Hi, As @JonB already explained you need to properly encapsulate the various aspects of your logic. One class to handle the communication with the camera. That class shall not care at all about the UI. That's not its job. It should provide feedback through signals. What is connect to it, again, not its problem. The job of your UI is to give the user the option to load a file and configure stuff. The UI will be responsible for reconfiguring whatever needs to be. As for the sequential command handling, load the file, parse it, send the first command and once your "communicator" class is done with it, make it emit a signal to signify that the task is done. In a slot connected to that signal, send the next command.