Post by bingo on PLC Shell commands via ST Code ^{CODESYS Forge talk (Post)}
Suppose you need to switch PLC IP dynamically between 192.168.1.10\192.168.2.10, First, set PLC IP to 192.16.1.10. Create a PGVL with a flag ‘xUseSecondry’ xUseSecondry : bool ; create a function that use socket to update IP: FUNCTION fSwitchIP : bool VAR_INPUT useMainIP:bool; END_VAR --------------------------------CODE------ if useMainIP then SysSockSetIPAddress(‘0’, ‘192.168.1.10’); PGVL.xUseSecondry := 0; else SysSockSetIPAddress(‘0’, ‘192.168.2.10’); PGVL.xUseSecondry := 1; end_if Now, if during execution, you need to switch IP, call the function ‘fSwitchIP()’, Set input to 1 for main IP, 0 for secondary IP. In order to set secondary IP at startup, you can do the following: in your PLC_PRG add a flag: xInit : bool := 1 ; and the code: if xInit then if PGVL.xUseSecondry then fSwitchIP(0); end_if xInit := 0 ; end_if *Alternative way is to use system events.
Last updated: 2025-03-03

Post by user3000 on Can't find an Extended Pulse Timer (TP and LTP) ^{CODESYS Forge talk (Post)}
Hello, For my program I need an extended pulse timer, which can be referred to as a retriggerable pulse timer. Where every rising edge of the input resets the elapsed time zero, extending the lenght of the output pulse. The Codesys pulse timer (TP) is a one-shot timer and only resets the elapsed time with the falling edge of the input. There is also a pulse timer (LTP) in codesys, but in my simulation it was also functioning as a one-shot even though the description sounds like LTP should be retriggerable. I have uploaded some timing plots from another PLC program for reference. I am looking for a timer equivalent to the "TEP" diagram. Is there an Extended Pulse Timer in Codesys? Maybe there is a way to manipulate the input so it resets the elapsed time outside the function block?
Last updated: 2023-12-06

Post by abinvest579 on TCP Client ^{CODESYS Forge talk (Post)}
Hi All, I am using codesys based plc to read and control magna power DC supply over LXI protocol using SCPI command. To connect device required socket programming for that i am using Net base service library function block TCP_Client to establish connection over TCP/IP , TCP_Write to write SCPI commands and TCP_Read to read data from Magna power DC supply. I have attached screenshot for logic developed. I am able to connect and write commands to device but i not receiving any information from device. For writing Commands i also tried various end of line character like \n,<nl>, A, D, 10, 13, 0x0A, 0x0D but not received any status from device. For testing purpose i am using simple command '*IDN?' to read data. Also if tried to check on hercules software what data actually plc read, first it read correct data after that is read wrong data as see in screen shot. 'Hello World' was correct read and after that Codesys in replaced with 'Codesysorld' that is not correct way. Same issue also appeared for send data. Any one have face same issue how i can read data directly from device correctly and send data please suggest solution on this.</nl>
Last updated: 2024-07-01

Post by ruobian on Analog Input Delay Timer ^{CODESYS Forge talk (Post)}
Hello there, I am new here and in programming. I need help with the basics. I am trying to do what I mentioned in the title. I have an analog input. So I have a real or integer data type value. I want to delay it. TON and TOF only work with bool. I think there is a function block that has two inputs, 1 for real or int and 1 for bool. And if bool is true, it will give the output as real or int. I don't know but I need something like this. Actually, it is not exactly like that. In other words, it will not show the real value at the input at the output after a certain period of time. I want it to show the real value from 2 seconds ago continuously. The purpose of doing this is to compare the real value I received with the value from 2 seconds ago and find out whether it went up or down. I am using only FBD. Please help me with this. Thanks in advance.
Last updated: 2024-08-20

Post by ellocco on XOR with four Inputs with OR-, NON- and AND-Operators ^{CODESYS Forge talk (Post)}
My topic is more of academic nature, I would like to implement an XOR-operation with four inputs on my own (without the predefined XOR-operator) in a function block diagram (FBD). I have two proposals. One works fine and the other one is just an idea, but I do not know, if it is possible to code it in CODESYS V3.5 SP18 in form of a FBD. Here the one that works: And here an idea, which I have not managed to code it as an FBD: Any ideas? Is the 2nd diagram a correct interpretation of the coding task? And is there a way to implement it in form of an FBD in CODESYS V3.5 SP18? Followup (08-Nov-2024): Also in the current version of CODESYS (V3.5SP20Patch3) I have not managed to connect the existing blocks. In the alternative SPS-IDE PLCnext Engineer it is possible.
Last updated: 2024-11-08

