Siemens SINUMERIK 840Di Function Manual page 1574

Detailed Description
2.5 Programming
Read SD43202
The constant cutting speed is read from setting data:
SD43202 $SA_SPIND_CONSTCUT_S [m/min] or [feet/min]
with the positive edge of the start signal:
DB31, ... DBX30.1 (spindle start CW)
and
DB31, ... DBX30.2 (spindle start CCW).
Note
Rewriting of the setting data is not activated until the next positive edge of the start signals:
DB31, ... DBX30.1 (spindle start CW)
and
DB31, ... DBX30.2 (spindle start CCW)
for the current spindle speed.
The content of the setting data is only accepted with the next spindle start signal.
Supplementary condition
To ensure that constant cutting rate settings are active, the spindle concerned must be a
master spindle in the channel handling the spindle.
This condition is met when NC/PLC IS:
DB31, ... DBX84.0 = 1 (constant cutting rate active)
is set on the axial VDI interface.
Writing from the part program
When writing from the part program, the value for the constant cutting rate is interpreted as
follows:
If G710 is active in the 12th G Group:
If G700 is set in the 12th G Group:
With G70, G71 and when programming from external (MMC) the setting in machine data:
MD10240 $MN_SCALING_SYSTEM_IS_METRIC
determines the interpretation of the programmed value.
For more detailed information about the metric/inch unit system, please refer to
References:
/FB1/ Descriptions of Functions, Basic Machine; Velocities, Setpoint/Actual-Value Systems,
ClosedLoop Control (G2)
2-70
Metric
Inch as [feet/min]
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
Spindles (S1)