Post by rafa on MODBUS TCP SERVER DON'T AUTOMATIC STARTUP ^{CODESYS Forge talk (Post)}
Dear all, I have a project where I have two ModbusTCP communication drivers in the application. It's working normally until a power outage or the installation panel is restarted. As soon as the PLC CPU is restarted, the Ethernet port is OK, but the TCP Server displays an "UNDEFINED" error. I can't reset the error using the diagnostic confirmation or the "mbserver.xConfirmError" bit. I noticed that the error only appears in the "mbserver.byModbusError" memory and the description is "UNDEFINED." The "mbserver.xError" memory doesn't flag an error. When using the warm restart function and then START CPU, the devices return to normal operation. The following demonstration images; The main question is: How can I make devices boot automatically? Um using Codesys Version 3.5.20.30 Patch 3+ My CPU is a Weintek Cmtx Built-int - ( CMT3092x )
Last updated: 2025-07-15

Post by smeitink on Timeout Error in Modbus Communication with WAGO PFC200 and iEM2050 Meter using 750-652 Module ^{CODESYS Forge talk (Post)}
Hi all, I'm looking for help with an issue I've come across while trying to facilitate Modbus communication between a WAGO PFC200 PLC using a 750-652 communication module and an iEM2050 Series Single Phase Energy Meter. I believe to have everything wired and setup correcty, but I keep running into a "Error time out" message, and by now I don't really know what else to try. My setup is as follows: A PFC200 Wago PLC, which has 2 750-652 Serial Interfaces extension modules connected to its field bus. I'm using one of these to talk to a Schneider iEM2050 - kWh-meter over modbus. I have connected terminal 23 (A) of the iEM2050 to connector 6 (A) on the 750-652. I have connected terminal 24 (B) of the iEM2050 to connector 2 (B) of the 750-652. I'm using 200mm of twisted together wires to connected them both, and I have placed a 120 ohm resistor between A and B at both ends. I've attached relevant pinout images to this post. I then wrote a simple program that configures the Mobus port, as per the datasheet of the iEM2050. You can find an image of the relavent page attached to this post too. This is my program: PROGRAM PLC_PRG VAR Master: FbMbMasterSerial; xIsConnected: BOOL; xError: BOOL; iIndex: INT := 1; xTrigger: BOOL; utQuery : typMbQuery := ( bUnitId := 1, // The Modbus unit or slave address bFunctionCode := 4, // Function code for reading input registers uiReadAddress := 1829, // adress for the Power on off counter uiReadQuantity := 1 // Quantity of registers to read ); iStep: INT; oStatusModbus: WagoSysErrorBase.FbResult; utResponseModbus: typMbResponse; xConnect: BOOL := FALSE; delayTimer: TON; END_VAR Master( xConnect:= xConnect, I_Port:= _750_652_24_1, udiBaudrate:= 9600, usiDataBits:= 8, eParity:= WagoTypesCom.eTTYParity.Even, eStopBits:= WagoTypesCom.eTTYStopBits.One, eHandshake:= WagoTypesCom.eTTYHandshake.None, ePhysical:= WagoTypesCom.eTTYPhysicalLayer.RS485_HalfDuplex, xIsConnected=> xIsConnected, xError=> xError, oStatus=> oStatusModbus, eFrameType:= WagoAppPlcModbus.eMbFrameType.RTU, tTimeOut:= T#5S, utQuery:= utQuery, xTrigger:= xTrigger, utResponse:= utResponseModbus); delayTimer(IN := TRUE, PT := T#3S); // Use the Q output of the timer to set xConnect after the delay IF delayTimer.Q THEN xConnect := TRUE; END_IF CASE iStep OF 0: //Wacht totdat de master de poort geopend heeft IF xIsConnected THEN iStep := 1; END_IF 1: //Stuur request naar de slave xTrigger := TRUE; iStep := 2; 2: //Wacht totdat de master klaar is met het afhandelen van de request IF NOT xTrigger THEN iStep := 3; END_IF END_CASE The TON delay before opening the port is due to a an error I encountered when opening it straight away. This seems to be a bug, as described here. However, the TON solved that particular issue. I tried reading multiple registers, but like I said, I still always end up with the "Error time out". What else can I test or try at this point?
Last updated: 2024-02-24

