This block delays the Boolean input by an infinitesimal small time delay and therefore breaks algebraic loops. In a network of logical blocks, in every closed connection loop, at least one logical block must have a delay, since algebraic systems of Boolean equations are not solvable.
This block returns the value of the input signal u
from the
last event iteration. The event iteration stops once both
values are identical, i.e., if u = pre(u)
.