{"id":"beckhoff-twincat-3","model_id":"TwinCAT 3 XAR","name":"Beckhoff TwinCAT 3 Runtime (XAR)","summary":"TwinCAT XAR is the real-time runtime environment of TwinCAT 3. It runs control applications on a target control computer and is installed separately from the TwinCAT 3 engineering environment (XAE). A reduced XAR-only setup is used for new installation or update of the runtime system on a control computer.","study_notes":["XAR is installed as a separate setup; it contains only the components needed for the TwinCAT 3 runtime and is smaller than the full TwinCAT 3 installation.","The XAR-only setup is intended for new installation or update of the TwinCAT 3 runtime system on a target system.","TwinCAT 3.1 Build 4026 can install the runtime in kernel mode (XarMode KM), user mode (UM), or both (KMWithUM); user mode is for engineering and debugging without real-time behavior.","Only one TwinCAT Runtime System (XAR) may be active at a time; TcSwitchRuntime switches between TwinCAT 2 and TwinCAT 3 installations.","The XAR status is shown by a blue icon in configuration mode and a green icon in run mode in the Windows menu bar.","During a custom XAR installation, the runtime environments TwinCAT 3 PLC, TwinCAT 3 C++, and TwinCAT 3 MC can be selected; deselecting one prevents the corresponding module from running on that computer.","ADS (TwinCAT Automation Device Specification) is a medium-independent protocol for communication with or between TwinCAT components and is normally installed together with XAE or XAR.","TwinCAT 3 is installed by default in C:\\TwinCAT\\3.x (x = TwinCAT version number); changing the installation path is not recommended."],"safety_notes":["Installation and commissioning are intended only for trained specialists in control, automation and drive technology who are familiar with the applicable national standards.","Modifications to hardware or software configurations other than those described are not permitted and void the liability of Beckhoff Automation GmbH & Co. KG.","User mode runtime provides no real-time behavior and can execute a minimum cycle time of 1 ms, so timing can differ from real control systems.","Only one TwinCAT Runtime System (XAR) may be active at a time.","Flawless real-time behavior cannot be guaranteed when TwinCAT XAR is used on PCs from third-party providers."],"sources":[{"url":"https://download.beckhoff.com/download/document/automation/twincat3/TC3_Installation_EN.pdf","title":"TC3 Installation EN","accessed":"2026-10-26"}],"verification":{"status":"source_checked","checked_at":"2026-10-26","values":2,"method":"llm_source_check"},"updated_at":"2026-10-26","type":"controller","spec":{"manufacturer":"beckhoff","kind":"runtime","series":"TwinCAT 3","protocols":[],"standards":[]},"url":"https://machineschema.com/controller/beckhoff-twincat-3","license":"https://creativecommons.org/licenses/by/4.0/"}