Post by alexgooi on Modbus writing on value change ^{CODESYS Forge talk (Post)}
The way I usally tackle this is by syncing only words (then you are able to use the FB above). If you then want to write a Boolean simply type it like this. Value[1].0 := Bool1; Value[1].1 := Bool2; Value[1].2 := Bool3; Uints have the same number of bits than a INT/WORD so these ones will work as well (they are only represented diffrently). A Real will work but you will loose some infomration in the conversion. If you want to keep the information you can convert 2 words to a float with a function (for example with the IEEE-754 standard) . In this way the syncing to the server is very simple and in the Codesys Program you decide what part of the word you want to use.
Last updated: 2024-04-03

Post by paro on Modbus Client Request Not Processed ^{CODESYS Forge talk (Post)}
Hi, works in my case if I increase the timeout! to_udint(t#100ms) -> 100 -> 100us.. FUNCTION_BLOCK MODBUS_master_example_ST VAR initDone : BOOL := FALSE; aIPAddress : ARRAY [0..3] OF BYTE := [127,0,0,1]; clientTcp: ModbusFB.ClientTcp; // buffer to read input registers aDataInputRegisters : ARRAY[0..9] OF UINT; // some client requests clientRequestReadInputRegisters: ModbusFB.ClientRequestReadInputRegisters; xExecute: BOOL; uistart: UINT := 100; udiTimeout1: UDINT; END_VAR IF NOT initDone THEN initDone := TRUE; // configure clientTcp clientTcp(aIPaddr:=aIPAddress, uiPort:=502, udiLogOptions := ModbusFB.LoggingOptions.All); // configure clientRequestReadInputRegisters clientRequestReadInputRegisters(rClient:=clientTcp, uiUnitId:=1, udiTimeout:=1000000); // 1sec END_IF // call the client FB's clientTcp(); clientRequestReadInputRegisters(rClient:=clientTcp,xExecute := xExecute AND NOT clientRequestReadInputRegisters.xBusy ,uiStartItem:=uistart, uiQuantity:=3, pData:=ADR(aDataInputRegisters[0]));
Last updated: 2024-05-30

Post by zer0g on Modbus Client Request Not Processed ^{CODESYS Forge talk (Post)}
I'm using the code bellow which is based on the Codesys example: FUNCTION_BLOCK MODBUS_master_example_ST VAR initDone : BOOL := FALSE; aIPAddress : ARRAY [0..3] OF BYTE := [127,0,0,1]; clientTcp: ModbusFB.ClientTcp; // buffer to read input registers aDataInputRegisters : ARRAY[0..9] OF UINT; // some client requests clientRequestReadInputRegisters: ModbusFB.ClientRequestReadInputRegisters; xExecute: BOOL; END_VAR IF NOT initDone THEN initDone := TRUE; // configure clientTcp clientTcp(aIPaddr:=aIPAddress, uiPort:=502, udiLogOptions := ModbusFB.LoggingOptions.All); // configure clientRequestReadInputRegisters clientRequestReadInputRegisters(rClient:=clientTcp, uiUnitId:=1, udiTimeout:=TO_UDINT(T#1000MS)); END_IF // call the client FB's clientTcp(); clientRequestReadInputRegisters(rClient:=clientTcp,xExecute := xExecute AND NOT clientRequestReadInputRegisters.xBusy ,uiStartItem:=2, uiQuantity:=3, pData:=ADR(aDataInputRegisters[0])); As you can see the clientTCP is called cyclically with the same result.
Last updated: 2024-05-30

