Siemens SINUMERIK 840D sl Function Manual page 170

Safety Functions Integrated in the System/Drive
6.8 Safety software cams and safety cam track (SN)
for 840D sl:
MD 36901: $MA_SAFE_FUNCTION_ENABLE, bit 7
for SINAMICS S120:
p9501: SI Motion enable safety functions (Control Unit), bit 7
The cam SGAs including the hysteresis, but without synchronization are displayed
in the service screen and servo trace.
Hysteresis of cam SGAs
When cam synchronization is activated, cam signals are output with a hysteresis
that takes into account the approach direction (refer to Figure 6-16, "Hysteresis of
the cam SGAs"). This helps to prevent the SGAs from "flickering" if the axis is
positioned exactly on the cam.
The magnitude of the hysteresis is determined by the following data:
for 840D sl:
MD 36940: $MA_SAFE_CAM_TOL
(tolerance for safe software cams)
for SINAMICS S120:
p9540: SI motion SCA (SN) tolerance (Control Unit)
Fig. 6-16
If the cam is incorrectly/inadmissibly parameterized, then this is indicated by Alarm
27033.
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.
6-170
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 05.2008 Edition
Cam position
SGA = 1
SGA = 0
Hysteresis of cam SGAs
Tolerance
for safe
cams
© Siemens AG 2008 All Rights Reserved
05.08
s