Remote Debugger: A Tool to Remotely Monitor and Operate IOPT-Nets Controllers

This paper describes an interactive tool to remotely debug, control, and monitor controllers designed using IOPT Petri nets. The controllers run on physical hardware devices using code automatically generated from a Petri net model. A web-based user interface allows remote controllers to analyze, test, and debug, present a graphical view of the original Petri net model, and mark an evolution in quasi-real-time. Debugging capabilities include execution pausing, step-by-step execution and continuous execution, and the definition of break-points associated with transition firing. Users may remotely force values on input signals and inspect the values of output signals to test conditions that would otherwise require physical interaction with the hardware systems. The tool records the evolution of all signals and state variables. These are presented as waveforms, and the respective data can be exported, allowing posterior analysis with external tools of systems running at high-speed execution rates, The tool is already integrated into the IOPT-Tools framework, runs in a standard web browser, and does not require additional software installation. The tool employs a lightweight protocol based on HTTP to communicate with the code running on the embedded controllers. The protocol was designed to minimize CPU, memory, and bandwidth resources. Thus, the controller code generated automatically by the IOPT-Tools framework includes a minimal HTTP server for communication with the debugger tool running on a browser. The paper presents an example of an application employing a simple car-park controller model.