Detect in simulink if the current and past 4 values are same or not

Hi, I am interested in designing a simulink block which detects if the past 4 and the current input values are same or not. How to do it using the delay blocks and relational operators since the relational operators take only two inputs at a time?

Answer 1

[Titus Edelhofer]

You can use 4 delay blocks, and feed x_t and x_{t-1} into one relational block, x_{t-1} and x_{t-2} into the next relational block, and then use AND blocks to combine.

Titus

Answer 2

[Anthony Poulin]

Hello,

Do the picture attached solve your question?

[Abubakar Muqaddas]

No, since it doesn't compare all the past 5 values at the same time

[Azzi Abdelmalek]

Abubakar, why do you think they are not compared at the same time?

Answer 3

[Azzi Abdelmalek]

You can use Matlab function without any delay block.

function y = fcn(u)
%#codegen
persistent u1 u2 u3 u4
if isempty(u1)
  [u1,u2,u3,u4]=deal(0)
end
y=isequal(u,u1,u2,u3,u4)
u4=u3
u3=u2
u2=u1
u1=u

Or

function y = fcn(u)
%#codegen
persistent u1
if isempty(u1)
  u1=zeros(1,4)
end
a=[u u1];
y=~any(diff(a));
u1=[u1(2:4) u];