How to determine the maximum nth occurrence of an event at a given duration?

Question

How can it be determined that the time interval of the nth event of an event is not more than a certain period of time? For example, an event can occur up to ‍5 ti‍mes every 10 minutes.

In STL we can use this

VAR
    counter:CTU;
    timer:TON;
    Event:BOOL;
    bMaxEventHappend:BOOL;
    tElapsedTime:TIME;
END_VAR


counter(CU:=Event);
IF counter.CV=1 THEN
    timer(IN:=TRUE);
END_IF
IF counter.CV=5 THEN
    bMaxEventHappend:=TRUE;
    counter(Reset:=TRUE);
END_IF

//resetProcess
IF counter.CV=1 AND timer.et>=T#10M THEN
    timer(IN:=FALSE);
    counter(Reset:=TRUE);
ELSIF counter.CV=2 THEN
    tElapsedTime:=timer.et;
    IF timer.ET-tElapsedTime >=T#10M THEN
       timer(IN:=FALSE);
       counter(Reset:=TRUE);
    END_IF
ELSIF counter.CV=3 THEN
    tElapsedTime:=tElapsedTime+timer.et;
    IF timer.ET-tElapsedTime >=T#10M THEN
       timer(IN:=FALSE);
       counter(Reset:=TRUE);
    END_IF
ELSIF counter.CV=4 THEN
    tElapsedTime:=tElapsedTime+timer.et;
    IF timer.ET-tElapsedTime >=T#10M THEN
       timer(IN:=FALSE);
       counter(Reset:=TRUE);
    END_IF
ELSIF counter.CV=5 THEN
    tElapsedTime:=tElapsedTime+timer.et;
    IF timer.ET-tElapsedTime >=T#10M THEN
       timer(IN:=FALSE);
       counter(Reset:=TRUE);
    END_IF
END_IF

This method does not seem to be optimal for achieving the desired. Is there another optimal method?

Any help would be appreciated.

Answer 1

Finally, I found this method for this problem:

PROGRAM MAIN
VAR
    trigger:r_Trig();
    event: BOOL;
    tDuration:TIME:=T#10M;
    tTimeInit: TIME:=TIME()-tDuration;
    aTime:ARRAY[1..5] OF TIME:=[tTimeInit,tTimeInit,tTimeInit,tTimeInit,tTimeInit];
    alarm:BOOL;
    i:INT;
END_VAR


trigger(clk:=event);
IF trigger.Q THEN
    IF (TIME()-aTime[i+1]<tDuration) THEN
        alarm:=TRUE;
    END_IF
    aTime[i+1]:=TIME();
    i:=(i+1) MOD 5;
END_IF

and seems it works(have been tested for tDuration:TIME:=T#10s;)