Siemens SINUMERIK 840D sl Function Manual page 705

8.6 Measurement accuracy and functional testing
8.6.1 Measurement accuracy
Accuracy
The propagation time of the measuring signal is determined by the hardware used. The
delay times when using SIMODRIVE 611D are in the 3.625 μ ... 9.625 μ range plus the
reaction time of the probe.
The measurement uncertainty is therefore:
Measurement uncertainty = propogation time of the measurement signal x traversing velocity
The allowed traversing velocities depend on the number of programmed measurement
edges and the relation between the IPO/position control clock cycle.
Correct results only comply to traversing velocities for which not more than 1 equal and not
more than 4 different trigger signals per position control clock cycle arrive.
Extended Functions
Function Manual, 03/2009, 6FC5397-1BP10-4BA0
Measurement accuracy and functional testing
Measurement (M5)
705