Post by fless on FB having single input but initialized with Array ^{CODESYS Forge talk (Post)}
Why will it retain the sum value from the last call? This is how PLC work. Usually variables only get initialized after a download or a reset (i.e. power loss). RETAIN variables are saved in a special kind of RAM and keep their value after a power loss. To initialize variables on every call of your FB use the VAR TEMP block. VAR_TEMP sum : INT; END_VAR
Last updated: 2024-05-07

Post by hammer on Cartesian XY Chart — 2-D array binding: "Element to use" enumerates the wrong dimension ^{CODESYS Forge talk (Post)}
Title: Cartesian XY Chart — 2-D array binding: "Element to use" enumerates the wrong dimension; documented example (Dialog: XY Chart Configuration, "Two-dimensional array of base type REAL") appears transposed Product / version: CODESYS Development System V3.5 SP21 Patch 40 (3.5.21.40). Cartesian XY Chart visualization element (System_VisuElemXYChart / VisuElemXYChart). Summary: When a curve's Data X/Data Y is bound to a two-dimensional array, the element treats the last array dimension as the per-point record (the one selected by "Element to use") and iterates the first dimension as the sequence of curve points. The online documentation's worked example has the dimensions in the opposite order, so following it produces a non-functional curve and a nonsensical "Element to use" list. Steps to reproduce (fails — matches the documented layout): 1. Declare aData : ARRAY[0..1, 0..4095] OF LREAL; (2 data sets × 4096 points, i.e. first dimension = set, second = point). 2. In XY Chart Configuration, bind a curve's Data X (and Y) Variable to this array. 3. Observe the "Element to use" combobox. Actual result: The "Element to use" combobox lists 4096 entries (the indices of the second dimension) instead of 2 (the data sets in the first dimension). Selecting a row does not produce the expected curve; at most a single/degenerate point is plotted. Steps to reproduce (works — transposed): 1. Declare aData : ARRAY[0..4095, 0..1] OF LREAL; (points first, set second). 2. Bind Data X/Y to this array; "Element to use" now correctly lists [0] and [1]. 3. Populate aData[point, set] and the curve plots as expected. Expected result: Either the documented example should select the data set from the first dimension (as its [1]/[2] "Element to use" implies), or the documentation should state that the last dimension is the record dimension (stride) and the first dimension is the point sequence — consistent with how the element actually behaves. Analysis: The behavior is self-consistent if the element always walks a single array by a fixed byte stride, reading one element per point — the same mechanism as the documented "one-dimensional array of a DUT" case, where it strides by SIZEOF(DUT) and "Element to use" picks the member offset. For a 2-D array the record is the last dimension: to plot column/set c it starts at [0, c] and strides by the last-dimension length to reach [1, c], [2, c], … (row-major layout makes this a contiguous column walk). Under that rule, ARRAY[0..N, 0..1] is correct (record length 2 → "Element to use" [0]/[1]), and the documented ARRAY[1..2, 1..50] with "Element to use" [1]/[2] is transposed. Documentation reference: Dialog: XY Chart Configuration → Data X / Data Y → "Example: Two-dimensional array of the base type REAL" (ARRAY[1..2, 1..50], Element to use [1]/[2], "100 array values are displayed"). This example does not plot as described in 3.5.21.40; transposing to ARRAY[1..50, 1..2] does. Request: Please confirm whether this is (a) a documentation error (example dimensions reversed) or (b) an element defect (combobox enumerates the wrong dimension). Either way, a corrected example plus an explicit statement of which dimension is the point sequence vs. the record/stride dimension would prevent others from hitting this. Two separate 1-D arrays for Data X and Data Y work correctly and are unaffected.
Last updated: 2026-08-14

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 wiresplus on INT_TO_WORD function not working ^{CODESYS Forge talk (Post)}
Hello, I need to take an INT input, and convert it to a WORD value. VAR DRV2Speed : WORD; //IO card takes a WORD where 16000 = full 10V output (equivalent to 50Hz) PumpFillSpeed : INT; //Users enter a value between 0 and 50 END_VAR IF <conditions> THEN DRV2Speed :=INT_TO_WORD((PumpFillSpeed/50)*16000); END_IF </conditions> According to me this should work - but it stays at 0, no matter what. What am I doing wrong?
Last updated: 2024-01-26

