Post by trusty-squire on Read "Homed" status from EtherCAT drive ^{CODESYS Forge talk (Post)}
Hi, Is there a way to read the homed status from the EtherCAT drive directly? I am currently flagging the homed status on the succesful completion of the MC_Home function block, but I have had false triggers where the drive didn't actually execute the homing procedure but the MC_Home FB is marked as complete without error. I looked at other MC/SMC function blocks but the closest I can find is the "Homing" bit from MC_ReadStatus FB, but this doesn't show if the drive is succesfully homed, only that it's homing. Any guidance is welcome. Thanks!
Last updated: 2025-01-07

Post by elsmart on Sequential read and triggering of Modbs RTU channels in application ^{CODESYS Forge talk (Post)}
Hello I need some help understanding how to use Modbus RTU (COM port) in Codesys enviroment. I defined a Modbus Server device (slave) in device tree and added some channels to read from (function 3). Also I set trigering mode to Application. I have a POU in which I want to trigger each channel one after the other something like this (C code for better visualisation): for (int i = 0; i < channelsCount; i++) { triggerChannel(channelsArray[i]); // Start transmission while(channel.xBusy); // Wait for transmission to complete } I have found ModbusChannel function block documentation but examples are scarce. I don't understand how rising edge triggering works. What would be the best solution for achieving sequntial channel triggering? What is the common way to read multiple Modbus channels once every time a specified POU is executed?
Last updated: 2025-05-16

Post by qkkk on Device Scan ^{CODESYS Forge talk (Post)}
Hello all, I have developed a custom I/O driver in CODESYS that communicates via a Unix Domain Socket. In my DeviceDescription.xml, I have set up the following: <scan supported="true"> <scanfbinstance fbname="IOScanDevice"> The goal is to allow the user to scan for connected I/O modules from the CODESYS GUI ("Scan for Devices") and automatically populate the device tree with detected submodules.</scanfbinstance></scan> The function block IOScanDevice is implemented in the driver library and added to the main device's FB instances. However, when I initiate the scan from the GUI, nothing appears to happen the function is not executed. Is there an example project or driver (open source or from CODESYS Forge) that demonstrates a working custom scan implementation?
Last updated: 2025-05-26

Post by jbcregen on Accessing parameters from a structure or function block with the web interface ^{CODESYS Forge talk (Post)}
I have a project with hundreds of OPC-UA variables available on the network. A lot of these variables are used actively in various scripts that run in background in the OS (Linux). I'm experimenting with Automation Server and I have a hard time understanding how the web interface populates its parameters list for a given PLC (<plc details="" parameters="" for="" plc="" 'xyz'="">).</plc> In this page, it looks like the only variables available are the ones that are of a "base" type : bool, TIME, String, INT, etc. All the variables that are nested into function blocks or structures are not available in the web interface, even if they are available to any OPC-UA client. Is this a limitation of the Automation Server or is there something that can be done in Codesys?
Last updated: 2025-12-01

Post by fefefede on Get the numer of day ^{CODESYS Forge talk (Post)}
Hello i tro to create a program to turn on or off the air condition in relationship temperature and numer of day. I can't get the number of day. I try this after installing SysTime library but this not work and have this error on debug ------ Build started: Application: Device.Sim.Device.Application ------- Typify code... Generate code... [ERROR] giorno_accensione_aria: PLC_PRG Device: PLC Logic: Application: C0032: Cannot convert type 'Unknown type: 'SysTimeCore(TRUE)'' to type 'TIME' [ERROR] giorno_accensione_aria: PLC_PRG Device: PLC Logic: Application: C0035: Program name, function or function block instance expected instead of 'SysTimeCore' [ERROR] giorno_accensione_aria: PLC_PRG Device: PLC Logic: Application: C0032: Cannot convert type 'Unknown type: 'DayOfWeek(CurrentTime)'' to type 'INT' [ERROR] giorno_accensione_aria: PLC_PRG Device: PLC Logic: Application: C0035: Program name, function or function block instance expected instead of 'DayOfWeek' [INFORMATION] giorno_accensione_aria: PLC_PRG Device: PLC Logic: Application: C0181: Related position Build complete -- 4 errors, 0 warnings : No download possible PROGRAM PLC_PRG VAR Temperatura: UDINT; AriaCondizionata: BOOL := FALSE; CurrentDayOfWeek: INT; //Variabile Giorno CurrentTime: TIME; GiornoDellaSettimana: INT; DayOfWeek: INT; END_VAR CurrentTime := SysTimeCore(TRUE); // Ottieni l'ora corrente CurrentDayOfWeek := DayOfWeek(CurrentTime); CASE GiornoDellaSettimana OF 1: // Azioni per Lunedì 2: // Martedì se più 10° accend altrimenti spegni IF Temperatura >= 10 THEN AriaCondizionata := TRUE; ELSE AriaCondizionata := FALSE; END_IF 3: // Mercoledì se più di 50° accendi altrimenti spegni IF Temperatura >=50 THEN AriaCondizionata := TRUE; ELSE AriaCondizionata := FALSE; END_IF 4: // Giovedì se più di 40° accendi altrimenti spegni IF Temperatura >=40 THEN AriaCondizionata := TRUE; ELSE AriaCondizionata := FALSE; END_IF 5: // Venerdì se più di 50° accendi altrimenti spegni IF Temperatura >=50 THEN AriaCondizionata := TRUE; ELSE AriaCondizionata := FALSE; END_IF 6: // Sabato se più di 25° accendi altrimenti spegni IF Temperatura >=25 THEN AriaCondizionata := TRUE; ELSE AriaCondizionata := FALSE; END_IF 7: // Domenica sempre spenta AriaCondizionata := FALSE; END_CASE
Last updated: 2023-09-14

