Siemens SINUMERIK 840D Function Manual page 851

Separate following spindle interpolator
The separate following spindle interpolator allows a number of following spindles from different
channels or from another NCU to be coupled as defined by the user to a single leading spindle.
The following spindle interpolator is
● COUPON or COUPONC activated and
● COUPOF or COUPOFS deactivated
and is always located in the channel in which the COUPON, COUPONC command has been
programmed for the following spindle. If the following spindle to be activated was previously
programmed in another channel, COUPON/COUPONC initiates an axis replacement and fetches
the spindle into its own channel.
Certain synchronous spindle functions can be controlled from the PLC by means of coupling-
specific axial VDI interface signals. These signals act exclusively on the slave spindles and do
not affect the leading spindle (see Section "Controlling synchronous spindle coupling via PLC
(Page 859)").
Definition of synchronous spindles
Before synchronous operation is activated, the spindles to be coupled (FS, LS) must be
defined.
This can be done in two ways depending on the application in question:
1. Permanently configured coupling:
Machine axes that are to function as the following spindle (FS) and leading spindle (LS) are
defined in channel-specific MD21300 $MC_COUPLE_AXIS_1[n].
The machine axes programmed as the LS and FS for this coupling configuration cannot be
altered by the NC part program.
If necessary, the coupling parameters can be modified with the NC part program.
2. User-defined coupling:
Couplings can be created and altered in the NC part program with language command
"COUPDEF(FS, LS, ...)". If a new coupling relationship is to be defined, it may be necessary
to delete an existing user-defined coupling beforehand (with language
command COUPDEL(FS, LS)).
The axis names (Sn, SPI(n)) for the following and leading spindles must be programmed
with FS and LS for every language command COUP..., thus ensuring that the synchronous
spindle coupling is unambiguously defined.
The valid spindle number must then be assigned axis-specific machine data of a machine
axis:
MD35000 $MA_SPIND_ASSIGN_TO_MACHAX.
IS "Following spindle active" (DB31, ... DBX99.1) and IS "Leading spindle active" (DB31, ...
DBX99.0) indicate to the PLC for each machine axis whether the axis is active as a leading or
following spindle.
The LS can be programmed either via a part program, PLC or also using synchronized actions.
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
S3: Synchronous spindle
19.1 Brief description
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