# Overview

## Task

Due to cascaded processing in the NC channel there is a time delay between decoding an NC program and executing the motion blocks in the interpolator. This means that decoding always precedes execution.

With HSC programs this look-ahead function may involve several hundred motion blocks. In addition, changes initiated by the user in the NC program may only become effective with a time delay.

By limiting the decoder block ahead function the reaction time to program influences can be shortened.

## Properties

With certain technologies, such as flame or water-jet cutting, the user can adapt specific process parameters by using variables, e.g. feed rate in the running NC program.

When the block-ahead limit is active, it means that these changes become effective rapidly and are included timely in the cutting process.

## Parametrisation and programming

Two types of block ahead limiting can be activated:

1. By configuration in the channel list, whereby block-ahead limiting becomes immediately effective at program start.
2. By programming in the NC program, whereby block-ahead limiting can also be activated only for specific program parts.