Siemens SINUMERIK 828D Function Manual page 348

G2: Velocities, setpoint / actual value systems, closed-loop control
7.3 Metric/inch measuring system
JOG and handwheel factor
The machine data:
MD31090 $MA_JOG_INCR_WEIGHT
consists of two values containing axis-specific increment weighting factors for each of the two measuring
systems.
Depending on the actual setting in machine data:
MD10240 $MN_SCALING_SYSTEM_IS_METRIC
the control automatically sets the appropriate value.
The user defines the two increment factors, e.g., for the first axis, during the installation and startup phase:
• Metric:
MD31090 $MA_JOG_INCR_WEIGHT[0;AX1]=0.001 mm
• Inch:
MD31090 $MA_JOG_INCR_WEIGHT[1;AX1]=0.00254 mm ≙ 0.0001 inch
In this way, MD31090 does not have to be written on every inch/metric switchover.
Remaining distances are not accumulated during incremental traversing with JOG when the measuring system is
changed, since all internal positions always refer to mm.
Data backup
Data sets which can be separately read out of the control and have data where the system of units is relevant,
receive - when reading - as a function of machine data:
MD10260 $MN_CONVERT_SCALING_SYSTEM
an INCH or METRIC identification corresponding to machine data:
MD10240 $MN_SCALING_SYSTEM_IS_METRIC
This specifies the measuring system in which the data were originally read out.
This information is intended to prevent data sets from being read into the control system with a measuring
system, which is different from the active system. In this case, alarm 15030 is triggered and the write process is
interrupted.
Since the language instruction is also evaluated in parts programs, these can also be "protected" against
operator errors as described above. You can, therefore, prevent parts programs containing only metric data, for
example, from running on an inch measuring system.
Archive and machine data sets are downwards compatible for a setting:
MD11220 $MN_INI_FILE_MODE = 2
348
Function Manual, 09/2011, 6FC5397-0BP40-2BA0
Basic Functions