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 egr99 on Modbus TCP Server connection is ESTABLISHED but all holding registers are value 0? ^{CODESYS Forge talk (Post)}
Hi there, Read the above description and experienced the same: Reading coil/discrete input/input register/holding register doesn't fill the mapped I/O variable. Any suggestions? Defined (see attachment): - Ethernet (with parameters according to the used Ethernet adapter of my Windows 11 laptop) - -Modbus TCP Client - - -LOGO231 as Modbus TCP Server - - -WS242 as Modbus TCP Server (WaveShare Modbus TCP <-> RTU converter) - - - -WS242_01 as Modbus Server, COM port (slave-id 1 RTU) - - - -WS242_03 idem (slave-id 3 RTU) - - - -WS242_11 idem (slave-id 11 RTU) Writing coil/holding register works from a mapped I/O variable works fine. Verification of Modbus traffic with WireShark: QUERY to and the RESPONSE of all slave-ids are correct Status of all defined is CONNECTED, RESPONSE_SUCCESS, RUNNING etc. Request counters increase with expected frequency. Error counter = 0. (To have all counters works fine I had to change Modbus TCP Client's parameter OptimizationON to FALSE). LOGO231 works fine: values in mapped I/O conform expectation WS242 without Modbus Server, COM port and with defined channels (for only 1 slave-id possible) works fine. PLC Settings: Update I/O while in stop: I see xBusy changing from FALSE to TRUE and vice versa. Always update variables: Enabled 1
Last updated: 4 days ago

Post by e13740e on Parameterized Property syntax for array element processing ^{CODESYS Forge talk (Post)}
Since parameterized (indexed) properties are not possible, I decided to use architectural approach "Indexing Property Adapter" to achieve the intended goal — avoiding code duplication for validated access to array elements. Essence: Create a Function Block Adapter (FB_PropertyAdapter) that encapsulates the logic for working with a single element of the target array (e.g., with one settings structure). Declare Properties inside the adapter block for accessing each individual field of the data structure. All validation logic is implemented within the Set accessors of these properties. Data Binding via VAR_IN_OUT: The adapter block receives a reference to a specific data element from the global array through its VAR_IN_OUT section, which ensures direct work with the original data without copying. Create an Array of Adapters: In the parent POU (e.g., FB_SettingsManager), an array of these adapter blocks is created — one for each element of the global array that needs to be managed. Initialize Bindings: In a FOR loop, each adapter instance from the array is given a reference to the corresponding data element. Result: This approach allows accessing the data via the index of the adapter array, and then through the property name, which simulates the behavior of an indexed property: MyAdapterArray[Index].MyProperty Thus, the validation and data access logic is written only once inside the adapter block and is then reused multiple times by creating instances of it in an array. This completely solves the problem of code duplication while providing a clean, scalable, and object-oriented architecture compatible with standard CODESYS features. Question closed.
Last updated: 2025-10-19

Post by critcho on WebVisu Numpad dialog - Dialogtitle not accepting string variable ^{CODESYS Forge talk (Post)}
I have a WebVisu page which is re-used for multiple types of gas; it displays the alarm thresholds etc. for one gas at a time. I have an array of structures holding the set-points for each of the gasses. I'm trying to change the dialog title for the value input pop-up (VisuDialogs.Numpad). The Dialogtitle is set to Gas_Alarms.HighAlarmActivationLevelDialog, which is a string(50): When the gas type is changed (page first loaded, or prev/next buttons), METHOD Gas_Alarms.Update_Display_Variables is called, to update the strings used for the dialog titles so it shows GasName High Alarm Activation Level (EngineeringUnits), e.g. CO2 High Alarm Activation Level (PPM): HighAlarmActivationLevelDialog := Insert(' High Alarm Activation Level ()', EngineeringUnits, 30); HighAlarmActivationLevelDialog := Insert(HighAlarmActivationLevelDialog, GasName, 0); (That's not where the problem is, I'm just explaining why I'm using a variable dialogue title.) The variables used are definitely strings, but i'm always getting the error: "The type of the dialog title must be either STRING or WSTRING". I've tried moving HighAlarmActivationLevelDialog etc. to the GVL and also changing them to WSTRING, I even tried adding them to the structure array, but I always get the same error. Clearing the dialog title for that element removes the error - so I'm confident it's not a phantom error caused by something else. But I should be able to add these titles, can't just nuke them all to make it work. The MinVal and MaxVal for the Numpad are called from the array, e.g. GVL.Gas_Alarm_Configs[0].ScaledValueMIN, they are not getting an error. I am using array indexes 1 - 5 for the gasses, when I load the form or change gas, I copy the selected index to index 0 of the array, and values from Gas_Alarm_Configs[0].[ALL] are displayed on the page. When they hit save, I copy Gas_Alarm_Configs[0].[ALL] to Gas_Alarm_Configs[CurrentGasIndex].[ALL]. (ALL just means every element, I can't figure out how to display an asterix in this question... :) ) I've searched online for variable title dialog, but not found anything to help. Thanks for your help!
Last updated: 2025-05-29

