There are 3 mistakes, compare yours to below one.

Code
function run()
{
   set(PLOTNOW);
   LookBack = 48;
   BarPeriod = 24 * 60; // 1 day
   asset("EUR/USD");
   vars PriceHL = series(priceHigh() - priceLow());

   var CellO = SMA(PriceHL, 48) + StdDev(PriceHL, 48);

   printf("Result = %.4f\n", CellO);
	
   plot("Max15Chars", CellO, NEW, RED);
}

Last edited by ozgur; 01/07/21 18:55.