pid control and constraining a variable

Hi,

i'm making a pid control of a heat exchanger and I need to constraining the inlet velocity of fluid. The inlet velocity is calculated by the pid control law, but need to be constrained between 3.5<u<10 How can I make this in comsol? For example:


if u < 3.5 m/s
u = 3.5

if u > 10 m/s
u = 10



best regards,


gustavo