Siemens Sinumerik 840D sl Function Manual page 179

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Warning
!
As a result of the cam hysteresis, for increasing actual values, the cams SGA do
not switch at the configured cam position (SN) but at the position increased by the
cam tolerance (hysteresis) (SN+TOL).
Users must carefully take this into consideration when configuring the cam
positions and cam tolerance.
Safe software cams for endlessly turning rotary axes
For rotary axes with cams, the modulo range (cam actual value range) can be set
using the following machine data/parameters:
for 840D sl:
MD36902 $MA_SAFE_IS_ROT_AX
for SINAMICS S120:
p9502 SI Motion axis type (Control Unit)
for 840D sl:
MD36905 $MA_SAFE_MODULO_RANGE
for SINAMICS S120:
p9505 SI Motion SCA (SN) modulo value (Control Unit)
The cam actual value range should be selected as wide as the modulo display of
the safe actual value.
For rotary axes, the modulo display of safe actual values is selected and parame-
terized using the following machine data:
for 840D sl:
MD30300 $MA_IS_ROT_AX
MD30320 $MA_DISPLAY_IS_MODULO
MD30330 $MA_MODULO_RANGE
Limiting the cam positions
When parameterizing the cam positions, the following conditions close to the
modulo limits must be maintained.
When cam synchronization is not active:
S -- Mod_Pos + Pos_Tol < SN_Pos < Mod_Pos -- Pos_Tol
When cam synchronization is active:
S -- Mod_Pos + Pos_Tol + Cam_Tol < SN_Pos < Mod_Pos -- Pos_Tol -- Cam_Tol
Meanings:
Pos_Tol: Actual value tolerance
MD36942 $MA_SAFE_POS_TOL for 840D sl
p9542 SI Motion actual value comparison tolerance (crosswise) (Control Unit) for
SINAMICS S120
© Siemens AG 2015 All Rights Reserved
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) - - 10.2015 Edition
Safety functions integrated in the system/drive
6.8 Safety software cams and safety cam track (SN)
6-179