A Stop-Loss Delta is an absolute number that acts as a stop-loss for CO (cover order) and OCO (one-cancels-the-other) Positions.

For example - 

You place a buy CO order for Reliance-EQ with

Quantity: 100

Limit price: ₹2000

Stop-Loss Delta: 30

 
This means your buy order with a quantity of 100 shares would get placed at ₹2000 and once traded, automatically a sell Stop-Loss order would get generated for the quantity of 100 shares at

Sell Stop-Loss: (Buy order Traded price - Stop loss delta) i.e. (₹2000-30) = ₹1970.

 

Similarly, in case of OCO order, a buy OCO order is placed for Reliance-EQ with

Quantity: 100

Limit price: ₹2000

Target Price Delta: 50

Stop-Loss Delta: 30

 

This means your buy order with a quantity of 100 shares would get traded at ₹2000 and automatically a Sell Stop-Loss order would get generated for the quantity of 100 shares at

Sell Stop-Loss: (Traded price - Stop loss delta) i.e. (₹2000-30) = ₹1970.