How to get data from simulink to matlab and then simulink?

Hello, I want to get data from simulink and sent it to matlab for calculation. And again I want to send the data to simulink. How will I do? As an example, I have two equations: 1. zddot = (u/m)-g 2. u = m(kp*e+kv*edot+g). so, to solve the first equation I need the value of u. And u will be calculated by knowing the value of kp, kv, e and edot. Moreover, I want to use PID control. So, how will I solve it? Basically I want to know the value of z.