Siemens SINUMERIK 840D sl Programming Manual page 39

The deceleration rate of the axis must also be taken into account.
Together they produce an axis-specific velocity-dependent deceleration distance.
The Kv factor is the axis MD 32200 $MA_POSCTRL_GAIN.
The maximum axis acceleration / deceleration rate a is saved in axis MD 32300
$MA_MAX_AX_ACCEL . It may have a lesser effect due to other influences.
Always use the lowest values of the axes involved in the measurement.
Measuring accuracy
A delay occurs between detection of the switching signal from the probe and transfer of the
measured value to the control. This is caused by signal transmission from the probe and is
defined by the control hardware. In this time a path is traversed that falsifies the measured
value. This influence can be minimized by reducing the measuring speed.
The rotation when measuring a milling tool on a rotating spindle has an additional influence.
This can be compensated using compensation tables.
The measurement accuracy that can be obtained is dependent on the following factors:
● Repeat accuracy of the machine
● Repeat accuracy of the probe
● Resolution of the measuring system
Note
Precise measurement is only possible with a probe calibrated under the measurement
conditions, i.e. working plane, orientation of the spindle in the plane and measuring velocity
are the same for both measurement and calibration. Deviations result in measurement errors.
If, in MD51740 $MNS_MEA_FUNCTION_MASK, bit 6 is set =1, then 100% feed rate override
traversing velocity is used for the measuring blocks (MEAS) in the measuring cycles if the
feedrate override is set > 0.
Measuring cycles
Programming Manual, 12/2017, 6FC5398-4BP40-6BA1
Description
2.8 Measurement principle
39