Post by opineiro on Stack overflow with really simple function ^{CODESYS Forge talk (Post)}
Hi, I have an issue with a function which sends a message through API Rest. I'm using a function from httpCLient library. I have tested this function inside a program and it works fine. But when I want to use it inside a function (so I can call it simultaneously from 2 different points on the main program) it gives a stack overflow error. In detail it says: "C0297 Stack Overflow on Main Task. Stack sizes... Call hierarchy:" I have simplified as much as I can the function, but I'm hitting a wall with this. Anybody has an idea of what's wrong? Thanks!
Last updated: 2024-09-16

Post by thecolonel26 on How to use FB_Init with nested Function Blocks? ^{CODESYS Forge talk (Post)}
Delete ME
Last updated: 2023-08-31

Post by mubeta on Strange problem with the ‘MC_SetPosition’ function ^{CODESYS Forge talk (Post)}
No errors in any condition. The function terminate correctly with the 'done' bit. Now I leave the machine and I don't know when I will be there again. The assumption you made I had considered. The operational limits of the axis are all fit for purpose, and this function should operate virtually without even noticing the motion limits. In fact in practice with the axis at low speed the function corrects any numerical value of the position in the range 0 ... 360° without any problem whatsoever in a single PLC scan cycle.
Last updated: 2025-01-10

Post by schnepper on Minor UI bug: cannot create SFC POU after creating a Function POU ^{CODESYS Forge talk (Post)}
After creating a Function POU, it is not possible to then create an SFC POU. Steps to recreate: * Create a new Function POU. SFC is not allowed for Functions, so SFC does not show in the Implementation language dropdown. * Click Add Object -> POU... Function is selected for Type. * Select Program * SFC is not present in the Implementation language dropdown
Last updated: 2024-05-23

Post by duvanmoreno24 on Modbus writing on value change ^{CODESYS Forge talk (Post)}
Hi all, I want to know if someone has an idea of how I can write on value change in Modbus Codesys. I have a Wago PLC and I was used to work with E-cockpit which it was quite easy to do that without the necessity to trigger any value when there was a change in the variable ( I will put how easy is ). how you can see just changing the trigger in "On value Change" will do that channel writing automatically when It detects a change in those arrays. On the other hand, in Codesys if I enable the rising edge in Codesys It ask me to put a bool variable and if triggers is going to write that value. That is making me that I have to create a function or a logic to detect the change, the problem I have is that doing that is very tedious. I first approach I got it was to create a Function who returns a bool when the value change, but I tried to keep the old value but what is happening is that in Functions all the data is erased every cycle so I can not keep any Old value. so in the Main program the trigger is going to be TRUE all the time due, the old value is cero every cycle. The second approach I got it was using a function Block (POU_1) and it works but I dont want to instance that function for every Channel or value that I want to check if the value change, Basically if I have 200 values to write trhough modbus I have to create 200 instances of that function which I think it is not practicall at all. It should be a better way to implement this as e-Cockpit from Wago Does. However, I haven't been able to know how.
Last updated: 2024-03-26

