For buy order, when price rises:
1. Fixed pips: SL is kept at a fixed pips from bid price.
2. ATR: SL is moved according to current Low price - (ATR14 * Factor)
3. Half Volatility: SL is moved according to current Low - (High + Low)*Factor
For sell order, when price falls:
1. Fixed pips: SL is kept at a fixed pips from ask price.
2. ATR: SL is moved accordingly to current High + (ATR14 * Factor)
3. Half Volatility: SL is moved accordingly to current High + (High + Low)*Factor
Note:
* Factor: Dynamic Factor
* SL: Stop Loss
* ATR: Average True Range indicator, built-in MetaTrader.
* ATR14: ATR of 14 bars period.