Siemens SINUMERIK 840D sl Programming Manual page 309

Sequence
Position before measuring cycle call
Before the cycle is called, the tool must be
moved to the starting position, as is shown
in the diagram for turning tools, e.g.: with
traversal in JOG:
The "tip" of the calibration tool in the
measuring axis _MA within distance
2 · _FA in front of the measuring surface.
The center of the cutting edge radius on the
turning tool in the other axisis in the center
of the probe. If the cutting edge radius =0, it
is the tool nose.
For milling tools the axial or radial position of the tool must be specified in _MVAR; as with
Measure with reversal:
First the measuring point is measured in the selected axis and in a milling spindle position
according to starting angle _STA1. The tool (milling spindle) is then rotated through 180
degrees plus the value in _CORA and measured again. The average value is the measured
value.
If the milling spindle is activated when the cycle is started, measurement will be performed
with a rotating spindle. In that case, the user must exercise special care when selecting the
speed, direction of rotation, and feedrate!
If _CHBIT[20]=1, selected measuring variants are possible for a milling cutter without taking
the starting angle _STA1 into account (see Subsection "Milling cutter: Suppression of start
angle positioning _STA1").
Position after end of measuring cycle
When the cycle is complete, the tool nose is again located at the starting position.
Measuring cycles
Programming Manual, 03/2009 Edition, 6FC5398-4BP10-2BA0
Measuring Cycles for Turning Machines
6.3 CYCLE982 tool: Measure turning and milling tools
309