express KeltnerBands

vars
input $Period_EMA(1,50,20), $Period_ATR(1,50,20), $Coefficient(1.0,5.0,1.5,0.1,1);
series Volatility, EMA, BandLow, BandHigh;

calculation

//CalculateAtEveryTick(false);
if IsFirstBar() then
begin
  ExpMovingAverage(close,EMA,$Period_EMA);
end
Volatility = ATR($Period_ATR)*close/100;
if (CurrentBarIndex() < $Period_ATR) then
begin
  BandHigh = void;
  BandLow = void;
end
else
begin
  BandHigh = EMA + $Coefficient * Volatility;
  BandLow = EMA - $Coefficient * Volatility;
end

interpretation
begin
end 

plotband (BandHigh,"blue",1,BandLow,"blue",1,"lightgreen");//@@@cs:312299-3443346-174039_cs@@@