Can't run my simulation because of integrator. Error pop ups plz help!!!

Hello,

I'm have copied a simulation from a document that my school gave me. I did excally what they asked of me, but I get this error when I try to play the simulation:

Derivative of state '1' in block 'untitled/Integrator' at time 0.0 is not finite. The simulation will be stopped. There may be a singularity in the solution. If not, try reducing the step size (either by reducing the fixed step size or by tightening the error tolerances)

I have attached a printscreen from two simulations that the error pop ups by.

I have search the internet. but non of the options that I read about helped me!

Can someone plz help me?

Simulation 2:

Simulation 3:

Answer 1

[Fangjun Jiang]

You have the Clock as the input. Clock starts from zero when you start the simulation. Taking 1/u of zero results infinite.

[Martijn Roks]

I needed to set te time from 0 to 1 and then it was fixed! Thanks for commenting