Post by anonymous on Hi, I try to send and receive data using a UDP connection via SysSocket 3.5.17.0. While sending data works fine, I have problems with the receiving part. I am able to capture the received data of client side in wireshark But unable to capture it on the codesys ^{CODESYS Forge talk (Post)}
Hi, I try to send and receive data using a UDP connection via SysSocket 3.5.17.0. While sending data works fine, I have problems with the receiving part.I am able to capture the data of client side in wireshark but i am unable to capture it in the codesys. Heres the below part of code of client side. PROGRAM POU_udpclient_program VAR istep : INT := 1;//step variable for state machine xStart: BOOL;// Flag to start the UDP protocol iecSocketId: syssocket_interfaces.RTS_IEC_HANDLE;//socket handle for receiving iecCreateResult: syssocket_interfaces.RTS_IEC_RESULT; ipAddr: syssocket.SOCKADDRESS;//Socket address structure for receiving sIpAddress : STRING := '192.168.0.2'; wPort: WORD:= 12346; iecConnectResult : syssocket_interfaces.RTS_IEC_RESULT;//connect paramters sDataRec : STRING[255];//Buffer for received data xiRecBytes : __XINT;//number of bytes received iecRecResult : syssocket_interfaces.RTS_IEC_RESULT;//receive data parameters iecCloseResult : syssocket_interfaces.RTS_IEC_RESULT; END_VAR syssocket.SysSockInetAddr(sIpAddress,ADR(ipAddr.sin_addr)); ipAddr.sin_family := syssocket.SOCKET_AF_INET; ipAddr.sin_port := syssocket.SysSockHtons(wPort); CASE istep OF 1: //create socket IF xStart THEN iecSocketId:= syssocket.SysSockCreate(syssocket.SOCKET_AF_INET,syssocket.SOCKET_DGRAM,syssocket.SOCKET_IPPROTO_IP,ADR(iecCreateResult)); IF iecSocketId = syssocket_interfaces.RTS_INVALID_HANDLE THEN xStart := FALSE; istep := 1; ELSE istep := 2; END_IF END_IF 2: //connect to socket server using setoption iecConnectResult := syssocket.SysSockSetOption(iecSocketId,syssocket.SOCKET_SOL,syssocket.SOCKET_SO_REUSEADDR,ADR(ipAddr),SIZEOF(ipAddr)); istep := 3; 3: //receive data xiRecBytes := syssocket.SysSockRecvFrom(iecSocketId,ADR(sDataRec),SIZEOF(sDataRec),0,ADR(ipAddr),SIZEOF(ipAddr),ADR(iecRecResult)); istep := 4; 4: //close socket iecCloseResult:= syssocket.SysSockClose(iecSocketId); xStart := FALSE; istep := 1; END_CASE
Last updated: 2024-06-03

Post by timvh on Detect "Cancel" Press in FileOpenSave Dialog ^{CODESYS Forge talk (Post)}
Maybe there is a better way, but a long time ago I created a test application that worked like this: With a button I opened the dialog and I added a "Input configuration - OnDialogClosed" "Execute ST-Code" action to this same button which called the following Function when the dialog was closed: F_OnFileDialogClosed(pClientData); Below this Function which handled the result: // This function is called from the visualization when the dialog is closed. FUNCTION F_OnFileDialogClosed : BOOL VAR_INPUT pClientData : POINTER TO VisuElems.VisuStructClientData; END_VAR VAR dialogMan : VisuElems.IDialogManager; FileOpenCloseDialog : VisuElems.IVisualisationDialog; result : VisuElems.Visu_DialogResult; _sFileName : STRING(255); END_VAR // the DialogManager is provided via the implicitly available VisuManager dialogMan := VisuElems.g_VisuManager.GetDialogManager(); IF dialogMan <> 0 AND pClientData <> 0 THEN FileOpenCloseDialog := dialogMan.GetDialog('VisuDialogs.FileOpenSave'); // gets the FileOpenSave dialog IF FileOpenCloseDialog <> 0 THEN result := FileOpenCloseDialog.GetResult(); // gets the result (OK, Cancel) of the dialog IF result = VisuElems.Visu_DialogResult.OK THEN // Original code gvlFile.FileListProvider(); _sFileName := CONCAT(gvlFile.FileListProvider._stDirectory, gvlFile.FileListProvider.stFile); // do something with this file name... END_IF END_IF END_IF
Last updated: 2023-09-19

Post by psychoengineer on Cannot Save CSV File on Windows Computer Using CODESYS and Control Win ^{CODESYS Forge talk (Post)}
I am currently working on a project using CODESYS and Control Win on a Windows computer. I've encountered an issue where I am unable to save a CSV file. I have followed the standard procedures and used the appropriate file handling functions, but the file is not being created or saved as expected. IF xStartTest THEN sFileName := '\logs.txt'; sFileName := CONCAT(gvl.g_sMainDirectory, sFileName); sFileNameCopy := '\CAAFileCopy.txt'; sFileNameCopy := CONCAT(gvl.g_sMainDirectory, sFileNameCopy); //eWriteState := FILE_OPEN_TRIGGER; xTestDone := FALSE; xError := FALSE; xStartTest := FALSE; END_IF VAR_GLOBAL g_sMainDirectory : STRING := 'C:\LogFiles'; // file path for CSV file END_VAR Despite this, the file does not appear in the specified directory, and no error messages are being generated. I've checked the directory permissions and ensured that the path is correct. Has anyone else experienced a similar issue or have any suggestions on how to resolve this? Any help would be greatly appreciated. Thank you!
Last updated: 2024-07-04

