# Block ahead limiting via number of NC motion blocks (P-CHAN-00246)

P-CHAN-00246 | Selecting decoder ahead limiting via number of NC motion blocks
Description | Parameter for activating and configuring the decoder block ahead limiting function based on NC blocks by setting a value unequal to zero. The value defines the maximum number of pure NC motion blocks by which the decoder may be ahead of the interpolator.
Parameter | max_motion_blocks_ahead
Data type | UNS32
Data range | 0: No decoder block ahead limiting (default). >0: After program start the decoder block ahead limiting function is immediately active with the defined number of NC motion blocks and remains selected until main program end M02/M30.
Dimension | ----
Default value | 0
Remarks | Only one type of decoder block ahead limiting function may be active. This is active immediately after program start and it remains selected until main program end M02/M30.