How can I create a code to get a value at any time from scope data in simulink (fn matlab module) from input scope data ??

how i can create a code to get a value at any time from scope data in simulink system to build algorithm for example if i have delta (angle) that change with time (curve); and i want this value at any specific time such as δn at present time, δn-1, δn-2 , δn-3 at the different time and the shift between each of them is fixed T= 200ms ; after that δm that shifted from δn by T=100ms, δm-1, δm-2 , δm-3 then i will use this values in mathematical Equations how i can do that by code

from the figure attached [u]= δ (angle) difference with time how i relate y output with u by code in fcn module to get delta in numerical value ?

i tried to use matlab fn module from simulink library to connect it with input scope but i can't get the function which i need.