Siemens SINUMERIK 840D sl Function Manual page 894

Synchronous Spindles (S3)
14.4 Special features of synchronous mode
If the "Servo enable" signal is not set for either of the spindles before synchronous operation
is selected, synchronous operation is still activated when the coupling is switched on. The LS
and FS however remain at a standstill until the servo enable signal is set for both of them.
Set "servo enable" for FS and LS:
When the signal edge of IS "Servo enable" = 1, the spindle either moves back to the old
position (position on cancellation of servo enable) following the IS "Follow-up mode" (signal
status = 0: Stop active) or the current positions (position offset) are used again (signal status
= 1: Follow-up active).
Note
If the "servo enable" signal is canceled for the FS after Spindle STOP without the coupling
being deactivated beforehand, then any synchronism error resulting from external
intervention (e.g. manual rotation) will not be compensated when the "servo enable" signal is
activated again.
This may result in the loss of the defined angular reference between the FS and LS for
special applications. The programmed offset can be reproduced with the following interface
signal:
IS "New synchronization" (DB31, ... DBX31.4).
Follow-up mode (DB31, ... DBX1.4)
The interface signal "Follow-up mode" is only relevant if the "servo enable" for the drive is
canceled. Depending on the IS "follow-up mode," when "servo enable" is set for the FS and
LS, either the spindle will return to the position recorded on cancellation of the servo enable
signal (signal state = 0: Stop active) or the current positions will be used again (signal status
= 1: Follow-up active).
Position measuring system 1/2 (DB31, ... DBX1.5 and 1.6)
Switchover between the position measuring systems for the FS and LS is not locked out in
synchronous operation. The coupling is retained. It is however recommended that the
measuring systems only be switched when synchronous mode is not active.
If "Park" status is selected for the FS or LS in synchronous operation, then the system
responds as if "servo enable" had been canceled.
Delete distance to go / Spindle Reset (DB31, ... DBX2.2)
When Spindle reset is set for the LS in synchronous operation, the LS is decelerated to
standstill at the selected acceleration rate. The FS and LS continue to operate in
synchronous mode. The overlaid motion (except with COUP...) is terminated as quickly as
possible.
Spindle stop (Feed stop) (DB31, ... DBX4.3)
When "Spindle stop" is set for the FS or LS, both coupled spindles are decelerated to
standstill via a ramp, but continue to operate in synchronous mode.
As soon as IS "Spindle STOP" is no longer active for any of the spindles in the coupling, it is
accelerated back up to the previous speed setpoint.
894
Function Manual, 01/2008, 6FC5397-1BP10-3BA0
Extended Functions