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 timvh on control loop library IIR filter ^{CODESYS Forge talk (Post)}
In the Control Loop Library package are multiple example projects, including one for the filters. Program containing: GVL.filterIIR( xEnable:= GVL.xEnableFilter, lrValue:= GVL.lrYOriginal, lrFilteredValue=> GVL.lrOutputIIR); GVL.filterFIR( xEnable:= GVL.xEnableFilter, lrValue:= GVL.lrYOriginal, lrFilteredValue=> GVL.lrOutputFIR); GVL.filterSOS( xEnable:= GVL.xEnableFilter, lrValue:= GVL.lrYOriginal, lrFilteredValue=> GVL.lrOutputSOS); GVL containing aCoefficientsA_IIR : ARRAY[0.. 4] OF LREAL := [1,-2.3695130071820376,2.31398841441588,-1.0546654058785676,0.18737949236818494]; aCoefficientsB_IIR : ARRAY[0.. 4] OF LREAL := [0.0048243433577162282,0.019297373430864913,0.028946060146297369,0.019297373430864913,0.0048243433577162282]; filterIIR : Ctrl.Filter_IIR := (palrCoefficientsA:= ADR(GVL.aCoefficientsA_IIR), udiSizeCoefficientsA:= SIZEOF(GVL.aCoefficientsA_IIR), palrCoefficientsB:= ADR(GVL.aCoefficientsB_IIR), udiSizeCoefficientsB:= SIZEOF(GVL.aCoefficientsB_IIR)); aCoefficientsB_FIR : ARRAY[0.. 5] OF LREAL := [0.01982722552692669,0.1325131219866022,0.34765965248647102,0.34765965248647107,0.13251312198660226,0.019827225526926694]; filterFIR : Ctrl.Filter_FIR := (palrCoefficientsB:= ADR(GVL.aCoefficientsB_FIR), udiSizeCoefficientsB:= SIZEOF(GVL.aCoefficientsB_FIR)); aCoefficientMatrix_SOS : ARRAY[0.. 1] OF Ctrl.FilterCoefficients_SOS := [(b0:= 1, b1:= 2, b2:= 1, a0:= 1, a1:= -1.048599576362609, a2:= 0.2961403575616683), (b0:= 1, b1:= 2, b2:= 1, a0:= 1, a1:= -1.320913430819428, a2:= 0.6327387928852787)]; lrG : LREAL := 0.004824343357716228; filterSOS : Ctrl.Filter_SOS := (paCoefficientMatrix:= ADR(GVL.aCoefficientMatrix_SOS), udiSizeCoefficientMatrix:= SIZEOF(GVL.aCoefficientMatrix_SOS), lrGain:= GVL.lrG); lrX : LREAL; lrYOriginal : LREAL; lrOutputFIR : LREAL; lrOutputIIR : LREAL; lrOutputSOS : LREAL; xEnableFilter : BOOL := TRUE;
Last updated: 2025-08-01

Post by wollvieh on Array of UDT Compare ^{CODESYS Forge talk (Post)}
use sysmemcmp. https://content.helpme-codesys.com/en/libs/SysMem23/Current/POUs/SysMemCmp.html
Last updated: 2024-04-08

Post by kislov on Table How to set row number from 1 ( not from 0) ^{CODESYS Forge talk (Post)}
Use declaration with ARRRAY [1..x] instead of ARRAY [0..x]
Last updated: 2024-05-27

Post by albertovalente on How extract JSONElement containing Array data ^{CODESYS Forge talk (Post)}
Hi Creator: hazarath, Have you fix the problem? because I have the same issue Thanks a lot
Last updated: 2025-11-12

Post by albertovalente on How extract JSONElement containing Array data ^{CODESYS Forge talk (Post)}
Hi Creator: hazarath, Have you fix the problem? because I have the same issue Thanks a lot
Last updated: 2025-11-12

Post by gatto on warning C0195 ^{CODESYS Forge talk (Post)}
I answer myself: xyz : ARRAY [1..10] OF BYTE := [10(BYTE#100)] ; // no warning :-)
Last updated: 2025-11-20

