R1: Reference point approach
15.9 Referencing with absolute value encoders
Basic Functions
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Function Manual, 09/2011, 6FC5397-0BP40-2BA0
Parameter assignment
• reference point approach with zero marks:
MD34200 $MA_ENC_REFP_MODE = 1
• A reference point offset should not be input in the following MD:
MD34090 $MA_REFP_MOVE_DIST_CORR
This MD describes, in connection with absolute encoders, the offset between machine and absolute encoder
zero, and it therefore has a different meaning.
• The load-side zero mark search rate MD34040 $MA_REFP_VELO_SEARCH_MARKER
should not exceed the limiting frequency of the absolute trace of the encoder
MD36302 $MA_ENC_FREQ_LIMIT_LOW
.
If the speed is too high, absolute information cannot be read any more, and thus, no equivalent zero marks
are generated.
• If no zero marks are found within:
MD34060 $MA_REFP_MAX_MARKER_DIST
otherwise, an alarm will be triggered.
• A start of the zero mark search with the override of a BERO (MD34200 = 5) is not supported. MD34200 = 0 is
to be used as a equivalent.
• The following MD must be set if the absolute encoder retains even the referenced status through POWER
OFF, besides the last position:
MD34210 $MA_ENC_REFP_STATE = 2
Data backup and standard commissioning
Some properties of an absolute encoder restrict the transfer of series startup files to other machines. The
following machine data must be checked and corrected if necessary after loading the series startup:
• MD30250 $MA_ACT_POS_ABS (internal encoder position)
• MD30270 $MA_ENC_ABS_BUFFERING (traversing range extension)
• MD34090 $MA_REFP_MOVE_DIST_CORR (absolute offset)
• MD34210 $MA_ENC_REFP_STATE (adjustment status)
• MD34220 $MA_ENC_ABS_TURNS_MODULO (Modulo range)
• MD34230 $MA_ENC_SERIAL_NUMBER (encoder serial number)
