Taking Into Account Selector Gearboxes - Siemens SINUMERIK 840D sl Function Manual

Basics on the Safety Functions Integrated in the System/Drive
5.4 Actual value conditioning
Interlocking the user agreement
Before a user agreement can be issued, the interlock must be cancelled:
S Key switch
in setting 3 –> the user agreement can be issued
After the user agreement has been issued, the interlocking must be again set (e.g.
key switch position 3 must be left and the key withdrawn).
5.4.5

Taking into account selector gearboxes

The possible gearbox ratios must be known in order that the NC and drive can
evaluate the position actual values referred to the load.
For this purposes, various gearbox ratios can be selected on an axis-for-axis basis
in the machine data and selected using the "safety-related inputs/outputs" (SGEs/
SGAs).
The following points must be carefully observed for drives with selector gearboxes
(these are generally used with spindles).
S If the drive is operated with an (indirect) encoder (motor measuring system), i.e.
the safety-related actual value for the NCK and drive are derived from the same
measuring system, then the gearbox ratios (gearbox stage selection for Safety
Integrated), must also be selected for both monitoring channels. The state of
the SGE signal ratio selection (bits 0..2) is not subject to a crosswise data com-
parison; however, the safety-related actual values from the NCK and drive are
compared to evaluate if there is any deviation (< MD 36942
$MA_SAFE_POS_TOL or parameter p9542 SI motion, actual value comparison
tolerance).
S If the drive is operated with an (indirect) motor encoder and a (direct) spindle
encoder, the safety-relevant actual values are derived from the direct encoder
and those of the drive from the indirect encoder. For the direct encoder, the
gearbox changeover is not relevant and the gearbox stage changeover only has
to be configured/engineered for the drive.
S Using the two machine data fields
MD 36921[0..7] $MA_SAFE_ENC_GEAR_DENOM[n] denominator, gearbox
ratio encoder/load and
MD 36922[0..7] $MA_SAFE_ENC_GEAR_NUMERA[n] numerator, gearbox
ratio encoder/load
or
p9521[0..7] SI motion, denominator, gearbox encoder/load and
p9522[0..7] SI motion, numerator, gearbox, encoder/load
8 different gearbox stage pairs for NCK/drive can be defined. For this definition,
there is no special function for an index value – e.g. interdependency on the
operating mode of the spindle. These 8 pairs must be parameterized and se-
lected depending on the encoder configuration.
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SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 03.2006 Edition
© Siemens AG, 2006. All rights reserved
03.06