Process is called 'bumping.'

Schenck Process, Whitewater, Wis., has adopted a method that reduces batch feeding errors by up to 50%.  The process, which utilizes Schenck’s Process VKD software in its Disocont Tersus feeder controller, is known as “bumping.” It follows the philosophy of running a dry material feeder at full speed, stopping it prior to the batch set point and then having the controller bump the helix motor in a range anywhere from 100 millisecond to 100 sec intervals until the batch is within the specified tolerance. 

To follow this method of batching requires operators to disable the automatic adaption on the controller, which prevents it from changing the correction amount. By doing so the controller can be stopped short of the batch set point and then bumped to the tolerance specified in the parameter. Lab testing has proven this method to reduce batch feeding errors by up to 50% dependent on the material and helix type.