal DEVICE1.COM2.Com_Port_Ist_Offen is TRUE, and the other signals also read as TRUE or FALSE. I have tried instantiating the second one as the first one, changing COM3 to COM4, I've tried a lot of things but it wont ever open the channel. I don't know if you have any recommendations for me. For both physical modules, both witness LEDs A and E are on. First one is instantiated like this: PROGRAM DEVICE1 VAR wBaudRate : WORD := BAUD_9600; bDataBits : BYTE := 8; bParity : BYTE := 0; bFlowControl : BYTE := 3; (RS422 FullDuplex with continous send) i : INT; COM2 : SERIAL_INTERFACE; xOpenPort2 : BOOL := TRUE; ( Flag to open the Port ) xInitPort2 : BOOL; ( Flag to initiallize the Port ) ReceiveBuffer2 : typRing_Buffer; END_VAR COM2( bCOM_PORT_NR := 2, cbBAUDRATE := wBaudRate, cbsBYTESIZE := bDataBits, cpPARITY := bParity, csSTOPBITS := STOPBITS_1, cfFLOW_CONTROL := bFlowControl, utRECEIVE_BUFFER := ReceiveBuffer2, ptSEND_BUFFER := ADR(SendString2), xINIT := xInitPort2, xOPEN_COM_PORT := xOpenPort2, iBYTES_TO_SEND := LEN(SendString2)+1, xSTART_SEND := xSendActive2 ); Second one like this: PROGRAM DEVICE2 VAR COM4 : SERIAL_INTERFACE; xInitPort4 : BOOL := TRUE; xOpenPort4 : BOOL := TRUE; ReceiveBuffer4 : typRing_Buffer; fbModbus : MODBUS_EXTENDED_MASTER_RTU; fbError : enumMB_ERROR; stQuery : typModbusExtendedQuery; stResponse : typModbusResponse; au16Data : ARRAY[0..14] OF WORD; i : INT; tPoll : TON; END_VAR COM4( bCOM_PORT_NR := 4, cbBAUDRATE := BAUD_9600, cbsBYTESIZE := 8, cpPARITY := 0, csSTOPBITS := STOPBITS_1, cfFLOW_CONTROL := 2, ( RS-485 half-duplex ) utRECEIVE_BUFFER := ReceiveBuffer4, xINIT := xInitPort4, xOPEN_COM_PORT := xOpenPort4, xSTART_SEND := xSendActive4, ); stQuery.SlaveAddress := 1; stQuery.FunctionCode := 3; stQuery.Read_StartAddress := 0; stQuery.Read_Quantity := 15; (Poll code) fbModbus( ENABLE := TRUE, bCOM_PORT := 4, ( COM4=> 750-652 port ) cbCOM_BAUDRATE := BAUD_9600, cpCOM_PARITY := 0, csCOM_STOPBITS := 1, cbsCOM_BYTESIZE := 8, cfCOM_FLOW_CONTROL := 2, TimeOut := T#500ms, StartFunction := xStart, ExtQuery := stQuery, Response := stResponse, MB_Error => fbError ); FOR i := 0 TO 14 DO au16Data[i] := stResponse.Data[i]; END_FOR;
Last updated: 2025-11-28

Post by baltzer on ICertificateVerifier.VerifyCertificate doesn't appear to override an ERR_CERT_HAS_EXPIRED rejection in TCP_Client.Upgrade() ^{CODESYS Forge talk (Post)}
Follow-up: working workaround found (routing TLS outside CODESYS) For anyone finding this thread later with the same problem (a third-party device presenting a self-signed and/or expired certificate that ICertificateVerifier/udiVerificationMode won't let you connect through) - we never got a working fix within NBS itself, but found a practical workaround worth sharing. Approach: run a local TLS-terminating proxy on the same host as the CODESYS runtime, and have CODESYS talk plain, unencrypted TCP to it instead of connecting to the remote device directly over TLS: CODESYS --plain TCP--> 127.0.0.1:<port> --stunnel/TLS--> <remote device>:<port> We used stunnel (client mode), with certificate verification explicitly disabled at that layer (verifyChain = no, verifyPeer = no) - a simple, well-documented one-line option, unlike anything we could get working inside NBS. Running it as a systemd service with Restart=always means it survives reboots and recovers automatically if the proxy or the remote device drops. On the CODESYS side, this required no changes beyond pointing TCP_Client at 127.0.0.1 instead of the device's real IP, and removing the TLSContext/ICertificateVerifier code entirely - the rest of our application-layer logic (framing, checksums, etc.) was completely unaffected, since none of that ever depended on where the TLS termination happened. Confirmed working end-to-end against a real device with an expired self-signed certificate, running on CODESYS Control for Raspberry Pi SL (Linux). We haven't yet set this up on Windows - stunnel does have Windows builds available, so the same general approach should be possible there too, but that combination isn't tested or confirmed by us at this point. Caveat: this only makes sense when the proxy and the CODESYS runtime are on the same trusted host (in our case, both on the same Raspberry Pi) - don't expose the proxy's plaintext side on a reachable network interface, since that would create an unauthenticated plaintext path to the device. The original question - whether there's a supported way to override an ERR_CERT_HAS_EXPIRED/self-signed rejection from within NBS's own TLSContext/ICertificateVerifier - remains open as far as we know. Still happy to hear from anyone who's solved that particular piece, since the workaround above is a practical detour rather than an actual answer to the original question.
Last updated: 2026-08-06

