Why can’t engineers test controllers using a normal simulation? 🤔#HIL #opalrt #engineering #learning

Added: 2026-05-23

[00:00:00]Why can't engineers test controllers using an offline simulation? Most simulations are offline. You run the model, wait for the calculations to finish, and analyze the results afterwards. For many engineering tasks, [music] that works perfectly well. The problem starts when you connect a real controller >> [music] >> to the simulation. A physical controller interacts with the system continuously.

[00:00:21]So, the simulator has to execute calculations predictably and exchange data with the controller within strict timing constraints. If the model represents 1 millisecond of system behavior, the required calculations for that interval must complete before the next execution deadline. Otherwise, the controller starts reacting to the delayed information instead [music] of the current simulating system state.

[00:00:42]This is also why standard operating systems are usually not enough for these applications. A regular computer may interrupt calculations unpredictably because of background services, memory scheduling, and other system processes.

[00:00:55]Real-time simulators are designed [music] differently. Their job is to execute calculations on a deterministic schedule. So, [music] external hardware can interact with the model consistently during the test. OPAL-RT develops real-time simulators [music] platforms used in hardware-in-the-loop testing and rapid control prototyping applications.

[00:01:13]Engineers use these [music] platforms to validate controllers before deploying them into the real equipment. Follow OPAL-RT for more content about real-time simulation and control systems testing.