Referencing Variants Not Supported; Automatic Restoration Of The Machine Reference - Siemens SINUMERIK 840D sl Function Manual

R1: Referencing

15.10 Automatic restoration of the machine reference

15.9.9

Referencing variants not supported

The following referencing variants are not supported when used with absolute encoders:
● Referencing/calibrating with encoder zero mark
● Distance-coded reference marks
● BERO with two-edge evaluation
15.10 Automatic restoration of the machine reference
Without a defined machine reference when traversing machine axes, no position-dependent
functions such as transformations or tool frames can be executed. In various machine
situations, these functions must be available immediately with the encoder activation, e.g. after
the control is switched on or after terminating "Parking a machine axis (Page 113)" to traverse
the axes. However, the machine axes should not or cannot be traversed again for referencing.
Absolute encoders
For measuring systems with adjusted absolute encoders, the machine reference is restored
immediately without any additional measures when the encoder value is read.
Incremental encoders
With incremental measuring systems, the machine reference can be restored without
traversing the axes through "Automatic referencing" or "Restoration of the actual position".
Supplementary conditions
Incorrect synchronization of the position measuring system caused by offset of the actual
machine axis position
During the time in which the measuring system of the machine axis is switched off, it is not
permissible that the axis is mechanically moved. Otherwise this results in an offset between
the last buffered actual position and the real actual position of the machine axis. This would
lead to an incorrect synchronization of the measuring system resulting in danger to personnel
and machine.
The machine manufacturer must provide such measures as holding brakes, etc. on the
machine so that the actual position is not changed, and this must be ensured by the user.
The responsibility for this rests exclusively with the machine manufacturer / user.
If axis motion cannot be prevented mechanically in the shutdown state, either an absolute
encoder must be used or the axis must be referenced again with reference point approach
after switching on.
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WARNING
Function Manual, 01/2015, 6FC5397-0BP40-5BA2
Basic Functions