R1: Reference point approach
15.6 Referencing with distancecoded reference marks
Basic Functions
1222
Function Manual, 09/2011, 6FC5397-0BP40-2BA0
15.6
Referencing with distancecoded reference marks
15.6.1
General overview
Distancecoded reference marks
Measuring systems with distance-coded reference marks consist of two parallel scale tracks:
• Incremental grating
• Reference mark track
The distance between any two consecutive reference marks is defined. This makes it possible to determine the
absolute position of the machine axis when two consecutive reference marks are crossed. For example, if the
distance between the reference marks is approx. 10 mm, a traverse path of approx. 20 mm is all that is required
to reference the machine axis.
Referencing can be performed from any axis position in the positive or negative direction (exception: end of travel
range).
15.6.2
Basic parameter assignment
Linear measuring systems.
The following data must be set to parameterize linear measuring systems:
• The absolute offset between the machine zero point and the position of the first reference mark of the linear
measuring system:
MD34090 $MA_REFP_MOVE_DIST_CORR (reference point/absolute offset)
See also below: Determining the absolute offset
• Orientation of the length measuring system (equidirectional or inverse) relative to the machine system
coordinate system:
MD34320 $MA_ENC_INVERS (length measuring system inverse to the machine system)
Figure 15-12 DIADUR graduated glass scale with distance-coded reference marks(dimensions in mm for 20 mm scale
division)
5HIHUHQFHPDUN
