procedure AppOnIdle(Ticks: integer);
begin
	if Ticks mod (60 * 30) = 0 then begin
		WriteLn('30 seconds has passed');
	end;
end;


-OR-


procedure AppOnIdle(Ticks: integer);
begin
	if Ticks mod (60 * 30) = 0 then
		WriteLn('30 seconds has passed');
end;