Post by jroddball79 on PM556-TP-ETH — How to change IP address without overwriting the PLC program? ^{CODESYS Forge talk (Post)}
Still looking for a solution. I have gathered more information that might help: Device: ABB AC500 PM556-TP-ETH Firmware version: 2.4.2.14993 (dated 2014) Open ports confirmed: 502 (Modbus TCP), 1200 and 1201 (CODESYS runtime). SSH (22) and HTTP (80) are not reachable. No SD card in the PLC. I can connect via Automation Builder using the current IP and Online Login works, but I have no original source project available. Automation Builder requires a full PLC download to apply IP changes, which we want to avoid as it would overwrite the running program. Any guidance on how to change the IP without a full download would be greatly appreciated. I am also open to solutions using third party tools, DCP protocol, or scripts. Thank you
Last updated: 5 days ago

Post by yannickasselin on Question about Demo License limitations for Modbus TCP communication and Fieldbus Instances ^{CODESYS Forge talk (Post)}
As far as I know, there is no other limitations than the 2 hours limit. The demo mode should be plenty enough for testing purposes. Regarding instances. In the device tree, 1 master = 1 instance, no matter how many slaves the master is communicating with. But it is also possible that your Codesys runtime act as a slave. In this case, each slave in the device tree is one instance. You can also use the license metric tool in the IDE. This will tell you exactly how many instances you have in your project. https://content.helpme-codesys.com/en/CODESYS%20Development%20System/_cds_edt_device_licensed_software_metrics.html
Last updated: 2026-02-28

Post by egr99 on Modbus TCP Server connection is ESTABLISHED but all holding registers are value 0? ^{CODESYS Forge talk (Post)}
You're absolutely right. Sorry for that. In the meantime I wrote a Function block to handle the reads and writes to the different attached RTU-devices. It processes the parameter like (str_Modbus:=(usiSlave:=1, uiFC:=5, uiLEN:=1, uiOFFSET:=0, uiInterval:=500)) and the corresponding output, waits for the response and processes next request in a 5-state procedure. It's working for 2 gateways (stable without errors, although error recovery is included). But nevertheless it should be possible with the Channel definitions of Codesys. Much easier to maintain :)
Last updated: 2026-04-08

Post by jroddball79 on PM556-TP-ETH — How to change IP address without overwriting the PLC program? ^{CODESYS Forge talk (Post)}
We have checked open ports. SSH (22) and HTTP (80) are not reachable. The only open ports are: 502 (Modbus TCP — used for lighting control) 1200 (CODESYS runtime) 1201 (CODESYS runtime) We can connect via Automation Builder using the current IP, but we don't have the original project source — only an empty project. This is why we are afraid of doing a full download, as it would overwrite the running application. Is there any way to change the IP through the CODESYS runtime protocol on ports 1200/1201 without affecting the running program?"
Last updated: 2026-05-20

Post by ihatemaryfisher on Sorting array of any-sized structure ^{CODESYS Forge talk (Post)}
With that I could make an array of varying size, but would still have to define the array type in the function's declaration VAR_IN_OUT stArray: array [*..*] of <pre-defined data type> END_VAR I wanted a function that could take an array of any type (e.g., a structured VAR) as an input. That way I could call it in multiple POUs to handle different arrays structures.
Last updated: 2023-08-18

Post by docker on Canopen connection. Unknown node id. ^{CODESYS Forge talk (Post)}
hi, i am currently trying to adapt an i/o device for a project. the node id is unknown and there is no eds file available. no data is being emitted from the device as a giveaway, the baudrate is known but useless without the node id. is there an sdo request available to determine the id? i cannot get the device to leave pre op status even with a global nmt request. please help. no hair left.
Last updated: 2023-09-25

Post by timvh on Specify Input Configuration "OnDialogClosed" Action to only react to certain Dialogs ^{CODESYS Forge talk (Post)}
What maybe helps is the Visu Dialog ST demo project: https://store.codesys.com/en/visu-dialog-st.html This has an application IECOpenDialog where dialogs are opened using the VU.FbOpenDialogExtended function blocks. The fbOpenConfigurationDialog call has a reference (interface) to the "close listener" FB of which it's method is automatically called when the dialog is closed. This way you can create specific function blocks for each dialog when it is closed and do what you want with the data that might have been changed.
Last updated: 2023-09-28

