Post by rk-gaw on Unhandled exception and refactoring error ^{CODESYS Forge talk (Post)}
Hello everyone. I hope this is the right place to ask for help, this error is causing me a great amount of time loss and I really would like to end this nightmare. I don't know why but at times if I try to Browse -> Display Cross Reference on a variable Codesys just crashes. I'll attach the file with the complete crash report hoping someone can figure why it happend. I think that the unhandled exception comes from the PersisranceManager Module and is connected with the other big problem I'm facing: I cannot refactor in my project, if I'll try to refactor a POU name the whole POU will become "frozen", it's like its desynchronizing from the project and the project cannot find the pointer to the POU once I refactor it. And when I open the project a warning pop-up will show up with the frozen POUs name, but I cannot figure out what the warning is telling me. I'll attach every warning and error pop up the project is showing me, and thanks in advance to anyone who can figure something out.
Last updated: 2025-12-10

Post by animesh on SoftPLC (CODESYS Control x86 RTE V3 x64) OPC UA binds only to 127.0.0.1 — Not binding to LAN IP ^{CODESYS Forge talk (Post)}
Hello everyone, I am facing a persistent issue with the OPC UA Server on Advantech Soft PLC with hard realtime for Win64 (V3_5_2010_3) and need help from the community. Device Information Name: Advantech Control x86 RTE V3 x64 Vendor: Advantech Co., Ltd. Categories: PLCs Version: 3.5.20.10 Description: Advantech Soft PLC with hard realtime for Win64 (V3_5_2010_3) Problem Summary The OPC UA Server works perfectly when accessed via: opc.tcp://localhost:4842 opc.tcp://<hostname>:4842</hostname> But it does NOT work when using the LAN IP: opc.tcp://192.168.0.XX:4842 In UAExpert I get: Discovery FindServers on opc.tcp://192.168.0.XX:4842 failed (BadCommunicationError) Port is LISTENING in windows Firewall.. Tried with turning off the firewall completely. System Information Windows 10 x64 Advantech CODESYS RTE Soft-PLC (hard real-time) Network IP: 192.168.0.XX Hostname: WINDOWS-XXXXX Need your Support
Last updated: 2025-11-24

Post by bertus on Can't get SMC_SmoothPath to work ^{CODESYS Forge talk (Post)}
Hi Georg, thanks for your time. What is the value of D_ANGLE_TOL? It is set to 0.01. Do you need the assignment bAbort := NOT bDecoder? Does it help to leave it out? This seems to make no difference. Any errors (e.g. SMC_SmoothPath.Error/ErrorID) or PLC log messages? No errors or log messages. What if you comment out SMC_SmoothMerge and SMC_LimtiDynamics, is corner smoothing still not working? Indeed. Is bDecode written from a different task (e.g. visu)? Then I would recommend to assign to a local variable (bDecodeLocal := bDecode) and use that for all FBs. Otherwise, FBs might see different values of bDecode in a single cycle, which will cause problems. It is a local variable, written from a state machine inside this program. But there is new information: During some trial and error, I tried skipping "stage 2: merge short linear segments" (SMC_SmoothMerge). And suddenly it rounds the corners, see attached image. Looking a bit closer, I noticed that (with the original program) after a download (cold start?), it in fact did round the corners, but only once. Ever next cycle in which the NC program was executed, the corners where not rounded. Not sure if there is any relation, but SMC_SmoothMerge is also the only FB which has no bAbort input. Perhaps I need to reset it (or any buffers) by other means?
Last updated: 2025-12-18

