Residual Risks - Siemens SINUMERIK 840D sl Function Manual

System Features

3.2 Residual risks

3.2 Residual risks
Risk assessment enables the machine manufacturer to determine the residual risk
for his machine with respect to the control. The following residual risks are defined:
S Safety Integrated is only activated if all of the system components are pow-
ered-up and have been booted.
S Faults in the absolute track (C-D track), cyclically interchanged phases of motor
connections (V-W-U instead of U-V-W) and a reversal in the control direction
can cause an increase in the spindle speed or axis motion. Category 1 and 2
Stop functions according to EN 60204–1 (defined as Stop B to E in Safety Inte-
grated) that are provided are however not effective due to the fault.
Category 0 stop function according to EN 60204–1 (defined as Stop A in Safety
Integrated) is not activated until the transition or delay time set via machine
data has expired. When SBR is active, these errors are detected (STOP B/C)
and the Category 0 stop function according to EN 60204–1 (STOP A in Safety
Integrated) is activated as early as possible irrespective of this delay (see Sec-
tion 6.4, "Safe braking ramp"). Electrical faults (defective components etc.) can
also result in the response described above.
S When incremental encoders are used, the functions safe software limit switch"
(SE) and "safe software cam" (SN) can only be used after referencing has been
successfully completed.
S When no user agreement has been given (see Subsection 5.4.4. "User agree-
ment"), the safe software limit switches (SE) are not operative; the safe soft-
ware cams (SN) are operative, but are not safe as defined by Safety Integrated.
S The simultaneous failure of two power transistors (one in the upper and the
other offset in the lower inverter bridge) in the inverter may cause the axis to
move briefly.
Example: Synchronous motor:
For a 6-pole synchronous motor, the axis can move by a maximum of 30 de-
grees. With a ballscrew that is directly driven by, e.g. 20 mm per revolution, this
corresponds to a maximum linear motion of approximately 1.6 mm.
Example, synchronous linear motor:
For a synchronous linear motor, the movement can be a maximum of one pole
width. This corresponds to the following distances:
1FN1-07 2
1FN1-12/-18/-24
1FN3
3-40
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 03.2006 Edition
7 mm
36 mm
20 mm
© Siemens AG, 2006. All rights reserved
03.06