Siemens SINUMERIK 840D sl Function Manual page 413

2.2.3 Manual switchover of the basic system
General
The relevant softkey on the HMI in the "Machine" operating area is used to change the
measuring system of the controller.
The change in the measuring system occurs only under the following boundary conditions:
• MD10260 $MN_CONVERT_SCALING_SYSTEM=1
• Bit 0 of MD20110 $MC_RESET_MODE_MASK is set in every channel.
• All channels are in the Reset state.
• Axes doe not traverse with JOG, DRF or PLC.
• Constant grinding wheel peripheral speed (GWPS) is not active.
Actions such as part program start or mode change are disabled for the duration of the
measuring system changeover.
If the measuring system cannot be changed, this is indicated by a message to that effect on
the user interface. These measures ensure that a consistent set of data is always used for a
running program with reference to the measuring system.
The actual change in the measuring system is made by writing all the necessary machine
data and subsequently activating them with a RESET.
Machine data:
MD10240 $MN_SCALING_SYSTEM_IS_METRIC
and the corresponding G70/G71/G700/G710 settings in machine data:
MD20150 $MN_GCODE_RESET_VALUES
are switched automatically and consistently for all configured channels.
The value of machine data:
MD20150 $MC_GCODE_RESET_VALUES[12]
changes between G700 and G710.
This process takes place independently of the protection level currently set.
Note
The availability of the soft key and, therefore, its functionality, can be configured using the
compatibility machine data:
MD10260 $MN_CONVERT_SCALING_SYSTEM.
If several NCUs are linked by NCU-link, the switchover has the same effect on all linked
NCUs. If the prerequisites for a switchover are not fulfilled on one of the NCUs linked, no
switchover will take place on none of the NCUs. It is assumed that interpolations between
several NCUs will take place on the existing NCUs, whereby the interpolations can provide
correct results only if the same unit systems are used.
References:
/FB2/ Function Manual, Extended Functions; Several Control Panels on Multiple NCUs,
Decentralized Systems (B3)
Basic logic functions: Velocities, Setpoint/Actual Value Systems, Closed-Loop Control (G2)
Function Manual, 11/2006, 6FC5397-0BP10-2BA0
Detailed description
2.2 Metric /inch measuring system
25