hi, i'm using scilab scicos 4.2 : wonderfull unfortunatly i want to use a recursive form s(t)=e(t)+s(t-1) for this, i use a sample and hold and a loop and i get an error "algebraic loop" i understand, but how can i simulate this recursive form ? thanks a lot -- Bruno Chaumontet http://bruno.chaumontet.net bruno at chaumontet.net