Using OpenModelica, the default dassl integration solver seems to be unable to solve the derivative of a ramp function ? No problem with a constant signal or a sine but impossible for a ramp or a step.
I have tried to use a low pass filter between the signal and the derivative (to avoid a discontinuous derivative) without any real success.
Using the Euler integration solver seems to solve the problem but I would like to use the default integration solver.
Thanks!