Siemens SINUMERIK 840D sl Function Manual page 135

Figure 7-11
Calculating the SBR tolerance of the actual speed
The following applies when parameterizing the SBR tolerance:
The possible speed increase after initiating a STOP B/C is obtained from the effective
acceleration a and the duration of the acceleration phase. The acceleration phase lasts from
one monitoring clock cycle MC (delay from detecting a STOP B/C until n
OFF3 ramp):
SBR tolerance
Actual speed SBR = acceleration * acceleration duration
The following setup rule is derived:
For a linear axis:
SBR tolerance [mm/min] = a [m/s
For a rotary axis/spindle:
SBR tolerance [rev/min] = a [rev/s
The following machine data should be taken into account when determining the acceleration:
MD32300 $MA_MAX_AX_ACCEL
MD35200 $MA_GEAR_STEP_SPEEDCTRL_ACCEL
MD35210 $MA_GEAR_STEP_POSCTRL_ACCEL
MD35410 $MA_SPIND_OSCILL_ACCEL
Recommendation:
The value entered for the SBR tolerance should be approx. 20% higher than the calculated
value.
A velocity overshoot must be taken into account when braking with n
be less than the sum of $MA_SAFE_STOP_VELO_TOL and n
$MA_SAFE_VELO_X - $MA_SAFE_VELO_X_HYSTERESIS (if synchronization, hysteresis
and filtering n<n
otherwise the SBR function could be inadvertently initiated, therefore resulting in a STOP A.
Timing when the actual stop limit value is exceeded
If the Safe Acceleration Monitor function is active, then the following timing is obtained when
the actual stop limit value is exceeded:
Safety Integrated
Function Manual, 12/2017, 6FC5397-4BP40-6BA1
Characteristic of the SBR tolerance of the actual speed
] * MC [s] * 1000 [mm/m] * 60 [s/min]
2
] * MC [s] * 60 [s/min]
2
active). This must be checked by taking the appropriate measurements, as
x
Safety functions integrated in the system/drive
7.4 Safe Acceleration Monitor
=0. The overshoot must
set
velocity limit or
x
= 0 / activation
set
135