Post by fless on Von SNMP auf IIoT wechseln ^{CODESYS Forge talk (Post)}
Wie gesagt ich hatte noch keinen Kontakt mit SNMP. Um die Beispiele zu verstehen hier ein paar Tips: SetEngineId und CreateSNMPV3User sind Funktionsbausteine. Klicke rechts auf den Namen, Symbol suchen - Gehe zu Definition Dann sieht du entweder den Quelltext oder landest in der Bibliothek und kannst dir die Dokumentation ansehen. In deinen Fall siehst du den Quelltext. Die Funktionsbausteine sind in den Projekt POUs gespeichert weil das Projekt aus mehreren Applikationen besteht die alle diese FBs nutzen. sOID (drei Balken)oid → was wird da gemacht? In die Stringvariable sOID (String old ID?) wird der Inhalt von oid geschrieben. oid ist Member der Strukturvariable snmpVarBindings. Dem SNMP_SET Aufruf wird snmpVarBindings übergeben und geändert. Und da müsste doch irgendwo eine Verschlüsselung eingetragen werden oder? Beim Anlegen der SMNP-User wird ein Passwort vergeben, siehe CreateSNMPV3User. Dem SNMP_SET Aufruf wird nur der User übergeben, hier "readwrite". Die Bibliothek sucht sich die Einstellung des Users selbst.
Last updated: 2024-09-01

Post by george32 on TCP Server ^{CODESYS Forge talk (Post)}
Thank you for your advice Rinie, I have tried to follow this example but found one problem.When I disconnect with Hercules the system does not acknowledge the lost of its connection this could result in critical errors. Because of this error I am trying to implement the Syssocket library. With this library I am having a problem which I could not solve. I have the following code: ip_adres : STRING :='0.0.0.0'; port : WORD := 5000; iStep : INT := 1; // Socket information Socket_handler : SysSocket_Interfaces.RTS_IEC_HANDLE; Socket_handler_result : SysSocket_Interfaces.RTS_IEC_RESULT; Socket_adress : SysSocket_Interfaces.SOCKADDRESS; Addres_Convert : SysSocket_Implementation.RTS_IEC_RESULT; // Bind information Bind_handler : SysSocket_Interfaces.RTS_IEC_RESULT; // Listener Information Listener_handler : SysSocket_Interfaces.RTS_IEC_RESULT; Addres_Convert := SysSocket_Implementation.SysSockInetAddr(szIPAddress:= ip_adres,pInAddr:= ADR(Socket_adress.sin_addr)); Socket_adress.sin_family:= SysSocket_Interfaces.SOCKET_AF_INET; Socket_adress.sin_port := SysSocket_Implementation.SysSockHtons(usHost:= port); CASE iStep OF 1: // Create Socket Socket_handler :=SysSockCreate( iAddressFamily :=SysSocket_Interfaces.SOCKET_AF_INET, diType:=SysSocket_Interfaces.SOCKET_STREAM, diProtocol:=SysSocket_Interfaces.SOCKET_IPPROTO_TCP, pResult:=ADR(Socket_handler_result)); IF Socket_handler = SysSocket_Interfaces.RTS_INVALID_HANDLE THEN iStep := 1; ELSE iStep := 2; END_IF 2: Bind_handler := SysSocket_Implementation.SysSockBind( hSocket:=Socket_handler, pSockAddr :=ADR(Socket_adress), diSockAddrSize:=SIZEOF(Socket_adress) ); 3: Listener_handler := SysSocket_Implementation.SysSockListen( hSocket :=Socket_handler, diMaxConnections :=1); END_CASE When I am trying to get this working, the SysSockBind function gives a value of 16#207 which means adress already in use. I find this weird because of the IP-adress of 0.0.0.0. I think I am converting the Ip-adress in the wrong way, but the code does not give a error arround this. So therefore I cannot find the solution to this problem. I hope someone could help me with this problem. Thanks in advance George
Last updated: 2025-02-20

Post by pernockham on Inheritence of struct, ^{CODESYS Forge talk (Post)}
Im looking for a way to define predefined version of the same structures through "extends"/inheritance. What I want to do is best shown with an example: TYPE log_item_val_type : ( BOOL_ := 0, INT_, REAL_, STRING_ ); END_TYPE TYPE LOG_DATA_BASE STRUCT val_type : log_item_val_type; (* value, name etc *) ENDSTRUCT ENDTYPE (* this/below is not possible as I understand from the compiler?? *) TYPE LOG_DATA_BOOL extends LOG_DATA_BASE : STRUCT val_type : log_item_val_type := log_item_val_type.BOOL_; END_STRUCT END_TYPE TYPE LOG_DATA_INT extends LOG_DATA_BASE : STRUCT val_type : log_item_val_type := log_item_val_type.INT_; END_STRUCT END_TYPE etc. for LOG_DATA_REAL and ..STRING. The system will not allow me to "re-define" "val_type" however. Instead I must do the work-around of defining four different types with all fields individually defined. The benefit if I could extend the base item would be that Im (more) sure the structures are identical. In usage I can call in a specific type rather use the base type and assign which type. Usage by pointer/ref to log_data_base would also be easier.. (* Usage: *) log_data : log_data_int := (name, value etc.) (* Instead of: *) log_data : log_data_base := (name, value, val_type).. Is this possible to achieve in some way that I have missed?
Last updated: 2025-03-05