Post by hyplcmotion on The element of type 'VisuFbElemImage' could not be updated. Reason: Index was outside the bounds of the array. ^{CODESYS Forge talk (Post)}
Hello, I’m encountering the same issue. I only receive these errors when downloading to the PLC—there are no errors during the build—after upgrading to CODESYS 3.5.21.10. Is there any known fix or recommended solution? Visualization seems running ok, no PLC log error. Visualization: Error: The element of type 'VisuFbLabel' could not be updated. Reason: Source array was not long enough. Check srcIndex and length, and the array's lower bounds. Visualization: Error: The element of type 'VisuFbElemSimple' could not be updated. Reason: Source array was not long enough. Check srcIndex and length, and the array's lower bounds. Visualization: Error: The element of type 'VisuFbElemSimple' could not be updated. Reason: Source array was not long enough. Check srcIndex and length, and the array's lower bounds. Visualization: Error: The element of type 'VisuFbElemImage' could not be updated. Reason: Source array was not long enough. Check srcIndex and length, and the array's lower bounds. Visualization: Error: The element of type 'VisuFbElemSimple' could not be updated. Reason: Source array was not long enough. Check srcIndex and length, and the array's lower bounds. Visualization: Error: The element of type 'VisuFbElemSimple' could not be updated. Reason: Source array was not long enough. Check srcIndex and length, and the array's lower bounds. Visualization: Error: The element of type 'VisuFbElemImage' could not be updated. Reason: Source array was not long enough. Check srcIndex and length, and the array's lower bounds. Visualization: Error: The element of type 'VisuFbElemButton' could not be updated. Reason: Source array was not long enough. Check srcIndex and length, and the array's lower bounds. Visualization: Error: The element of type 'VisuFbElemButton' could not be updated. Reason: Source array was not long enough. Check srcIndex and length, and the array's lower bounds. Visualization: Error: The element of type 'VisuFbElemSimple' could not be updated. Reason: Source array was not long enough. Check srcIndex and length, and the array's lower bounds.
Last updated: 2026-01-26

Post by timvh on Configuring a 2's compliment ^{CODESYS Forge talk (Post)}
You could create a DUT of the Type Union and add an array of 2 bytes + an Int. Then write the byte values in the array of the Union and read the Int. Or VAR iInt : INT; byHigh : BYTE := 2#1111_1111; byLow : BYTE := 2#1111_1111; END_VAR iInt := TO_INT(byHigh*16#100 + byLow);
Last updated: 2024-09-28

Post by rafaelbrito on The element of type 'VisuFbElemImage' could not be updated. Reason: Index was outside the bounds of the array. ^{CODESYS Forge talk (Post)}
When trying to use the Visualization ToolBox, no objects appear and the following error appears. Could you tell me what this error could be? The element of type 'VisuFbElemImage' could not be updated. Reason: Index was outside the bounds of the array. Can anyone tell me what this error is?
Last updated: 2024-12-03

Post by tvm on Cannot pass array of constant size to a function as a reference ^{CODESYS Forge talk (Post)}
maybe this would be a better approach, then you don't have to pass the constant at all. FUNCTION fun : INT VAR_IN_OUT arr: ARRAY[*] OF INT; END_VAR VAR lower: DINT; upper: DINT; END_VAR lower:= LOWER_BOUND(arr, 1); upper:= UPPER_BOUND(arr, 1); see here as well https://help.codesys.com/api-content/2/codesys/3.5.12.0/en/_cds_datatype_array/
Last updated: 2024-01-08

Post by timvh on Limiting Memory Access of an Array to Within its Bounds ^{CODESYS Forge talk (Post)}
Add the object "POU for Implicit Checks" to your application, then select "Bounds check". This will create a function which is automatically called each time an array is write accessed. In the function you can handle "out of bounds" situations. By default it will be limited to its lower or upper bound.
Last updated: 2024-03-06

Post by bjarne-pagaard on Multiple WebVisu ^{CODESYS Forge talk (Post)}
You can use the switch frame variable, but there should be a variable for each active visu user. You can put the switch frame variable in an array, and use CURRENTCLIENTID as index into the array to get what you want. The CURRENTCLIENTID is assigned to new users automagically by the Visu Management.
Last updated: 2024-03-14

