Traversing With Feedforward Control (Ffwon, Ffwof); Programmable Contour Accuracy (Cprecon, Cprecof) - Siemens SINUMERIK 840D sl Programming Manual

Work preparation
3.14 Path traversing behavior
Example 2: Read or write a specific field element
Maximum acceleration for roughing, axis X
Program code
R1=$MA_MAX_AX_ACCEL[2,X]
$MA_MAX_AX_ACCEL[2,X]=5
3.14.3

Traversing with feedforward control (FFWON, FFWOF)

The feedforward control reduces the velocity-dependent overtravel when contouring towards
zero. Traversing with feedforward control permits higher path accuracy and thus improved
machining results.
Syntax
FFWON
FFWOF
Meaning
FFWON:
FFWOF:
Note
The type of feedforward control and which path axes are to be traversed with feedforward
control is specified via machine data.
Default: Velocity-dependent feedforward control
Option: Acceleration-dependent feedforward control
Example
Program code
N10 FFWON
N20 G1 X... Y... F900 SOFT
3.14.4

Programmable contour accuracy (CPRECON, CPRECOF)

The "Programmable contour accuracy" function reduces the path error on curved contours
through automatic adaptation of the velocity.
The contour accuracy to be maintained is specified depending on the configuration of the
machine (MD20470 $MC_MC_CPREC_WITH_FFW; see machine manufacturer
844
Command to activate the feedforward control
Command to deactivate the feedforward control
Comment
; reading
; writing
Programming Manual, 12/2019, 6FC5398-2EP40-0BA0
NC programming