Post by tk096 on Some 'pathetic' errors in SoftMotion program ^{CODESYS Forge talk (Post)}
Meanwhile, I would like to understand why the motion FB instances must still be called even after the Execute is set to FALSE, especially in view of the fact that the next instruction is programmed to abort the previous one, with BufferMode set to 'Aborting'. All these unnecessary FB calls are an unnecessary overhead on the CPU anyway. Is there any precise rule about when to cease calling the various instances? (It should precisely be the 'done' status that says this one has finished its work). In general: - Motion function blocks have to be called until they report 'Done', 'Error', 'CommandAborted' or a subsequent motion FB with BufferMode=Aborting is started in the current cycle. - Setting the Execute input to FALSE will not abort any ongoing motion of the motion function block. For example, one case that is often problematic is the execution of the Axis Halt instruction. When, after a MoveAbosulte instruction this returns the event as 'done' and indeed the axis is in standstill, the state machine first sets the move instruction to FALSE, and the next cycle sets the Halt request to TRUE. Some of the time everything works out fine. Occasionally, however, in this exchange, the axis goes into fault, also losing the OPERATIONAL state. I think the error SMC_FB_WASNT_CALLED_DURING_MOTION is only a follow-up (and misleading) error that results from the axis not being in operational state anymore (bus problems). Is there an error 'regulator or start not set' in the device log before the error 'motion generating FB wasn't called for at least one cycle'? Which error does the respective function block (Halt.ErrorId) report?
Last updated: 2024-07-22

Post by timvh on Get Alarm status in Codesys ^{CODESYS Forge talk (Post)}
You are right, that you can use the GetState method, but it is not that simple. You first have to get a list of (filtered) alarms from the AlarmManager. You can find an example in Forge how to do this. See https://forge.codesys.com/prj/codesys-example/alarm-manager/home/Home/ Then you can go through this list to get the state of all the (filtered) alarms. See below the code which you could use. This is all based on the example from forge. Create a program: // This example shows how to access alarms via structured text. PROGRAM PLC_PRG VAR xInit : BOOL := TRUE; udiResult : UDINT; fbAlarmFilterCriteriaAll : FB_AlarmFilterCriteriaAll; fbAlarmManagerClient : FB_AlarmManagerClient; itfAlarmManagerClient : IAlarmManagerClient := fbAlarmManagerClient; 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; fbAlarmManagerClient.itfAlarmFilterCriteria := fbAlarmFilterCriteriaAll; // register alarm client to get updated about alarm status / changes udiResult := AlarmManager.g_AlarmHandler.RegisterClient(itfAlarmManagerClient, 0, 0); END_IF // Polling the number of alarms udiResult := AlarmManager.g_AlarmHandler.GetActiveAlarms(itfAlarmManagerClient, 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 See below some details about the function blocks: One function block should implement the IAlarmFilterCriteria interface. This can be empty except a few methods. FUNCTION_BLOCK FB_AlarmFilterCriteriaAll IMPLEMENTS AlarmManager.IAlarmFilterCriteria Method implementation (others related to interface are empty) METHOD AreAllAlarmClassesSelected : BOOL AreAllAlarmClassesSelected := TRUE; METHOD AreAllAlarmGroupsSelected : BOOL AreAllAlarmGroupsSelected := TRUE; METHOD GetPriorityFrom : USINT GetPriorityFrom := 0; METHOD GetPriorityTo : USINT GetPriorityTo := 255; The other function block should implement IAlarmManagerClient and get a reference to the FB which implements the IAlarmFilterCriteria FUNCTION_BLOCK FB_AlarmManagerClient IMPLEMENTS AlarmManager.IAlarmManagerClient VAR_INPUT itfAlarmFilterCriteria: AlarmManager.IAlarmFilterCriteria; END_VAR Method implementation (others related to the interface are empty) METHOD GetFilterCriteria : AlarmManager.IAlarmFilterCriteria // see VAR_INPUT for filter GetFilterCriteria := itfAlarmFilterCriteria; Off course you have to add the AlarmManager to your application and add some alarms to it.
Last updated: 2025-09-02

