Siemens SINUMERIK 840D sl Function Manual page 939

Spindle override (DB31, ... DBB19)
The "Spindle override" VDI interface (DB31, ... DBB19) only impacts on the speed
component additionally programmed for the following spindle. If the spindle override switch is
transferred to all axial inputs, then any change in the spindle override value is applied doubly
to the following spindle:
● once indirectly by a change in speed for the leading spindle and
● once in the programmed component of the following spindle.
The offset value can be adjusted accordingly in the PLC program.
Coupling deselection
If the coupling is deactivated, the following spindle continues to rotate at the speed
corresponding to the sum of both speed components. The motion transition upon coupling
deselection is at continuous speed.
With COUPOF, the spindle behaves as if it had been programmed with the speed and
direction transferred from the other spindle. In the example, this would be M4 S400.
When COUPOFS is programmed, the following spindle is decelerated to standstill from the
current speed.
Activate additional functions
The following spindle can also be a master spindle. In this case, it is capable of additional
functions.
● Rotational feedrate with G95, G96 and G97. With G96 S2=... the "constant cutting speed"
● Rigid tapping without compensating chuck with G331, G332.
Extended Functions
Function Manual, 03/2009, 6FC5397-1BP10-4BA0
can be activated for the following spindle.
The speed dependent on the position of the transverse axis is the setpoint speed for the
speed interpolator of spindle 2 and is therefore included in the total speed of S2.
Synchronous Spindles (S3)
Special features of synchronous mode
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