Post by mavitia on Application based license problem - Modbus TCP ^{CODESYS Forge talk (Post)}
I am running ubuntu on a raspberry pi, and installed an application based license Control Basic M on it, it runs a demo program fine, does not timeout etc. however, when I add a modbus TCP device, I start getting errors: <Entry severity="error" component="CmpApp" user="nobody" timestamp="12/18/2023 3:49:42 PM" infoId="24">Online change denied. Application Application is in exception state!</Entry> <Entry severity="error" component="CmpApp" user="nobody" timestamp="12/18/2023 3:49:42 PM" infoId="68">Download failed: Application=Application</Entry> <Entry severity="exception" component="CmpApp" user="nobody" timestamp="12/18/2023 3:49:41 PM" infoId="0">Application app=Application has invalid license metrics!</Entry> the modbus tcp slave runs, and the counter ticks up, however, when I call the variables on the %IX0.0 in my program, and try to upload the changes, I am getting the error messages which stop the program as far as I understand, the application based, M includes 2 fieldbus instances, but on the other side is fairly new, anything obvious I am missing out here?
Last updated: 2023-12-18

Post by aris on Modbus write via FB failure ^{CODESYS Forge talk (Post)}
Hi all, I am using CoDeSys V3.5 and a soft controller Win V3x64. I am trying to read a modbus slave via Function Blocks and not via the channels of the hardware tree for the Slave. I created some requests of type ModbusRequest and I notice that I can read Input Registers and Coils but I can not write Holding Registers and Coils. I am using the library IoDrvModbusTCP 4.1.0.0. When i just use a single modbus request with FC06 (or FC16), there is no request sent to the slave and although the xExecute takes its true value from a pulse of 2 seconds duration, I take almost every 3 minutes an error "TCP_COMMUNICATION_ERROR - 16#A5 - TCP Port. error. Request was not sent". My code is ok because if i change the function code for reading registers, everything works fine. Did anyone have this issue in the past? Thank you in advance.
Last updated: 2025-11-06

Post by itsthefabs on (no subject) ^{CODESYS Forge talk (Post)}
Hallo zusammen, ich nutze eine Wago 8212 als Modbus Client (in früheren Codesys Versionen hieß der Modbus Master) und habe einen weitere Wago 8212 als Modbus Server (früher Modbus Slave). Bisher habe ich für den Client den Funktionsblock FbMbMasterTcp aus der WagoAppPlcModbus-Library genutzt. Zukünftig würde ich das allerdings gerne über das Anhängen eines Modbus-Geräts am Ethernet-Knoten im Projektbaum realisieren. Zum besseren Verständnis habe ich ein Bild beigefügt. Der Modbus mit dem Server läuft auch. Kommt es allerdings zum Fehler des Modbus, z.B. kurzzeitig keine Verbindung oder timeout, wird der Fehler nicht automatisch quittiert. Ich muss dann manuell über den Status des Server-Knotens einen Button mit "Bestätigen" drücken. Im Betrieb kann ich mich aber nicht jedes Mal einloggen um einen Fehler zu quittieren. Gibt es hier irgend einen Trick, wie ich das aus dem Programm-Code quittieren kann? Vielen Dank schon einmal.
Last updated: 2025-02-26

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

Barcode-Reader O2I (TCP/IP) mit Codesys auslesen ^{CODESYS Forge talk (Thread)}
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Last updated: 2018-04-01

Problem trying Net Base Services 3.5.15.0 TCP connection ^{CODESYS Forge talk (Thread)}
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Last updated: 2022-03-19

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Last updated: 2012-12-20

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Last updated: 2023-06-30

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Last updated: 2019-12-13

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TCP server on WAGO 750-841: SysSockSelect problem ^{CODESYS Forge talk (Thread)}
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Last updated: 2018-01-29

Write/Read JSON data to communicate by TCP/IP ^{CODESYS Forge talk (Thread)}
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Last updated: 2018-02-08

Komplette Datei (G-Code/ Textdatei) über TCP/UDP empfangen/senden ^{CODESYS Forge talk (Thread)}
Komplette Datei (G-Code/ Textdatei) über TCP/UDP empfangen/senden
Last updated: 2022-05-25

Convert STRING to DWORD for TCP/IP client ^{CODESYS Forge talk (Thread)}
Convert STRING to DWORD for TCP/IP client
Last updated: 2022-06-11

TCP Server in Halcon example errors after client disconnects ^{CODESYS Forge talk (Thread)}
TCP Server in Halcon example errors after client disconnects
Last updated: 2015-09-07

TCP/IP Anbindung Touchpanel an die SPS ^{CODESYS Forge talk (Thread)}
TCP/IP Anbindung Touchpanel an die SPS
Last updated: 2006-06-26

TCP Verbindung zu Drucker in Codesys 3.5 ^{CODESYS Forge talk (Thread)}
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Last updated: 2021-02-10

TCP/IP Connection monitoring based on Network 3.5.7.0 Library ^{CODESYS Forge talk (Thread)}
TCP/IP Connection monitoring based on Network 3.5.7.0 Library
Last updated: 2020-09-18

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