Post by brouwyka on JSONByteArrayWriter string result incorrect order ^{CODESYS Forge talk (Post)}
Additional note: When doing all additions to a JSON array one after another without additions outside the array inbetween (and no more additions to the array after an item outside the array has been added) - which is not a viable solution for us as we might add items to any of the arrays at any time, but we tested regardless to be thorough - we get the following result: { "id": "machine_1", "readings": [ { "temp_mid": 153.8 }, { "temp_mid": 98.3 } ], "status": "RUNNING" } This mostly matches our expected outcome, aside from the JSONByteArrayWriter not adding indenting before closing square brackets ("]") at all. That doesn't matter for JSON of course, as it's not sensitive to indenting, but it's still a bug regardless. Also, it adds an unnecessary newline between items in the array (at least when having an array of objects, we haven't tested with arrays of primitives). I also want to reiterate that this is not a viable workaround for the issue for us - we have to be able to add to any array at any time, which should be possible according to the docs, and we are 100% sure indexes are correctly being managed and built up by the JSONBuilder and our wrapper (to track the index of each array & the latest item added to each exactly to make use of the documented possibility to add anything anywhere in the JSON at any time as long as you keep track of the returned indexes) around it.
Last updated: 2026-06-10

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 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 alberto on ExportPLCopenXML is failing ^{CODESYS Forge talk (Post)}
I'm trying to export my whole project through the option ExportPLCopenXML. It seems working, but when I'm trying to import the xml I have the following error during the importation process: Object reference not set to an instance of an object. It seems a usual issue with this process that affects to the pointer to user classes inside a procedure. I receive this error for two general functions that have this pointer declarations in the VAR_INPUT section. It seems a bug into the export/import process of CodeSYS and I couldn't skip it so far. Anyone could help me? Thanks in advance.
Last updated: 2025-03-15

Post by artem1223 on Synaxis of library declarations in the ST ^{CODESYS Forge talk (Post)}
Codesys 3.5 17.30, plc - crevis GN-9373. I need to use RTC of pls for write in registers (need to check difference of writen 100 and 200 registers). For this i try to use SysTimeRtc (SysTimeRtc.SysTimeRtcGet) but its not working. After it i tryed to use SysTimeGetMs and something like this but still not working. Library? Mb but check project, SysTime with SysTimeRtc already, all what i know - already is here. Its my first try to learn ST (early used fbd and ladder, yeah), pls help with it. Mb problem with a syntaxis, but im not sure.
Last updated: 2025-11-26

Post by mxj262 on FB having single input but initialized with Array ^{CODESYS Forge talk (Post)}
I am adding elements of an ARRAY using pointer to access each element inside a FOR loop and the FOR loop does not stop! What is the right way to use pointers in such case?? I have another loop that is not using pointer and it stops but the loop using pointer keep on adding. METHOD FB_Init: BOOL VAR_INPUT bInitRetains: BOOL; // TRUE: the retain variables are initialized (reset warm / reset cold) bInCopyCode: BOOL; // TRUE: the instance will be copied to the copy code afterward (online change) END_VAR VAR_IN_OUT // basically REFERENCE TO window_buffer: ARRAY [*] OF INT; // array of any size END_VAR THIS^.windowPtr := ADR(window_buffer[0]); THIS^.windowSize := UPPER_BOUND(window_buffer, 1) - LOWER_BOUND(window_buffer, 1) + 1; FUNCTION_BLOCK FB500 VAR_INPUT END_VAR VAR_OUTPUT END_VAR VAR windowPtr: POINTER TO INT; windowSize: DINT; currentIndex: UINT; element1:INT; element2:INT; i:INT; j:INT; sum:DINT:=0; END_VAR element1:=windowPtr[0]; // read the first element of the Array dynamic memorry element2:=windowPtr[1]; FOR i:=0 TO (TO_INT(windowSize-1)) BY 1 DO // this loop does not stop Sum:=sum + windowPtr[i]; END_FOR FOR j:=0 TO 5 BY 1 DO // this loop stops j:=j+1; END_FOR https://ibb.co/k3DhkZT
Last updated: 2024-05-06

