Post by manuknecht on Maximum dynamic limits of MC_MoveLinearAbsolute and MC_MoveLinearRelative ^{CODESYS Forge talk (Post)}
Hello all I use an axis group with two linear axes in a kinematic system. Using MC_MoveLinearAbsolute and MC_MoveLinearRelative, I am trying to realise dynamic movements (set velocity: 1 m/s, set acceleration: 30 m/s^2) with the highest possible jerk, as I want to compare this with a movement with a trapezoidal velocity profile. However, my measurements show that the axes accelerate with a maximum jerk of approx. 800 m/s^3, even if the value in the function block was set to 10,000 m/s^3. I have already increased the dynamic limits of the two axes accordingly (Velocity: 5000 u/s, Acc-/Deceleration: 250'000 u/s^2, Jerk: 100'000'000 u/s^3, where 1 u = 1 mm), but this had no effect. I have checked the input parameters of the function blocks and the VelFactor, AccFactor and JerkFactor factors are all set to the maximum (value 1). Reducing the cycle time has resulted in a higher jerk, but as we are already working with a cycle time of 1 ms, there is nothing more that can be done here. The axes themselves are still a long way from drawing the maximum current, which is why I assume that this should not be a problem either. Are there other factors or parameters that influence the dynamic limits and therefore allow faster movements? The PLC I am using is a Raspberry Pi 4 and Codesys V3.5 SP20 with all libraries up to date. Thanks in advance Manuel
Last updated: 2024-05-08

Post by mubeta on Some 'pathetic' errors in SoftMotion program ^{CODESYS Forge talk (Post)}
Hello everyone, I have a very simple program for the process, but it's driving me crazy and I can't see the problems I'm left with: Short topological description: Dual Core Berghof controller with softmotion runtime version 3.5.19.30; Two axes with servodrive on canopen bus, clocked distributed from master; Ethercat I/O node; 2 ms ethercat task, 2 ms canopen bus cycle time; I/O objects of the canopen master and canopen drives connected to the ethercat task cycle; Problem 1: Two separate programs each manage their own axis and drive, with separate state machines. A first axis moves primarily in velocity, except having to position itself absolutely at a predetermined point at the end of the job; the second axis, on the other hand, is a paper unwinder that changes, for each job cycle, from actions in absolute, relative, and cam displacement with the master axis. Well, the state machine of both axes was written in such a way as to call running the useful FB and change it on state change in this way: CASE i_stateMachine OF 0: o_Power(Enable := TRUE, bRegulatorOn := FALSE, bDriveStart := FALSE, Axis := o_PaperUnwinderAxis); o_MoveAbs(Execute := FALSE, Axis := o_PaperUnwinderAxis); o_MoveRel(Execute := FALSE, Axis := o_PaperUnwinderAxis); o_CamSelect(Execute := FALSE, Master := o_MachineAxis, Slave := o_PaperUnwinderAxis, CamTable := cam_PaperUnwinder); o_CamIn(Execute := FALSE, Master := MachineEncoder, Slave := o_PaperUnwinderAxis); o_CamOut(Execute := FALSE, Slave := o_PaperUnwinderAxis); o_SetPosition(Execute := FALSE, Axis := o_PaperUnwinderAxis); IF ... THEN i_StateMachine := 10; END_IF; 10: o_Power( Enable := TRUE, bRegulatorOn := TRUE, bDriveStart := TRUE, Axis := o_PaperUnwinderAxis ); IF o_Power.Status THEN i_StateMachine := 20; END_IF; 20: (* Avanzamento carta *) o_MoveAbs( Execute := TRUE, Position := o_Somewhere, Velocity := 25.0, Acceleration := 3666.7, Deceleration := 3666.7, Jerk := 48000.0, Direction := MC_DIRECTION.positive, Axis := o_PaperUnwinderAxis ); IF o_MoveAbs.Done THEN o_MoveAbs(Execute := FALSE, Axis := o_PaperUnwinderAxis); i_StateMachine := 30; END_IF 30: d_HomingPosition := ...; o_SetPosition( Execute := TRUE, Position := d_HomingPosition, Mode := FALSE, Axis := o_PaperUnwinderAxis ); (* ... *) IF o_SetPosition.Done = TRUE THEN o_SetPosition(Execute := FALSE, Axis := o_PaperUnwinderAxis ); o_LogServer.Append(sMessage := '...', lscClass := LOGSERVER_CLASS.ALWAYS, sdt := o_CommonsMgrData.systime.sdtLocal); i_StateMachine := 40; END_IF; 50: ... The code above is a sketchy example of what I wanted to write. But it gives me a spot problem: in some, the state change results in a drive error, which is unrecoverable except with a reinitialization via SM3_ReinitDrive(). Things are improved a little if in the program I always run the call of all softmotion blocks in this way: o_Power(Axis := o_PaperUnwinderAxis); o_Jog(Axis := o_PaperUnwinderAxis); o_Halt(Axis := o_PaperUnwinderAxis); o_MoveAbs(Axis := o_PaperUnwinderAxis); o_MoveRel(Axis := o_PaperUnwinderAxis); o_CamIn(Master := MachineEncoder, Slave := o_PaperUnwinderAxis); o_CamOut(Slave := o_PaperUnwinderAxis); If I don't execute all the calls of all the motion FBs used, when exchanging machine state often (but not always), the axis goes into error with event id THE_FB_WASNT_CALL... Done a little diagnostics it seems that the FBs return the bDone, before they are completely terminated. I tried doing the machine state exchange not with the bDone bit of the FBs, but with the 'standstill' state of the axis. It didn't seem to change anything. Problem 2: During the use SM3_ReinitDrive() I get the erro in the log: "NetID 0: SDO read error for object 16#607C..." Assuming that the device involved it's one of the two servodrive, (no others device are present in the network), I don't found any object 0x607C in the 'possible object list in/out' of the two drive, and I don't understand where this object can be listed. So any ideas and suggestions regarding these two issues will be very, very welcome. If you need the source project, I am willing to send it.
Last updated: 2024-07-17

