Siemens SINUMERIK 840D Function Manual page 154

V1: Feedrates
5.2 Path feedrate F
This corresponds to a reference radius of:
FGREF = 360 mm / (2π) = 57.296 mm
This default is independent of the active basic system
(MD10240 $MN_SCALING_SYSTEM_IS_METRIC) and the currently active G70/G71/G700/
G710 setting.
Special features of the feedrate weighting for rotary axes in FGROUP:
Program code
N100 FGROUP(X,Y,Z,A)
N110 G1 G91 A10 F100
N120 G1 G91 A10 X0.0001 F100
The programmed F value in block N110 is evaluated as a rotary axis feedrate in degrees/min,
while the feedrate weighting in block N120 is either 100 inch/min or 100 mm/min, depending on
the current inch/metric setting.
NOTICE
Different systems of units
The FGREF factor also works if only rotary axes are programmed in the block. The normal F
value interpretation as degree/min applies in this case only if the radius reference corresponds
to the FGREF default:
● For G71/G710: FGREF[A]=57.296
● For G70/G700: FGREF[A]=57.296/25.4
Example
The following example is intended to demonstrate the effect of FGROUP on the path and path
feedrate. The variable $AC_TIME contains the time of the block start in seconds. It can only be
used in synchronized actions.
Program code
N100 G0 X0 A0
N110 FGROUP(X,A)
N120 G91 G1 G710 F100
N130 DO $R1=$AC_TIME
N140 X10
N150 DO $R2=$AC_TIME
N160 X10 A10
N170 DO $R3=$AC_TIME
N180 A10
N190 DO $R4=$AC_TIME
N200 X0.001 A10
N210 G700 F100
N220 DO $R5=$AC_TIME
154
Comment
; Feedrate = 100 mm/min or 100 degrees/min
; Feedrate = 100 mm/min, path = 10 mm, R1 = approx. 6 s
; Feedrate = 100 mm/min, path = 14.14 mm, R2 = approx.
8 s
; Feedrate = 100 degrees/min, path = 10 degrees, R3
= approx. 6 s
; Feedrate = 100 mm/min, path = 10 mm, R4 = approx. 6 s
; Feedrate = 2540 mm/min or 100 degrees/min
Function Manual, 06/2019, A5E47437747B AA
Axes and spindles