Siemens sinumerik 840D sl Function Manual page 612

2.2 Speed/torque coupling (up to SW 5.x)
2.2.1 General information
The speed/torque coupling (master-slave) function is required for configurations in which two
drives are mechanically coupled to one axis. With this type of axis, a torque controller must
ensure that each motor produces exactly the same torque, otherwise the two motors would
work in opposition.
Master-slave operation possible only with digital 611D drives.
One of the two drives, the "master", is programmed, while the other drive, the "slave", is
linked via the speed setpoint coupling.
This function essentially consists of:
• A speed setpoint coupling and
• A torque controller between the master and slave axes
A master-slave operation without permanent mechanical coupling does not make sense
because no torque distribution to the common mechanical connection can take place in this
case.
When you activate a master-slave coupling, the NC loses the position reference of the slave
axis. It is maintained on the real axis by way of a fixed mechanical coupling.
The function is not implemented as a difference position control but only as a coupling on the
speed/torque plane. A difference position control would not make sense as it would cause
the controllers between the master and slave to work in opposition.
This function allows each axis to be assigned to a master as a slave, which means that
several master-slave couplings can co-exist.
To achieve a tensioning between the master and slave, a configurable tension torque can be
applied to the torque controller via machine data.
Master and slave axis need not be programmed in the same channel. The speed setpoint
coupling is done in position control cycles.
Special functions: Speed/Torque Coupling, Master-Slave (TE3)
Function Manual, 11/2006, 6FC5397-2BP10-2BA0
Detailed description
2.2 Speed/torque coupling (up to SW 5.x)
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