Post by ryandmg on Web Client (HMI) Disconnects from Webvisu (Weidmuller u-OS) ^{CODESYS Forge talk (Post)}
Thanks So Much for the reply! Were using the Weidmuller UV66-ADV-10-CAP-W The HMI is pointed to the URL which is assigned through u-OS. Basically when you log into the controller's webserver via browser you can view the installed apps. One of which is the Codesys runtime. When you click on that it takes you to the visualization. That corresponding url is what the HMI is looking for. I apologize I don't have that on hand as I'm in the office right now. I don't think I tried connecting using the port you mentioned and https in lieu of the u_OS URL. I can certainly try. Out of the box the u-OS is set for HTTP. Since we're isolated I havent changed that yet. When this has happened while logged on via chrome on my laptop, simply refreshing brings the visualization right back. In the case of the HMI in kiosk mode, we power cycle the HMI to force a reconnect, log back in u-OS and the visualization is back.
Last updated: 2023-09-06

Post by danwoodlock on RPI Zero w - Edge gateway cant install ^{CODESYS Forge talk (Post)}
Hello all, First post. I recently acquired an RPI zero W from amazon, and have been using it with Codesys v3.5 SP19 patch 2. I first got it working yesterday, and after installing the runtime on the Pi, I was prompted to install the edge gateway. Installation of the edge gateway failed because of unsupported architecture, undeterred I was able to connect to the pi and program as I wanted. The issue I've noticed is that if I do not load anything to the pi overnight, I can then no longer connect to the pi and download, although I can still ping it from my pc. I found that if I power cycle the PI, I am then able to connect again, and it works as normal. I did some googling and found instances where people recommended downloading the newest edge gateway, which brings me here. Wondering if there are any suggestions, or if this is a known issue. I actually tried installing all 3 versions of edge gateway for science, but all fail with the same message. Thanks -Dan
Last updated: 2023-09-13

Post by sturmghost on Initialization of visualization variables and cyclic code execution ^{CODESYS Forge talk (Post)}
I'm looking for a smart and short way to implement initialization of visualization variables depending on the visualization input. For an easy example consider a rectangle which rests at XPos := 0 when the input state is false and at XPos := 50 when the input state is true. My visualization variables look like this: VAR_IN_OUT State : BOOL; END_VAR VAR XPos : INT; END_VAR I put this rectangle via a visualization frame element into another visualization and link a frame reference variable with the state to it. If the variable is true, the rectangle should rest at XPos := 50 and false at XPos := 0 at visualization init but how should I assign the 50 or 0 to the internal visualization variable XPos? I would need some init-methode for the visualization but I dont want a global init-method for such tasks. I want to do it inside of the visualization element but I can't see any solution for this? It would be good to be able to define ST-code within the visualization element which runs cyclic at each VISU_TASK task-cycle then I could just check the input state and change the XPos accordingly. Does someone have a solution?
Last updated: 2023-10-01