Post by peterned on Array to String ^{CODESYS Forge talk (Post)}
max. string length in Codesys is 255 chars. It's not possible to cram 20,000 things in a string. If you need to send the data to another device, send the whole data[] array (as byte array, without doing anything to it) and extract the information on the other end. As each struct member has a fixed size (81 bytes, as per you declaration), this will be easy. To save some resources, consider declaring string lengths - e.g. if the max possible length for key is 10 chars, declare it key: STRING(10); and it will occupy 11 bytes instead of 81
Last updated: 2024-07-20

Post by levih on FbHTTPs_Get how to get data from a website and use it in codesys ^{CODESYS Forge talk (Post)}
You get an array of DWORD into your receive buffer. You need to process this into usable data, before you can fit it into your DUT. I've made it work using FbWrite_ToIEC_ByRule in stead of Fb_JSON_ParseAndModify. I've attached images of the code. You receive the data into ARRAY[0..1023] OF DWORD. Then you use that array as the input for fbWrite_ToIEC_ByRule. To get the output from this you define a rule to fit the expected data structure including nesting levels. The you feed the rule into FbWrite_ToIEC_ByRule and then you can set the output to be of your DUT type.
Last updated: 2025-06-16

Post by simover on TCP/IP client ^{CODESYS Forge talk (Post)}
I want to send a string to a tics TCP/IP server. I got i working with the Net Base lib. for communication good with this tcis i need to by array of byte I want to include a string in the third position of the array TCIS_Send[1] :=254; //this valus is fix for evry communication TCIS_Send[2] :=80; //this valus is fix for evry communication TCIS_Send[3] := ; here I put my and my string is lik this 5806509-DRAP10#AB#3452302073 TCIS_Send[4] :=252; //this valus is fix for evry communication
Last updated: 2023-12-18

Post by mgabryel on Problems with CAN 2.0 comunication on Wago PLC (Codesys 3.5) ^{CODESYS Forge talk (Post)}
Hello, I am trying to program CAN Bus comunication on WAGO PLC (more precisely on WAGO Touch Monitor model TP600). I am using for this purpose library "WagoAppCanLayer2" from Wago company. My IDE for programming this device is CODESYS V3.5 SP19 Patch 2 + (64-bit). My program is written in Structured text using function blocks from previously mentioned library. Here is code of this program: 1) Variables declarations: PROGRAM PLC_PRG VAR oOpenInterface : WagoAppCanLayer2.FbCanL2Open :=( udiBaudrate := 125000 ); xInterfaceIsOpen : BOOL; sInterfaceInfo : STRING; oReceive : WagoAppCanLayer2.FbCanRx29BitFrame :=( xBufferMode := FALSE, wCanId := 16#181 ); xRecv : BOOL; sReceiveInfo : STRING; oSend : WagoAppCanLayer2.FbCanTx29BitFrame :=( dwCanId := 16#100, //was 16#201 xRtrFrame := FALSE ); xSend : BOOL; sSendInfo : STRING; oCanDiag : WagoAppCanLayer2.FbCanErrorInfo; xRst : BOOL; aSendData : ARRAY [1..8] OF BYTE; bSendLen : BYTE; TON_0 : TON; TON_1 : TON; END_VAR 2) Program body: oOpenInterface( xEnable := NOT xInterfaceIsOpen, I_Port := IoConfig_Globals.WAGO_CAN_LAYER2_DEVICE ); sInterfaceInfo := oOpenInterface.oStatus.GetDescription(); xInterfaceIsOpen S= oOpenInterface.xValid AND NOT oOpenInterface.xError; oReceive( xEnable := xInterfaceIsOpen, I_Port := IoConfig_Globals.WAGO_CAN_LAYER2_DEVICE, xRxTrigger := xRecv ); sReceiveInfo := oReceive.oStatus.GetDescription(); IF NOT xRecv THEN IF oReceive.bRxNBytes > 0 THEN oReceive.aRxBuffer[1]; oReceive.aRxBuffer[2]; oReceive.aRxBuffer[3]; oReceive.aRxBuffer[4]; oReceive.aRxBuffer[5]; oReceive.aRxBuffer[6]; oReceive.aRxBuffer[7]; oReceive.aRxBuffer[8]; END_IF xRecv := TRUE; END_IF aSendData[1] := 224; aSendData[2] := 13; aSendData[3] := 14; aSendData[4] := 15; aSendData[5] := 222; aSendData[6] := 13; aSendData[7] := 14; aSendData[8] := 15; bSendLen := 8; TON_0(IN:= NOT TON_1.Q, PT:= T#2S , Q=>xSend, ET=> ); TON_1(IN:= TON_0.Q, PT:= T#2S , Q=>, ET=> ); oSend( xEnable := xInterfaceIsOpen, I_Port := IoConfig_Globals.WAGO_CAN_LAYER2_DEVICE, aTxBuffer := aSendData, bTxNBytes := bSendLen, xTxTrigger := xSend ); sSendInfo := oSend.oStatus.GetDescription(); oCanDiag( xEnable := TRUE, I_Port := IoConfig_Globals.WAGO_CAN_LAYER2_DEVICE, xTriggerResetCounter := xRst, xValid=> , xError=> , oStatus=> , wBusState=> , wBusDiag=> , uiRxOverflowsL2=> , uiTxOverflowsL2=> , uiRxOverflows=> , uiMsgTimeouts=> , uiBusOffs=> , uiBusWarnings=> ); Program first opens comunication on CAN 2 device and then periodically try send one CAN data frame. After starting program CAN 2 interface is properly open. The xSend variable is toggling with period 2s. When program sends data an "Tx overflow" error appears. When I am watching CAN_H line on DSub 9 socket i am not able to see proper CAN frames - see screenshot attached to this message. Could somebody help me determine what is wrong with this program. Best regards
Last updated: 2024-08-02