Post by jackbrady on Function Blocks and arrays of function blocks ^{CODESYS Forge talk (Post)}
Hello, I am new to Codesys and PLC programming in general (please go easy ha!) I'm not looking for code to be written for me just some help and pointing in the right direction. I am writing some code to send commands to a relay based on input values (to put it simply). Quite basic stuff. I have wrote a function block that takes a global variable (Open_command:BOOL) and outputs to another global variable (Opened : BOOL). The function block is simulating a device so I'll eventually get the globals from that. I now need to create multiple versions of this function block/ device (lets say 100) but I need each iteration of that function block to reference it's own relevant global variable. I think that the best way of doing this would be to use arrays, although I could be wrong. I am aware that for up to 100 instances I could very well manually assign everything but that seems rather time consuming and I want a fancier way of doing it. Here is a very basic example of what I am looking to do, please note I have not written this in proper code it's just to show what I mean. Global Variables V[0-100] int Open_command [0-100] Bool Opened [0-100] Bool Function Block var input x : BOOL Var output y : BOOL if x then y = TRUE ELSE y = FALSE The input to my function block will be Open_command, output will be Opened Example code. If V[x] > 10 then Open_command [x] = TRUE ELSE Open_command [x] = FALSE (So when V1 goes above 10 I need Open_command1 = TRUE therefore initiating FB1 output. V2 > 10, open_command2 = True > FB2 output V3 > 10, open_command3 = True > FB3 output ... ... ) What I can't seem to figure out is how to tie all this together, I have read through the codesys documentation and if anything it has confused me more! ha. Apologies for the poorly written post but hopefully you understand what I am trying to get at. Thanks, Jack
Last updated: 2024-02-14

Post by dandyk on Dynamic Images ^{CODESYS Forge talk (Post)}
Hello, I have very similar problem, but it seems that your solution does not work for me. I am using TwinCAT XAE Shell v3.1.4024.55 and TwinCAT Runtime. Sorry for writing here on codesys forge, but since I found the only relevant topic here and since TwinCAT is almost the same with CODESYS in many applications, I chose to write here. I simply need to dynamically update image in visualization based on camera trigger (I am doing a machine vision application). Camera triggers an image, my program processes it (applies thresholding, draws contours etc...) and saves the processed image in the runtime location (the same one you were mentioning). This was done successfully. I need to make it work at runtime, while the program is executing and I need to refresh the image in the visualization each time camera triggers a new image and program processes it. When I create image element in the visualization and define the bitmap ID variable as STRING which contains the image ID defined in the image pool, then it displays the image in the image pool, but does not work at runtime, while the program is executing. I also used the Bitmap Version. I declared it in Global variable list as integer with initial value of 0 and wrote the variable in the bitmap version in the image element in visualization. Each time new image is saved to the runtime location, I wrote a program to increment Bitmap Version by 1. It increments and the image does not update in the visualization, unfortunately. I think that bitmap version is working correctly and deletes the cached image as it is supposed to, but the Image Pool does not update the image ID with the new image... the path to the image is always the same... only the actual image changes with the same file name. Image Pool is not dynamic and cannot refresh the image in the path to the actual one at runtime. How can I refresh the image ID in the image pool at runtime? Bitmap version only deletes cached image and reloads the image from the image ID, but the image ID has the same image, because image pool won't update at runtime. Do you know any solution to this problem?
Last updated: 2024-04-06

