Input case triggered (I/O) output delay

Hello,

Im looking into creating an on/off signal (IO) based controller for heating water monitoring a temperature of a dynamic input 't'. When 't' falls below the value of 25 i would like the controller to output a value of 1 (Output = B) for 1600 seconds of the simulation before resetting to 0 (The controller output would raise the value of 't' above 25). The controller would then monitor (t) until the value falls below 25 and the process would repeat.

I have attempted this with a simulink function but cant get it to work.

where:

control (i/o) output = [B] t = temp;

Simulation time (from simulink clock) = time

Function [B]=logic(temp,time)
B=0;
checkit=0;
if temp<=26 && checkit==0
temp_time=time;
checkit=1;
B=1;
end
if B==1 && temptime-time >=1600;
B=0;
checkit=0;
end
  %

Is my logic correct? And secondly is there a standard simulink block that can do this?

with thanks.