Safe Acceleration Monitor - Siemens SINUMERIK 840D sl Function Manual

Safety functions integrated in the system/drive

7.4 Safe Acceleration Monitor

7.4 Safe Acceleration Monitor
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.
Functional features
The most important functional features include:
● Fastest possible detection if the axis starts to re-accelerate when braking
● SBR is automatically activated, when a STOP B or C has been initiated
● 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.
● For an encoder fault in a 1-safety encoder system, the "Safe Acceleration Monitor" function
is not active as a result of the defective encoder. Depending on how parameter p9516 has
been parameterized, a Category 0 or 1 (EN 60204-1) stop response is realized (see also
the warning notes in Chapter "Safety information & instructions and residual risks
(Page 44)").
In case of a Category 1 stop response, the standard system brakes the defective drive at
with the current limit. The pulses are canceled after the speed parameterized in MD36960
$MA_SAFE_STANDSTILL_VELO_TOL - or the time parameterized in MD36956
$MA_SAFE_PULSE_DISABLE_DELAY.
Activating 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 speed 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 speed 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 (speed limit n<n
For SINAMICS S120:
p9546 SI Motion SSM (SGA n < n
134
)
x
) speed limit (CU)
x
Function Manual, 12/2017, 6FC5397-4BP40-6BA1
Safety Integrated