How Drive-Controlled Homing Works In Incremental Measuring Systems - Bosch Rexroth OptiFeed-FS EcoDrive 03 FLP04VRS Functional Description

8-6
Functions

How Drive-Controlled Homing Works in Incremental Measuring Systems

Definition of the Reference Point
To establish congruency between the coordinate systems of the drive
(measuring system) and machine, it is necessary for the drive to have
precise information about its relative position within the machine
coordinate system. The drive receives this information by detecting the
home-switch signal edge and/or the reference mark.
Note: Evaluation of the home switch alone is not recommended,
since detecting the position of the home-switch signal edge is
less precise than detecting the reference mark!
The coordinate systems are matched by comparing the desired feedback
position at a specific point within the machine coordinate system with the
actual feedback position ("old" drive coordinate system). A distinction
must be made in this case between "Evaluation of a reference
mark/home-switch signal edge" (type 1 .. 3) and "Evaluation of distance-
coded reference marks".
• With "Evaluation of a reference mark/home-switch signal edge," the
"specific" point within the coordinate system is the so-called reference
point. The desired feedback position at this point is stipulated in
parameter C011, Reference distance. The physical position of the
reference point is the result of the position of the reference mark. After
detecting the reference mark, the drive knows the position of this
marker and, thus, also the position of the reference point in the "old"
drive coordinate system. The desired position in the new coordinate
system based on the machine zero point is provided in parameter
C011, Reference distance.
• With "Evaluation of distance-coded reference marks" the "specific"
point is the zero point (position of the first reference mark) of the
distance-coded measuring system. By detecting the position difference
between two adjacent reference marks, it is possible to determine the
position of the first reference mark in the "old" drive coordinate system.
The desired feedback position at this point is defined by the position of
the first reference mark in the machine coordinate system at this point,
plus the value in C011, Reference distance.
In both cases, the difference between the two coordinate systems is
added to the "old" drive coordinate system. The two coordinate systems
will then conform to one another.
ECODRIVE03-FL*-04VRS
DOK-ECODR3-FL*-04VRS**-FK01-EN-P