Explanation of How this SCL code works

Dear Experts,

Need help understanding this SCL code .

IF (#SimOn = 0) THEN
IF (#DI_In <> #Mem) AND (#Mem1 = 0) THEN
#RemTime := #Tf;
#Mem1 := 1;
ELSIF (#DI_In = #Mem) THEN
#Mem1 := 0;
END_IF;

IF (#Mem1 = 1) AND (#RemTime > 0) THEN
#RemTime := #RemTime - #SampleTime;
ELSIF (#Mem1 = 1) AND (#RemTime <= 0) THEN
#Mem := #DI_In;
#Mem1 := 0;
END_IF;

#PV_Out := #Mem;
ELSE
#PV_Out := #SimPV_In;
END_IF;

first, without the complete code including the headers it's not very clear what the variables mean or what type they are.
second, this seems not to be the most complicated code... maybe ask what you are not understanding about it?

From the manual provided it is a filtered digital input.
The input has to be on for more than Tf/SampleTime scans before the output turns on

It doesn't use timers but relies on the program cycling at a sample rate.

It is effectively a TON without timers.

code with header

delayed input with selectable simulation

It is easier to undestand if you look online view and change variables SimOn, SimPV_in, DI_in and look variables remtime and PV_out