Post by leon78 on Codesys 3.5 SP17 Patch 2 CheckBounds (POUs for Implicit Checks) ^{CODESYS Forge talk (Post)}
Hello! I use CheckBounds (POUs for Implicit Checks). But I have a problem. I use an array as an VAR_IN_OUT of Function Block. If I try to monitor the array of variable length ([* ]), its does't work. The CheckBounds POU isn't called. If I use the array of fixed lenght ([lower..upper]), the CheckBounds POU is called. Why?
Last updated: 2023-11-14

Post by leon78 on Codesys 3.5 SP17 Patch 2 CheckBounds (POUs for Implicit Checks) ^{CODESYS Forge talk (Post)}
Hello! I use CheckBounds (POUs for Implicit Checks). But I have a problem. I use an array as an VAR_IN_OUT of Function Block. If I try to monitor the array of variable length ([* ]), its does't work. The CheckBounds POU isn't called. If I use the array of fixed lenght ([lower..upper]), the CheckBounds POU is called. Why?
Last updated: 2023-11-14

Post by gurkan on OPCUA array max length? ^{CODESYS Forge talk (Post)}
We are using codesys 3.5.16.30 and we have a array with strings of length 5000. We are having issues subscribing to this variable from an OPCUA client. Is there any limit in the OPCUA Server in codesys for how long an array can be on the opcua server?
Last updated: 2024-02-16

Post by alexgooi on Init Array input on a method ^{CODESYS Forge talk (Post)}
Dear Forum, I would like to initialize an array input on a method. When I do this, I get the following error: "The type of ARRAY [1..2] OF BOOL cannot have a default value in this context." I attached a picture for more clarity. Is this simply not possible or is there a different way of tackling this problem? Thank you in advance
Last updated: 2024-02-26

Post by rckalex on Changing Trace Variable at Runtime ^{CODESYS Forge talk (Post)}
Is it possible to change the variable being traced during runtime? I would like to use the CURRENTCLIENTID in combination with an array of real numbers to alter the traced variable in a display window, without needing to create separate visualizations for each variable.
Last updated: 2025-01-22

Post by gurkan on OPCUA array max length? ^{CODESYS Forge talk (Post)}
2000 works. When testing with UA Expert there is a timeout from the OPCUA Server when trying to subscribe to the variable CPU do not seems to be to affected. The memory(RAM) however is building up
Last updated: 2024-02-19

Post by davidbo on RETAIN PERSISTENT only stored at gracefully shutdown? ^{CODESYS Forge talk (Post)}
I have {attribute 'checksumnoinit_override' := '2629838988'} {attribute 'init_related_code' := '5c6efcf8-e0f4-4166-a9fa-17eadd8908df'} VAR_GLOBAL RETAIN PERSISTENT {attribute 'order_in_persistent_editor' := '0'} segmentValue: ARRAY[0..49] OF REAL; {attribute 'order_in_persistent_editor' := '1'} segmentTime: ARRAY[0..49] OF REAL; // Generated instance path of persistent variable PRG.test: INT; // Generated instance path of persistent variable PRG.nw_storage: SysSocket_Implementation.SysSocket_Interfaces.SOCK_ADAPTER_INFORMATION2; END_VAR When I have changed PRG.nw_storage it will not be stored at a power off, but if I do a: sudo systemctl restart codesycontrol and then a power off it will be stored. Is there a way to store persistent variables without a restart of codesyscontrol? Can anyone explain how and when CODESYS store persistent variables?
Last updated: 2025-11-17

Post by hazarath on How extract JSONElement containing Array data ^{CODESYS Forge talk (Post)}
I want to extract each element of an Array. Can someone help me with this. When I use JSONElementToString (part of JSON Utilities SL), I am seeing output as "ARRAY" instead of actual data. Here is the JSON content that I want to read : { "value1Unit": { "units": "M" }, "data": { "stepSize": 300.23, "points": [6,8] } } I would like to read each item of the element "points" i.e. 6 and 8. Here is the code I used, // Reading the content as JSON reader ( xExecute := execute , pwData := ADR ( converted_value ), jsonData := jsonDataStorage ); // Get the JSON Element jsonDataStorage.FindFirstValueByKey( wsKey := fidKeyVar, diStartIndex := searchElem, jsonElement => jsonElement ); JSON.JSONElementToString ( element := jsonElement , wsResult := valueWstring ); The content of the output of valueWstring is shown as "ARRAY" instead of the array items i.e. 6 and 8 Please can someone help me.
Last updated: 2024-07-30