Post by ilya-vah on Table element issues ^{CODESYS Forge talk (Post)}
Hello, First post here. I would like to clarify whether the following behavior is known or if it is a bugs. Issue 1 — First row not displayed when using Maximum array index with 1-based arrays Description: When displaying data from an array that is indexed starting from 1 (e.g., ARRAY[1..N]), and the number of displayed rows is limited using the Maximum array index property, the first row of the array is not shown in the visualization. Steps to reproduce: Create an array indexed from 1 (e.g., ARRAY[1..N]). Bind the array to a Table element. Limit the number of displayed rows using the Maximum array index property. Run the visualization. Actual result: The first array element (index 1) is not displayed in the table. Issue 2 — Tooltip string placeholder cannot be bound to string variable from array Description: It is not possible to use a string placeholder in the tooltip that is bound to a string variable from the array. Steps to reproduce: Use a table bound to an array containing string variables. Configure a tooltip using a string placeholder referencing a string field from the array. Run the visualization. Actual result: Tooltip doesn't show any text. A test project demonstrating both issues is attached. Thank you for your time and support.
Last updated: 2026-02-16

Post by charleskirkland on Connect to Azure IoT Hub ^{CODESYS Forge talk (Post)}
It sounds like your TLS setup is basically correct, since the handshake works via OpenSSL, so the issue is likely on the CODESYS side rather than the certificates themselves. From what I’ve seen with the Azure IoT Hub Client SL library, you should double-check that the SAS token is actually being generated and passed correctly to the function blocks (especially wsDeviceSaS) and that the MQTT/HTTPS FB is really triggered cyclically-otherwise the controller won’t initiate the connection at all. Also, make sure DNS, time (NTP), and full certificate chain trust are properly configured on the controller, since IoT Hub authentication depends on them even when using SAS tokens. Another thing worth checking is the library/runtime version-there are reports that certain versions changed behavior and caused connection issues. I’d recommend starting with the official demo project (AzureMQTTDemo) and comparing it step by step with your setup to see what’s missing or not triggered. Speed Stars
Last updated: 2026-04-27

Post by garyl on Comments in arrays and assigning RST coil's to 600 outputs ^{CODESYS Forge talk (Post)}
Hello all, im working on a project that requires me to convert an old automation direct DirectSoft PLC d2-250-1. One of the problems im encountering is that all of the comments are attached to members of the different addresses. When i convert the addresses (1777 "C" registers, 777 X registers, and 20,0000 V registers) im running into difficulties keeping the inputs/outputs correct since they are missing documentation. Is there a good way to retain the comments of the indexes in the array? Secondly, initially i was declaring the "C" and "V" addresses individually and this worked to retain the comments as to which register did what, however i ran into a problem when one rung reset (or set to 0) approximately 600 C Addresses. Since each tag is separately declared this proved to be nearly impossible without a literal wall of code that attempted to crash the program. So i converted all of the registers (C,X,Y,V) into separate structs, declared them as arrays and pointed all of the original call outs in the program to the newly defined structs. However i have now lost comments and the program is very hard to follow. Thanks for any help with this issue.
Last updated: 2023-08-31

Post by danwoodlock on RPI Zero w - Edge gateway cant install ^{CODESYS Forge talk (Post)}
Hello all, First post. I recently acquired an RPI zero W from amazon, and have been using it with Codesys v3.5 SP19 patch 2. I first got it working yesterday, and after installing the runtime on the Pi, I was prompted to install the edge gateway. Installation of the edge gateway failed because of unsupported architecture, undeterred I was able to connect to the pi and program as I wanted. The issue I've noticed is that if I do not load anything to the pi overnight, I can then no longer connect to the pi and download, although I can still ping it from my pc. I found that if I power cycle the PI, I am then able to connect again, and it works as normal. I did some googling and found instances where people recommended downloading the newest edge gateway, which brings me here. Wondering if there are any suggestions, or if this is a known issue. I actually tried installing all 3 versions of edge gateway for science, but all fail with the same message. Thanks -Dan
Last updated: 2023-09-13

