Taking Into Account Control Gears - Siemens SINUMERIK 840D sl Function Manual

05.08
Interlocking the user agreement
Before a user agreement can be issued, the interlock must be cancelled:
S KeySwitch
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key switch position 3 must be left and the key withdrawn).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 control gears

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 ba-
sis in the machine data and selected using the "Safety–related inputs/outputs"
(SGEs/SGAs).
The following points must be carefully observed for drives with control gears (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 comparison; however, the safety–related actual values from the NCK and
drive are compared to evaluate if there is any deviation (< 36942
$MA_SAFE_POS_TOL or parameter p9542 SI motion, actual value comparison
tolerance (crosswise) (Control Unit).
S If the drive is operated with an (indirect) motor encoder and a (direct) spindle
encoder, the safety–related 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
36921[0..7] $MA_SAFE_ENC_GEAR_DENOM[n] denominator, gearbox encod-
er/load and
MD 36922[0..7] $MA_SAFE_ENC_GEAR_NUMERA[n] numerator, gearbox
encoder/load
or
p9521[0..7] SI motion gearbox encoder/load denominator (Control Unit) and
p9522[0..7] SI motion gearbox encoder/load numerator (Control Unit)
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.
© Siemens AG 2008 All Rights Reserved
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 05.2008 Edition
Basics on the Safety Functions Integrated in the System/Drive
5.4 Actual value conditioning
5-105