We often want to use a stop loss at a certain low - N*ATR,
But it is too troublesome to manually calculate a certain day low - ATR.
This indicator simply calculates it for you, by marking the value of day low - ATR.
By default the hardcoded ATR value is 0, which means "Uses the ATR at that day with configured look back period".
If you want to use a specific ATR value, e.g.
1) You want to set the stop loss using today's ATR but another day's day low (Very often)
2) You want to set the stop loss in another timeframe - N*ATR
You can type in the value of ATR into the "hardcoded ATR" field.
(Actually this should be the most used way)