Post by laurits on Max lines of code, codesys CNC ? ^{CODESYS Forge talk (Post)}
Hi, okay here's the project, it's a modified version of "CNC Example 10: Programming Dynamic CNC Paths", no need for G Code text file (i have also tried with G code text file, same problem) in "PROGRAM PLC_PRG" you can set bStart to true, and the program should start running, go to "PROGRAM CNC" and you can see axis moving. lrXpos := IoConfig_Globals.XAixs.fSetPosition; lrYpos := IoConfig_Globals.YAxis.fSetPosition; Now you can can change the number of movements in the the "PROGRAM PLC_PRG" From this number of movements in "program PLC_PRG" BUF : ARRAY[0..32010] OF SMC_GEOINFO; xp : ARRAY[1..32000] OF REAL; yp : ARRAY[1..32000] OF REAL; to this number to this number of movements BUF : ARRAY[0..132010] OF SMC_GEOINFO; xp : ARRAY[1..132000] OF REAL; yp : ARRAY[1..132000] OF REAL; Now if you start the program again you should see an error in the "sMC_Interpolator: SM3_CNC.SMC_Interpolator;" function block Let me know if you can not get it running.
Last updated: 2025-06-03

Post by brell on Automatic xExecute NBS.TCP_write ^{CODESYS Forge talk (Post)}
I've recently started experimenting with CODESYS for a project and am fairly new to it. I'm currently working with Function Block Diagrams (FBD) to set up TCP communication between a server and a client, where the client is implemented as a Python script. Once the communication is established, my connection status changes to True, which is the expected behavior. My challenge arises with the TCP write module, which requires the xEnable_write flag to toggle between True and False. If xEnable_write remains True, the module only performs a single write operation. To address this, I introduced a falling edge trigger (F_TRIG), expecting it to help in toggling xEnable_write and it does, However, I've encountered an issue where in the beginning after connxion established I need to manually set xEnable_write to True for the system to work as intended. I'm looking for a way to automate this process so that xEnable_write becomes True automatically upon establishing a connection . Initially, I tried setting xEnable_write to True from the start, but this approach didn't work well since it left the flag permanently True, preventing further toggling. I also experimented with using a TON timer, but I faced similar issues. I am seeking a solution that automatically toggles xEnable_write between True and False after a connection is established, ensuring continuous write operations without manual intervention. Any advice or guidance on how to achieve this would be greatly appreciated."
Last updated: 2024-03-05

Post by mtho on JSON Utilities - JSON file written with invalid structure ^{CODESYS Forge talk (Post)}
I'm using the JSON Utilities SL library to write configurations in my program to a file. I'm generating the JSON data using the builder function block and all appears to work correctly. When I write the jsondata to file, I'm finding that some of the JSON elements are not being written in the right location in the file. Rather than writing they keys under the parent object, they get written outside the root JSON object at the end of the file. If I then try to read the file back into the program, I get an invalid_structure error. I don't get any errors when populating the JSON data or when writing the file. I attached an example of the JSON writer output. The problems begin with key P200. Each P200 should go under MBR1 through MBR3. Among the rest of the keys, they are supposed to be under different parent objects. I am using default values for wsLineBreak and encoding.
Last updated: 2024-03-06

Post by william-blandon on RecipeManCommands.ReloadRecipes ^{CODESYS Forge talk (Post)}
Hi Dave. Thanks for your answer. I still struggling with this. I have done everything according with the Codesys help even I have looked in detail at the example. I have double checked the recipe manager configuration and the use of all the methods. There are two methods that do not work as expected. I'm using Codesys 3.5.19.20 and recipe management 4.4.0.0 .CreateRecipe just create a recipe in the recipe definition but do not create the file. This have a walk around just giving a .ReadAndSaveRecipe afterwards. .ReloadRecipes do nothing but do not generate any error as well. After calling it I call the .GetRecipeCount and the number is always 0. When I create a new recipe (using the function block methods) then the number changes. Looks like this method is looking to the wrong directory finding nothing. I don't know if there is a missing configuration in the CODESYSControl.cfg file. I'm thinking in a walk around for this but I need to create a strings array with the recipe names as retentive and making all the management when deleting and adding recipes. Have had some one the same problem?
Last updated: 2024-05-23

