Restore Synchronism Of Following Spindle - Siemens SINUMERIK 840D sl Function Manual

14.4.2

Restore synchronism of following spindle

Causes for a positional offset
When the coupling is reactivated after the drive enable signals have been canceled, a
positional offset can occur between the leading and following spindles if follow-up mode is
activated. A positional offset can be caused by:
● A part has been clamped or both spindles have been turned manually (machine area is
● After the spindle enable signals are canceled, the two spindles coast to standstill at
● A drive alarm occurs (internal follow-up mode):
● A synchronization was not executed due to a synchronization lock of the following
Basic procedure
If the following and leading spindles have fallen out of synchronism, or failed to synchronize
at all, synchronism can be restored between them by the following measures:
1. Set the axis enable signals and cancel synchronization disable signal if this has been set.
2. Start following spindle resynchronization with the NC/PLC interface signal:
3. Wait until the coupled spindles have synchronized.
Enable resynchronization
Setting the enabling signals closes the coupling at the current actual positions. The two
following NC/PLC interface signals are set:
DB31, ... DBX98.1 (coarse synchronism)
DB31, ... DBX98.0 (fine synchronism)
The following preconditions must be fulfilled for resynchronization to work:
● The axis enabling signal must be set for the following spindle.
● The PLC must not set any synchronization disables for the following spindle:
Extended Functions
Function Manual, 09/2009, 6FC5397-1BP20-0BA0
open, drives are disconnected from supply).
different speeds if they are not mechanically coupled.
DB31, ... DBX61.3 (follow-up mode active) = 1
When the alarm is cleared, the NC must not trigger any synchronization motion.
spindle:
DB31, ... DBX29.5 (Disable synchronization)
DB31, ... DBX31.4 (resynchronization)
Only after the re-synchronization process is complete can the setpoint-end synchronism
be fully restored.
DB31, ... DBX31.5 (Disable synchronization)
S3: Synchronous spindle
14.4 Special features of synchronous mode
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