Detailed description
2.2 Metric /inch measuring system
Basic logic functions: Velocities, Setpoint/Actual Value Systems, Closed-Loop Control (G2)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
29
Rounding machine data
All length-related machine data are rounded to the nearest 1 pm when writing in the inch
measuring system (MD10240 $MN_SCALING_SYSTEM_IS_METRIC=0 and MD10260
$MN_CONVERT_SCALING_SYSTEM=1), in order to avoid rounding problems.
The disturbing loss of accuracy, which occurs as a result of conversion to ASCII when
reading out a data backup in the inch system of measurement, is corrected by this procedure
when the data is read back into the system.
2.2.4
FGROUP and FGREF
Programming
It should be possible to program the effective machining feedrate in the usual way as a path
feedrate via the F value in processing procedures where the tool, the workpiece or both are
moved by a rotary axis (e.g., laser machining of rotating tubes).
In order to achieve this, it is necessary to specify an effective radius (reference radius) for
each of the rotary axes involved. You can do this by programming the modal NC address:
FGREF[
<axis name>
]
= reference radius
The unit of the reference radius depends on the
G70
/
G71
/
G700
/
G710
setting.
In order to include the axes in the calculation of the path feedrate, they must all be specified
in the
FGROUP
command.
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
Special features of the feedrate weighting for rotary axes in FGROUP:
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.
Summary of Contents for SINUMERIK 840D sl
Page 282: ...Index Basic logic functions Acceleration B2 64 Function Manual 11 2006 6FC5397 0BP10 2BA0 ...
Page 388: ...Basic logic functions Travel to fixed stop F1 Function Manual 11 2006 6FC5397 0BP10 2BA0 52 ...
Page 962: ...Index Basic logic functions Emergency Stop N2 20 Function Manual 11 2006 6FC5397 0BP10 2BA0 ...
Page 1704: ...Constraints Basic logic functions Spindles S1 94 Function Manual 11 2006 6FC5397 0BP10 2BA0 ...
Page 1716: ...Index Basic logic functions Spindles S1 106 Function Manual 11 2006 6FC5397 0BP10 2BA0 ...
Page 1996: ...Index Basic logic functions Tool Offset W1 208 Function Manual 11 2006 6FC5397 0BP10 2BA0 ...
Page 2150: ...Table of contents Basic logic functions Appendix 4 Function Manual 11 2006 6FC5397 0BP10 2BA0 ...
Page 2184: ...Glossary Basic logic functions Appendix 38 Function Manual 11 2006 6FC5397 0BP10 2BA0 ...