Siemens SINUMERIK 802D sl Function Manual page 320

Reference Point Approach (R1)
18.2 Referencing with incremental measuring systems
Reference cam adjustment
The reference cam must be calibrated exactly. The following factors influence the response
time of the control when detecting the reference cam ("Reference point approach delay"
interface signal):
● Switching accuracy of the reference cam switch
● Delay of the reference cam switch (NC contact)
● Delay at the PLC input
● PLC cycle time
● Internal processing time
Practice has shown that the signal edge of the reference cam, which is required for
synchronizing, is aligned between two synchronized pulses (zero marks). This can be
achieved by:
● Set MD34080 REFP_MOVE_DIST = MD34090 REFP_MOVE_DIST_CORR = MD 34100
● Reference axis
● In JOG mode, traverse the axis to half the path length between the two zero marks. This
● Calibrate the cam switch so that switching is done at exactly this position (IS "Reference
● Alternatively, the value of MD34092 REFP_CAM_SHIFT can be changed instead of
320
REFP_SET_POS = 0
path is independent of the pitch of the leadscrew S and the gear ratio n (e.g. S=10
mm/rev, n=1:1 produces a path of 5 mm).
point approach delay" (V380x 1000.7))
moving the cam switch.
WARNING
If the reference cam is not calibrated precisely, an incorrect synchronizing pulse (zero
mark) may be evaluated. In this case, the control assumes an incorrect machine zero
and moves the axes to incorrect positions. Software limit switches act on incorrect
positions and are therefore not able to protect the machine.
Turning, Milling, Nibbling
Function Manual, 11/2012, 6FC5397-1CP10-5BA0