Siemens SINUMERIK 840D sl Programming Manual page 465

Together CPRECON and CPRECOF form the G function group 39 (programmable contour
accuracy).
Note
The user can specify a minimum velocity for the path feedrate via the setting data
$SC_MINFEED (minimum path feedrate with CPRECON).
The feedrate is not limited below this value, unless a lower F value has been programmed or
the dynamic limits of the axes require a lower path velocity.
Note
The "Programmable contour accuracy" function only considers the geometry axes of the
path. It has no effect on the velocities of positioning axes.
Example
Program code
N10 G0 X0 Y0
N20 CPRECON
N30 G1 G64 X100 F10000
N40 G3 Y20 J10
N50 G1 X0
...
N100 CPRECOF
N110 G0 ...
References
For the programming of CTOL, see "Programmable contour/orientation tolerance (CTOL,
OTOL, ATOL) (Page 488)"
For more detailed information on the "Programmable contour accuracy" function, see:
Function Manual, Special Functions; Contour Tunnel Monitoring (K6), Section:
"Programmable contour accuracy"
Job Planning
Programming Manual, 03/2013, 6FC5398-2BP40-3BA1
10.5 Programmable contour accuracy (CPRECON, CPRECOF)
Comment
; Activating the "Programmable contour accuracy".
; Machining with10 m/min in the continuous-path mode.
; Automatic feedrate limitation in the circular block.
; Feedrate without limitation again (10 m/min).
; Deactivating the "Programmable contour accuracy".
Path traversing behavior
465