Safe Acceleration Monitoring (Sbr) - Siemens Sinumerik 840D sl Function Manual

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6.4

Safe acceleration monitoring (SBR)

Description
Using this function, the effectiveness of braking, initiated using stop responses B
and C, along the current limit/OFF3 ramp is checked through two channels.
Features
The most important features include:
S Fastest possible detection if the axis starts to re--accelerate when braking
S SBR is automatically activated, when a STOP B or C has been initiated
S When SBR responds, a STOP A is initiated and Alarm 27013 "Axis %1 safe
monitoring for acceleration exceeded" and the drive messages C01706/C30706
"Acceleration monitoring limit exceeded" initiated.
S For an encoder fault in a 1--safety encoder system, the "Safe acceleration moni-
toring" function is not active as a result of the defective encoder. Depending on
how parameter p9516 has been parameterized, a Category 0 or Category 1
(EN 60204--1) stop response is realized (also refer to the warning notes in
Chapter3.5 "Safety information & instructions and residual risks").
In case of a Category 1 stop response, the standard system brakes the defec-
tive drive at with the current limit. The pulses are canceled after the speed para-
meterized in MD36960 $MA_SAFE_STANDSTILL_VELO_TOL -- or the time
parameterized in MD36956 $MA_SAFE_PULSE_DISABLE_DELAY.
Activating the SBR
When a STOP B or C is initiated, the actual speed plus the speed tolerance,
defined in the machine data/parameter, is activated as the speed limit. When the
actual decreases, then this speed limit is correspondingly corrected; however, for
an increased speed, it is not changed. If the drive speed exceeds the actual speed
limit then a STOP A is initiated. If the axis starts to re--accelerate while braking,
this is detected as quickly as possible and prevented.
Machine data/parameters for the SBR speed tolerance:
for 840D sl:
MD36948 $MA_SAFE_STOP_VELO_TOL
for SINAMICS S120:
p9548 SI Motion SBR actual velocity tolerance (Control Unit)
The speed limit is corrected until the speed, defined in the following machine data,
is undershot (fallen below). After that, the limit value of the SBR monitoring is
frozen to the value in MD/parameter 36946/p9546 plus the value in MD/parameter
36948/p9548.
for 840D sl:
MD36946 $MA_SAFE_VELO_X (velocity limit n<n
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SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) - - 10.2015 Edition
Safety functions integrated in the system/drive
6.4 Safe acceleration monitoring (SBR)
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