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 liamb on Converting CANbus to Decimal from signed 2's complement ^{CODESYS Forge talk (Post)}
I need to combine two 8 bit CANbus messages to 16 bits signed int then convert to decimal Decimal from signed 2's complement. I've been using the below code to read for new messages, combine them then assign them to a variable What is the best way to do this for from signed 2's complement? fbRxMessage351(Data := RxMessage351Data); IF fbRxMessage351.NewMessage THEN ChargeVoltage := (WORD_TO_REAL((RxMessage351Data[0]) + ((RxMessage351Data[1]) * 256))) * 0.1; END_IF
Last updated: 2024-08-16

Post by egau on Mutate Hash table value ^{CODESYS Forge talk (Post)}
Hi, using the ElementCollections Library, why isn't it possible to mutate a value found within a HashTable? From what I understand, the only way to change a value would be to use the RemoveByKey(), followed by AddKeyValuePair(). My goal is to use a Data Structure that works like a Dictionary in Python. The HashTable seems to come close to this, except that the values themselves seem to be immutable... In python, we can mutate a dict easily (see attached picture).
Last updated: 2024-08-29

Post by gustavocsw on MQTT memory leak problem ^{CODESYS Forge talk (Post)}
Hello everyone, I'm using the IoT Library to implement the MQTT communication with my local broker server in order to publish and subscribe at specifics topics to share and consume information about my application. But, it seems that are occurring some memory leak problem in a "high" frequency (more than 10 Hz) subscribe process. I follow the same method as in IoT Lib exemples, and at first looks perfect but my PLC was rebooting frequently and when I check its memory usage that was increasing as fast as the subscribe massage was sent. I'm using a WEG PLC410 and a WEG PLC500, and this error occurred in both of them (including in CODESYS Control Win x64). The application sends to the system a message JSON with the float payload Ex. {"data" : 0.8500}, but this happens with a INT, or BOL as well. I use the follow code in my application to find the value: //FindFirstValueByKey VARs PROGRAM JSON_VELO VAR //------Setting the JSON Subscriber to Set the Relay Value jsonDataVelo : JSON.JSONData; jsonByteArrayReaderVelo : JSON.JSONByteArrayReader; xST1okVelo : BOOL; FindFirstValueByKeyVelo : JSON.FindFirstValueByKey; jsonElementVelo : JSON.JSONElement; xDoneReaderVelo : BOOL; xDoneFindVelo : BOOL; //STRING and WSTRING for Subscribe the massage sPayloadJsonVelo : STRING := 'opa'; psPayloadJsonVelo : POINTER TO BYTE := ADR(sPayloadJsonVelo); //wsPayloadJsonRelaySet : WSTRING := "opa"; wsPayloadJsonVelo : WSTRING := STRING_TO_WSTRING('opa'); pwsPayloadJsonVelo : POINTER TO WORD := ADR(wsPayloadJsonVelo); lrVelo : LREAL; xKeepAliveVelo : BOOL; xSetVelo : BOOL; RSSet : RS; LIMPAR : STRING; //Find the msg end sFindVelo : STRING := '}'; psFindVelo : POINTER TO STRING := ADR(sFindVelo); iLenVelo : INT; iSizeVelo : INT := 12; udiContMsg : UDINT; END_VAR // FindFirstValueByKey CODE // Relay Set configuration xSetVelo := MQTT_SUBSCRIBER.RSVelo.Q1; IF xSetVelo THEN xKeepAliveVelo := TRUE; END_IF IF xKeepAliveVelo THEN udiContMsg := udiContMsg + 1; iLenVelo := TO_INT(StrLenA(psPayloadJsonVelo)); iSizeVelo := iLenVelo - TO_INT(MQTT_SUBSCRIBER.udiPayloadSizeVelo); StrDeleteA(psPayloadJsonVelo,iSizeVelo,iLenVelo); wsPayloadJsonVelo := STRING_TO_WSTRING(sPayloadJsonVelo); pwsPayloadJsonVelo := ADR(wsPayloadJsonVelo); //MQTT.ConvertUTF8toUTF16(sourceStart:= ADR(sPayloadJsonVelo), targetStart:= ADR(wsPayloadJsonVelo), dwTargetBufferSize:= TAM, bStrictConversion:= 1); //Reset jsonByteArrayReader jsonByteArrayReaderVelo ( xExecute := TRUE, pwData := pwsPayloadJsonVelo, jsonData := jsonDataVelo, xDone => xDoneReaderVelo ); FindFirstValueByKeyVelo( xExecute := xDoneReaderVelo, wsKey := "data", diStartIndex:= 0, jsonData := jsonDataVelo, jsonElement => jsonElementVelo, xDone => xDoneFindVelo ); IF xDoneFindVelo THEN lrVelo := jsonElementVelo.value.lrValue; //Reset jsonByteArrayReader jsonByteArrayReaderVelo ( xExecute := FALSE, pwData := pwsPayloadJsonVelo, jsonData := jsonDataVelo, xDone => xDoneReaderVelo ); FindFirstValueByKeyVelo( xExecute := FALSE, wsKey := "data", diStartIndex:= 1, jsonData := jsonDataVelo, jsonElement => jsonElementVelo, xDone => xDoneFindVelo ); xKeepAliveVelo := FALSE; GVL.xSetVeloRead := TRUE; END_IF END_IF And this to subscribe at the topic: //SUBSCRIBE VAR: //----------------- Subscribe Velocity ----------------------- MQTTSubscribeVelo : MQTT.MQTTSubscribe;//Variable MQTTSubscriber block -X - function-X wsTopicSubscribeVelo : WSTRING(1024) := "CORE/odometry/GET/data/simp"; // Topic to publish a message sSubscribeMassageVelo : STRING; udiPayloadSizeVelo : UDINT; xSDoneVelo : BOOL; xSErrorVelo : BOOL; xReceiveVelo : BOOL; eSTypeVelo : MQTT.MQTT_ERROR; eSMQTTErrorVelo : MQTT.MQTT_ERROR; RSVelo : RS; udiCont : UDINT; //SUBSCRIBE CODE: MQTTSubscribeVelo( xEnable:= MQTT_CLIENT.xConnection_Broker AND NOT xSErrorVelo AND NOT JSON_VELO.xKeepAliveVelo, pbPayload:= JSON_VELO.psPayloadJsonVelo, udiMaxPayloadSize:= SIZEOF(JSON_VELO.sPayloadJsonVelo), udiPayloadSize => udiPayloadSizeVelo, mqttClient:= MQTT_CLIENT.ClientMQTT, wsTopicFilter:=wsTopicSubscribeVelo, xDone => xSDoneVelo, xError=> xSErrorVelo, xReceived => xReceiveVelo, eMQTTError=> eSMQTTErrorVelo ); RSVelo(SET := xReceiveVelo, RESET1 := JSON_VELO.xKeepAliveVelo);
Last updated: 2024-09-09

Post by docker on Webvisu client connection monitoring ^{CODESYS Forge talk (Post)}
Hi mate, With this snippet i was able to see the lastusage variable count, but it would not iterate between clients? i was only able to access the data of the target visu. it threw an error with the array of pointers stating it was not able to convert etc. also when i tried it with the while loop it created an endless loop and crashed the program. any ideas? Thankyou
Last updated: 2024-09-10

Post by mani-i4point0 on Codesys (Ethernet IP Scanner ) and Python (Ethernet IP Adapter) ^{CODESYS Forge talk (Post)}
Hi, I am currently developing the software to establish the communication and data transfer between Python Module as a Ethernet IP - Adapter coding is running my laptop and Codesys as a Ethernet IP scanner in the resperry PI hardware. I am trying to look for some available recourses online, Can anyone suggest me to develop this function in Codesys and Python ? Best Regards, Mani
Last updated: 2024-09-24

