Are there further information about the console physics parameters?

Hi,

are there further information available for the three parameters of the console concerning the physics?:

-physics.timestep
-physics.max_substeps
-physics.solver_iterations

Are there any limits for these variables (beside the int and float ranges)?
And what exactly do the max_substeps and the solver_iterations variable do?

I tested it today in my program wired with an Advantech Driver, but there were no influences.

Thank you so lot.