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 shamcke on Array with generic constant as persistent variable ^{CODESYS Forge talk (Post)}
Hello, I have written a function block that uses a generic constant for the upper bound of an array. I wanted to have this array in the persistent memory area, thus I constructed my FB as follows: FUNCTION_BLOCK FbWithGenericArrayLength VAR_GENERIC CONSTANT uiArrayLength : UINT := 10; END_VAR VAR PERSISTENT arr : ARRAY[1..uiArrayLength] OF INT; END_VAR In my PLC_PRG I declare an instance of said FB PROGRAM PLC_PRG VAR myFb : FbWithGenericArrayLength<10>; END_VAR This compiles just fine. When I let CODESYS fill my persistent list, it adds duplicate entries {attribute 'qualified_only'} VAR_GLOBAL PERSISTENT RETAIN // Generated instance path of persistent variable PLC_PRG.myFb.arr: ARRAY [1..uiArrayLength] OF INT; // Generated instance path of persistent variable PLC_PRG.myFb.arr: ARRAY [1..uiArrayLength] OF INT; END_VAR so I manually delete the duplicate. When i now compile, I get errors ------ Build started: Application: Device.Sim.Device.Application ------- Typify code... [ERROR] Sandbox_FW31: PersistentVars [Device: PLC Logic: Application](Line 4): C0161: Border 'uiArrayLength' of array is no constant value [ERROR] Sandbox_FW31: PersistentVars [Device: PLC Logic: Application](Line 4): Type of mapped variable is not equal to original type Compile complete -- 2 errors, 0 warnings Build complete -- 2 errors, 0 warnings : No download possible Is is simply not possible to use a generic constant for the persistent array? Thanks in advance. Edit: It seems I can manually replace the uiArrayLength in the persisten list by the value 10 I used as the generic constant for this particular instance.
Last updated: 2026-05-29

Post by imdatatas on CFC editor: enable inline value entry on unconnected input pins (as in Ladder Logic editor) ^{CODESYS Forge talk (Post)}
In the CODESYS Ladder Logic editor, there's a really practical feature available while logged in (online) to the PLC: for an existing function block (e.g. TON or MC_MoveAbsolute), double-clicking on an unconnected input pin directly opens a value entry window right in the editor — with no need to assign any variable — and you can type a value directly. Likewise, if the input pin is of an ENUM or STRUCT type, it lets you pick a value of that type straight from a dropdown list. It also doesn't require assigning a variable or adding it to a watch list, etc. Unfortunately, in the CFC editor you can't write values directly to those unconnected input pins the way you can in Ladder — CFC only supports monitoring/display there. I wish this existing Ladder editor feature were also available in CFC — it would make the CFC editor far more usable. I think this would be a relatively small addition to the CFC editor, but it would make a real difference in daily commissioning and debugging work. It would be great to hear the development team's thoughts on whether this could be considered for a future release. Thanks in advance for reading!
Last updated: 2026-09-10

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

Post by macros8 on Alarm Management - Import and Export of AlarmGroup ^{CODESYS Forge talk (Post)}
Hi, I struggle with exporting my Alarm Messages and following importing back to my project. Because filling in one by one is very time consuming I want to use export function and edit .csv file in Excel. As soon as I modify the file the import back to project does not work at all and function returns errors. Would you pls give me a hint how to properly use this functionality? Thanks a lot for help. Regards, M.
Last updated: 2023-12-02

Post by shawn-plc on Return value from a tag given a string literal ^{CODESYS Forge talk (Post)}
Good afternoon everyone, I am looking for a way to return a value given a string tag path. I put together a pseudo-example to illustrate my use-case and was wondering if anyone in this forum can help. The function fnValueFromTagPath is the function I am looking to either create or use from existing library. I would greatly appreciate it. Please see the attachment for additional detail. -Shawn
Last updated: 2024-08-13

