In distributed machines without a mechanical line shaft the individual drives are synchronized on a virtual master, because the movements are performed more accurately than with a real master.

The virtual master generates setpoints without any deviation from the theoretically ideal shape. There are no signs of the undesirable velocity fluctuations that always occur with real axes.

When operating with a virtual master, all slaves are synchronized by a clock signal from the master at the same sampling point.

The slave axes move at synchronous angles in relation to a master axis. The position of the real master axis is recorded by a resolver, an incremental encoder or a SINCOS encoder. The maximum resolution is 2,097,152 increments per revolution.

Thanks to the short cycle time, the slave in the Baumuller synchronization
module tracks master movement changes much more quickly and accurately than the majority of other servo controllers. The master axis for each slave can also be a virtual master.

The synchronization function can be dynamically coupled in the process.

The electronic gear unit adds gear ratio adjustment to the functionality of the synchronization. The gear ratio from 32,767 : 1 to 1 : 65,535 is specified as a quotient from two natural numbers.

Compared to mechanical gearboxes, the gear ratio can be changed quickly and finely tuned.The following are particularly useful for technology gearbox applications:

• Rapid gear ratio adjustments
• Switching to a virtual master
• Rapid changeover to another virtual or real master.

The dancer controller extends the scope of functionality of the „electronic gear unit“ module. A dancer shaft that has constant force applied to it keeps the tensile force in the web constant. The position of the dancer shaft is recorded as an actual value.

The dancer shaft is kept within the permitted position range by correcting the gear ratio in the “Gear unit” module.

The cam disk links the cyclic movements of a real or virtual master with the cyclic movements of a slave via a cam function. The master and slave cycles can also be of different durations, but must always be in an integer ratio to each other.

Each master angle position has a slave position assigned to it via a table. This table contains the movement profile (cam) for the slave axis.

This table contains a maximum of 16,384 entries, each with 32-bit resolution. Several cams can be stored at the same time. You can switch between cams with the same number of interpolation points in the process. Switching over takes place:

• Via an external signal,
• At a preselected angle position,
• Within a certain master angle range.

Switching over can be defined for a certain movement direction. A special positioning algorithm subsequently compensates for setpoint jumps or unsteadiness during a cam change or when the clutch is being engaged/ disengaged. The master position can also be specified via a virtual master.

The winder operates as a core winder. The tensile force of the web can have open or closed loop control. The current diameter is calculated from the web velocity and the angle shaft velocities compared with the parameterizable monitoring thresholds and signaled.

Externally measured values can also be evaluated.

The winder can be set to different winding characteristics:

• Constant tensile force
• Constant torque
• Externally specified tensile force
• Storable winding curve

   

In controlled operation the following compensation is possible:

• Compensation for friction loss in dependence on the velocity (this curve
  is either parameterized or recorded in a self-learning teach-in procedure)
• Compensation for the mass inertia of the winder when accelerating
  and braking

   

Web breaks are detected by continuously comparing calculated and measured velocity values or via an external signal. If a break occurs the winder is
immediately slowed down to a standstill.

Static Positioning
Positioning is a basic controller function. In combination with the PLC, several thousand positions can be stored or different acceleration ramps specified, depending on the amount of memory in the PLC.

Dynamic Positioning
Dynamic positioning contains all of the functionality of static positioning. A new setpoint can also be specified during an active movement process. The drive takes over the new setpoint immediately.

A special algorithm ensures that the transition from the old setpoint to the new setpoint is continuous and smooth.

The most well-known application for register control is multi-color printing: All colors must be accurately printed on top of each other in successive printing groups.

In order to do this, a mark is printed at the edge of each copy in the first printing group. As soon as sensors in the downstream printing groups detect the mark, the angle position of the respective printing roller is stored (Web/cylinder comparison).

Alternatively, the register error can also be recorded in each printing group as
the difference between the reference mark and the printing groups “own” mark
(web/web comparison). If the angle position of the printing group cannot be correctly aligned, the difference is corrected.Register control is not just suitable for rotating systems, but also flat-bed systems that use linear movements. Instead of aligning the processing station on the material, the material itself can be aligned in relation to the processing station
using the infeed drives (insetting).

Any number of drives can be interlinked using the register control technology module in a decentralized system. During operation, a drive can be removed from the register control system and put back in again later. The drive synchronizes itself again automatically and maintains the register. Register control is basically suitable for all machines where a workpiece is distributed over several stations that move synchronously in relation to each other and have to process the workpiece in-register, such as bag forming, filling and sealing machines and deep-drawing machines.

Certain actions must be triggered depending on a certain master axis, particularly on machines with high chopping rates. In a cam controller, signals are triggered depending on the current position of the master. The on/off switching points are freely selectable. Switching off can also be timer-controlled.

The cam controller also has idle time compensation. This makes it possible to switch valves that close slowly at the correct point in time, for example.

The number of cams is only limited by the amount of memory in the drive PLC, and can be of the magnitude of several hundreds.

The cross-cutter consists of a synchronous drive with compensation positioning of a slave axis in relation to a master axis. The slave axis for the cross-cutter is linked to the virtual master via CANsync or can be read in via a real master in the form of a shaft encoder. The number of cutters per cylinder circumference varies between 1 and n.

The cross-cutter can be combined with register control. This makes it possible to make variable run-time format changes.

EiA master axis moves a product that is moving
toward a certain target point. A slave axis should
catch up with the master at this target point, whereby the slave reaches the same velocity and therefore becomes synchronous.

The slave can be nearer to or further from the target point than the master. After the synchronousmovement the slave is reset again or immediately
synchronized to the next target point.