Post by jerry-sorrells on Find Function: Object reference not set to an instance of an object. ^{CODESYS Forge talk (Post)}
Build: CODESYS 3.5 SP19 Patch 1 (64-bit) Host OS: Windows 10 Target: Linux SL I have a project with programs in Structured Text and Ladder Diagram. When I try to use the Find function, it works for the Active Editor; however, when I try to use Find for the Entire Project, I get the error "Object reference not set to the instance of an object." I know what this error means in the context of the program, but I have no idea why the find function is returning this error. The variable I am searching does not matter: it happens with all variables. Any help with this will be greatly appreciated. I generally use the Find function quite often as I am developing and not having it is really slowing me down.
Last updated: 2023-10-23

Post by alimans on OPC-UA Server, Symbol Set: Raise an error: Object reference not set to an instance of an object. ^{CODESYS Forge talk (Post)}
Hi everyone, I just created a very simple library without any code and, added it to my very simple project. after adding this library, I get an error when I try to open "Symbol Set" in "OPC UA Server" in "Communication Manager". Here is the code of my POU in the library: FUNCTION_BLOCK POU VAR eCommand : (CMD_NONE:=0, CMD_RESET:=-1) INT := CMD_NONE; END_VAR Attached is the error that I get. I also noticed that by removing the enumeration variable above (eCommand), I can open the "Symbol Set" again. Anybody has any idea why this error is raised and how could I use enumeration variables without error in "OPC UA Symbol Set"?
Last updated: 2024-08-08

Post by cfam on Codesys Control for PLCnext SL, Bus not running ^{CODESYS Forge talk (Post)}
Good day I would appreciate it if you can give me some advice on how to fix my "Bus Not Running Error". I am Using Codesys 3.5 SP20 and Codesys Control PLCnext SL V4.12.0.0. Codesys control was installed on the device and I can log into it but it seems that it does not pick up the PLC or the IO attached (Please see attached Image). The Bus Cycle Task of the AXL F 2152 is set to Main Task and the "Always update Variable" is Enabled on each IO Module. My Main Task interval is set to 100ms and Priority is set to 0. I have tried other options and none seem to work. Your response to this issue will be highly appreciated.
Last updated: 2024-08-12

Post by cfam on Codesys Control for PLCnext SL, Bus not running ^{CODESYS Forge talk (Post)}
Good day I would appreciate it if you can give me some advice on how to fix my "Bus Not Running Error". I am Using Codesys 3.5 SP20 and Codesys Control PLCnext SL V4.12.0.0. Codesys control was installed on the device and I can log into it but it seems that it does not pick up the PLC or the IO attached (Please see attached Image). The Bus Cycle Task of the AXL F 2152 is set to Main Task and the "Always update Variable" is Enabled on each IO Module. My Main Task interval is set to 100ms and Priority is set to 0. I have tried other options and none seem to work. Your response to this issue will be highly appreciated.
Last updated: 2024-08-12

Post by micik on Reverse bytes in an array ^{CODESYS Forge talk (Post)}
Hello, I'm getting the data in Codesys that is an array of 8 bytes. From this array, I need to foram LREAL number, however, because of different endiannes I need to reverse bytes in this array and then copy to a LREAL variable. For this I'm using a loop and it works OK. I wonder if there is a built in function to do this. I have found CAA Memory library but it has functions like reverse bytes in DWORD. But it seems it doesn't have what I need. https://content.helpme-codesys.com/en/libs/CAA%20Memory/Current/CAA_Memory/Reverse-Bit-Swap-ByteWord-order/ReverseBYTEsInDWORD.html What I need is a function to reverse bytes in an 8 byte array, or something similar.
Last updated: 2024-08-22

