By default, the Emblaser operates in 'absolute' movement mode.
This means that if you issues a command of x10, y100, no matter where the laser is currently positioned, it would move to x10,100 within the workspace.
It is possible to set the Emblaser into an 'incremental' mode which causes it to behave differently. In incremental mode, the Emblaser would move the an amount from its current location. So if the laser was positioned at x50,y50, then a command of x10, y100 would cause it to move to x60, y150.
By issuing the G91 gcode command the movement mode is set to 'incremental'.
Issuing the G90 gcode command will return the Emblaser into 'absolute' movement mode.
This can, for instance, be done by entering the command via UGS.