# Jerk within the polynomial

The curvature of the polynomial results in a jerk for the axes running across the path trajectory. This jerk is normally checked with the maximum dynamic parameters of the axes (P-AXIS-00199). If the jerk is too strong, path velocity is reduced accordingly. In some user-specific applications, this reduction in velocity is undesirable because of the maximum jerk. This can be defined specifically by control commands in the NC command #CONTOUR MODE. The control commands overwrite the pre-definition in the channel parameter list P-CHAN-00110 and are valid modal up to program end.

In the example below, the block transition from N6 to N7 is contoured by polynomials and this is considered by the jerk. The transition from N7 to N8 is also contoured but with no consideration for jerk on the path contour.

## Programing Example

Jerk within the polynomial

%poly_jerk.nc

(default setting in the channel parameter list: (check_jerk_on_poly_path)

#SLOPE[TYPE=TRAPEZ]

#CONTOUR MODE [ DEV, PATH_DEV 4, RELEVANT_PATH 51]

N0003 G1 X0 Y100 Z0 F4

N0004 G261

N0005 G1 G91 X100

N0006 Y-50

N0007 #CONTOUR MODE [CHECK_JERK=1]

N0008 X100

N0009 #CONTOUR MODE [CHECK_JERK=0]

N0010 Y-50

N0009 G260

N0055 M30