Post by martinlithlith on Mux I2C ^{CODESYS Forge talk (Post)}
Hi! I´ll try to get this thread going again as i´m having simliar problems. Right now i get a red triangle on my connected devices (i´m testing with a BME280 sensor and a PCA9685 resvo driver). The TCA9548 have the green symbol beside it. On the "red" devices i get that the bus is not running. I have tried to either run it using the parent bus cycle setting or creating a new freewheeling task prio 1 but nothing helps. I have compared my settings to the settings from the example from the MUX package and i have read (i think) every thread in forge that could be of interest. EDIT: The ic2detect only shows the mux (70-70) and the servo drive (70-76) so i´ll look in to if i managed to burn the 280-sensor while soldering). Another question regarding the 280 sensor. I have a sensor GY-BM E/P 280 that should record humidity and temperatur. Could this be a problem with the library? Does anyone have an idea of what i might be doing wrong? I have some experience from Codesys but not much so this could be an easy one. All suggestions are welcome. I tried to upload the project archive but it did not work. Should i upload the export or how could i show you my horrible project? Best, Martin
Last updated: 2023-10-22

Post by riccardo on VisuElems.CurrentUserGroupId is not stable ^{CODESYS Forge talk (Post)}
GoodMorning everyone. I have a system that, in case of alarm, have to block. When the operator logs in must have to acknoledge the alarm and should operate in the system freely. To perform this I detect the logged User by (VisuElems.CurrentUserGroupID <> 0) with a similar code to the the following: PROGRAM AlarmMngt VAR alarm : BOOL:= FALSE; Ack : BOOL:= TRUE; PushBottonOpening : BOOL:= FALSE; Valve : BOOL := FALSE; Flag: BOOL := FALSE; END_VAR IF alarm AND Ack AND (NOT Flag) THEN valve := FALSE; PushBottonOpening := FALSE; Ack := FALSE flag := TRUE; ELSIF (NOT alarm) AND Ack THEN flag := FALSE; END_IF (* if the system is in alarm but there is a logged operator that acknowledge the alarm the system allows the valve opening.*) IF (VisuElems.CurrentUserGroupID <> 0) AND Ack AND Alarm AND PushBottonOpening THEN Valve := TRUE; ELSIF (VisuElems.CurrentUserGroupID = 0) AND Alarm THEN valve := FALSE; END_IF The problem I have is in the last 5 lines of the code: Even if there is a logged in user, the GroupID variable is subjected to a refresh that cyclically set for an instant it to 0 and this close the valve making difficult to the user to work Now I solved it creating a time hysteresys cycle but it is not a good solution. Someone is able to explane me why the GroupID variable is sobjected to this refresh and how to stabilize to avoiding it? Thank you in advance, Riccardo
Last updated: 2023-11-10

Post by open on How to create a stopwatch? ^{CODESYS Forge talk (Post)}
Hi @ph0010421, I tried the program the TimeTaken is calculated when stop is triggered. I want the TimeTaken to be continuously calculated and counting when a BOOL variable is true. I tried to program this way: Declaration: PROGRAM PLC_PRG VAR bStartStop: BOOL := FALSE; // Start/Stop button bReset: BOOL := FALSE; // Reset button bRunning: BOOL := FALSE; // Flag indicating whether the stopwatch is running tStartTime: TIME; // Variable to store the start time tElapsedTime: TIME; // Variable to store the elapsed time END_VAR Implementation: // Main program logic IF bReset THEN // Reset button pressed, reset the stopwatch bRunning := FALSE; tElapsedTime := T#0s; ELSIF bStartStop THEN // Start/Stop button pressed, toggle the running state IF bRunning THEN // Stop the stopwatch bRunning := FALSE; ELSE // Start the stopwatch bRunning := TRUE; tStartTime := tElapsedTime; END_IF; END_IF // Update the elapsed time when the stopwatch is running IF bRunning THEN tElapsedTime := tElapsedTime + T#1s; // Adjust the time increment as needed END_IF However counting of the seconds is not accurate. I tried changing the main task cycle time interval to 1000ms. The counting of seconds become slower. (see attached) Please help
Last updated: 2023-12-08

Post by trusty-squire on Confused by dwIpoTime input for SMC_Interpolator ^{CODESYS Forge talk (Post)}
Hi, Learning Codesys CNC, and I am confused by the dwIpoTime parameter. I have a basic demo application, using SMC_Interpolator feeding into SMC_TRAFO_Gantry2Tool2, which then sets the position of the x/y SM_Drive_Virtual axis. I also have a C axis which revolves the tool, which is controlled using a simple tangential angle calculation SMC_CalcDirectionFromVector. The GCode I'm using has feed/accel set at 500. The axis configuration limits are well above that (2000). What's strange is that, when I run the simulation, the feed speed changes drastically when I update the variable dwIpoTime. The larger the number, the faster it moves. What's going on here? The documentation only says "This variable has to be set for each call. It represents the cycle time in μsec." Why does it change the feed speed I'm seeing the in simulation? What is a good number to use? The example I was looking at set it at 5000. Screenshot attached.
Last updated: 2024-07-18