Post by micik on Reverse bytes in an array ^{CODESYS Forge talk (Post)}
Hello, I'm getting the data in Codesys that is an array of 8 bytes. From this array, I need to foram LREAL number, however, because of different endiannes I need to reverse bytes in this array and then copy to a LREAL variable. For this I'm using a loop and it works OK. I wonder if there is a built in function to do this. I have found CAA Memory library but it has functions like reverse bytes in DWORD. But it seems it doesn't have what I need. https://content.helpme-codesys.com/en/libs/CAA%20Memory/Current/CAA_Memory/Reverse-Bit-Swap-ByteWord-order/ReverseBYTEsInDWORD.html What I need is a function to reverse bytes in an 8 byte array, or something similar.
Last updated: 2024-08-22

Post by thn-power on How to change OPC NodeId IdentifierType ^{CODESYS Forge talk (Post)}
Hi Yet another OPC UA question. When setting up a OPC server using "Communcation manager" (Symbol set and information model) in Codesys the NodeId is always given as "opaque" type. At least when browsing using UAExpert. Other standard OPC objects use numeric (or string) identifier, but for some reason my variables seems to get opaque/binary type. See attached photo. How can I change this? I can't see that this is a parameter in the CodesysControl.cfg. Can this be specified in the information model nodeset? And is it possible to specify the exact numeric or string NodeId for each instance? And on a related topic, is there a way to export the OPC server nodeId's with variable name so that it can be imported in a OPC Client? The .xml files in the project folder does not seem to contain the NodeId.
Last updated: 2024-09-20

Post by sigurdrb on Codesys and error messages, warnings exceptions etc. ^{CODESYS Forge talk (Post)}
Hi, I tried some different libraries (CmpApp etc.) to find some global variables that I could read out as a variable in the codesys environment. Do any one of you know which libraries are best suited for this, and how I can read it out? My goal is to send messages, warnings etc. to the system that communicates to the PLC. Currently if something goes wrong I need to see the logfiles, or go online with the controller. I think I could save a lot of time if I could read the errors from our user interface that is connected to the PLC by TCP/IP.
Last updated: 2024-11-06

Post by askic on Name Validation of Visualization objects ^{CODESYS Forge talk (Post)}
Hello, In my projects, I'm following this recommendation about the rule names in Codesys https://content.helpme-codesys.com/en/CODESYS%20Development%20System/_cds_rules.html, so I always use backtick identifiers, not only for variables, but also for the object names. However, I have noticed that in the current version of Codesys, when adding Visu object, it is not allowed to used these identifiers in the name. This is very different from all other objects like, folder names, POU names, Variable list names etc. I wonder if there is some hidden settings I can use to enable backtick identifiers in the Visu object names? Attached is a screenshot with the details. Thank you!
Last updated: 2025-01-10

Post by pedegani on "Do you really want to perform" dialog boxes ^{CODESYS Forge talk (Post)}
I have the same annoying problem. The confirmation prompt for every single action appeared recently after an update from CODESYS 3.5 SP20 Patch 3 to Patch4, but I don't think it's due to this. Having to confirm every operation while debugging an application is a considerable waste of time and does not help at all to concentrate on development, not to mention that many times you miss the long-awaited event because you are busy looking for the 'yes' button to resume debugging or force a variable. Does anyone know how to disable the confirmation messages?
Last updated: 2025-02-14

Post by eaglealex on Length of string and Array of bytes ^{CODESYS Forge talk (Post)}
Hello! I have tried read a file to the string variable. But I faced a problem - there is about 2800 bytes of information in file, but string have a limit 2393 bytes. I made two variables with same address (for automatic convertion) - string[3000] and array of bytes[1..3000]. And I noticed that array of bytes contains all information from file, but string shows only first 2393 bytes. So I have lost information. Is there really such a limitation? Or I have an error in my program and Codesys 2.3 have no limit for such kind of conversation between string and array of bytes? Thank you very much!
Last updated: 2025-04-01