Post by serwis on Dynamic target position tracking ^{CODESYS Forge talk (Post)}
Hello, I am trying to control a servo drive and dynamically set its position. I control the drive via EtherCAT with a cycle time of 500us. I use the MC_MoveAbsolute block for this. The problem is that when using a PID controller, I generate the positions I want the drive to move to on an ongoing basis, and I would like the position to be set immediately. The MC_MoveAbsolute block must receive a rising edge to execute, and I would like the movement to be performed without waiting for this edge. I have created a function that generates a rising edge every 1 ms, but I am unable to change this time to 500 µs because the TON function does not support times shorter than 1 ms. Below is the code to call the rising edge: IF Exe = TRUE THEN delay1(IN:=TRUE, PT:=T#1MS); IF delay1.Q = TRUE THEN Exe := FALSE; delay1(IN:=FALSE); END_IF END_IF IF Exe = FALSE THEN delay(IN:=TRUE, PT:=T#1MS); IF delay.Q = TRUE THEN Exe := TRUE; delay(IN:=FALSE); END_IF END_IF END_IF Here is the code for calling the MC_MoveAbsolute function: MoveDegree( Axis:= Tilt, Execute:= Exe, Position:= position_target - (base_angle_real * feedforward_turn), Velocity:= vel, Acceleration:= acc, Deceleration:= dec, Jerk:= jerk, Direction:= MC_DIRECTION.shortest, BufferMode:= MC_BUFFER_MODE.Aborting, Done=> , Busy=> , Active=> , CommandAborted=> , Error=> , ErrorID=> ); I realize that there are probably better methods for performing this type of task. How can I implement motion with a dynamically changing setpoint? THANKS
Last updated: 2025-09-05

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 bertoldo on Robo Scara3 ^{CODESYS Forge talk (Post)}
the interpolation block does not start from the absolute value. It returns to zero even when writing to dLastWayPosX , Y , Z.
Last updated: 2024-10-15

Post by ojz0r on Leitungsverzweigung mit einem existierenden Block (z.B. AND-Glied) zu verbinden ^{CODESYS Forge talk (Post)}
What you want is to use the CFC language instead of FB.
Last updated: 2024-11-11

Post by enricoghisla on Functional block ^{CODESYS Forge talk (Post)}
How can i access to the variable in the FB from outside without put them in the in/out?
Last updated: 2024-04-16

Post by enricoghisla on Functional block ^{CODESYS Forge talk (Post)}
How can i access to the variable in the FB from outside without put them in the in/out?
Last updated: 2024-04-16

Post by transmin01 on CANbus issue ^{CODESYS Forge talk (Post)}
Hi, I have been trying to get a CANbus device working with Codesys 3.5SP19 patch1 via a Beckhoff EL6751 gateway without success. I have the CANOpen_Manager and CANopen device configured but this will not run. Is there any code required to kickstart the CANbus comms into action? Regards Trevor
Last updated: 2023-09-13

Post by sturmghost on Specify Input Configuration "OnDialogClosed" Action to only react to certain Dialogs ^{CODESYS Forge talk (Post)}
You could work around this problem by implementing some sort of "state machine". Each dialog sets a boolean variable when they are closed so you know which dialog was closed. Then you can react to this accordingly.
Last updated: 2023-10-01

Post by nz-dave on FAILURE TO OPEN PROJECT ON ANOTHER COMPUTER ^{CODESYS Forge talk (Post)}
I have tried Achives but still get many errors. just now have tried to load a projectachive from last night and the visualization is [unknowen] as well as a action from the main pou.
Last updated: 2025-01-21

Post by yannick on Alarm Configuration Notification Action ^{CODESYS Forge talk (Post)}
Hello, I'm trying to configure an alarm variable that changes to True when an error is activated. Unfortunately, the variable is not changing to True. I'm using Codesys V3.5 SP19 Patch7 + Raspi Pi 5. Thanks.
Last updated: 2024-05-13

Post by snhatton on How to write a for loop in ladder? ^{CODESYS Forge talk (Post)}
Hi there, little late to the party, but you could also use the ST block for in-line ST code and implement a for loop as you normally would. ST Block is super handy if you just need a small amount of in-line structured text code without creating a new POU. Hope this helps!
Last updated: 2025-10-06

After un upgrade of "CODESYS Control for Raspberry Pi MC SL" from v4.7 to v4.9 SysFileOpen function stopped working ^{CODESYS Forge talk (Thread)}
After un upgrade of "CODESYS Control for Raspberry Pi MC SL" from v4.7 to v4.9 SysFileOpen function stopped working
Last updated: 2023-08-22

Post by sedoerr on Check For Open Dialogs On Client ^{CODESYS Forge talk (Post)}
You need to create a function around this function to check the dialogs you use in your program. That's the way i have done it.
Last updated: 2023-09-26

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