Post by edvard-munch on How I can get "Done flag" for "Modbus Slave Channel"? ^{CODESYS Forge talk (Post)}
This is from 10 years ago, I know. But I have been using (SLAVE_DEVICE.iChannelIndex = CHANNEL_NUMBER) AND (SLAVE_DEVICE.xDone) I suppose that it shows xDone for the channel that shows up in the iChannelIndex at the same cycle? It seems to be working properly for two devices that I have been using it before But now I have another device and using two write channels, for one register each. One channel works properly and returns DONE flag When another channel is triggered, I see that it shows up in iChannelIndex, but flag DONE not received, but no Error for the channel. Also, when i check the register in the device it's evident that data has been transferred. Is this could happen sometimes with CODESYS, so DONE flag not received? Or this is a problem with a given device? With this certain register
Last updated: 2024-12-19

Post by mondinmr on Direct Pointers in IOMapping for EtherCAT with IoDrvEthercatLib.ETCSlave_Dia ^{CODESYS Forge talk (Post)}
Using SDO, I can read the EtherCAT mappings and offsets from various registers like 0x1c12, 0x1c13, etc. When I obtain registers mapped in the PDOs and various offsets, I could technically access directly to the statusword, controlword, etc., if they are mapped. I have noticed that on IoDrvEthercatLib.ETCSlave_Diag I can find pointers to the input and output buffers. However, although the input buffer can be easily read by referring to what has been obtained from the SDOs, it is not possible to write to the output buffer, as it is overwritten in each cycle by the data from the IOMapping task. Is there a way, knowing an instance of IoDrvEthercatLib.ETCSlave_Diag, to obtain the pointer to the first data in the IOMapping? The offsets are identical to those of the PDOs, but obviously the data is a copy. For me, the cleanest thing would be to access the pointers on IOMapping, for DS402a devices to retrieve the key data and point them to internal references. I need to know this as, having developed our own motion library, I would like to simplify the initial setup by eliminating unnecessary and nonsensical mappings that can lead users to unnecessary errors. In the current version that we have been using for years, we have to map everything manually. I would like to pass only the slave reference to the FB_init constructors and eliminate the mapping.
Last updated: 2024-02-12

Post by rmaas on Fieldbus has lost synchronicity ^{CODESYS Forge talk (Post)}
Hi, On a gantry system with 2 axis i am getting the following error: SMC_DI_FIELDBUS_LOST_SYNCRONICITY This happens random, sometimes it happens every 5 minutes and sometimes no error for 2 hours... The Setup: - Using codesys 3.5 SP20 with all latest libs... - Kontron AL Pi-Tron CM4 with Preempt realtime patch (Raspberry Pi 4) - Codesys runtime 4.11.0.0 (single core) - CODESYS Control for Raspberry Pi SL licensed - Softmotion + CNC + Robotics licensed - 2x Leadshine EL8-EC400 servo drives - Axis group for a 2-axis T-Gantry Ethercat network wiring: Ethercat master softmotion -> Beckhoff EK1100 -> Servo drive #1 -> Servo drive #2 Ethercat Cycle time = 4ms Max Jitter = 140~150 What i have tried so far: - changed the sync offset from 20% to 30% - changed ethercat task priority from 1 to 0 Running tasks: - Ethercat tast: Prio = 0, Interval = 4ms - Main task: Prio = 1, Interval = 8ms - Visu task: Prio = 31, Interval = 100ms - Softmotion planning task: Prio = 15, Freewheeling - 3 other default tasks that were created by AC_Persist Motion fb's are called in the ethercat task... Does anyone have an idea how to fix this? Any help is greatly appreciated!
Last updated: 2024-04-11