Post by manuknecht on Persistence Manager does not save alphabetically first value ^{CODESYS Forge talk (Post)}
I have several libraries which contain values that should be saved on a PLC. As apparently no Persistent Variable List is available within Libraries, I use the Persistence Manager to create a Persistence Channel in the Project which imports the library. I then specify the persistence channel in the library using the {attribute 'ac_persist':='PersistenceChannel_CT'} specifier. This generally works very well and gives me exactly the properties I require. However, it came to my attention that the (alphabetially) first value from the library is not saved in the created ASCII file. When checking the content of the Persistence Channel, it shows all the variables as defined in the library. But the created file does not contain the first value and it is not restored after restart or reset. (see attached picture) I disabled Periodic Saving and set xSaveOnChange to TRUE and so the file usually updates immediately after changing one of the values. When changing the first value, it does not update which is consistent with this value not being saved. I also created a sample project and library from scratch which shows the same issue both using a Raspberry Pi and using a Linux machine. Does someone know what the reason for this could be or did someone make similar experiences? Looking forward to hearing your suggestions. Thanks in advance and best wishes Manuel
Last updated: 2023-10-17

Post by mondinmr on Jitter problems on imx8 ^{CODESYS Forge talk (Post)}
We are experiencing serious jitter issues on an ARM64 imx8. Until now, on rpi and beaglebone derivatives, and on Intel, we never encountered jitter issues unless they were already present on the device. In this case, as can be seen from the attached graph, we have excellent maximum latency. The cyclictest on the isolated core dedicated to IEC CODESYS tasks shows a latency of 37µs, with an average of 14µs. Usually, on all other devices, with an RT kernel, with the appropriate parameters to avoid frequency throttling, with properly managed IRQs, and with the disabling of large page sizes, the jitter measured by CODESYS is very close to the cyclictest latency. However, on this imx8, we are noticing a fluctuating value of +/- 300µs that seems to be added to this latency, as if something occasionally miscalculates the sleep times by exactly +/- 300µs. Two screenshoot attached. - Result of cyclictest - Jitter on CODESYS Tasks are assigned to isolated core!
Last updated: 2023-10-18

Post by nizrahel on OpC UA server on Raspberry Pi 64 SL runtime ^{CODESYS Forge talk (Post)}
Hi all! I'm working on an home project using a Raspberry Pi 3 device with Codesys for Raspberry Pi 64 SL runtime. I would like to create the HMI interface with Siemens WinCC Unified (or Advanced) configuring the Raspberry as OPC UA server. I tryed everything, but I didn't find the way to let the OPC UA connection works using UaExpert. I tryed to use anonymous connection, authenticated connection and the ip address instead of the server name in the path connection. There is no way to connect to the OPC UA server and I was asking myself if this feature is really supported for the runtime version used. Another strange thing I noted, is that is not possible to quickly create an OPC UA certificate in the Security Screen, as show in any tutorials. I have correctly created the Symbol Configuration enabling the OPC UA feature. I attach to this topic some printscreen of the actual configuration (sorry for the italian language interface, but I didn't find the way to switch to english). Thank you very much in advance for your support and advices!
Last updated: 2023-12-03

Post by climblinne on Calling OPC UA Methods from UaExpert ^{CODESYS Forge talk (Post)}
Hello, I hope someone could help me. I installed the newest Codesys 3.5 SP 20 Patch 1. When loading the demo files from @i-campbell I can upgrade them to the latest version and everthing works on the OPC-UA client side as expected (object "a" is visible, I can use the "ExampleMethod"). Now I * remove the "Information Model", * delete the "OPC_UA_Symbols Objects", * Add "Information Model" again * add "TestRootObjectType" again and "Generate IEC declarations" * and search for mapped instances (to get instance "a" again) Very good still working as expected. Now I delete the OPC_UA_Symbols and add it again referring to the "objecttest" from 16.9.2020. Also I redo the steps from above. The result is now, that I can't see the "a" object in the "Root/Objects" folder. Why ist this and how can I make it running? I think, it could may be a different version of the UA configuration file. I tried to build my own model definition files and got the same problem (but I am really not an expert). When someone has a actual model, which is also running in the actual Codesys I would be very grateful. Or even better, how to make the correct model in e.g. UA Modeler SW (I followed the description https://documentation.unified-automation.com/uamodeler/1.6.0/html/howprojnet_sec.html).
Last updated: 2024-07-01

