Detailed Description
2.8 Referencing in follow-up mode
Reference Point Approach (R1)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0
2-45
Unique zero mark
Referencing of an incremental measuring system is based on the explicit position of the
encoder zero mark relative to the overall traversing range of the machine axis.
Because the reference cam signal is not evaluated by the NC during referencing in follow-up
mode, unique identification of the reference point when referencing in follow-up mode will
only result with:
• Only one encoder zero mark in the traversing range of the machine axis
• Linear measuring systems with distancecoded reference marks
• Modulo rotary axes (absolute position within one revolution)
Zero mark selection when several zero marker signals occur
If several encoder zero marks are detected in the traversing range of the machine axis due
to machine-specific factors, e.g., reduction gear between encoder and load, a BERO must
be mounted on the machine and connected to the relevant drive module (SIMODRIVE 611D)
via a BERO input in order to uniquely specify the reference point. The position of the
reference point is then derived from the combination of BERO signal and encoder zero mark.
Zero mark evaluation with BERO must be parameterized as the referencing mode:
MD34200 $MA_ENC_REFP_MODE = 5
Negative edge evaluation
In the case of a referencing operation with a negative edge evaluation of the BERO signal:
MD34120 $MA_REFP_BERO_LOW_ACTIVE = FALSE
synchronization is with the next encoder zero mark encountered after the BERO is exited.
Positive edge evaluation
In the case of a referencing operation with a positive edge evaluation of the BERO signal:
MD34120 $MA_REFP_BERO_LOW_ACTIVE = TRUE
synchronization is with the next encoder zero mark encountered after the BERO is
approached.
Mechanically, the BERO must be sized in such a way that the positive BERO signal covers
the entire width of the encoder zero mark.
Enable
The "Referencing in follow-up mode" function is enabled with:
MD34104 $MA_REFP_PERMITTED_IN_FOLLOWUP = TRUE
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