Siemens SINAMICS S120 Function Manual page 47

NOTICE
The speed limit set at the SSM function (p9346/p9546) is also used as shutdown limit for
the SBR function (safe acceleration monitoring). The SBR is deactivated if the speed is
below this limit.
The effect of the SSM safety function is therefore heavily limited if a relatively high
SSM/SBR speed limit is set and the SS1 and SS2 stop functions are activated.
Figure 4-5
Calculating SBR tolerance of the actual speed
The following rules are valid for the parameterization of SBR tolerance:
The maximum speed increase after STOP B/C was triggered is derived from the effective
acceleration and the duration of the acceleration phase. The duration of the acceleration
phase is equivalent to one monitoring clock cycle (p9300/p9500) MC (delay from detecting a
STOP B/C until n
SBR tolerance
Actual speed SBR = acceleration * acceleration duration
The following setup rule is derived thereof:
At linear axes:
SBR tolerance [mm/min] = a [m/s
At rotary axes:
SBR tolerance [rev/min] = a [rev/s
Recommendation:
The SBR tolerance value entered should be approx. 20% higher than the calculated value.
Safety Integrated
Function Manual, (FHS) , 07/2007 Edition, 6SL3097-2AR00-0BP0
Characteristics of the shutdown limit for SBR
= 0):
set
] * MC [s] * 1000 [mm/m] * 60 [s/min]
2
] * MC [s] * 60 [s/min]
2
Extended Functions
4.6 Safe Acceleration Monitor (SBR)
47