how to retrieve the data from simulink during simulation

I have read many posts and comments on this regard but still, coudn't figure out How can have access to block data during simulation.I have followed this instruction but something is still wrong. Can anybody help me on this?

Here is my code: ( in this code I ma simply trying to get the Clock block data from simulation) load_system('Engine1') set_param('Engine1','SimulationCommand','Start'); block = 'Engine1/Clock'; rto = get_param(block, 'RuntimeObject'); time = rto.OutputPort(1).Data plot(time,'or','MarkerSize',5,'MarkerFaceColor','r')

The plot is just showing the last output equal to zero!!