Set step-time as variable in exported code

Hello,

I've developed a controller in simulink and am trying to export it as a pure C class using simulink coder for deployment on our microcontroller.

We are using a fixed-step solver in simulation, however, when the exported code gets used on our actual plant, the computation step-size may change depending on load of the processor.

My concern is this: say I have set the fixed-timestep as 0.05s in simulation (and therefore the exported code assumes it is being executed every 0.05s), but then the microprocessor somtimes executes after 0.1s, and somtimes after 0.03s, etc. I think this would cause some unwanted behaviours.

Is there a way to have simulink coder create a variable for step-time that we can adjust during runtime? That is, measure how long it has been since the last execution, and then fill in the variable during each execution.

For an analogy, in videogame programming the update functions usually include a dt paramater so we know how long its been since the last frame.

Thanks

[Jeff Hough]

The only solution I can find is to manually search and replace the step size in all the integrator blocks however that seems error prone.