Siemens SINAMICS S120 Function Manual page 153

Calculating the SAM tolerance of the actual speed
● The following applies when parameterizing the SAM tolerance:
– The maximum speed increase after SS1 or SS2 is triggered results from the effective
– The duration of the acceleration phase is equivalent to one monitoring cycle (MC
● Calculating the SAM tolerance:
Actual velocity for SAM = acceleration · acceleration duration
The following setup rule is derived thereof:
– For a linear axis:
– For a rotary axis:
● Recommendation
The SAM tolerance value entered should be approx. 20% higher than the calculated
value.
● You set the tolerance such that the "overshoot" is tolerated that necessarily occurs when
standstill is reached after braking along the OFF3 ramp. However, it cannot be calculated
as to just how high this is.
Note
First monitoring cycle
For SAM, in the first "SI Motion monitoring cycle" (p9500) a higher SAM tolerance is taken
into account in order to compensate for possible settling operations without resulting in an
incorrect initiation. The increase factor is calculated as follows:
SI Motion monitoring cycle (p9500) / SI Motion actual value acquisition cycle (p9511)
Example:
SI Motion monitoring cycle (p9500) = 12 ms
SI Motion actual value acquisition cycle (p9511) = 1 ms
SAM tolerance (p9548) = 300 rpm
Actual speed = 250
Rotary axis
In the first cycle after activation of the monitoring, the SAM limit value is therefore:
Actual speed + SAM tolerance · (12 ms/1 ms) =
250 rpm + 300 rpm · 12 =
approx. 3850 rpm
Safety Integrated
Function Manual, 12/2018, 6SL3097-5AR00-0BP1
acceleration (a) and the duration of the acceleration phase.
p9500) (delay from detecting an SS1 / SS2 until n
SAM tolerance [mm/min] = a [m/s
SAM tolerance [rpm] = a [rev/s
Description of Safety Integrated functions
4.2 Safety Integrated Extended Functions
= 0)
set
] · MC [s] · 1000 [mm/m] · 60 [s/min]
2
] · MC [s] · 60 [s/min]
2
151