Post by mp9876 on Problem using MeasureFrequence FB ^{CODESYS Forge talk (Post)}
Hi everyone, new at Codesys and PLC programming in general. I am using Codesys Win V3.5 SP20 I would like to measure an encoder's frequency output (obtaining that pulse train from Factory IO) and intended to use the MeasureFrequence FB (Intern/CAA/Utilities/CAA Mathematics/3.5.19.0). As mentioned in the title what I need to measure is low frequency, such as lower than 40hz (a cycle every 25mS) or so; I could even go lower frequency if required as this is for test purposes) therefore I am not expecting problem measuring a low frequency with that FB The library in question appears to be installed as I can retrieve it from the Library Repository. I can also see it from the Device's Library Manager. Problem arises when I am trying to instantiate this particular FB. I go like this: VAR MeasF:MeasureFrequence; END_VAR Please note that as soon as I start typing the "MeasureFrequence", the MeasureFrequence comes out as a viable option in auto-typing; seems to indicate that the FB is recognized somehow. But there is no way I can compile this as it comes back with the following: C0046: Identifier 'MeasureFrequence' not defined. Tried to rename that to ABC instead of MeasF; same issue. Possibly that the library is not properly installed ? Placeholder ? I would greatly appreciate a bit of guidance if possible. Thank you and regards, Mike
Last updated: 2024-06-24

Post by jonasz on Deploy LicenseServer for Linux SL ^{CODESYS Forge talk (Post)}
Good morning, I'm digging into this topic because I'm curious about resolving my problem in a test environment. In my previous message, I asked about the CODESYS Safe Timeprovider SL package (4.18.0.0), which I saw in the illustration. I noticed that it runs as a service. I am asking about this because from the perspective of an "ordinary" user, this service provides easier access to the settings of the time provider's operating parameters. The basic time provider configuration is outlined at https://content.helpme-codesys.com/en/CODESYS%20Control/_rtsl_virtual_safe_time_provider.html. Why my questions? They stem from my specific case, which is experiencing timeout issues. I know that my environment is currently only a test environment. I'm assuming a real-world scenario in which I won't be able to achieve a better result with my configuration, and I will ultimately need to increase the time provider's cycle time. By running the time provider service, I can easily influence the time provider's operation and thus eliminate the problem. I know, I know, safety systems are not life-enhancing extras.
Last updated: 2025-11-19

Post by mrkm-dic on CODESYS: Combining Master Redundancy with EtherCAT Ring Topology – Is it Supported? ^{CODESYS Forge talk (Post)}
Hello, I would like to ask whether it is technically supported (and practically achievable) to combine CODESYS Master Redundancy with EtherCAT ring (loop) redundancy in the same system. System setup CODESYS version: CODESYS 3.5.21.40 CODESYS Control SL for Weidmuller u-OS-4.12.2.0 Controllers (Masters): Weidmuller UC20-M4000 ×2, configured as Active / Standby using CODESYS redundancy EtherCAT Slaves: Weidmuller UR20-FBC-EC ×3, supporting EtherCAT ring / line break detection Topology: EtherCAT ring (loop) Main question Is it officially supported to use: ・CODESYS PLC/Master redundancy (Active/Standby) and ・EtherCAT ring topology (for cable redundancy) at the same time? Expected behavior Our expectation is: ・When the Active PLC fails, the Standby PLC becomes Active ・The Standby PLC then takes over the role of EtherCAT Master ・EtherCAT communication is re-established ・I/O control continues after reinitialization (a short interruption is acceptable; no strict bumpless requirement) We do not expect completely seamless / zero-cycle switchover, but we want to understand: ・Whether this combination is supported by design ・Or whether there are known limitations or restrictions when EtherCAT ring mode is used together with Master redundancy Clarification At this stage, the question is mainly about feasibility and support, not about a specific error message yet. Any official guidance, limitations, or real-world experience would be greatly appreciated. Thank you in advance.
Last updated: 2026-02-05

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 mubeta on Some 'pathetic' errors in SoftMotion program ^{CODESYS Forge talk (Post)}
Yes, this is the error the sometimes show up. What make me crazy is the fact that it happens randomly and not each times. I know very well where the problem is, in wich one program row it's located. For each actions of the state machine I have all events recorded with log on text file. it is not problematic for me to find the application point of the fault, but I need to understand why occasionally and for no apparent reason, switching the state machine and thus changing the motion FB, sends the axis into failure (but only occasionally). 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. 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).
Last updated: 2024-07-18

