Siemens SINUMERIK 840D Function Manual page 883

Preconditions
Basic requirements for differential speed programming:
● Synchronous spindle functionality is required.
● The dynamic response of the following spindle must be at least as high as that of the leading
spindle. Otherwise, the system may suffer from reduced quality, for example, rigid tapping
without a compensating chuck G331/G332.
● The differential speed must be programmed in the channel in which the following spindle is
also configured. The leading spindle can be programmed in a different channel.
● The differential speed must be enabled for the following spindle by the PLC via IS "Enable
overlaid movement" (DB31, ... DBX26.4). If the enable signal has not been set, alarm 16771
"Channel% Following axis% Overlaid movement not enabled" is output. This alarm is
cleared when IS "Enable overlaid movement" (DB31, ... DBX26.4) is set or the coupling is
opened.
Note
Positioning motion such as SPOS, SPOSA, M19 and axis motion do not have to be enabled.
Note
The differential speed does not therefore affect the coupling process.
The following or leading spindle cannot change gear stages while a coupling is active.
Activate coupling with COUPONC
When the coupling is activated, the following spindle is accelerated, as before, to the leading
spindle speed through application of the coupling factor. If the following spindle is already
rotating (M3, M4) when the coupling is activated, it continues with this motion after coupling.
Deactivate coupling
If the coupling is deactivated, the following spindle continues to rotate at the speed
corresponding to the sum of both speed components. The spindle behaves as if it had been
programmed with the speed and direction transferred from the other spindle. When
deactivating, there are no differences to the previous behavior.
Differential speed
A differential speed results from the renewed programming of the following spindle (in the
example, S2=...) or M2=3, M2=4 in speed control mode during an active synchronous spindle
coupling or by adopting the speed of the following spindle for COUPONC.
Condition:
Speed S... must also be re-programmed with direction of rotation M3 or M4. Otherwise alarm
16111 "Channel% Block% Spindle% No speed programmed" is displayed.
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
S3: Synchronous spindle
19.4 Special features
883