Post by pistola on C0357: "GetNextClient" is obsolete, use VisuUtils instead ^{CODESYS Forge talk (Post)}
I'm having some troubles with this same issue and I'm wondering if someone can help me out. On a settings visual I allow the operator to enter some values however if they activate the page change button it will change the change with the Numpad dialog open. Since I'm using Visuelems.CURRENTVISU to change the pages I came across this code noted below for determining if the Numpad dialog was active. This code worked great however now in 3.5.19 it's now obsolete. I've tried following the directions in the attached program above however I can't see to get it to work in my program. Can anyone provide some help to determine if a dialog is open? FUNCTION Check_Dialog_Open : Bool VAR_INPUT sDialogName : STRING; // Input variable for the name of the dialog END_VAR VAR pstClientData : POINTER TO VisuElems.VisuStructClientData; // Pointer to the client data structure itfDialogManager : VisuElems.IDialogManager; // Interface for the dialog manager itfMyDialog : VisuElems.IVisualisationDialog; // Interface for the specific visualisation dialog END_VAR // Begin the iteration over the client manager VisuElems.g_ClientManager.BeginIteration(); // Loop through each client until no more clients are found WHILE (pstClientData := VisuElems.VisuElemBase.g_ClientManager.GetNextClient()) <> 0 DO // Get the dialog manager interface itfDialogManager := VisuElems.g_VisuManager.GetDialogManager(); // Get the specific dialog interface using the dialog name itfMyDialog := itfDialogManager.GetDialog(sDialogName); // Check if the dialog is open for the current client Check_Dialog_Open := VisuDialogs.VisuDlgUtil_IsDialogOpen(itfMyDialog, pstClientData, itfDialogManager); // If the dialog is open, exit the loop IF Check_Dialog_Open THEN EXIT; END_IF END_WHILE
Last updated: 2025-03-27

Post by francescoc on Custom log CmpLog ^{CODESYS Forge talk (Post)}
Hi, I am trying to create a log in my application. Since I cannot find any documentation regarding modifying the codesys configuration file to be able to log in ms, i tried to create a new log via CmpLog.LogCreate. Below is the part of the code where I create the logger and write a test string. In the log tab of codesys I actually see the new log that was created, but it is empty, and in the folder I cannot find any files. I can't find any detailed documentation. Can you guys give me support? Are there any examples? Thank you IF NOT FirstCycle THEN LogName:= 'LOGS/TestLog'; LogOptions.bEnable:= 1; LogOptions.iMaxEntries:= 5000; LogOptions.iMaxFiles:= 100; LogOptions.iMaxFileSize:= 5000; LogOptions.szName:= LogName; LogOptions.uiType:= CmpLog.LogTypes.LT_TIMESTAMP_RTC_HIGHRES; LogOptions.uiFilter:= CmpLog.LogClass.LOG_ALL; LogHandle:= CmpLog.LogCreate(pOptions := ADR(LogOptions), pResult:= ADR(Result)); LogHandle:= CmpLog.LogOpen(pszName:= LogName, pResult:= Result); Component_Manager.CMAddComponent2('TestLogNEW', 16#00000001, ADR(udiCmpIdNEW), 0); CmpLog.LogAdd2(LogHandle, udiCmpIdNEW, CmpLog.LogClass.LOG_INFO, 1, 1, 'Logger started...'); END_IF IF TestWrite THEN TestWrite:= FALSE; CmpLog.LogAdd2(LogHandle, udiCmpIdNEW, CmpLog.LogClass.LOG_INFO, 1, 1, 'Write test'); END_IF
Last updated: 2024-03-16

Post by joshskellig on Publish a JSON payload via MQTT Publish (using IIot Libraries) ^{CODESYS Forge talk (Post)}
I am trying to figure out how to get a JSON payload to properly publish to my MQTT Broker. I am able to generate JSON using the examples from Codesys, but when I send that payload via MQTT there are characters that are extra or not recognized by my MQTT client. Any idea what could be causing it? PROGRAM PLC_PRG VAR hostname: STRING := 'localhost'; port: UINT := 1883; topic: WSTRING(1024) := "testing/"; payload: BYTE; factory : JSON.JSONDataFactory; eDataFactoryError : FBF.ERROR; pJsonData : POINTER TO JSON.JSONData := factory.Create(eError => eDataFactoryError); fb_JBuilder : JSON.JSONBuilder; wsValue : WSTRING := "Value1"; diRootIndex, diObject1Index : DINT; iValue : INT := 1234; jsonArrayWriter : JSON.JSONByteArrayWriter; wsJsonData : WSTRING(1000); xFirst : BOOL := TRUE; mqttClient: MQTT.MQTTClient; mqttPublish: MQTT.MQTTPublish; mqttPublishProperties: MQTT.MQTTPublishProperties := (bPayloadFormatIndicator := 1, wsContentType := "application/json"); END_VAR // Json Functionality IF xFirst THEN fb_JBuilder(pJsonData := pJsonData, diRootObj => diRootIndex); fb_JBuilder.SetKeyWithValue("Key1", wsValue, diParentIndex := diRootIndex); diObject1Index := fb_JBuilder.SetKeyWithObject("Key2", diParentIndex := diRootIndex); fb_JBuilder.SetKeyWithValue("Key3", iValue, diParentIndex := diObject1Index); xFirst := FALSE; END_IF jsonArrayWriter(pwData := ADR(wsJsonData), udiSize := SIZEOF(wsJsonData), jsonData := pJsonData^, xAsyncMode := FALSE); MSU.StrTrimW(pString:= ADR(wsJsonData)); // MQTT Functionality mqttClient( sHostname:=hostname, uiPort:=port, eMQTTVersion:=MQTT.MQTT_VERSION.V5 ); mqttPublish( mqttClient:=mqttClient, pbPayload:=ADR(wsJsonData), udiPayloadSize:=SIZEOF(wsJsonData), wsTopicName:=topic, mQTTPublishProperties:=mqttPublishProperties );
Last updated: 2024-04-10