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

Post by avenue68 on REFERENCE TO in an array ^{CODESYS Forge talk (Post)}
That's because the array only contains structures themselves, not references. It doesn't matter that what consists of each struectures unless they are not pointers.
Last updated: 2025-05-21

Post by reinier-geers on Read a webclient value ^{CODESYS Forge talk (Post)}
Hi i get a json value from an energy site. Every hour a value. to cut the answer in an array so i can read every hour it try FindWString . find Marketprice. But it turns in every array on a diverent position. Why ?
Last updated: 2026-10-08

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 voffi on Converting UINT into bytes and converting 2Bytes into UINT ^{CODESYS Forge talk (Post)}
There are some ways. One is to use SHR and SHL and it depends on your byte order in the data array. For Motorola byte order: PROGRAM PLC_PRG VAR u : UINT; byte_array_in : ARRAY [1..8] OF BYTE := [16#11, 16#12, 16#13, 16#14, 16#15, 16#16, 16#17]; byte_array_out : ARRAY [1..8] OF BYTE; END_VAR u := SHL(TO_UINT(byte_array_in[2]), 8) + TO_UINT(byte_array_in[1]); byte_array_out[1] := TO_BYTE(u); byte_array_out[2] := TO_BYTE(SHR(u, 8)); If it's Intel byte order just change 1 and 2 in the array indexes.
Last updated: 2023-12-07

Post by timvh on Active alarm access in ST ^{CODESYS Forge talk (Post)}
See https://forge.codesys.com/forge/talk/Engineering/thread/280fdf4806/#9fe5 And https://forge.codesys.com/prj/codesys-example/alarm-manager/home/Home/ The application should contain: - an FB which implements AlarmManager.IAlarmFilterCriteria (see example - FB_AlarmFilterCriteria) - an FB which implements AlarmManager.IAlarmManagerClient (see example - FB_AlarmManagerClient) Then register the client and get the information through this client. VAR xInit : BOOL := TRUE; udiResult : UDINT; fbAlarmFilterCriteriaAll : FB_AlarmFilterCriteria; fbAlarmManagerClientAll : FB_AlarmManagerClient; itfAlarmManagerClientAll : IAlarmManagerClient := fbAlarmManagerClientAll; xAlarm1 : BOOL; xAlarm2 : BOOL; xWarning : BOOL; iNrOfAlarmsInAlarmList : INT; iNrOfActiveAlarmsInAlarmList : INT; paitfAlarm: POINTER TO ARRAY [0..0] OF AlarmManager.IAlarm; iAlarmIndex : INT; eAlarmState: AlarmManager.AlarmState; END_VAR IF xInit THEN xInit := FALSE; fbAlarmManagerClientAll.m_itfAlarmFilterCriteria := fbAlarmFilterCriteriaAll; // register alarm client to get updated about alarm status / changes udiResult := AlarmManager.g_AlarmHandler.RegisterClient(itfAlarmManagerClientAll, 0, 0); END_IF // Polling the number of alarms udiResult := AlarmManager.g_AlarmHandler.GetActiveAlarms(itfAlarmManagerClientAll, parritfActiveAlarms => paitfAlarm, iCountActiveAlarms => iNrOfAlarmsInAlarmList); iAlarmIndex := 0; iNrOfActiveAlarmsInAlarmList := 0; WHILE iAlarmIndex < iNrOfAlarmsInAlarmList DO eAlarmState := paitfAlarm^[iAlarmIndex].GetState(); IF eAlarmState = AlarmManager.AlarmState.Active OR eAlarmState = AlarmManager.AlarmState.ActiveAcknowledged THEN iNrOfActiveAlarmsInAlarmList := iNrOfActiveAlarmsInAlarmList + 1; END_IF iAlarmIndex := iAlarmIndex + 1; END_WHILE
Last updated: 2025-04-23

