I would suggest you to save both K and Vout at each time step from simulink with a simout-workspace block. And then after the simulation run a m-script to detect K rises and associated values of Vout and discard the other.

I am not sure that simulink provides the ability to save data at discrete non-periodic instant.

Thanks Nicolas! 

The issue is saving the all the sampled values on the HDD or in matrix form from the parameter sweep. Simulink have these blocks for sampling the output "RISE, FALL or both". The simulation time is 120ms with sampling from 80ms to 120ms. This takes some time to run. Doing a parameter sweep of 250 loops could last way over 48hrs to do so. What MATLAB code would allow writing to HDD of the parameter sweep?

If think I got something wrong because if I do the maths it takes you around 12min to complete one loop, thus to simulate 120ms.

Anyway if the quantity of data you want to save is not to big the aforementioned solution should work, otherwise you can try to have a user-defined block with m-code saving data in a file, to reduce deterioration of performance I would suggest to write a table once per loop instead of opening/writing/closing the file at each sampling step.

All parameters in the loop must be in the form of arrays. Then save all work space. Or save specific parameter to a file. Or export to excel. For a loop within Simulink, define the variable as a persistent array. Then for every step in  the loop save the value. By the end of the simulation you will keep all values.

Thanks Prof Essam Mohamed Adel Soliman... I will try that..