Post by paulg on RasPi CAA Serial example - unexpected behavior during debug ^{CODESYS Forge talk (Post)}
I've trimmed down the CAA Serial Codesys example to only listen on one port but, when stepping through the Case structure in debug mode, it jumps out of the structure during a specific point in every scan (I'll point it out below after describing the setup and listing the code). I'm using a Pi 4 Model B, and I have an Arduino Nano Every plugged in via USB which is streaming the following serial message at 1 Hz: Time since opening connection: 1 s Time since opening connection: 2 s ...and so on. The Pi shows the Nano at /dev/ttyACM0 so I edited CODESYSControl_User.cfg to read: Linux.Devicefile=/dev/ttyACM The code in my PLC_PRG is (ignore some of the comments, I hadn't deleted them out from the original example): PROGRAM PLC_PRG VAR xStartTest : BOOL:= TRUE; iState : INT; xTestDone : BOOL;(* True, when the test was done succesfully *) (* Settings to communicate with the COM Port *) aCom1Params : ARRAY [1..7] OF COM.PARAMETER; como1 : COM.Open; comc1 : COM.Close; comw1 : COM.Write; comr1 : COM.Read; //sWrite : STRING := 'Test String!'; sRead : STRING(25); szRead : CAA.SIZE; xCom1OpenError : BOOL; xCom1CloseError : BOOL; xCom1WriteError : BOOL; xCom1ReadError : BOOL; END_VAR //This example shows the communication of two COM Ports with each other. //The first one writes a string of characters, which is read by the second one. //After successful execution, the two COM Ports are closed and the test is done. IF xStartTest THEN CASE iState OF 0: //The parameters are set for the COM Port aCom1Params[1].udiParameterId := COM.CAA_Parameter_Constants.udiPort; aCom1Params[1].udiValue := 1; // the correct Port should be adapted aCom1Params[2].udiParameterId := COM.CAA_Parameter_Constants.udiBaudrate; aCom1Params[2].udiValue := 115200; aCom1Params[3].udiParameterId := COM.CAA_Parameter_Constants.udiParity; aCom1Params[3].udiValue := INT_TO_UDINT(COM.PARITY.NONE); aCom1Params[4].udiParameterId := COM.CAA_Parameter_Constants.udiStopBits; aCom1Params[4].udiValue := INT_TO_UDINT(COM.STOPBIT.ONESTOPBIT); aCom1Params[5].udiParameterId := COM.CAA_Parameter_Constants.udiTimeout; aCom1Params[5].udiValue := 0; aCom1Params[6].udiParameterId := COM.CAA_Parameter_Constants.udiByteSize; aCom1Params[6].udiValue := 8; aCom1Params[7].udiParameterId := COM.CAA_Parameter_Constants.udiBinary; aCom1Params[7].udiValue := 0; //The first Port is opened with the given parameters como1(xExecute := TRUE, usiListLength:=SIZEOF(aCom1Params)/SIZEOF(COM.PARAMETER),pParameterList:= ADR(aCom1Params)); IF como1.xError THEN xCom1OpenError := TRUE; iState := 1000; END_IF //After a successful opening, the next state is reached IF como1.xDone THEN iState := 15; END_IF 15: // the reading process is started comr1(xExecute := TRUE,hCom:= como1.hCom, pBuffer:= ADR(sRead), szBuffer:= SIZEOF(sRead)); IF comr1.xError THEN xCom1ReadError := TRUE; END_IF //After completion the size of the written bytes are saved IF comr1.xDone OR comr1.xError THEN szRead := comr1.szSize; iState := 20; END_IF 20: // If everything was successful the ports are closed and the handles are released comc1(xExecute := TRUE,hCom:= como1.hCom); IF comc1.xError THEN xCom1CloseError := TRUE; END_IF IF comc1.xDone OR comc1.xError THEN iState := 25; END_IF 25: // The first port is closed and the used handle released xTestDone := TRUE; xStartTest := FALSE; iState := 0; como1(xExecute := FALSE); comw1(xExecute := FALSE); comc1(xExecute := FALSE); ELSE iState := 0; END_CASE END_IF I realize as I write this that the .udiPort should be 0 and not 1, but that shouldn't be causing the issue I'm seeing. I'm forcing xStartTest:=TRUE every scan so that I can step into each line and observe what's happening. What I see is that the port parameters are set and the port is opened with no errors, but the code jumps out of the case structure to the last line every time it reaches (and I step into) the iState:=15 line (at the end of the iState:=0 block). So every scan cycle it goes through the block for iState=0 and jumps out at the same spot. I'm a little new to PLC programming so I may be misunderstanding the flow, but shouldn't this case structure keep moving down in the same scan? If it only handles one case per scan, why doesn't the value of iState persist? Thanks! Update: I restarted the Codesys control today and I was then able to see an error for como1.eError of "WRONG_PARAMETER". I tried doing some digging and another post made me think I should add another line to CODESYSControl_User.cfg, so I now have: [SysCom] Linux.Devicefile=/dev/ttyACM portnum := COM.SysCom.SYS_COMPORT1 So now when I set .udiPort to 1, I get "NO_ERROR" but I also don't read anything from the port (i.e. szRead = 0 always). If I try setting the port to 0 (which I'm confused about, because I added a COMPORT1 line but the device shows on the Pi as ACM0), I get the "WRONG_PARAMETER" error again. Is there an easier way to troubleshoot the Pi and view what ports the Codesys runtime is actually able to see while the Pi is running?
Last updated: 2024-06-06

