6
Functions
Festo – GDCP-CMMP-M3-FW-EN – 1203NH
53
6.5.5
Scope of functions for cam discs (CAM)
The term “electronic cam disc” designates applications in which an input angle or an input position is
depicted through a function as an angle setpoint value or a setpoint position. These applications are
typically master-slave applications.
The CMMP-AS-...-M3 has the option of processing 16 cam discs each with 4 assigned cam tracks. The
CMMP-AS-...-M3 provides the following functionality for this purpose via FHPP:
–
Slave with synchronisation operation onto external input with cam disc
–
Virtual master (internal) with cam disc.
A requirement is the positioning mode operating mode (record selection or direct mode). Additional
information on parameterisation can be found in the Help for the CMMP-AS plug-in. For complete in-
formation on the cam disc function, see the special cam disc manual P.BE-CMMP-CAM-SW-....
6.6
Second measuring system
6.6.1
Technology
Purpose
A second measuring system is used if the displacement measurement integrated into the motor is not
sufficient. There are 2 main reasons for this:
–
double safety (for instance, at safely reduced speed)
Inclusion of a displacement encoder for secure applications is not described further here.
–
The accuracy is not sufficient
For instance, if the resolution of the motor encoder is not sufficiently large. But more frequently, it is
the mechanics between the motor and positioned unit (for instance, slide of a toothed belt axis)
that is not precise enough.
Absolute positioning accuracy
Most frequently, a second displacement encoder is used to improve the absolute positioning accuracy.
Here, an absolute reference is used directly for the moving mass. The second measuring system cor-
rects inaccuracies between the motor encoder and the moving mass.
The relative positioning accuracy results from the system of all components (motor, gear unit, coupling,
axis,…) and is used, for example, when teaching positions. For most applications, a high relative posi-
tioning accuracy, also called repetition accuracy, is sufficient.
Since a second displacement encoder means expense, both mechanically and in parameterisation, the
accuracies of common systems are compared in the following:
Содержание CMMP-AS-***-M3 Series
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