Post by mondinmr on Unexpected behavior in cyclic encoder read method during INT overflow (wrap-around) ^{CODESYS Forge talk (Post)}
Hi everyone, I’m investigating a potential issue with a cyclic method we use for reading incremental encoders in our libraries. I’ve come across two implementations that, at first glance, appear to perform the same operation: motionUnit.vlPositionActualValue is UINT due strange encoder type. Version A METHOD PROTECTED cyclicReadField VAR_INST actPosFieldOld: INT; rI: INT; delta: INT; END_VAR rI := TO_INT(motionUnit.vlPositionActualValue); delta := rI - actPosFieldOld; m_actPosRaw := m_actPosRaw + TO_LREAL(delta); actPosFieldOld := rI; IF settings.velocityFeebackMapped THEN m_actVelRaw := TO_LREAL(motionUnit.velocityActualValue); END_IF Version B METHOD PROTECTED cyclicReadField VAR_INST actPosFieldOld: INT; END_VAR m_actPosRaw := m_actPosRaw + TO_LREAL(TO_INT(motionUnit.vlPositionActualValue) - actPosFieldOld); actPosFieldOld := TO_INT(motionUnit.vlPositionActualValue); IF settings.velocityFeebackMapped THEN m_actVelRaw := TO_LREAL(motionUnit.velocityActualValue); END_IF Both use INT and the same delta logic, so they seem equivalent. However, when an overflow (wrap-around) occurs, version A continues correctly as expected, while version B unexpectedly resets to -32768 without a clear reason. Has anyone experienced similar behavior or can shed light on what might be happening here? It almost seems as if the cast to LREAL is being applied before the calculation — but that would be illogical and potentially very dangerous in many situations! Thanks!
Last updated: 2025-05-13

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 duvanmoreno24 on Modbus writing on value change ^{CODESYS Forge talk (Post)}
Yes, I tried to do what you put in the first code. However, I have a problem with that and that is that the inputs must be declared with the type. I have many data types running in my code (real, int, uint, bool) and I can't put them in the same function, another thing is that I need to instantiate that function for everything I want to write to the slave. You put a for to 200 but it means that it has to be the same data type and inside the array, but I want to get them individually. I'm struggling to do it in a good and efficient way like wago's E-cockpit does. in the first screenshot you can see, you simply type in value, change the package of things you want to write in value change and it does everything by itself automatically, without comparing any old and new values and even less having the need to activate a bool. , it is perfect.
Last updated: 2024-04-03

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 szotyi on Array of Program ^{CODESYS Forge talk (Post)}
Hi! What is the proper and the easiest way to call programs through looping of array of programs, or pointer of program? instead of calling the programs one by one: prog1(inputX: 11); prog2(inputY: 12); prog3(inputZ: 13); similar like: VAR programsToCall : ARRAY [1..3] OF PROGRAM; END_VAR programsToCall[1] := prog1(inputX: 11); programsToCall[2] := prog2(inputY: 12); programsToCall[3] := prog3(inputZ: 13); FOR i := 1 TO 3 DO programsToCall[i] (); END_FOR Thanks.
Last updated: 2024-08-28

Post by imdatatas on Problem of assigning physical addresses to variables of type ARRAY OF ARRAY as MW and QW ^{CODESYS Forge talk (Post)}
Hello, I am encountering an interesting problem as below in SP20patch5 variable definition area. I think this is a bug. As can be seen in the attached screenshot, it assigns the same %MW or %QW address to all elements of the array. I hope Codesys team can solve this problem in the next version. Best regards, Imdat
Last updated: 2025-03-17

Post by rodberna on Library for arrays ^{CODESYS Forge talk (Post)}
Hi, I'm creating a program where I need to handle arrays, like: - Declare lenght variable arrays - [array(1..var) of "sometype"]. This is not possible in pure codesys, right? - Know array lenght, min, max, avg values in runtime - append/delete itens in an array - and so on Is there a library know for this in codesys. Is it possible to build our own libraries using some high level language like python or java script?
Last updated: 2024-01-10

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