Post by caprez95 on Deleting the trend recording history ^{CODESYS Forge talk (Post)}
Hallo Ich möchte eine laufende Trendaufzeichnung stoppen, den Inhalt löschen und Trend-Diagramm auf 0 zurücksetzen. Laut Codesys soll das mit dem folgenden Code möglich sein: You can insert an input element in the visualization which the operator can use to delete the previous value recording in the trend visualization at runtime. The curve displayed until then is removed and the display starts over. In the application (example: in the program PLC_PRG), implement the following code: itfTrendRecording : ITrendRecording; itfTrendStorageWriter : ITrendStorageWriter; itfTrendStorageWriter3 : ITrendStorageWriter3; sTrendRecordingName : STRING := 'TrendRecording'; itfTrendRecording := GlobalInstances.g_TrendRecordingManager.FindTrendRecording(ADR(sTrendRecordingName)); xClearHistoryTrend: BOOL; IF xClearHistoryTrend THEN itfTrendRecording := GlobalInstances.g_TrendRecordingManager.FindTrendRecording(ADR(sTrendRecordingName)); IF itfTrendRecording <> 0 THEN itfTrendStorageWriter := itfTrendRecording.GetTrendStorageWriter(); IF __QUERYINTERFACE(itfTrendStorageWriter, itfTrendStorageWriter3) THEN itfTrendStorageWriter3.ClearHistory(); END_IF END_IF In the visualization of the trend recording, add a button for deleting the previous curve. Configure its Toggle property with the variable PLC_PRG.xClearHistoryTrend. ⇒ When xClearHistoryTrend is set to TRUE, the previously recorded curve is deleted. The recording immediately starts again. Dies löscht auch die Daten vom Trend, aber das Diagramm wird nicht auf 0 zurückgesetzt, sondern läuft einfach da weiter wo man gestoppt hat. Braucht es für den Diagramm-Reset noch einen zusätzlichen Befehl? Gruss
Last updated: 2024-06-11

Post by fredashbolt on Dynamically Update JSON Payload ^{CODESYS Forge talk (Post)}
I am trying to generate a JSON payload populated with a value that updates for use with a telemetry system, the payload is to be published by MQTT. I have established the MQTT client and can publish a working JSON payload but I can't get the payload to update as the value (iValue) changes. I am using a timer to trigger the .SetValue function periodically, but the JSON will only give the value as it is when it is first initialized using xFirst IF statement. Any suggestions? Thanks VAR pJsonData : POINTER TO JSON.JSONData := factory.Create(); fb_JBuilder : JSON.JSONBuilder; diRootIndex, diObject1Index : DINT; iValue : INT := 10 ; jsonArrayWriter : JSON.JSONByteArrayWriter; wsJsonData : WSTRING(1000); xFirst : BOOL := TRUE; utf8JsonData : STRING(2000); diTempVal : DINT ; PublishTimer : TON ; END_VAR IF xFirst = TRUE THEN fb_JBuilder ( pJsonData := pJsonData , diRootObj => diRootIndex ) ; diObject1Index := fb_Jbuilder.SetKeyWithObject ( "Device" , diParentIndex := diRootIndex ) ; diTempVal := fb_Jbuilder.SetKeyWithValue ( "Temp" , iValue , diParentIndex := diObject1Index ) ; xFirst := FALSE ; END_IF PublishTimer ( IN := PublishTimer.Q = 0 , PT := T#5S ) ; IF PublishTimer.Q THEN fb_JBuilder.SetValue ( iValue , diTempVal ) ; END_IF jsonArrayWriter( xExecute := PublishTimer.Q , pwData := ADR(wsJsonData), udiSize := SIZEOF(wsJsonData), jsonData := pJsonData^, xAsyncMode := FALSE ) ; JSON.Stu.ConvertUTF16toUTF8( ADR ( wsJsonData ) , ADR ( utf8JsonData ) , SIZEOF ( utf8JsonData ) , bStrictConversion := TRUE ) ;
Last updated: 2026-03-10

Post by chaylak on MC_ReadActualPosition with ST code ^{CODESYS Forge talk (Post)}
hi everyone, i am trying use MC_ReadActualPosition module in ST but i cant do it,( if i use CFC yes i read it) my axis is SoftMotion General Axis Pool->VirtAxisZ [Device: SoftMotion General Axis Pool] codesys V3.5 SP20 program: PROGRAM PLC_PRG VAR VirtAxisZ : AXIS_REF_VIRTUAL_SM3; fbPowerZ : MC_Power; fbReadPos : MC_ReadActualPosition; bEnable : BOOL := TRUE; lrActPos : LREAL; bValid : BOOL; bError : BOOL; fbResetZ : MC_Reset; xZ_Valid : BOOL; xZ_Busy : BOOL; xGlobalPower : BOOL; xGlobalReset : BOOL; xBtnTeachingMode : BOOL; lrGrvZ_OffsetTorque : LREAL := 0.5; lrPulseMmZ : LREAL; rPosFromBlock : LREAL; xZ_IsPowered : BOOL; xZ_PowerError : BOOL; iZ_PowerErrorID : LREAL; rZ_ActualPos : LREAL; lrTargetTorque : LREAL; sZ_ErrorString : STRING; //********** jog fbJogZ : MC_Jog; xJogForward : BOOL; xJogBackward : BOOL; rZ_ActVelocity : REAL; END_VAR fbResetZ( Axis:= VirtAxisZ, Execute:= xGlobalReset); fbPowerZ( Axis:= VirtAxisZ, Enable:= xGlobalPower, bRegulatorOn:= xGlobalPower, bDriveStart:=xGlobalPower , Status=> xZ_IsPowered, Busy=> xZ_Busy, Error=> xZ_PowerError, ErrorID=> iZ_PowerErrorID ); IF xGlobalPower THEN fbJogZ( Axis:= VirtAxisZ, JogForward:= xJogForward, JogBackward:= xJogBackward, Velocity:= 100, Acceleration:= 100, Deceleration:= 100, Jerk:= 1000); END_IF fbReadPos( Axis := VirtAxisZ, Enable := TRUE, Valid => bValid, Position => lrActPos, Error => bError ); IF VirtAxisZ.bError THEN sZ_ErrorString := 'Z Ex err'; ELSIF NOT xZ_IsPowered THEN sZ_ErrorString := 'Z Ex (Power Off)'; ELSE sZ_ErrorString := 'Z Ex Ready'; END_IF IF xBtnTeachingMode THEN lrTargetTorque := lrGrvZ_OffsetTorque; ELSE lrTargetTorque := 0; END_IF VAR_INPUT CFC_Motion: INT; END_VAR
Last updated: 2026-05-15