Post by andrebrandt on FB string and naming ^{CODESYS Forge talk (Post)}
Hi all. I have a FB written in ST. FUNCTION_BLOCK NTC10k VAR_INPUT Syst:STRING; In:REAL; END_VAR VAR_OUTPUT Out:REAL; OTag:STRING; Out_St:Struct_NTC10K; END_VAR VAR Tag:STRING; InstanceName: STRING; Structure:Struct_NTC10K; END_VAR What i'm trying to do, is to pass data to structure. In structure i want to add a tag with systemnumber and sensorname. '320.001-RT401' In pou i use this RT401: NTC10k;, and tried this RT401: NTC10k(Tag:='RT401'); Anyone done this?
Last updated: 2024-09-26

Post by mubeta on Profibus DP master with EL6731 and automatic restart of slaves ^{CODESYS Forge talk (Post)}
The problem is looking for a bug somewhere in CoDeSys in that, when the slave returns, the cyclic data exchange resumes, but the diagnostics do not update and the node continues to resulting off-line. it is not a problem with the PB master, but with its 3S/CoDeSys management. CoDeSys 3.5.19.20 runtime. Any ideas on how to fix it? Thank you.
Last updated: 2025-02-03

Post by trusty-squire on Which database to use? ^{CODESYS Forge talk (Post)}
How large and how complex? It's tough to make a recommendation without additional details. The simplest thing is to just use data arrays (or even arrays of arrays). Not knowing your requirements, it might be sufficient and the simplest option is often the best. https://content.helpme-codesys.com/en/CODESYS%20Development%20System/_cds_datatype_array.html You might also look into using Recipes? https://forge.codesys.com/prj/codesys-example/recipe-manageme/home/Home/ Some more complex options below. https://forge.codesys.com/prj/codesys-example/element-collect/home/Home/ https://store.codesys.com/en/mysql-library-sl.html
Last updated: 2025-03-04

Post by imdatatas on TO_STRING operator not working for IMPLICIT ENUM ^{CODESYS Forge talk (Post)}
Hi Everyone, It is a very useful feature to be able to obtain the enum value as a string with the TO_STRING operator by defining {attribute 'to_string'}. However, unfortunately the same function does not work for IMPLICIT ENUMs. I hope that {attribute 'to_string'} behavior can also work for Implicit Enumeration data types in one of the upcoming Codesys versions. https://content.helpme-codesys.com/en/CODESYS%20Development%20System/_cds_pragma_attribute_to_string.html https://content.helpme-codesys.com/en/CODESYS%20Development%20System/_cds_datatype_implicit_enumeration.html Best regards, Imdat
Last updated: 2025-03-27

Post by installwhat on Ethercat and profinet on together ^{CODESYS Forge talk (Post)}
I'm curious about the impact of having profinet and Ethercat (specifically softmotion so frame at start of task?) running together. Since it's advised to access the data from the bus task should have both profinet io and ethercat on the same task? Are there any implications around this one should be aware of especially since the frame at task start is just, so far as I'm aware, an ethercat thing? Thanks
Last updated: 2025-04-08

Post by romrot on MS SQL Compact cutting off Database name? ^{CODESYS Forge talk (Post)}
I'm trying to use an fbMsSQL_compact function to read data from an SQL database. It works with some databases, but there is one database that I can't seem to get it to work on. It's set up the same as the other databases that I've tested with the only difference I see is that the name of the database is cut off in the status message. I'll get a message like "User: User logged out succesfully from database: 12345" But the whole name of the database is something like 1234567.
Last updated: 2025-08-21

Post by tvm on VisuFbFrameBase.SetInputPositionData: The element id for the input position cannot be determined ^{CODESYS Forge talk (Post)}
I'm getting this error on one of my projects. Searching for it I came across this https://www.codesys.com/fileadmin/data/Images/System/Releaseinformation/Patch-Note-CODESYS-Visualization-4300.html which says it was a bug VIS-1394, fixed in Visualization 4.3.0.0. I'm using a previous visu version, what is the cause of this error, and what can be done to work around it?
Last updated: 2024-02-08

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