Problems with STEP FUNCTION

Hi everybody,

I have an inlet in a water reactor working in the following way: 10 s on, 80 s off, 10 s on, 80 s off....

-Fist of all, I have built a PIECEWISE (pw1) function (0<t<10 = 1, 10<t<90 = 0)
-Then, using this piecewise function I have built an ANALYTIC function (an1) with a periodic extension 0-90, and plot parameters 0-900. When I plot it, everything is OK.
- Finally I have created a variable for the inlet velocity: 0.265[m/s]*an1(t[1/s])

When I compute my model, the inlet works only in the first 10 seconds, but after 90 seconds it doesn´t start working agains as an inlet, there is no velocity.

Why????

Thank you so much