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 otbeka on CAA File Handling: "Read only" error ^{CODESYS Forge talk (Post)}
Hi, On CODESYS V3.5.19.50 I am using the latest 3S File Access library (CAA File & CAA Types) to save and retrieve configuration data from the User Data section of an SD card, via file called config.txt. The application reads the file to memory once upon initialisation, and then the only other operation is overwriting the file with the updated configuration whenever the user changes the settings. An issue is ocurring, seemingly randomly, where the config.txt file, and all surrounding directories, cannot be written to by the unit, returning a READ_ONLY_CAA error upon file open. This sometimes does not clear even after power-cycling the PLC several times, yet checking the file permissions with ls -l shows normal read, write, and execute access. I am wondering if this is caused by the PLC itself or by an issue in my application. I have included my CAA File handler function block (SD_Card_Bin(FB).txt) and any associated types/calls below: TYPE ConfigData : STRUCT Config : ARRAY[0..256] OF STRING(64); NumberOfStrings : UDINT; END_STRUCT END_TYPE TYPE Buffer : STRUCT Data : ARRAY[0..SIZEOF(ConfigData)] OF BYTE; DataLength : UDINT; END_STRUCT END_TYPE A case within my MAIN PRG: mode.WriteConfigDataToFile: VisuElems.CURRENTVISU := 'Screen_Write'; IF xModeHasChanged THEN iErrorCount := 0; iRoute := 0; END_IF CASE iRoute OF 0: inBuffer := ConfigData_To_Buffer(GVL.UnitData); xConfigError := FALSE; xDataConfigured := FALSE; iRoute := 1; 1 : //Read Data from Card SD_Card_Bin.strFileName :=FileName; SD_Card_Bin.iFileOperation := 2; SD_Card_Bin(xExecute :=TRUE, WriteBuffer := inBuffer, xDone =>xDataConfigured, xError=>xConfigError, strErrorCodes=>strError); IF xDataConfigured THEN SD_Card_Bin(xExecute :=FALSE); IF xConfigError THEN iRoute := 32767; ELSE iRoute :=100; END_IF END_IF 100: // The end bCurMode := mode.DisplayProcessVariables; 32767: // Config error iErrorCount := iErrorCount + 1; IF iErrorCount > 2 THEN // Repeats 3 times, if no progress abandons and returns error bCurMode := mode.WriteError; ELSE iRoute := 0; // Try again END_IF END_CASE I'd like to rule out my application as the cause of this bug - help via comments or criticism would be greatly appreciated.
Last updated: 2025-03-19

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 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 ppix on Establishing TLS Connection with MQTT Broker using MQTT Client SL Package ^{CODESYS Forge talk (Post)}
I’m currently working on establishing a TLS connection with an MQTT broker using the MQTT Client SL package in CODESYS. While I’ve successfully established communication with the broker without TLS, I'm encountering issues when trying to enable TLS. In the 'MQTT Explorer' application, I can easily upload the server certificate (.crt), client certificate (.crt), and client key (.key). However, in CODESYS, I can’t find a way to upload my client key (.key file). Here's a summary of my current setup: Certificates: I have uploaded both the client and server certificates to the certificate store under the 'Trusted Certificates' folder in the security screen. TLS Context Initialization: Despite setting the _sCommonName as the name of my client certificate, a new self-signed certificate is created and placed within the device’s certificates. I then need to manually move this certificate to the trusted certificates folder. This results in three certificates in my trusted certs folder: client cert, server cert, and the newly created cert. _ciDefaultCertInfo : MQTT.NBS.CERT_INFO := (psInfo := ADR(_sCommonName), udiSize := TO_UDINT(LEN(_sCommonName))); // CN of the certificate (common name) _sCipherList : MQTT.NBS.CIPHER_LIST := STRUCT(psList := ADR('HIGH'), udiSize := 4); // Cipher string see https://www.openssl.org/docs/man1.1.1/man1/ciphers.html _tlsContext : MQTT.NBS.TLSContext := ( sUseCaseName := _sCommonName, // A certificate is stored in the certificate store with the use case name. You can choose any name. Here we use the common name. ePurpose := MQTT.NBS.PURPOSE.CLIENT_SIDE, // For client certificates set this to NBS.PURPOSE.CLIENT_SIDE sTLSVersion := '1.3', // The TLS version sCipherList := _sCipherList, // Set the cipher list sHostname := sHostname, // The hostname of the broker udiVerificationMode := 2, // 2 => Active Peer verification ciCertInfo := _ciDefaultCertInfo, // Set the cert info itfCertVerifer := 0); // 0 => No Verifier mqttClient : MQTT.MQTTClient := (xUseTLS:=TRUE, itfTLSContext := _tlsContext, itfAsyncProperty := _asyncProperty); Additional Details: In the client FB, I’ve set uiPort:= 8883, xUseTLS:= TRUE, and configured itfTLSContext as mentioned above. The certificates are encrypted with SHA256RSA. sHostname is the IP address of my broker. I’ve attached a copy of the client FB, which shows straight lines where variables are assigned and boxes where they are not. I am currently trying this on the only 2 compatible versions of COSDESYS with my controller (V3.5.15.20 and V3.5.18.40) My Question: How do I correctly set up this mTLS connection? What might I be missing? Any guidance or suggestions would be greatly appreciated, especially considering I’ve already successfully established a non-TLS connection with the same broker. Thank you in advance for your help!
Last updated: 2024-06-19