Post by akrawczyk on Dynamically enabling/disabling Modbus slave devices in runtime (performance issue with timeouts) ^{CODESYS Forge talk (Post)}
Hi everyone, I'm working on a CODESYS-based project running on a Weintek cMT2078X HMI with a built-in CODESYS runtime. The system communicates with multiple Modbus RTU slave devices, arranged in a cascade. The number of connected units can vary between 2 and 8, depending on the installation. Each slave has 17 Modbus channels, which are polled cyclically every 5 seconds. The issue is that when fewer devices are physically connected (e.g. only 3 out of 8), the Modbus master still attempts to communicate with all configured slaves. This leads to massive delays due to timeouts (currently 200ms per channel). For one disconnected device, that’s: 17 × 200ms = 3.4 seconds of delay per polling cycle, and this quickly multiplies with each additional missing slave. This behavior significantly degrades the system's performance and responsiveness. We attempted a workaround where we tried to trigger polling based on a variable in the PLC program, but this caused instability and even led to hardware hangs/freezes on the cMT2078X – likely due to clashes in how the Modbus polling engine and program logic interact at runtime. My main questions are: Is there a way in CODESYS to dynamically enable/disable Modbus slave devices at runtime, using a BOOL or INT variable (e.g. indicating number of active slaves)? Can devices or channels be conditionally polled or temporarily disabled without removing them from the device tree? Are there any best practices or examples for handling variable numbers of Modbus slaves in scalable systems like this? Would splitting communication across tasks or interfaces help reduce the impact of timeouts? Any advice, documentation references, or architectural suggestions would be extremely helpful. I'm looking for a robust way to dynamically scale slave polling without degrading system stability or performance. Thanks in advance!
Last updated: 2025-08-11

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 testlogic on Sending Sequential Modbus TCP Packets ^{CODESYS Forge talk (Post)}
I have a Modbus TCP slave device where I need to do sequential writes to the same register. The register I'm writing to is kind of like a command line, each packet is a command word encoded in Hexadecimal. I am having difficulty implementing this system in CoDeSys 3.5 SP19. I feel like the structure of the program should be something along the lines of (Pseudocode): ModbusTCPSend(Command Register, Command1) ModbusTCPSend(Command Register, Command2) ModbusTCPSend(Command Register, Command3) I have tried to implement this with a rising edge trigger wMot1OPCode := 16#E1; //Stop Motor & Kill Program xMot1SendOP := TRUE; //Send OP on rising edge xMot1SendOP := FALSE; //Reset wMot1OPCode := 16#9E; //Disable Motor xMot1SendOP :=TRUE; //Send OP on rising edge xMot1SendOP := FALSE; //Reset Where "wMot1OPCode" is the IO map for writing to the command register, and "xMot1SendOP" is the rising edge trigger for that modbus channel. However, this doesn't work. The device never responds to the modbus commands. It seems like the trigger variable is switched too quickly for modbus to send the packet. I know the modbus register is working, because I can set the channel to cyclic and the device will respond. However, I can't use this reliably because I need each command to be sent once, in order. Cyclic keeps re-sending the commands and seems like it could miss a command as well if one was sent in-between cycle time. I have also trying using the Application trigger as described by https://faq.codesys.com/pages/viewpage.action?pageId=24510480, but this is also not working for me. See attached picture for my FBD code. This seems like a simple function, I can't tell what I'm doing wrong here. Thanks for the help.
Last updated: 2024-03-06

Post by dwpessoa on CNC Jumps G20 - SMC_NCInterpreter and long time to process ^{CODESYS Forge talk (Post)}
I am studying and developing a Softmotion+CNC system for a machine that executes multiple pieces. The G code program is written by the machine operator and each cycle execute 1 piece. The programs are large, exceeding 1000 lines and using up to 8 axes (X, Y, Z, A, B, C, P and Q). The machine needs to run cyclically, executing N pieces (selected by the Operator)... so I tested it using Looping and counters (G36 G37 and G20) and it worked, but it takes a long time to process, and the more pieces I need, the longer the processing time and this is totally impracticable. I found this solution which was very good, and for a few cycles it works well, but for 99999 pieces of a program with 1000 lines, it doesn't work very well... Another solution I tested is to maintain the interpolator with an automatic restart, that is, I load the program without looping (without G20) and give it another start as soon as it finishes. This partially resolved it, but there is still a delay in processing SMC_NCInterpreter in each restart :(. Another solution I thought of is to manually create the SMC_GEOINFO structure and then reuse it, avoinding the Interpreter, but reading the documentation and checking the structure filled by standard blocks, I noticed that there doesn't seem to be a "JUMP" function in the structure! In other words, the SMC_NCInterpreter actually keeps copying and copying the program section for each jump (G20)... If I repeat a 10-line program 1000 times, I will have a structure with more than 10000 lines... possibly this is the cause of take so long to process. Has anyone ever had a problem like this? I believe the same thing happens with typical applications with manipulator robots using Codesys in continuous cycles, and I would like to know if there is any solution, or even if I am misinterpreting the G20 question in SMC_GEOINFO. Thanks!
Last updated: 2023-09-20