Post by brouwyka on JSONByteArrayWriter string result incorrect order ^{CODESYS Forge talk (Post)}
Hi @TimvH, As discussed in our email contact, your example does not actually test/reproduce the bug I am describing: Adding to the JSON builder on later cycles works fine. Your example works because you do the following: 1. You finish the first cycle (xFirst) with adding an object to the array with 2 fields; 2. When the next cycle is triggered (xAdd), you immediately start with adding another object to that array. This works fine as the last thing you did before #2 was the addition of the array and an object to it. To reproduce the bug you should be doing the following instead, as I showed with the code I shared with my first post: 1. Create the array - save the index that is returned; 2. Add an item, either a primitive or an object, to the array; 3. Add an item outside the array (anything: a primitive, a new array, a nested object, etc); 4. Add another item to the array using the index you saved at #1. You will now see, as I shared in my initial post, that the second item is placed completely outside the root JSON object. This also happens to anything else you try to add after step #4: everything after this point will be added outside the root JSON object: the JSON is completely broken. Important to note is that this not only happens with arrays, but also with nested JSON objects. Once you add something outside of a nested JSON object, you can no longer add anything to that nested JSON object, as that causes the exact same bug. This also applies to arrays of objects, so if in your test you had tried adding a new key-value pair to the first nested object in your array after you created the second nested object, you would also run into this bug. It seems that the JSONByteArrayWriter (I haven't tested the other writers in the JSON Utilities SL library, so I don't know if they suffer from the same problem) simply does not handle any JSON fields that add brackets (so arrays with "[" & "]" and nested objects with "{" & "}") well, and closes them prematurely instead of checking if any later JSONElements in the JSONData's array belong to any of these bracketed fields. After reviewing the objects & functions of the JSON Utilities SL library, my guess is that either the JSONByteArrayWriter linearly goes through the array of JSONElements in the JSONData and only checks the diParentIndex of each JSONElement in direct ascending order, OR if it does use the JSONElement.GetChildren(); method, that this method is either broken and doesn't give all children correctly to the writer. Neither explains why everything completely breaks, and you cannot even add to the root JSON object anymore, however, so there is probably more than just that going wrong in the writer. To me, after a full week of testing and attempting workarounds, this seems like a bug in the library that needs to be fixed by Codesys, as I cannot see anything wrong in the JSONData constructed by the JSONBuilder - this seems purely a problem in the writer.
Last updated: 2026-06-15

Post by timvh on Sorting array of any-sized structure ^{CODESYS Forge talk (Post)}
Look all the way at the end of the link below. This provides a way to use arrays with various lengths: https://content.helpme-codesys.com/en/CODESYS%20Development%20System/_cds_datatype_array.html
Last updated: 2023-08-18

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