Post by ihatemaryfisher on Sorting array of any-sized structure ^{CODESYS Forge talk (Post)}
In my machine's operation, I need to display multiples tables containing arrays of structured variables. The arrays change during operation, and my supervisor has advised me to write a new bubble-sort for each array. I think I can make a function to sort an array of any data type. This was my own project, and I'm a relatively new coder. I want to know the weaknesses in my approach, and a better method, if one exists. As far as I can test, the function accepts an array of a structured variable of any size, and sort it by any VAR in that structure. But it relies heavily on pointers, which I've heard are bad practice? Function call: // SORT BY BYTE-SIZED VAR IF xDoIt[6] THEN FUNBubbleSortSansBuffer( IN_pbySourcePointer := ADR(astArray[1]), // address of first byte in first element of array IN_pbyComparePointer:= ADR(astArray[1].byCompByte), // points to first byte of the comparing variable (variable you sort by) IN_uiStructureSize := SIZEOF(TYPE_STRUCTURE), // size, in bytes, of the structured variable IN_uiCompareSize := SIZEOF(astArray[1].byCompByte), // size, in bytes, of the comparing variable (variable you sort by) diArrayElements := UPPER_BOUND(astArray,1), // number of elements in array IN_xSmallToLarge := xSortOrder // whether to sort by small2large or large2small ); END_IF Function: FUNCTION FUNBubbleSortSansBuffer : BOOL VAR_INPUT IN_pbySourcePointer : POINTER TO BYTE; // points to beginning of array (first byte of first element) IN_pbyComparePointer: POINTER TO BYTE; // points to first byte of the comparing variable (variable you sort by) IN_uiStructureSize : UINT; // size, in bytes, of the structured variable IN_uiCompareSize : UINT; // size, in bytes, of the comparing variable (variable you sort by) diArrayElements : DINT; // number of elements in array IN_xSmallToLarge : BOOL; // whether to sort by small2large or large2small END_VAR VAR j : DINT; // repeat iteration over array until array ends i : DINT; // iterarte over array, swapping when necesary k : DINT; // iterator from 1 to size of structure (stepping 'through' a single element in array) dwSize : DWORD; // internal var for use in MEMUtils.MemCpy(<size>) // FOR SORTING BY BYTE VAR pbySourcePointer : POINTER TO BYTE; pbySourcePointer2 : POINTER TO BYTE; pbyComparePointer : POINTER TO BYTE; pbyComparePointer2 : POINTER TO BYTE; pbyPointerToBuffer : POINTER TO BYTE; // pointer to single byte buffer byBufferByte : BYTE; // single byte buffer END_VAR dwSize := UINT_TO_DWORD(IN_uiStructureSize); // get structure size (number of bytes) pbyPointerToBuffer := ADR(byBufferByte); // assign pointer to address of buffer byte (because MEMUtils.MemCpy requires a pointer input) CASE IN_uiCompareSize OF // depending on the size of the VAR to sort by (current functionality for BYTE and WORD/INT 1: // BYTE (8 BIT) FOR j := 1 TO diArrayElements DO // for number of elements in array FOR i := 1 TO (diArrayElements-1) DO // same thing, but row[i+1] row is included in swap logic pbySourcePointer := IN_pbySourcePointer + dwSize*(i-1); // point at #1 byte in array element[i] pbySourcePointer2 := pbySourcePointer + dwSize; // point at #1 byte in array element[i+1] // NOTE: because of memory locations, each array element is offset from one another by a number of bytes equal to the size of the structure // We can "walk" from array[i] to array[i+1] via steps equal to the size of the structure // e.g., ADR(array[i+1]) == ADR(array[i]) + SIZEOF([array datatype]) pbyComparePointer := IN_pbyComparePointer + dwSize*(i-1); // point to sorting variable in array element[i] pbyComparePointer2 := pbyComparePointer + dwSize; // point to sorting variable in array element[i+1] // using sort order (small -> large/large -> small) IF SEL(IN_xSmallToLarge, (pbyComparePointer2^ > pbyComparePointer^),(pbyComparePointer2^ < pbyComparePointer^)) THEN // This is where it gets tricky. We've identified pointers for the starting bytes of aArray[i] and aArray[i+1] // and we know the size of aArray[i]. We are going to swap individual bytes, one at a time, from aArray[i] and aArray[i+1] // this allows us to use only a single byte var as a buffer or temporary data storage // e.g., consider a structure consisting of a word, a byte, and a string. it is stored like this // |------WORD-------| |--BYTE-| |STRING------...| // astArray[1] == 1000 0100 0010 0001 1100 0011 1010 1010.... etc // astArray[2] == 0001 0010 0100 1000 0011 1100 0101 0101.... etc // performing a single swap (copy into a buffer, etc.) of the first byte of each array element creates this // astArray[1] == 0001 0100 0010 0001 1100 0011 1010 1010.... etc // astArray[2] == 1000 0010 0100 1000 0011 1100 0101 0101.... etc // incrementing the pointer adresses for the swap by 1 and swapping again swaps the next byte in each array element // astArray[1] == 0001 0010 0010 0001 1100 0011 1010 1010.... etc // astArray[2] == 1000 0100 0100 1000 0011 1100 0101 0101.... etc // continuing this from k to SIZEOF(TYPE_STRUCTURE) results in a toally swapped row FOR k := 1 TO IN_uiStructureSize DO // copy single byte[k] of array element 1 to buffer MEMUtils.MemCpy(pbyDest := (pbyPointerToBuffer), pbySrc := (pbySourcePointer+k-1), dwSize := 1); // copy single byte[k] of array element 2 to 1 MEMUtils.MemCpy(pbyDest := pbySourcePointer+k-1, pbySrc := (pbySourcePointer2+k-1), dwSize := 1); // copy buffer to byte[k] array element 2 MEMUtils.MemCpy(pbyDest := (pbySourcePointer2+k-1), pbySrc := pbyPointerToBuffer, dwSize := 1); END_FOR END_IF END_FOR END_FOR
Last updated: 2023-08-17

