Start Position
From ATTWiki
Defined
The Start Position is the position of the Carriage or Feed Axis when the clamp closes on the part for the first bend.
Datum
The StartPosition is referenced primarly from the back of the bender, where the zero datum exists. Values can be entered from either the front or the back of the bender. But the resulting primary values are from the back of the bender.
If an operator is loading the part from the front of the bender, then the Start Position is often a lower number than the Load Position. This configuration would pull the part back to the Start Position before bending begins.