Siemens sinumerik 840D sl Function Manual page 273

Axial functions
Actual value coupling causes a position offset between the leading and following axis. This is
due to the deadtime in the position controller between the actual value of the leading axis
and the following axis necessitated by the IPO cycle.
By default, the position offset and following error are compensated by means of linear
extrapolation of the master value by this deadtime. The following machine data is used to
switch off deadtime compensation with master value coupling:
MD37160 $MA_LEAD_FUNCTION_MASK Bit 0 = 0 (function for master value coupling)
Interface to axis exchange
A master value coupled following axis receives its setpoint values from curve tables.
Overlaid programming of this axis is not possible in the parts program. Therefore, the master
value coupled following axis is removed from the channel in the same way as for axis
exchange. This is carried out automatically when the coupling is activated in the parts
program.
If the coupling is to be activated with synchronous actions, it must be prepared beforehand
with RELEASE, otherwise alarm 16777 "Channel %1 block %2 master value coupling:
Following axis %3 no longer available for leading axis %4" is issued.
After a master value coupling has been deactivated, the former following axis can be
programmed again in the parts program.
Spindles in master value coupling
A spindle can only be used as the master value coupled following axis if it has been switched
to axis mode beforehand. The machine data parameter block of the axis drive then applies.
Example (switch-on from synchronous action):
SPOS=0
B=IC(0)
RELEASE(Y)
ID=1 WHEN ($AA_IM[X]<-50) DO
LEADON(B,X,2)
Special functions: Axis Couplings and ESR (M3)
Function Manual, 11/2006, 6FC5397-2BP10-2BA0
2.3 Master value coupling
; switch spindle to axis operation
; release for synchronous action
; Y is coupled to X via curve table No.2
Detailed description
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