Post by tyronnosaurus on ReceiveWatchdog FB not working on J1939 P2P PGNs ^{CODESYS Forge talk (Post)}
Hi guys. I've got a device that sends a status message over J1939 and a PLC running Codesys to receive it. This message uses a P2P PGN (as opposed to a broadcast PGN). Codesys can only read it if I mark the J1939_ECU as "Local" (see screenshot 1). The message is received correctly, that is not the problem. The problem is detecting if the message stops being received. Local ECUs have no Watchdog checkbox to detect if the message has been received in the last X seconds. In order to implement a watchdog, I've used a ReceiveWatchdog FB. The same code works well for any non-P2P message, but doesn't work for this particular P2P message I'm trying to monitor. Even if I physically disconnect the device, ReceiveWatchdog.xBusy stays True, and ReceiveWatchdog.xError never triggers due to a timeout error. Is there any caveat in the ReceiveWatchdog FB that makes it unable to monitor P2P PGNs in Local J1939_ECUs?
Last updated: 2024-07-11

Post by simone on Cannot connect to webvisu on localhost ^{CODESYS Forge talk (Post)}
As I wrote before on the title, I have difficulties to connect to see webvisu from localhost. The story: while waiting for the plc+hmi to arrive, I'm preparing the software, mainly the visual parts trough the control Win3 x64 (same version as the ide 3.5.20.10). The problem is that I can't see the webvisu with the installed webbrowser. I don't know if this is a problem, but I changed the port to 9001 (randomly "free") because 80, 8000, 8080, 8088, 3000 are all occupied by other projects (all on the Apache server). Is there something wrong with the config file? This is the url: localhost:9001/webvisu_app.htm and here the config file part "CmpWebServer". [CmpWebServer] ;The handling of startup/shutdown of the webserver: ;0->automatically start, shutdown only on shutdown of the runtime;1->automatically start, could be shutdown on demand ;2(default)->start/shutdown on demand;3->start on demand, shutdown only on shutdown of the runtime StartupType=0 ;The TCP port the webserver listens on WebServerPortNr=9001 LocalAddress=localhost ;LocalAdapterName=LAN-Connection LocalAdapterName=EthernetPCPLC ;LocalAdapterNameUnicode=L\00A\00N\00-\00C\00o\00n\00n\00e\00c\00t\00i\00o\00n\00 LocalAdapterNameUnicode=E\00t\00h\00e\00r\00n\00e\00t\00P\00C\00P\00L\00C\00 Thanks for all the help!
Last updated: 2024-07-11

Post by berto on Opening PDF in Web Browser in Target Visu HMI ^{CODESYS Forge talk (Post)}
Hi everybody, I've been facing problems with the PDF visualization in Web Browser. I am trying to open a pdf file called 'sample.pdf' which I manually saved inside PlcLogic/visu folder. I am setting the web browser URL as: 'http://127.0.0.1:8080/sample.pdf' but I get 'refused connection'. I got a similar error trying to open https sites and I discovered that I can only open http websites. Opening 'http://de.wikipedia.org' everything works fine. I also tried to check using code whether the sample.pdf is present in the directory. Unfortunately, when I try to read directories of 'PlcLogic' I get file FILE_OPERATION_DENIED (I am using File.DirList). I would like to be able to open PDF files in web browser. Possibly to move new PDF files in the folder as my customer wants to display different pdf manuals on the hmi. Here you find some screenshots and my .project. I am using Codesys 3.5.19.70. Best regards, Berto
Last updated: 2024-07-11

Post by faceplant on CmpDynamicText unresolved references ^{CODESYS Forge talk (Post)}
Hello! I am new to codesys so I am sorry if this is not the right place to ask this question. I am using codesys V3.5 SP20 Patch 1 + (64-bit) and a Groov EPIC PLC (GRV-EPIC-PR2). I am trying to build and deploy my application to the PLC, but when I log in I get 6 errors (codesys_error.png). It seems that the errors have to do with the CmpDynamicText system library which I have as version 3.5.20.0. I have tried to add CmpDynamicText to the ComponentManager section in the PLC's CODESYSControl.cfg file as described in this forum post and still hit the same error. I noticed that the library is grayed out in the library manager, which I think might be the issue. However I don't remember if it was grayed out before I encountered this issue. Please let me know if I can provide anymore info. Thank you!!!
Last updated: 2024-07-19

