Siemens sinumerik 840D sl Function Manual page 615

Detailed description
2.2 Speed/torque coupling (up to SW 5.x)
MD63570 $MA_MS_TORQUE_CTRL_MODE = 1 (connecting the torque controller output)
Both torque controllers now attempt to match the torque of the slave axis to the torque of the
master axis, without adding speed setpoints to the master axis.
Axis in the channel
When the coupling is active, the motion of the slave axis is not displayed in the automatic
basic display and the actual value is frozen. If a coupling is always active, i.e. the slave axis
is never traversed individually, we recommend that this axis is displayed as the last axis in
the automatic basic display. This is achieved by entering this axis in the following machine
data as the last axis in the channel:
MD20070 $MC_AXCONF_MACHAX_USED (machine axis number valid in channel)
Multiple channels
The master axis and slave axis do not have to be programmed in the same channel. Multi-
channel couplings are possible for several active channels.
Axis replacement
An axis replacement between channels may be prepared (MD30550
$MA_AXCONF_ASSIGN_MASTER_CHAN), but can be performed only with restrictions.
These restrictions are described in Chapter "Constraints", "Speed/torque Coupling (SW 6
and higher)".
Spindles
A master-slave coupling can also include spindles. The slave axis must then always operate
in speed control mode and the position controller is deactivated. (DB3x.DBB61.5 = 0).
The master axis can be operated in all spindle modes, open-loop control mode with/without
position controller, oscillation mode or positioning mode; even changeover between spindle
modes is possible. Restrictions that apply to actual value display are described in Chapter
"Constraints", "Speed/torque Coupling (SW 6 and higher)".
Rotary axes
Master and slave axes can also be rotary axes. The restrictions described in Chapter
"Constraints", "Speed/torque Coupling (up to SW 5)", apply.
Motors rotating in opposite directions
If the motors have been mounted to run in opposite directions, the traversing direction is
inverted for one of the drives with MD32100 $MA_MOTION_DIR. In this case, the speed
setpoint and the output of the torque controller are calculated correctly; there is no need to
set further machine data.
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Special functions: Speed/Torque Coupling, Master-Slave (TE3)
Function Manual, 11/2006, 6FC5397-2BP10-2BA0