Siemens SIMATIC FM 453, Manual

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FM 453 Servo Drive / Step Drive Positioning Module
C79000-G7076-C453-01
is a defined point on the traversing path of the axis. It is defined by the me-
chanical position of a reference-point switch or in association with a cyclic
zero mark of an incremental encoder.
Creating the position reference between the internal FM position value and
mechanical position of the axis.
Irrespective of the approach direction, the synchronization point can be lo-
cated on the side of the lower or the higher actual position values in relation
to the reference point switch position. It is demarcated by the rising edge of a
zero pulse or by the reference point switch. This selection is made by the
MD18 (together with the approach direction).
Example
RPS
Axis dir
Synchronization point Cyclical zero mark Measurement
grid
With reference to the synchronization point, the reference point can be lo-
cated on the side of the lower or the higher position actual values. In the “ref-
erence point approach” operating mode the machine axis additionally tra-
verses this distance, during its last phase of motion, once the synchronization
point has been found. Consequently, the axis halts the motion, in each
instance, exactly on the reference point.
Example
Axis dir
Axis dir
RV +
RV –
Variant 1
Variant 2
Meas. grid Cyclical zero mark Synchronization point
Reference point RV – Reference point offset
Synchronization
Point
Synchronization
Measured Value
Synchronization
With Incremental
Encoders
Description of Functions