Encoders are required for position measurement (path and angle measurement) with high precision. Speed and acceleration can be derived from the position measurement. During path measurement, the resolution of these sensors is in the micrometer range and during angle measurement in the range of few thousandth degrees.
Encoder types:
Incremental encoder generates information on position, angle, and number of rotations in type-specific number of lines (number of steps/rotation). The number of lines per rotation defines the resolution. The relevant position is determined by counting these steps from a reference point. A reference run is required to determine an absolute position.
Absolute value encoder generates information on position, angle, and number of rotations in type-specific number of angular steps. A unique reference sample is assigned to each angular step. The number of existing code samples per rotation defines the resolution. As an absolute position is assigned to each code sample, no reference run is required. There are two types of rotating encoders. Encoders that can turn only one rotation and then begin at 0 (Single-Turn-Encoder) again, and encoders that can turn several rotations (Multi-Turn-Encoder).
Encoders are used as motor encoders in the PacDrive system (Motor feedback system) and as position encoders in machine mechanics.
An absolute encoder is always used for the motor encoder. This is also used to store the electronic nameplate. This means that the parameters of the motor are automatically known to the PacDrive system.
Incremental encoders as well as absolute encoders are used as position encoders on the machine mechanics. This depends on the machine concept.
Master encoders are speed or position sources and thus can be engine encoders or position encoders.
Possible Master Encoder:
LXM
Virtual encoder
Physical Master Encoder (SinCos)
Incremental encoder
Logical encoder
Sum encoder
Sum Master Encoder
Encoder network for sync encoder Input
To use and manipulate signals of a speed and position source in the PacDrive system independently, the logical encoder is integrated in the system as “Software encoder”.
Tasks of the logical encoder:
Coupling various encoder types to a “Standard encoder”
Coupling multiple logical encoders to a master encoder
Generating position values from the Master encoder speed value
Manipulating the master encoder speed signal
Software gear (multiplication) of the speed signal
Adding a speed signal to the speed signal of the master encoder
Software coupling
Realizing a phase displacement trough the system
Master position source for electronic curve (“x-axis”)
Master position source for cam switch
To add speed signals in the PacDrive system, the Sum Master Encoder was integrated in the system.
Tasks of the sum master encoder:
Registration Correction
The positive deviation of the print mark is compensated by feeding a correction curve via the Sum encoder.
Overlapping a corrective curve to the actual curve (phase shift)
When, for example, compensating a changing pressure angle of the belt drive, a constant production velocity can be achieved by feeding a corrective curve via the Sum Master Encoder.
The sum encoder is integrated in the system for adding speed position signals in the PacDrive system.
Tasks of the sum encoder:
Registration Correction
The position deviation of the print mark is compensated by feeding a correction curve via the Sum encoder.
Overlapping a corrective curve to the actual curve (phase shift).
When, for example, compensating a changing pressure angle of the belt drive, a constant production velocity can be achieved by feeding a corrective curve via the Sum encoder.
Therefore, the Sum Master Encoder must be used.