Siemens SINUMERIK 828D Function Manual page 1215

Setting notes
• reference cam
Aligning the signal edge of the reference cam directly between two zero marks has proven to be the most
practical method.
• Electronic reference cam offset
Information needed for parameterizing the electronic reference cam offset is to be found in the read-only
machine data:
MD34093 $MA_REFP_CAM_MARKER_DIST (distance between reference cam/reference mark)
The indicated value is equivalent to the distance between departure from the reference cam and detection of
the reference mark. If the values are too small, there is a risk that the determination of the reference point will
be non­deterministic, due to temperature effects or fluctuations in the operating time of the cam signal.
If the reference cam adjustment is faulty or inaccurate, an incorrect zero mark can be
evaluated. The control then calculates an incorrect machine zero. As a result, the
machine axis will approach the wrong positions. Software limit switches, protected areas
and working area limitations act on incorrect positions and are therefore incapable of
protecting the machine. The path difference is +/- of the path covered by the machine axis
between 2 zero marks.
Phase 2: Features
• Feedrate override is not active.
Internal motion with feedrate override = 100%.
If a feedrate override of 0% is specified, motion is aborted.
• Feed stop (channel­specific and axis­specific) is active.
• NC-STOP and NC-START are not active.
• If the machine axis does not arrive at Phase 2 within the parameterized distance of the reference mark
(encoder zero mark), the machine axis will be stopped:
MD34060 $MA_REFP_MAX_MARKER_DIST (max. distance to the reference mark)
Basic Functions
Function Manual, 09/2011, 6FC5397-0BP40-2BA0
WARNING
15.5 Referencing with incremental measurement systems
R1: Reference point approach
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