Post by biiebs on Aufbau von Ablaufsteuerungen ermitteln ^{CODESYS Forge talk (Post)}
Hallo Zusammen, gibt es in CODESYS bei Ablaufsteuerungen weitere Möglichkeiten außer den AS-Einstellungen z.B. die Aufbaustruktur der Ablaufsteuerung herauszufinden? Gesamtanzahl der verwendeten Aktionen / Schritte - Im besten Fall auch die einzelnen Verzweigungen? Ich würde den gesamten Aufbau der Schrittkette gerne als "View" in einer übergeordneten Software abbilden lassen, da sich die Ablaufsteuerungen, je nach Projekt im Aufbau unterscheiden bräuchte ich die Kenntniss über den Aufbau dieser Schrittketten. Oder müsste ich mir hier einen "Workaround" programmieren, der z.B. bei Init erstmal den Aufbau der Ablaufsteuerung durchläuft und mir die nötigen Informationen liefert? Natürlich wäre auch ein Weg den Aufbau des AS-Bausteins über die PLCopen XML zu exportieren, jedoch müsste dies bei Änderungen jeweils nachgezogen werden - was etwas unschön wäre, falls dies vergessen würde. Mittlerweile habe ich auch das Tool "SFC Visu Generator" gefunden, dessen Funktion im Prinzip genau das darstellt, was ich benötige - jedoch leider nur als CODESYS interne Visualisierung. Ich würde den Export des Bausteins gerne in meine übergeordnete Software implementieren. Gibt es hier die Möglichkeit das Vorgehen zu Erfahren oder den vom Baustein generierten Export bei mir zu implementieren? Hat hier jemand sowas ähnliches schonmal gelöst? Vielen Dank im Voraus Mit freundlichen Grüßen Biiebs
Last updated: 2024-07-25

Post by codesysbeginner on Eaton XC303 - USB Mounting / Trend manager ^{CODESYS Forge talk (Post)}
Hi, For a project I am using the trendmanager functionality, I changed the placeholder filepath to which the SQL database is saved to: home/disk_usb, $trend$. Which only works as long as the usb was mounted to the PLC at boot. However, I'd like to be able to switch the USB's out if they break or for data analysis. However when a new (or the same) USB is plugged back in the shortcut doens't exist on the device anymore. Also in the device directory under root/mnt/ a new folder appears SDB1 in addition to SDA1 to which the Trendmanager was originally writing. The SDA1 folder is empty/unreachable while the new SDB1 folder has the contents of the USB drive. I tried disabling the trendmanger while unplugging the USB's however this doesn't work. My question, how do I make it so that when I plug a USB drive back in, it will be mounted to SDA1 instead of SDB1? Kind Regards
Last updated: 2024-10-09

Post by etienneneu on loading delay with the option "check client animations and overlay of native elements" ^{CODESYS Forge talk (Post)}
Hey NicolaG_89, thanks for the tip. But I have seen in the developer tools of the Webclient that a multiple fetching of the image and script data occurs when changing frames (HTTP code 304 NOT Modified), although these are already in the clients cache, which leads to unnecessary loading of resources from the web server. This behavior can also be found if the option “Support client animations and overlay of native elements” is deactivated, but this does not lead to such long delays. I had already tested loading all Visu elements so that everything was fetched once before they could be used. But that didn't help either. To prevent this behavior (permanent fetching), I have used a different way of switching the Visu elements in the VisuDemo Project, which also uses HTML5 control elements. I implemented this with the visibility of entire Visu elements. As a result, it only has to be fetched once and does not have to be fetched again when reloading. But I am still unsure about this implementation if the scope of the visualization becomes larger, as the Codesys visualization documentation advises against using many invisible elements. Best regards Etienne
Last updated: 2024-11-19