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

Post by rossanoparis on Internal Error (ARM): Unsupported conversion! With new version v3.5 SP21 ^{CODESYS Forge talk (Post)}
I have updated CODESYS development tool to the version v3.5 SP21 (64bit) The previous version was v3.5.20.40 Compiling an existing application with the new evelopment tool I get the following error. kunbusiodrvrevpibridge, 1.4.1.0 (kunbus gmbh): IoDrvScanModules [IoDrvRevPiBridge](Line 51, Column 1 (Impl)): Internal Error (ARM): Unsupported conversion! This error was not reported in the previous compiler version and is now highlighted in a third-party library, which I cannot change or modify. The error is due to the following conversion: m_udiError := TO_UDINT(excCode); . The excCode variable is a system type, declared as shown below, and should be converted to a UDINT excCode : __SYSTEM.ExceptionCode; m_udiError: UDINT; . I would appreciate it if someone could provide feedback on this issue.
Last updated: 2025-04-15

Post by kut69 on Retain / Persistent Variables in Codesys for Raspberry Pi ^{CODESYS Forge talk (Post)}
Hi, I am interested in details about the .ret file in the filesystem. I have already a project where the file is used (write on demand, read by start) and I want to share it as 'default input' for test devices using the identical application. Opening the .ret file content in a hex editor (I only use a single string retain var) I asked myself what the meaning of the first 24 bytes is. It neither contains a handle to the application nor a reference to the variable. Is this maybe a timestamp? Or a CRC/checksum? Regards, Thomas
Last updated: 2025-05-19

Post by viksym on How to get the motor scaling value from code ^{CODESYS Forge talk (Post)}
Is there a way to see what value is set as the "Work travel distance per motor rotation" that is set in the Scaling menu of the axis ? I am working on my own homing function block for sensorless (hardstop) homing and I want to make it be universal between different axes with different motor's scaling for distance per rev so I need to know this value from the axis itself. I know I could do it by just creating an input variable for the function block but I'm leaving that option as a last resort.
Last updated: 2025-06-12

Post by hclai on Maximum Array Index Issue ^{CODESYS Forge talk (Post)}
I was trying to use a table object in visualization. I want to dynamically show the valid rows in the table. However, it does not work when there is 1 row. i put the maximum array index to 1. it does not show the 1st row. when i change to 2, it show the second row only. my project with older visualization profile version is working perfectly fine. I did some test and realized that i must use a Row Selection variable to change from 0 to 1. With this change of Row selection, then the row 1 will show up.
Last updated: 2025-06-19

Post by fedex03 on Read Global Variable from an IoT Device ^{CODESYS Forge talk (Post)}
Hello everyone, I am new to the forum, and to programming with CodeSys. I am dealing with IoT device for industry and I should check if a device is able to read/write global variables in an EtherNet/IP Master. Since I do not have an EtherNet/IP PLC, I thought of using CodeSys as a softPLC. I created a program with a set of global variables (GVL) and a task that increments them. I would like to know if I need to enable any options so that the global variables can be read by IoT devices. My device supports Class 2 Class (Explicit Messaging Connection) communication. Thank you in advance for your help.
Last updated: 2025-07-22

Post by timvh on Codesys 3.5.18.60 – Application Loss and Persistent Data Corruption ^{CODESYS Forge talk (Post)}
Which device do you use? Does this have persistent memory (e.g. NVRAM) available? Maybe first ask your PLC vendor about the possibilities and how they advice to use persistent variables? If you have no NVRAM available, CODESYS will store the variables in a file when the device gracefully shuts down. But on an abrupt power failure, this is not possible. If you have no NVRAM and you want to use persistent variables, then consider using a UPS. In this case when the power is lost, the UPS can keep the power on the PLC which then can gracefully shut down. Alternatively use the Persistence Manager to store the variable values in a file e.g. only on change. See: https://content.helpme-codesys.com/en/CODESYS%20Application%20Composer/ac_pm_overview.html
Last updated: 2025-08-26

Post by pernockham on AC Persistence - values are not read from file during start? ^{CODESYS Forge talk (Post)}
I swear I tested this like 20 times yesterday without success. Repeated it today and it works. Maybe the system needed a "real" power reboot? To note. To make a manual edit of a variable I tried some different approaches this is what worked for me. "system/online edited" gvl_var.example_variable REAL:F16#2FFB334H-4 767.7 "manually edited" (with runtime stopped followed by a "cold start" to read from file) gvl_var.example_variable REAL:790.1 (the system will use the manual value but will not set an equivalent "hex" value until next online edit/write cycle)
Last updated: 2025-09-03

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