Post by paulpotat on cm4 runtime problem ^{CODESYS Forge talk (Post)}
Hello, We are having the same kind of problem again with the last CM4 we received : ooops... this runtime was built for RASPBERRYPI. Hardware version or firmware version not supported! (-18, 0x00000BB8, 0xFFFFFFFB) Hardware Version $ cat /proc/cpuinfo processor : 0 model name : ARMv7 Processor rev 3 (v7l) BogoMIPS : 126.00 Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm crc32 CPU implementer : 0x41 CPU architecture: 7 CPU variant : 0x0 CPU part : 0xd08 CPU revision : 3 processor : 1 model name : ARMv7 Processor rev 3 (v7l) BogoMIPS : 126.00 Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm crc32 CPU implementer : 0x41 CPU architecture: 7 CPU variant : 0x0 CPU part : 0xd08 CPU revision : 3 processor : 2 model name : ARMv7 Processor rev 3 (v7l) BogoMIPS : 126.00 Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm crc32 CPU implementer : 0x41 CPU architecture: 7 CPU variant : 0x0 CPU part : 0xd08 CPU revision : 3 processor : 3 model name : ARMv7 Processor rev 3 (v7l) BogoMIPS : 126.00 Features : half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt vfpd32 lpae evtstrm crc32 CPU implementer : 0x41 CPU architecture: 7 CPU variant : 0x0 CPU part : 0xd08 CPU revision : 3 Hardware : BCM2711 Revision : a03141 Serial : 1000000097594db7 Model : Raspberry Pi Compute Module 4 Rev 1.1 Kernel Version $ uname -a Linux cmr-pv2-1t00-0001 6.12.25-rt9-v7l #1 SMP PREEMPT_RT Thu Sep 25 11:53:00 CEST 2025 armv7l GNU/Linux OS Version $ cat /etc/os-release PRETTY_NAME="Raspbian GNU/Linux 12 (bookworm)" NAME="Raspbian GNU/Linux" VERSION_ID="12" VERSION="12 (bookworm)" VERSION_CODENAME=bookworm ID=raspbian ID_LIKE=debian HOME_URL="http://www.raspbian.org/" SUPPORT_URL="http://www.raspbian.org/RaspbianForums" BUG_REPORT_URL="http://www.raspbian.org/RaspbianBugs" CodeSys runtime 4.13.0.0 So far we tested runtime versions up to 4.18.0.0, here are the results : * 4.13.0.0 --> Not working ❌ * 4.14.0.0 --> Not working ❌ * 4.15.0.0 --> Not working ❌ * 4.16.0.0 --> Not working ❌ * 4.17.0.0 --> Working ✅ * 4.18.0.0 --> Working ✅ There is nothing in the 4.17.0.0 release note that mentions that, so I'm not sure what to think about this. Is this a known problem within the CodeSys development team ? If yes, how do you follow CM4 hardware evolutions ? Is there a way of making this work without having to update the runtime version ? We have several products working with the 4.13.0.0 runtime and we would like to avoid having to update them all. BR
Last updated: 2026-02-02

