Siemens SINUMERIK 840Di Function Manual page 387

The current setting (selected with G70/G71) and the initial state can be the same or differ at
any given time. The current setting is channel-specific, the initial state applies to all
channels.
Application:
With this function it is possible, for example, with a metric basic system, to machine an inch
thread in a metric parts program. Tool offsets, zero offsets and feedrates remain metric.
Machine data are displayed on the screen using the basic system selected in machine data:
MD10240 $MN_SCALING_SYSTEM_IS_METRIC (metric basic system).
Machine coordinates, tool data and zero offsets are always displayed in the initial state,
workpiece coordinate displays are in the current setting.
If programs including data sets (zero offset, tool offset) programmed in the measuring
system, which differs from the basic system, are read in from an external source, the initial
state must first be changed via machine data MD10240.
Data exchange with the PLC of interface signals containing dimension information, e.g.
feedrate for path and positioning axes, is always carried out in the selected basic system.
Supplements
G700/G710 extends the functionality of G70/G71 as follows:
1. The feedrate is interpreted in the programmed measuring system:
2. System variables and machine data specifying lengths in the parts program are read and
This allows you to implement parts programs that are independent of the current default
measuring system.
Comparison of the effect of G70/G71 and G700/G710 on machine data and system variables
in the parts program:
• With G70/G71: reading/writing in the basic system
• With G700/G710: reading/writing in the programmed measuring system
Velocities, Setpoint/Actual-Value Systems, Closed-Loop Control (G2)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
– G700: length parameters [inch]; feedrates [inch/min]
– G710: length parameters [mm]; feedrates [mm/min]
The programmed feedrate is modal and therefore remains active after subsequent
G70/G71/G700/G710 commands. If the feedrate is to apply in the new
G70/G71/G700/G710 context, it must be re-programmed.
written in the programmed measuring system.
Detailed Description
2.2 Metric/inch measuring system
2-13