Siemens SINUMERIK 840D sl Programming Manual page 197

Starting position before the measurement
The probe is pre-positioned over the 1st measuring point P1 in the axes of the plane (for G17:
XY).
Positioning taking into account a protection zone
● Protection zone "no"
The probe is positioned in the measuring axis as a maximum at the distance of
measurement path DFA above the surface to be measured above measuring point P1 at
the measuring height.
● Protection zone "yes"
The probe is positioned in the measuring axis as a maximum at the distance of
measurement path DFA and the amount in parameter DZ (for G17 always measuring axis
Z) above the surface to be measured above measuring point P1 at the measuring height.
In both cases, when making the measurement, measuring point P1 must be able to be safely
reached.
If the distances from the reference surface are selected too large for the 1st measurement,
then a measurement is not made.
Measuring axis is always the 3rd axis of the plane (for G17: Z). Measuring point P1 should be
selected in the plane so that the distance to the 2nd measuring point (L2) and to the 3rd
measuring point (L3) results in positive values.
Positioning between measuring points P1, P2, P3
Intermediate positioning "parallel to the plane"
The probe traverses parallel to the reference surface at the distance of parameter L2 to
measuring point P2, or after the 2nd measurement at the distance of parameter L3 to
measuring point P3. In so doing, the angle from parameters α and TSA is taken into account.
TSA contains the value for the maximum permissible angular deviation.
After performing the measurement in P1, the probe is positioned to P2 in the 1st axis of the
plane and in the 3rd axis of the plane (for G17 in X and Z) taking into account angle β and a
maximum deviation in TSA. After the measurement in P2 has been performed the probe is
repositioned to P1 along the same path. The probe is positioned from P1 to P3 in the 2nd axis
of the plane (for G17 in X and Y) and the 3rd axis of the plane taking into account angle α and
maximum deviation in TSA and then a measurement performed.
Intermediate positioning "parallel to the axis"
Positioning from P1 to P2 is performed in the 1st axis of the plane, from P1 to P3 in the 2nd
axis of the plane. With the starting position P1 in the 3rd axis of the plane (for G17 in Z), P2
and P3 must also be able to be reached without any collision.
Position after the end of the measuring cycle
The probe is at a distance of the measurement path above the last measuring point (P3).
Measuring cycles
Programming Manual, 12/2017, 6FC5398-4BP40-6BA1
Measuring variants
3.3 Measure workpiece (milling)
197