Post by mubeta on Strange problem with the ‘MC_SetPosition’ function ^{CODESYS Forge talk (Post)}
CoDeSys 3.5.19.7 Target Berghof MX6 In a simple SoftMotion programme with two stepperless modular axes from CMZ, one is simply controlled in speed, but a spot must perform a positioning. I use the function MC_SetPosition() both to reference the axis at power-up and also to correct the actual position to a fixed machine reference detected with proximity. The function has only one instance and I actually use a booelan variable to control the ‘Execute’ input. Well, I cannot correctly change the axis position on the fly if it is running at high speed. The servomotor works in a speed range between 0°/s and 720°/s, (gearbox output with a 1:6 ratio). As long as the servomotor is operating at speeds below about 400 °/s, the function is able to correct the position correctly even when forcing values far apart, but at high speeds, from 400 °/s upwards, the correction no longer takes place. For example, trying to correct the position of 280° into 300° with absolute mode, the axis that is moving at speed actually shifts the position by a few degrees, not the expected 20. I don't understand why with the servo drive running slowly the position shift occurs correctly, while increasing in speed it no longer works.
Last updated: 2025-01-09

Post by mubeta on Strange problem with the ‘MC_SetPosition’ function ^{CODESYS Forge talk (Post)}
Hi gseidel, before moving to HW implementation, I had created the same program in simulation mode with virtual drives and, as far as I remember, everything worked fine simulating process and the few useful inputs. So it does not seem to be a SoftMotion library problem, but rather a problem with dynamics or physical axis adjustments. What escapes me, however, is the fact that this function is supposed to perform a position shift virtually, in fact without interfering with the axis itself, thus independent of its adjustments. MC_SetPosition() is not a homing function, in fact it is clearly intended to be executed on the fly with the axis moving. Now I'll see if I can reduce the program, although I don't like it very much. In my life I have learned that problem searches should be done on the part, and not in a more or less similar way.
Last updated: 2025-01-10

Post by timvh on STRING conversions to DWORD ^{CODESYS Forge talk (Post)}
I guess that the printer expects to receive an array of byte values. So where it is described that it expects to receive: Hercules String : 1B4F513030311B7532626C61636B04 it actually expects to receive an array of bytes with the values 1B,4F,51,30,30, etc. So what you can do is create an array of bytes and assign the byte value to each item in the array: VAR abyToSend : ARRAY[0..99] OF BYTE; END_VAR abyToSend[0] := 16#1B; // ASCII Escape character, hexadecimal representation uses 16# as prefix abyToSend[1] := 16#4F; // ASCII 'O' abyToSend[2] := 16#51; // ASCII 'Q' abyToSend[3] := 16#30; // ASCII '0' // you can do the rest yourself // maybe could be created a lot smarter, but gives you an indication how to handle this. Then with the serial communication (or TCP/IP?) you can send a message with the reference to the array (abyToSend) and the number of bytes to send (15 bytes for the string you gave as example).
Last updated: 2025-02-02

