Siemens SINUMERIK 840Di Function Manual page 395

In order to ensure compatibility with the behavior with no FGREF programming, the factor 1
degree = 1 mm is activated on system powerup and RESET.
This corresponds to a reference radius of:
FGREF = 360 mm/(2π) = 57.296 mm
This default setting is independent of the active basic system:
MD10240 $MN_SCALING_SYSTEM_IS_METRIC
and of the currently active inch/metric G code.
Table 2-2
N100 FGROUP(X,Y,Z,A)
N110 G1 G91 A10 F100
N120 G1 G91 A10 X0.001 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.
The time required to execute the two blocks can be differ greatly.
Note
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 setting, when:
•
•
Example:
The following example illustrates the effect of FGROUP on the path and the path feedrate.
N100 R1=0
N110 FGROUP(X,A)
N120 G91 G1 G710 F100
N130 DO $R1=$AC_TIME
N140 X10
N150 DO $R2=$AC_TIME
N160 X10 A10
Velocities, Setpoint/Actual-Value Systems, Closed-Loop Control (G2)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
Special features of the feedrate weighting for rotary axes in FGROUP:
G71/G710:
FGREF[A]=57.296
G70/G700:
FGREF[A]=57.296/25.4
2.2 Metric/inch measuring system
; Feedrate=100 mm/min or 100 deg/min
; Feedrate=100 mm/min
; Path=10 mm
; R1=6 s approx.
; Feedrate=100 mm/min
; Path=14.14 mm
; R2=8 s approx.
Detailed Description
2-21