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 rossanoparis on CAN TX regression in Control for Raspberry Pi 4.21.0.0 with CAN API library (RX works, TX silently fails) ^{CODESYS Forge talk (Post)}
Environment: Target: Revolution Pi (Kunbus RevPi), armv7l 32-bit OS: Raspbian GNU/Linux 9 (Stretch), kernel 4.19.95-rt38-v7 (SMP PREEMPT RT, built 2022-03-22) CAN: via SocketCAN (can0) Runtime: CODESYS Control for Raspberry Pi SL IDE: CODESYS V3.5 SP22 + patch 3 (previously V3.5 SP22 + patch 2, where everything worked with runtime 4.18.0.0) Library: CANBusAPI from the "CAN API" package, version 1.0.0.3 Summary: The setup worked correctly with V3.5 SP22 + patch 2 and runtime 4.18.0.0. After updating the IDE to SP22 + patch 3 and the runtime to 4.21.0.0, CAN transmission via the CANBusAPI library stopped working. Reception is unaffected. There are no error indications anywhere: the application runs normally and the CAN diagnosis reports a healthy bus. Systematic testing (below) shows the problem follows the runtime version, not the IDE update. Regression isolation: The same application (compiled under SP22 + patch 3, unchanged between tests) was downloaded to the same target with different runtime versions, changing only the runtime each time: 4.18.0.0: TX and RX both work 4.19.0.0: TX and RX both work 4.20.0.0: TX and RX both work 4.21.0.0: RX works, TX does not The behavior is fully reproducible in both directions (downgrading to 4.20 restores TX, upgrading to 4.21 breaks it again). Hardware, wiring, OS, project, and application code are identical across all tests. Diagnostic data (CANBusDiagnosis FB, while the application is transmitting on 4.21): ctSendCounter: incrementing normally ctTxErrorCounter: 0 ctRxErrorCounter: 0 eState: ERROR_FREE xBusAlarm: FALSE So the library accepts and counts the outgoing messages, no TX errors are reported, and the CAN controller state stays error-free, but the messages never reach the other nodes on the bus. Expected behavior: Messages sent via CANBusAPI (CANDriver / SendMessage) are transmitted on the bus, as with runtime versions up to and including 4.20.0.0. Notes: I am aware that the CAN API package (1.0.0.3, from 2016) is old; however, the regression is tied to the runtime version, since the identical binary works on 4.18-4.20. Questions: Is there a known change in CmpSocketCanDrv / CmpCAACanL2 between 4.20.0.0 and 4.21.0.0 that could affect TX via the CAN API library? Is runtime 4.21.0.0 still supported on Debian 9 Stretch (kernel 4.19, RT-patched), or is a newer OS required? If a minimum OS/kernel requirement was introduced with 4.21, is it documented?
Last updated: 2026-08-17

Post by caspershes on Checking the device tree, not just the code: what else is worth a static check? ^{CODESYS Forge talk (Post)}
I spend most of my time reviewing other people's CODESYS projects before commissioning, and two kinds of defects keep showing up. Both compile clean. Both read fine. One is in the code. A pause timer whose own input gets cleared inside the branch the timer is supposed to gate: rampDelay(IN := run_2); IF NOT run_2 OR rampDelay.Q THEN run_1 := TRUE; run_2 := FALSE; // the timer's own input, cleared right here ELSE run_1 := FALSE; run_2 := FALSE; END_IF Next scan IN is FALSE, the timer resets, the condition is true again, and the second pump starts immediately. A 30-second ramp delay that actually lasts one task cycle. The setpoint is on the HMI, the operator turns it, and nothing changes. The other is not in the code at all. On one site the outdoor temperature read 0.0 °C in mild weather. The ST was correct, the variable was bound to the channel — but the channel's sensor type was left at "disabled", so nothing was ever digitised. Same class: a module with Disable_module = TRUE, or an analog output bound to a variable while its mode is off. Nothing in the project reports any of this, and the code review never looks there, because the configuration lives in the device tree and not in the POUs. That second class is what pushed me to parse the .export format rather than PLCopenXML alone — the export carries the device tree and the visualization, so "nothing ever writes this alarm variable" stops being a guess and becomes a fact you can check against the screen bindings. Three things about the format that cost me time, in case they save you some: the same device parameter can appear three times (template, internal copy, actual configuration) — the last occurrence is the one in effect; the enum value of a parameter is not in the parameter itself, it is one level down in BaseType/Value; a channel counts as used when a variable is bound to SensorValueN.SensorValue — InputStatus is a bad indicator, people deliberately bind it on spare inputs. So the question. What else would you check automatically, given both the code and the device tree? I am collecting rules from sites, not from style guides, and the configuration side feels largely unexplored. For what it is worth, the checker I use for this is free and runs offline (single exe, no install, nothing uploaded anywhere): https://github.com/caspershes/plc-lint — 43 rules at the moment, reads .export and PLCopenXML. Happy to add rules people here suggest.
Last updated: 2026-10-27

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