Post by timvh on Device diagnosis ( EtherCAT IO card ) ^{CODESYS Forge talk (Post)}
You can get the state by just using the name of your node (same name as in device tree): VAR etcState: IoDrvEthercatDriverLib.ETC_SLAVE_STATE; END_VAR etcState := EJ1100.wState; Alternatively, you can iterate through the device tree to get the status of all (Ethercat) nodes. See here an example (no guarantee it works, just give as suggestion): PROGRAM P_IO_State VAR CONSTANT uiMAX_NR_OF_TERMINALS : UINT := 100; END_VAR VAR // general device diagnosis // can only be used when the Device - PLC Settings - Advanced settings - enable diagnosis for devices is enabled // this will add the DED library coupler: DED.INode; terminal: DED.INode; aDeviceState: ARRAY[0..uiMAX_NR_OF_TERMINALS - 1] OF DED.DEVICE_STATE; uiTerminalCount : UINT; uiIndex : UINT; // for each terminal check if it implements device diagnostics xQueryResult: BOOL; itfDevice : DED.IDevice2; xDiagAvailable: BOOL; eError: DED.ERROR; xEverythingOK: BOOL; END_VAR uiTerminalCount := 0; // start at the top of the device tree with the first EtherCAT coupler coupler := EtherCAT_Master.FirstChildNode; WHILE coupler <> 0 DO // for each coupler that is found start at the first terminal terminal := coupler.FirstChildNode; WHILE terminal <> 0 AND uiTerminalCount < uiMAX_NR_OF_TERMINALS - 1 DO // for each terminal that is found get the status through the device diagnosis interface xQueryResult := __QUERYINTERFACE(terminal, itfDevice); IF xQueryResult THEN aDeviceState[uiTerminalCount] := itfDevice.GetDeviceState(xDiagnosisInfoAvailable => xDiagAvailable, eError => eError); uiTerminalCount := uiTerminalCount + 1; END_IF terminal := terminal.NextSiblingNode; END_WHILE coupler := coupler.NextSiblingNode; END_WHILE uiIndex := 0; xEverythingOK := TRUE; WHILE uiIndex < uiTerminalCount DO IF aDeviceState[uiIndex] <> DED.DEVICE_STATE.RUNNING THEN xEverythingOK := FALSE; EXIT; END_IF uiIndex := uiIndex + 1; END_WHILE
Last updated: 2025-02-06

Post by atcprojectteam on Modbus Function Code 15, writing multiple coils ^{CODESYS Forge talk (Post)}
Hi all, I am using an RSTI-EP I/O card along with the EPXMBE101 Modbus/TCP network adapter. I have a Control Standard L license. I successfully connected to the I/O card via Modbus and can read inputs without any issues. However, when I try to write to the digital output modules using function code 15, I am unable to make any changes. Here’s what I have done so far: I created a small project using Structured Text. I set up Modbus channels (as shown in the attached image) and mapped the pins. When I use cyclic mode, the connection results in an error. However, when I use the rising edge, the connection works, but I don’t see any changes on the I/O card. For the output module, I assigned one bit to high. After that, I ran CODESYS Control Win V3. (Should I be running the PLC as well?) I built the program, but I am not receiving any response from the I/O card. Could you please advise on what might be causing this issue?
Last updated: 2025-02-26

Post by atcprojectteam on Modbus Function Code 15, writing multiple coils ^{CODESYS Forge talk (Post)}
Hi all, I am using an RSTI-EP I/O card along with the EPXMBE101 Modbus/TCP network adapter. I have a Control Standard L license. I successfully connected to the I/O card via Modbus and can read inputs without any issues. However, when I try to write to the digital output modules using function code 15, I am unable to make any changes. Here’s what I have done so far: I created a small project using Structured Text. I set up Modbus channels (as shown in the attached image) and mapped the pins. When I use cyclic mode, the connection results in an error. However, when I use the rising edge, the connection works, but I don’t see any changes on the I/O card. For the output module, I assigned one bit to high. After that, I ran CODESYS Control Win V3. (Should I be running the PLC as well?) I built the program, but I am not receiving any response from the I/O card. Could you please advise on what might be causing this issue?
Last updated: 2025-02-26

Post by ojz0r on Assignment Efficiency - Repetitive Assignment vs IF statement ^{CODESYS Forge talk (Post)}
Its important that you know the difference between the two. Example 1: Coils[0] := Coils[0] OR (Buttons[0] AND Sensors[0] > 6); In this case the statements will be evaluated every scan and result in either true or false for Coils[0]. Example 2: IF NOT Coils[0] AND Buttons[0] AND (Sensors[0] > 6) THEN Coils[0] := TRUE; END_IF In this example Coils[0] will latch the result in a true evaluation, if you want it to behave the same way as example 1 then you need to do it like example 3 below: IF NOT Coils[0] AND Buttons[0] AND (Sensors[0] > 6) THEN Coils[0] := TRUE; ELSE Coils[0] := FALSE; END_IF However back to the real question. There is no problem using either example 1 or example 3, if im not requiring a latch i usually go with example 1 as it is more compact.
Last updated: 2025-03-07

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