Post by imdatatas on MC_CamIn did not work properly with SMC_FreeEncoder on SoftMotion 4.17.0.0 ^{CODESYS Forge talk (Post)}
Hello, I am facing a problem with the new Softmotion 4.17.0.0 version. Has anyone encountered a similar problem, what is the solution? I would be happy if you could share it. Problem description: -- "SMC_FreeEncoder" encoder axis is the master, -- The motor of the servo driver on the EtherCAT bus is the slave axis. -- When the MC_CamIn block executed, the InSync output is activated. However, although the master encoder axis position value changes, there is no movement in the slave servo axis! Test steps: 1-) EtherCAT servo axis installed, configured and motion test was performed with MC_Jog. No problem. 2-) Softmotion general axis pool > SMC_FreeEncoder was added and pulse amount configuration was performed. No problem. 3-) Incremental encoder actual count value was transferred to the "SMC_FreeEncoder.diEncoderPosition" variable as DINT under the ethercat task in every cycle and the encoder axis position value was observed. No problem. 4-) A simple CAM table with a 1:1 ratio was created under the project tree. (For example: Simply, when the encoder rotates 1 turn, the motor will rotate 1 turn.) 5-) The SMC_FreeEncoder axis enabled with MC_Power and brought to the StandStill state. 6-) The MC_CamTableSelect block was run with default input values ​​(all absolute) and only the Cam table name was specified. The Done output was seen successfully. No problem. 7-) The MC_CamIn block was activated with default input values ​​(absolute) and only the master encoder axis name, slave servo axis name, CamTableID input pins was specified and then "Execute" input set to TRUE. 8-) The InSync output information of the MC_CamIn block observed as TRUE. However, although the encoder axis value changed, the position value of the slave axis did not change at all, it did not move. It always remained at 0.0mm. 9-) When I repeated the same steps above, only changing the master axis to SM_Drive_Virtual instead of FreeEncoder and gave movement to the virtual axis, this time the slave axis moved successfully. However, when the same steps and operations are performed with the same IDE just downgrade SoftMotion version from 4.17.0.0 to 4.10.0.0, everything works normally and without problems as expected in MC_CamIn block with FreeEncoder master. (By the way, The used IDE version is Codesys V3.5 SP20patch3.) Best Regards Imdat
Last updated: 2024-11-11

Post by madskaizer on Task Priority Documentation? ^{CODESYS Forge talk (Post)}
Hi All I was watching the Wago PFC300 webinar ( https://www.wago.com/global/lp-thank-you-onlineseminar-pfc-300 ), and the presenters comment about priority 1 being way above the Ethernet task priority, so that a priority 1 PLC program can actually loose SCADA connection, made me try to round up some hard evidence on Codesys Priorities. I find there is very little information on "correct" task priority configuration. There is a lot of different hardware manufacturers, using Codesys Runtime, that has different descriptions in their manuals on how to set up priority. https://doku.amk-motion.com/en/Subsystems/PDK_202975_A-Serie_en/Content/Projekt/AMKAMAC/PDK_202975_A4-A5_Produktbeschreibung/Funktionalitaet/PLC-Programming/PLC%20Tasks.htm?TocPath=PLC-Programming%7C_____7 https://product-help.schneider-electric.com/Machine%20Expert/V1.1/en/SoMProg/index.htm?#t=SoMProg%2FTask_Editor%2FTask_Editor-7.htm&rhsearch=priority&rhhlterm=priority&rhsyns=%20&SUBSTRSRCH=1 https://content.helpme-codesys.com/en/CODESYS%20Development%20System/_cds_f_task_configuration.html So my questions :) 1) If there is only 1 PLC_PRG task, does priority matter? 2) What is the priority of Ethernet / communication, if nothing is entered? 3) What is the priority of Codesys OPC UA server? 4) Some users here on forge mentions that Wago PLC programs should run as priority 11, but where does this recommendation origin from? 5) What are you recommendations for a relatively slow process, like building automation? It uses OPC UA for communication to SCADA, maybe some MODBUS-RTU and MODBUS-TCP, usually around 100 I/O, been running with everything in a single task at priority 1, 50-100ms cycle time. Some controllers have separate MODBUS tasks, but doesn't seem like a big difference. How would you recommend splitting up communication, IO fieldbus and programs into differently prioritized tasks? I know its a complex matter and all about my application, but I really miss there was just some kind of guidance in the documentations and with all new standard Codesys programs having priority 1 as default, makes it seem less important, than it really is.
Last updated: 2025-08-11