Post by imdatatas on Use MC_Home without enabling the drive for homing method 35 ^{CODESYS Forge talk (Post)}
Hello, As far as I know, no matter which home mode is selected, the axis must be in Standstill mode to run MC_Home according to PLCopen state machine. However, if the function you want can already be done from a parameter in the driver of the vendor you are using, you can try to perform the same function by sending the required value to that parameter via communication with the SDO write command. Regards, Imdat
Last updated: 2025-06-25

Post by eboyd on AOI's ^{CODESYS Forge talk (Post)}
Hello, I'm currently working on transferring a project I recently created on Studio 5000 to CODESYS and unfortunately CODESYS isn't compatible with AOI's so I was wondering if there was anyone who could help me transfer these L5X AOI blocks to ST Function Blocks that I can import into CODESYS so I can use them for this project or if you know where I can find preexisting Function Blocks for these AOI's. Thank you so much!
Last updated: 2025-09-02

Post by eboyd on AOI's ^{CODESYS Forge talk (Post)}
Hello, I'm currently working on transferring a project I recently created on Studio 5000 to CODESYS and unfortunately CODESYS isn't compatible with AOI's so I was wondering if there was anyone who could help me transfer these L5X AOI blocks to ST Function Blocks that I can import into CODESYS so I can use them for this project or if you know where I can find preexisting Function Blocks for these AOI's. Thank you so much!
Last updated: 2025-09-02

Post by tvm on multiply gives negatives ^{CODESYS Forge talk (Post)}
It's probably because you have an INT in the input to the MUL function, which will then try to output an INT as well. INT variables can only handle values of -32768 to 32767. Your value of 523000 won't fit in an INT, so it turns into an invalid number. Use a DINT. This is usually better for working with time values anyway, because time values are all 32 bit. Or if you can't, use INT_TO_DINT(gvlp.detectie_nalooptijd_s) in the input to the MUL function.
Last updated: 2024-01-04

Post by aniket-b on Multiple function blocks are not executing at the same time in ladder logic ^{CODESYS Forge talk (Post)}
I have two ethernet Ip drives and created Function Blocks for different motions tasks. I am using same FB for both the drives. When I try to execute the relative move start command on FB for both the drives it is not working. However, if I add 1ms second delay between the execution of each drive it is working. Also when I change the rung order it is working for the first drive in the rung. what could be the wrong here?
Last updated: 2024-03-12

Post by schnepper on Error building Extension SDK Linux code ^{CODESYS Forge talk (Post)}
I'm installed the CODESYS Control for Linux SL package and am trying to use the Extension API to call a simple C function. When I get to the step to run "make all" on the Linux machine, I get the error: build interface header: out/CmpFirstTestItf.h from CmpFirstTestItf.m4 ERROR: This functionname does not contain _cext (this is mandatory, see help for details): DEF_API(void',CDECL',external_struct__fb_init',(external_struct_fb_init_struct *p)',1,0x1F77E075,0x00000001) Why does "Generate Runtime System Files" create a function that does not have cext in the name? What am I missing?
Last updated: 2024-04-01

Post by nixola on Exception handler return value purpose in _CODESYS 3.5 ^{CODESYS Forge talk (Post)}
Hi, I was trying to figure out how to correctly handle system exceptions in a CODESYS project, but either the documentation falls short, or I'm unable to find the proper docs. I know I can register a function as an exception handler via Task Configuration > System Events > Add Event Handler, which will create a function with the correct interface; I am, however, unable to figure out what the returned DWORD is supposed to be, if anything. Is the interface for the exception handler documented and, if so, where can I find it?
Last updated: 2026-08-31

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 transmin01 on SafetyApp - "Invalid ERR Ack input" ^{CODESYS Forge talk (Post)}
Hi, I am trying to get a basic safety application to download but I keep getting an "Invalid ERR Ack input" and "The Standard Inputs Size of zero is not allowed". I am simply using 2 safety inputs through an "AND" block to 2 safety outputs. Any help would be appreciated. Regards Trevor.
Last updated: 2023-09-27

Post by transmin01 on SafetyApp - "Invalid ERR Ack input" ^{CODESYS Forge talk (Post)}
Hi, I am trying to get a basic safety application to download but I keep getting an "Invalid ERR Ack input" and "The Standard Inputs Size of zero is not allowed". I am simply using 2 safety inputs through an "AND" block to 2 safety outputs. Any help would be appreciated. Regards Trevor.
Last updated: 2023-09-27

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