MATLAB: SIMULINK step, ramp “Start time” on command

Simscapesimulinkstep

I need a step and a ramp block where the start time is not fixed. Something where I can use a switch to give the step block an input on when to start.
Imagine trying to actuate a valve that gets actuated depending on the pressure sensor value. So when the pressure sensor near to the valve reads, lets say 100 psi, it send a signal to actuate the valve. This is when the step/ramp function needs to start generating a signal.

Best Answer

A possible solution would be to use an enable subsystem, where the enable signal would be the result of checking the pressure sensor value.