Post by gmau on Station 'xyz': AR aborted by device (alarm.ind): AR consumer DHT expired ^{CODESYS Forge talk (Post)}
Hello, I am writing to You with the problem of Profinet communication in my Codesys V2.5 SP21 project working on Codesys Control RTE V3 x64 device. I have implemented multiple Profinet devices in the network, the Profinet itself is configured properly, based on the hardware and software parameters of the industrial PC (Windows 10 IoT). My Profinet network contains such Profinet devices as a robot, IO-Link master with some devices on it, IO modules, safety, vision sensor (the configuration is attached to this topic). Once every few hours, sometimes more often, sometimes not even once a day, the error show up at one, two or a few random modules at the same time, every one is the same: "Station 'xyz': AR aborted by device (alarm.ind): AR consumer DHT expired". The communication is then lost with that module, but it is up instantly. It is not such a problem when it comes to regular IOs, but with safety or rotation table, it causes errors and machine stops. I have tried multiple solution based on any forum suggestions, manuals, etc., but it is still happening. Mabye when I turned on the Watchdog for this communication, it is happening less times, but still, I could not turning up the Watchdog parameters at the expense of cycle time of the process. The same is with Send Clock, Reduction and DHT. I have one of the ethernet port on the PC configured with CmpEt1000Drv driver. The card itself is Intel Ethernet Connection I219-LM. These devices are connected to one EKI-2728-NI-A Profinet switch (it was changed from the standard non Profinet one, but still nothing has changed). As I said ealier, I am attaching all the configurations for each device and the communication itself - if any of You had the same problems or have any ideas what could be the cause, I would be much gratefull for any help. For now I am out of ideas, if You have any additional question, please ask. Sincerely, PF
Last updated: 2025-09-04

Post by risele on dynamic modbus devices ^{CODESYS Forge talk (Post)}
Have the same issue: I'm making a test setup for modbus devices testing and calibration. One is run for every possible address, and it starts with minimal request: if the device is found, it continue to work with it, otherwise it's set to Disabled temporary. Those state machines are running under FOR cycle, and disabled are just skipped. Every instance have its own timer for not running too frequently and a start delay, so the actual requests are separate in time. I also check not for a single error, but have some timer to allow one-two timeouts. The small program disables and re-enables devices temporary (manually, since i could not iterate over MB devices). VAR Reset:ARRAY[1..GVL_MB.MD_COUNT] OF R_TRIG; i:INT; END_VAR {IF hasconstantvalue(GVL_MB.MD_COUNT, 1, >= )} i:=1; MD_1.Enable:=GVL_MB.MDPortsEnable[i]; Reset[i](CLK:=GVL_MB.MDPortsEnable[i]); MD_1.xReset:=Reset[i].Q; {END_IF} {IF hasconstantvalue(GVL_MB.MD_COUNT, 2, >= )} i:=2; MD_2.Enable:=GVL_MB.MDPortsEnable[i]; Reset[i](CLK:=GVL_MB.MDPortsEnable[i]); MD_2.xReset:=Reset[i].Q; {END_IF} There is also program to re-enable devices periodically. METHOD ScanBus VAR_INPUT END_VAR VAR j:INT; (*block auto scanning if calibration is running for any device since it's data-reach process that should not be interrupted with modbus timeouts *) CalibrationBusy:BOOL:=FALSE; END_VAR CalibrationBusy:=FALSE; FOR j:=1 TO GVL_MB.MD_COUNT DO CalibrationBusy:=CalibrationBusy OR MD_Calibrate.AutoTesters[j].xBusy; END_FOR; IF CalibrationBusy THEN RETURN; END_IF tBusScanSchedule(IN:=(NOT tBusScanSchedule.Q), PT:=tBusScanPeriod); IF (NOT tBusScanDelayer.Q) AND (tBusScanSchedule.Q OR (NOT xFirstScanPerforemed)) THEN xBusScanBusy:=TRUE; MissingCounter:=0; xFirstScanPerforemed:=TRUE; FOR j:=1 TO GVL_MB.MD_COUNT DO (* MD_Calibrate is main calibration program. Identifiers - is array of State machines mentioned above Phase_Faulted is a state of Identifiers where I'm sure device is missing on the bus *) IF MD_Calibrate.Identifiers[j].state=eStateMDIdentifier.Phase_Faulted THEN MD_Calibrate.Identifiers[j].Rescan(); MissingCounter:=MissingCounter+1; END_IF END_FOR END_IF tBusScanPauser(IN:=tBusScanDelayer.Q AND (MissingCounter>0),PT:=tBusScanDelay*MissingCounter); xBusScanBusy:=tBusScanPauser.Q; xFirstScanPerforemed:=xFirstScanPerforemed OR tBusScanPauser.ET>=tBusScanPauser.PT; Also the GUI have buttons for each address possible that re-enables the device if required.
Last updated: 2026-02-13

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