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 brouwyka on JSONByteArrayWriter string result incorrect order ^{CODESYS Forge talk (Post)}
Hello everybody! We are currently working on implementing a call to an API that tracks data sent to it through a JSON body. Versions: CODESYS V3.5 SP19 Patch 7 using IIOT Libraries SL license, specifically JSON Utilities SL version 1.13.0.0. For simplicity, let's say we want to construct the following JSON body for our request (simplified to just 1 key-value pair in each of the array objects to keep things shorter, but we'd have multiple fields in each in reality): { "id": "machine_1", "readings": [ { "temp_mid": 153.8 }, { "temp_mid": 98.3 } ], "status": "RUNNING" } However, our "readings" data is added over time, not in creation, so calls to the builder would be somewhat out of order. In a simplified manner, our calls would look like this: jsonBuilder(pJsonData := JsonData, diRootObj => rootJsonIndex); // rootJsonIndex = 0. // Set "id" at root JSON object. wsValue := "machine_1"; jsonBuilder.SetKeyWithValue("id", wsValue, diParentIndex := rootJsonIndex); // JSONData KEY: diParentIndex = 0 & diIndex = 1, VALUE: diParentIndex = 1 & diIndex = 2. // ... Time passes, we get our first reading to add ... // The "readings" array does not exist yet, so we make it first at root JSON object before adding our first reading. readingsJsonArrayIndex := jsonBuilder.SetKeyWithArray("readings", diParentIndex := rootJsonIndex); // JSONData KEY: diParentIndex = 0 & diIndex = 3, VALUE: diParentIndex = 3 & diIndex = 4. // Then add the first reading, for which we first have to make an object. readingsJsonArrayObjectIndex := jsonBuilder.SetObject(diParentIndex := readingsJsonArrayIndex); // JSONData OBJECT: diParentIndex = 4 & diIndex = 5. // And then we add the field(s) in the object for the first reading. // NOTE the use of `readingsJsonArrayObjectIndex` so we set the field(s) in the first object in the array. rValue := 153.8; jsonBuilder.SetKeyWithValue("temp_mid", wsValue, diParentIndex := readingsJsonArrayObjectIndex); // JSONData KEY: diParentIndex = 5 & diIndex = 6, VALUE: diParentIndex = 6 & diIndex = 7. // ... Time passes, we want to add another root-JSON-level field ... // Set "status" at root JSON object. wsValue := "RUNNING"; jsonBuilder.SetKeyWithValue("status", wsValue, diParentIndex := rootJsonIndex); // JSONData KEY: diParentIndex = 0 & diIndex = 8, VALUE: diParentIndex = 8 & diIndex = 9. // ... Time passes, we want to add a second reading ... // "readings" array exists, so add the second reading, but first we have to make another object. // NOTE the re-use of the earlier stored `readingsJsonArrayIndex`, so we add the new object to that previously created array. readingsJsonArrayObjectIndex := jsonBuilder.SetObject(diParentIndex := readingsJsonArrayIndex); // JSONData OBJECT: diParentIndex = 4 & diIndex = 10. // And then we add the field(s) in the object for the first reading. // NOTE the use of `readingsJsonArrayObjectIndex` so we set the field(s) in the SECOND(, new) object in the array. rValue := 98.3; jsonBuilder.SetKeyWithValue("temp_mid", wsValue, diParentIndex := rootJsonIndex); // JSONData KEY: diParentIndex = 10 & diIndex = 11, VALUE: diParentIndex = 11 & diIndex = 12. // ... Finally, we want to send to the API, so we must convert the builder to data the client accepts as a body ... xTestWriteToJsonArray := TRUE; jsonArrayWriter( xExecute := xTestWriteToJsonArray, pwData := ADR(jsonDataString), udiSize := SIZEOF(jsonDataString), jsonData := JsonData^ ); IF jsonArrayWriter.xDone THEN // The writer was successful, the `jsonDataString` VAR should now contain a WString copy of the JSON object from the builder. xTestWriteToJsonArray := FALSE; END_IF We see that the JsonData STRUCT is correctly organised (in terms of the diParentIndex & diIndex set by it for each JsonElement) as we expect, as outlined in my comments in the simplified code above. However, as soon as we pass it to the jsonArrayWriter (which is a JSON.JSONByteArrayWriter), the resulting jsonDataString does not match our expectations, instead coming out like this: { "id": "machine_1", "readings": [ { "temp_mid": 153.8 } ] } { "temp_mid": 98.3 } "status": "RUNNING" The behaviour of the JSONByteArrayWriter thus seems to be the problem here. It does not seem to correctly process the children of JsonElements that are ARRAYs when additions to them are done broken up by additions to the lower level JSON OBJECT they are a part of. We have confirmed this by changing the order of the calls in our example to add both readings before adding the "status", in which case we get our expected outcome. However, in reality this is not possible for us - additions to any of the JSON's objects, arrays or array objects may happen at any time after other fields elsewhere in the JSON have been added. Does anyone know a way around this, a fix, or knows a solution we simply have not found? This same phenomenon was also noted on this forum by user @ryusoup at the end of 2023 (https://forge.codesys.com/forge/talk/Engineering/thread/c45929e2f1/#e27f) and user @mtho in early 2024 (https://forge.codesys.com/forge/talk/Engineering/thread/cd1bb450db/#1292) but both topics received no activity beyond both users' opening posts. Looking through the release notes of all the versions of the JSON Utilities SL library, I also did not see any remarks on resolutions of bugs in this vain. Thanks in advance for the assistance!
Last updated: 2026-06-10

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