Siemens SINUMERIK 828D Function Manual page 1214

R1: Reference point approach
15.5 Referencing with incremental measurement systems
Figure 15-8 Electronic reference cam offset
Reference cam adjustment
Encoder with equidistant zero marks
Always ensure that the reference cam of encoders that supply zero marks at equidistances is accurately adjusted
so that the correct zero mark is always detected during reference point approach.
Dynamic response
The following factors influence the dynamic response from the arrival of the reference cam to the machine up to
the detection of reference cam signals transferred from the PLC user program to the NC:
• Switching accuracy of the reference cam switch
• Delay of the reference cam switch (NC contact)
• Delay at the PLC input
• PLC cycle time
• Cycle time for updating the VDI interface
• Interpolation cycle
• Position control cycle
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Function Manual, 09/2011, 6FC5397-0BP40-2BA0
Basic Functions